Cell Bio Final

Ace your homework & exams now with Quizwiz!

In which cell cycle phase is DNA damage is NOT detected

(D)= M

Which phase is not a component of interphase

(D)=M

Orientations of Membrane Proteins

(N) - amino (C) - carboxy

CDK activity during stages of cell cycle

-M phase CDKs are cyclin A/CDK1 and cyclin B/CDK1 -Mid G1 phase: cyclin D/CDK4 and cyclinD/CDK6 -Late G1: cycle E/CDK2 and cyclin A/CDK2

Uncondensed, unduplicated chromosome have __________ and ________

1 Centromere, 2 arms

M phase takes ___ hour(s)

1 hour

What would happen if CDC25 was not functional?

1. CDC25 no longer removes inhibitory phosphate on Tyr-15. 2. CDK does not activate 3. Cells keep growing (become larger) but don't divide since never enters M-phase.

How is CDK activity regulated?

1. Cyclin proteins (synthesis of cyclin, localization, and degradation) 2. Phosphorylation of the CDK itself 3. Binding of inhibitors to the CDK

Smooth ER

- not associated with ribosomes - lipid metabolism

Protein Glycosylation in the ER

- proteins are glycosylated within the ER by the addition of a 14-sugar oligosaccharide to an acceptor asparagine (Asn) residue during translocation. - 3 glucose residues are removed while the protein is still within the ER. - the oligosaccharide is synthesized on a lipid carrier (dolichol) anchored in the ER membrane.

Incorporation of Secretory Proteins into Microsomes

- secretory proteins are targeted to the ER by a signal sequence at their amino (N) terminus, which is removed during incorporation of the growing polypeptide chain into the ER. - this was demonstrated by experiments showing that translation of secretory protein mRNAs on free ribosomes yielded proteins that retained their signal sequences and were therefore slightly larger than the normal secreted proteins. - When microsomes were added to the system, the growing polypeptide chains were incorporated into the microsomes and the signal sequences were removed by proteolytic cleavage. SUPPORT: signal sequence additions to normally non-secreted proteins is sufficient to direct the incorporation of the proteins into the rough ER.

Protein Sorting

- the first step of protein sorting takes place while translation is still in progress - proteins destined for the ER, golgi, lysosomes, the plasma membrane, and secretion from the cell are synthesized on ribosomes that are bound to the membrane of the ER. - as translation proceeds, the polypeptide chains are transported into the ER where protein folding and processing take place. - from the ER, proteins are transported in vesicles to the golgi apparatus where they are further processed and sorted for transport to endosomes, lysosomes, the plasma membrane, or secretion from the cell.

Bound TNF receptors recruit

"procaspases" to the intracellular domain of the receptor.

Components of a Checkpoint

1. Sensor of problem 2. Communication between sensor and cell cycle machinery 3. Ability to delay cell cycle

Which of the following adult cell types is arrested in G0?

1. endothelial 2. Fibroblasts 3. liver cells

15 ml of an 2 mM solution from 1 M solution?

1M/ (2x10^-3 M) = 500 DF 15/500= 0.03 ml concentrate 15-0.03 ml= 14.97 ml of H2O

15 ml of a 2mM solution from a 1 M solution

1mM/2 = 10^-3M/ x x= 0.002 M DF: 1/0.002= 500 15/500= 0.03 ml soln (1M) 14.97 ml water

Human cell might undergo cell division in ____ hours

Let 12n represent the amount of DNA present in a somatic cell of a eukaryotic organism. How much DNA would you expect to find in a cell in prophase of mitosis?

24n

5 ml of 0.1% solution using 3% solution which is in a 100 ml bottle

3/ 0.1 =30 DF 5ml/30 =0.167 ml of 3% solution (29) (0.167)= 4.83 water

5 ml of 0.3% solution using 3% solution which is in a 100 ml bottle?

3/0.3= 10 5/10= 0.5 ml of 3% soln. 4.5 ml water

30 ml of 2M solution of H2O2 (mw34g/mol)?

34x2=68 g 2mol/1 L = 68g/ 1000 ml = x/ 30 ml = 2.04 g H2O2 + add water up to 30 ml mark.

How many chromosomes are presented in the picture?

How many chromatids and how many strands of DNA are present in paired homologous chromosomes?

4 chromatids and 8 strands of DNA

S-Cdks stimulates the synthesis of

4 histone subunits that are assembled into nucleosomes via nucleosome assembly factors

Nuclei of human somatic cells each have ______

46 Chromosomes

How many chromosomes do elephant (somatic cells) have?

Phosphorylation of the Golgi matrix proteins by Cdk1 during mitosis a. mediates breakdown of the Golgi apparatus into vesicles. b. activates proteins to degrade the Golgi proteins. c. inhibits association of the Golgi with microtubules. d. causes microtubules to pull the Golgi into two parts.

Polar microtubules a. overlap in the center of the spindle. b. are attached to the contractile ring. c. are attached to kinetochores. d. pull kinetochores poleward.

Laminin

A collagen IV binding site allows it to be attached to the basal laminae (where the molecule is predominantly found). It has an integrin-binding site specifc for _6_1 integrins.

A nondividing state occupied by cells that have left the cell cycle (exit M phase). Can leave G0 to go to G1.

Cohesin forms what?

A ring. As long as the ring is intact, then sister cohesion is intact. **The ring is essential for sister cohesion.

SCF

A ubiquitin ligase which targets certain Cdk inhibitor proteins (CKIs) in late G1; destruction of these CKIs helps to activate S-Cdks and trigger DNA replication. SCF is ALWAYS ACTIVE (unlike APC). SCF can only bind and ubiquitinate its substrates when they become phosphorylated.

If a normal diploid cell has 12 chromosomes, how many chromosomes are present in each daughter cell following the conclusion of meiosis I? A. 6 B. 12 C. 24 D. more than 12 but fewer than 24 E. None of the above.

A. 6 During meiosis I a cell goes from being diploid to being haploid. This requires the halving of the number of chromosomes.

Which cyclin(s) is(are) required to pass the G1 restriction point in animal cells? A. Cyclin D and Cyclin E B. Cyclin A and Cyclin B C. Cyclin D D. Cyclin A

A. Cyclin D and Cyclin E

Cells that die as the result of acute injury undergo: Select one: a. Lysis. b. Sepsis. c. Apoptosis. d. Execution.

A. Lysis

aneuploidy

Abnormal number of chromosomes.

MicroRNAs can act as tumor suppressors by inhibiting expression of all of the following except

Akt

The part of chromatid to either side of centromere is a(n)_____

Arm

Branching of acting filaments can be initiated by

Arp 2/3

branching of actin filaments can be initiated by __________ complex

Arp 2/3

branching of actin filaments can be initiated by __________ complex

Arp2/3

cMyc

Associates with histone acetyltransferase complex and likely promotes global histone acetylation

___ and ___ promote centrosome maturation through ____

Aurora-A and Plk through phosphorylation

The number of cells in the different phases of a population can be determined most easily by using a(n) _______ to measure the amount of DNA per cell in a large sample of cells. a. scintillation counter b. flow cytometer c. fluorescence microscope d. phase-contrast microscope after autoradiography

Humans possess about _______ different cell types. Select one: a. 100. b. 200. c. 500. d. 1,000.

B. 200

Effector caspases cleave a. cytoskeletal proteins. b. All of the above c. DNase inhibitor. d. nuclear lamins.

B. All of the above

Ced-9 functions directly to _______ Ced- _______. Select one: a. Inhibit; 3. b. Inhibit; 4. c. Stimulate; 3. d. Stimulate; 4.

B. Inhibit; 4

Unphosphorylated Bad binding to Bcl-2 releases

Bak/Box.

___________ asexual reproduction method in a singled-cell organisms in which cell grows to roughly Double its size and divides

Binary Fission

A fertilized egg is called a(n) a. oocyte. b. blastula. c. zygote. d. embryo.

Orientation with internal signal sequence

C terminus in lumen, N terminus in cytosol in plasma membrane: C terminus is extracellular space, N terminus in cytosol

Apoptotic cells produce "eat me" signals, which include _______ of cell surface _______. Select one: a. Loss; carbohydrates. b. Loss; phosphatidylserines. c. Gain; phosphatidylserines. d. Gain; phosphatidylethanolamines.

C. Gain; phosphatidylserines

In adult organisms, cell death must be balanced by cell: Select one: a. Growth. b. Differentiation. c. Renewal. d. Migration.

C. Renewal

Within a given species, which two types of cells have the equivalent amounts of DNA? A. a cell in G1 of interphase and a cell in G2 of interphase B. a cell in G1 of interphase and a cell immediately after the completion of meiosis II C. a cell in G1 of interphase and a cell in metaphase II of meiosis D. a cell in G2 of interphase and a cell in metaphase II of meiosis E. None of the above.

C. a cell in G1 of interphase and a cell in metaphase II of meiosis Although a cell in G1 of interphase will have twice the number of chromosomes as a cell in metaphase II, the amount of DNA will be equivalent. For example, if a diploid cell had 12 chromosomes, a cell in G1 would have 12 chromosomes and 12 DNA molecules. Likewise a cell in metaphase II would have six chromosomes, each consisting of two chromatids for a total of 12 DNA molecules.

The key protein involved in "deciding" whether a cell with DNA damage should delay its cell cycle or undergo apoptosis is: Select one: a. Akt. b. pRB. c. p53. d. p15.

C. p53

What are the specialty factors that determine the substrates for APC?

CDC20: specificity factor, important for ubiquitination and degradation of Securin CDH1: Primary factor that allows for the ubiquitination of the mitotic cyclins. CDH1-APC allows cell to undergo M-G1 Transition.

p21

CKI protein binds to G1/S-Cdk and S-Cdk, inhibits their activities, and thus blocks entry into the cell cycle

Caspase-9 activates effector caspases such as

Caspase-3 which proteolyzes cell proteins

Later in ______, 2 sister chromatids of each duplicated hormones SEPARATE becoming _____________________ moving into 2 NEW Nuclei

Cell Division, Individual Chromosome

G1 =

Cell grows

Cells NOT dividing =

Chromatin in dispersed form (long, thin fiber)

Which of the following movements is NOT based on actin- myosin interactions

Chromosome movement

What distinguishes the ER, golgi, endosomes and lysosomes, from other cytoplasmic organelles?

Common involvement in the protein processing and connection by vesicular transport.

Translocon

Complexes of 3 transmembrane proteins called Sec61 proteins.

S =

Continues to grow as it COPIES its chromosome

Overlapping with the latter stages of mitosis, ___ completes the mitotic phase.

Cytokinesis

When a Xenopus oocyte is stimulated with the hormone progesterone, it enters meiosis and arrests at ______, awaiting fertilization by a sperm. a. prophase I b. metaphase I c. prophase II d. metaphase II

Which of the following is not involved in metaphase II arrest during meiosis? a. Cytostatic factor (CSF) b. Mos c. Rsk d. An increase in cytoplasmic calcium levels

Which of the following statements about cyclin B is false? a. It is a component of MPF. b. It accumulates throughout S and G2. c. It activates Cdc2 protein kinase. d. It cycles between active and inactive states in the cell cycle.

Effector caspases cleave: Select one: a. Nuclear lamins. b. Cytoskeletal proteins. c. DNase inhibitor. d. All the above.

D. All of the above

The gene ced-3 of C. elegans codes for a proteolytic enzyme that is a(n): Select one: a. Serine protease. b. Chymotrypsin. c. Ubiquitin-targeted protease. d. Caspase.

D. Caspase

The 2 Kinetochores face ____ directions

Different

When the sister chromatids separate, it _____ the # of chromosomes during cell division

Doubles

During which phase of meiosis do homologous chromosomes separate? A. prophase I B. anaphase II C. metaphase II D. metaphase I E. anaphase I

E. anaphase I Homologous chromosomes separate during anaphase I. Sister chromatids separate during anaphase II.

All microtubules within animal cells have their minus ends anchored at the centrosome.

Most mitochondria use the universal genetic code

FALSE

____________ fuses 2 gametes together returning chromosome # to 46

Fertilization

___________ = mitosis + cytokinesis producing around 37 trillion somatic cells - generating NEW cells to REPLACE dead/damaged ones

Fertilized Eggs

DNA damage checkpoint

Functions throughout entire cell cycle and detects damage to DNA. Cells with damaged are in cell arrest until damage is repaired. If damage is too severe, apoptosis.

Insufficient activity of an enzyme called glucocerebrosidase is a hallmark of _____________ disease

Gaucher's

Units of info specifying an organism's inherited traits

Genes

DNA Alone =

Genome sequencing

The Rise and Fall of MPF Activity During the Cell Cycle

Graph shows ability of the cytoplasm from an embryo to induce G2 oocyte to enter M phase. When MPF activity high, cell is in mitosis. When MPF activity low, cell is in interphase.

G2 =

Grows more as it completes the PREPARATION for cell division

Receptor tyrosine kinase (receptor binding of growth factors)

Growth factors bind cell specific receptors. The receptor consists of transmembrane protein with ligand (GF) binding site and cytoplasmic protein tyrosine kinase domain. GF binds, forms dimer and autophosphorylation at receptor, form docking sites to which particular signaling molecules can bind, leading to assembly of signaling complex.

1 set of unpaired chromosomes

Haploid

Most cells in an adult animal are in G0, or quiescent, phase. stem cells. actively proliferating. undergoing meiosis.

In G0, or quiescent phase

Symmetric divisions

Increase stem cell number - during normal development or injury recovery

Long part of cell cycle (90%)

Interphase

Is it possible to generate four recombinant chromosomes from a single homologous chromosome pair during a single meiosis? If so, how?

It is possible to generate four recominant chromosomes from a single homologous chromosome pair if two separate crossover events take place on different non-sister chromatids.

A structure of proteins----CENTROMERE that links each sister to the MITOTIC SPINDLE

Kinetochore

Involved in muscle contraction

p53 is regulated by

Mdm2

How do mitogens stimulate cell division?

Mitogens trigger the inhibition of Rb, which prevents Rb from inhibiting the cell cycle. (double negative). Rb (retinoblastoma): without a signal transduction pathway, Rb binds to a transcription factor and keeps it inactive, which keeps cells from progressing through G1.

A process of nuclear division in eukaryotic cells into 5 stages: -prophase -prometaphase -metaphase -anaphase -telophase

Mitosis

Nuclear Envelope Proteins

Move laterally rather than being transported by vesicles.

Observation of flagella in the biflagellate alga, Chlamydomonas reinhardtii, indicates that particles move toward the tips of flagella at a rate of 2.5μm/min, but the particles moving back toward the base of flagella move at 4μm/min. How do you explain this difference in rate of movement?

Particles use different motors with different velocities to move outward and inward.

what is a cellular function of pericentrin?

Pericentrin is an integral component of the centrosome that serves as a multifunctional scaffold for anchoring numerous proteins and protein complexes. Through these interactions, pericentrin contributes to a diversity of fundamental cellular processes.

START = Restriction Point

Point at which a G1 cell commits to go through another round of the cell cycle

How do Bcl-2 family proteins regulate apoptosis in mammalian cells?

Proapoptotic multidomain members of the Bcl-2 family induce apoptosis by promoting the release of cytochrome c from mitochondria, which leads to caspase activation.

_____undergo a type of reproduction in which cell DOUBLES IN size called Binary Fission

Prokaryotes

End of _____, the 2 centrosomes are 1 @ each POLE of spindle

Prometaphase

In which phase of meiosis do homologous chromosomes initiate pairing?

Prophase 1

The Spindle Microtubules elongates (polymerize)by putting more subunits of the ______________ together

Protein Tubulin

Tumor necrosis factor (TNF) is detected by a

TNF cell surface receptor.

The 5gh & Final Stage of Mitosis, in which the daughter nuclei are forming and cytokinesis has typically begun

Telophase

Loewenstein and colleagues injected cells with fluorescent molecules of different molecular weights, and a fluorescence microscope was then used to observe the movement of the molecules into adjacent cells. When molecules with molecular weight of 1926 were injected, they did not pass from cell to cell, but molecules with molecular weight of 1158 did.

The gap junctions that connect adjacent cells in insect salivary glands allow the passage of small molecules (molecular weight up to at least 1158 daltons), whereas larger molecules (1926 daltons) do not flow between cells.

What defining event marks the beginning of anaphase?

The separation of sister chromatids

Interphase

The time between M (mitosis) phases, comprised of three sub-phases: -G1, S and G2.

Which of the following is not a key property of stem cells in tissues?

They divide within each tissue to maintain a set number of cells.

How does a cell commit to another round of the cell cycle?

Through positive signals called mitogens. ex. EGF, PDGF (growth factors that initiate signal transduction pathway)

Catenation can be unwound by

Topoisomerase II

A mutant bcl-2 gene can be an oncogene. True or false

True

embryonic stem cells experimental affect

Using such cells to explore and identify the extracellular signals as well as the intracellular transcriptional regulators necessary to drive differentiation of a specific cell type.

Which of the following statements correctly describes why a series of closely spaced action potentials causes a sustained contraction rather than a series of closely spaced twitches?

When a series of action potentials is closely spaced, there is not sufficient time for Ca2+ uptake into the sarcoplasmic reticulum between action potentials, and Ca2+ remains bound to troponin throughout the series.

Is the central controller regulated?

Yes

Tumor initiation occurs in a

a single cell

In a cell with 4 chromosomes, how many sister chromatids are visible during anaphase? a. 8 b. 2 c. 4 d. 16

a. 8

Damaged DNA is sensed by a complex of proteins that activate the protein kinase a. ATM b. MCM. c. ABS. d. Akt.

a. ATM

5. Each monomer of actin binds one molecule of the nucleotide triphosphate a. ATP. b. GTP. c. CTP. d. UTP. e. TTP.

a. ATP

5. Each monomer of actin binds one molecule of the nucleotide triphosphate a. ATP. b. GTP. c. CTP. d. UTP. e. TTP. Textbook Reference: Structure and Organization of Actin Filaments, p. 474

a. ATP.

An apoptosome is a complex containing multiple subunits of a. Apaf-1, caspase-9, and cytochrome c. b. Apaf-1. c. Apaf-1 and caspase-3. d. Apaf-1 and caspase-9.

a. Apaf-1, caspase-9, and cytochrome c.

Which of the following signaling pathways is not important to stem cell physiology? a. Bax b. TGF-β c. Wnt d. Notch

a. Bax

Many stimuli that trigger cell death release the molecule _______ from mitochondria to bind to Apaf-1. Select one: a. Cytochrome c. b. Citric acid. c. Ubiquinone. d. ATP synthase.

a. Cytochrome c.

Growth-factor stimulation of the Ras/Raf/MEK/ERK pathway initially stimulates the synthesis of cyclin a. D. b. A. c. E. d. B.

a. D

30. The evolutionary ancestor of eukaryotic tubulins appears to be a protein similar to the bacterial protein a. FtsZ. b. Arp2/3 c. prototubulin d. coli-tubulin e. archae-tubulin

a. FtsZ

Which of the following is not phosphorylated by Akt? Select one: a. PI 3-kinase. b. p53. c. FOXO. d. Bad.

a. PI 3-kinase.

E-cadherin

adherens junctions

α-Catenin

adherens junctions

what two proteins provide the link between the spectrin-actin network and the plasma membrane?

ankyrin [protein 4.1 ]

SCF

another ubiquitin E3 ligase

A tumor is

any abnormal growth of cells

Caspases activate effector caspases, leading to

apoptosis.

Apoptosis, or programmed cell death, occurs in all of the following cases except a. in virus-infected cells. b. in cells damaged by injury. c. in cells with potentially cancer-causing mutations. d. during the elimination of tissue between the digits in the formation of human fingers.

Murine embryonic stem cells are grown in the presence of a growth factor. What growth factor is generally used for this? a. VEGF (vascular endothelial growth factor) b. LIF (leukemia inhibitory factor) c. PDGF (platelet-derived growth factor) d. EGF (epidermal growth factor)

Some differentiated cells retain the ability to proliferate as needed to repair damaged tissue throughout the life of the organism. Which of the following cell types do not retain this unique ability? a. Fibroblasts b. Neurons c. Endothelial cells d. Epithelial cells

The following is a signal transduction cascade (with one missing step) initiated by double-stranded DNA damage and ending with activation of apoptosis by the BH3-only proteins PUMA and Noxa: Double-stranded DNA damage; Chk2; _______; PUMA/Noxa; apoptosis. Which protein belongs in the blank space? a. Apaf-1 b. p53 c. Chk1 d. Bax

A hematopoietic stem cell may give rise to which of the following differentiated cells? a. Erythrocytes b. All of the above c. Granulocytes d. Macrophages

b. All of the above

Which of the following adult cell types is arrested in G0? a. Fibroblasts b. All of the above c. Endothelial cells d. Liver cells

b. All of the above

What normal cellular process would be affected in a cell line in which Bcl-2 was mutated? a. Terminal differentiation b. Apoptosis c. Cell cycle d. cAMP signaling

b. Apoptosis

7. Which of the following drugs blocks the assembly of actin filaments? a. Colchicine b. Cytochalasin c. Phalloidin d. Taxol e. Both b and c Textbook Reference: Structure and Organization of Actin Filaments, p. 476

b. Cytochalasin

17. Myosin _______ is present in muscle sarcomeres. a. I b. II c. III d. IV e. V Textbook Reference: Actin, Myosin, and Cell Movement, p. 490

b. II

Grim and Reaper act by _______ the activity of _______. Select one: a. Stimulating; inhibitors of apoptosis (IAPs). b. Inhibiting; inhibitors of apoptosis (IAPs). c. Inhibiting; apoptosomes. d. Inhibiting; caspase-3.

b. Inhibiting; inhibitors of apoptosis (IAPs).

3. Which of the following is not true of the assembly of actin filaments? a. It begins with the formation of an aggregate of three actin monomers. b. It requires ATP. c. Polymerization occurs from both the plus and minus ends. d. Polymerization is faster from the plus end than from the minus end. Textbook Reference: Structure and Organization of Actin Filaments, p. 474

b. It requires ATP.

Which of the following events is not part of apoptosis? a. Fragmenting of chromosomal DNA b. Lysis of cell fragments and release of their contents c. Fragmenting of the nucleus d. Fragmenting of the cell

b. Lysis of cell fragments and release of their contents

Cells are restricted to one round of DNA replication per cycle by origin of replication binding proteins called a. Akts. b. MCMs. c. Oris. d. ATMs.

b. MCMs.

Standard drugs used to treat cancer patients

block or kill cells undergoing cell division

If a cell is in G1 and has 20 chromosomes, how many pairs of homologous chromosomes are present? a. 40 b. 5 c. 10 d. 80 e. 20

c. 10

29. Microtubules are typically _______ in diameter. a. 7 nm b. 10-12 nm c. 25 nm d. 35 nm e. 55 nm

c. 25nm

49. In a cilium or flagellum, _______microtubules are arranged _______. a. 13; in a circle b. 9 triplet; in a circle c. 9 doublet; in a circle around a central pair of microtubules d. 2 microtubules; perpendicular to each other e. 2 microtubules; parallel to each other Textbook Reference: Microtubule Motors and Movement, p. 518

c. 9 doublet; in a circle around a central pair of microtubules

Entry into mitosis occurs because a. sufficient cyclin-dependent kinase is synthesized to trigger mitosis. b. cyclin is phosphorylated at the beginning of mitosis. c. Cdk1/Cyclin B (MPF) get activated. d. cyclin is destroyed at the beginning of mitosis.

c. Cdk1/Cyclin B (MPF) get activated.

The Cdk inhibitor, p16, binds specifically to Cdk4,6/Cyclin D complexes. What would be the predicted effect of the overexpression of p16 on cell cycle progression? a. Cells would be unable to enter M phase b. Cells would remain in the cell cycle, passing all checkpoints unregulated c. Cells would be unable to exit the G1 phase d. Cells would progess normally through the cell cycle

c. Cells would be unable to exit the G1 phase

33. The proteins Rab, Ran, and tubulin are all a. polymers. b. nuclear proteins. c. G proteins, regulated by bound GTP or GDP. d. parts of signal transduction pathways. e. components of mitotic spindles.

c. G proteins, regulated by bound GTP or GDP

S phase

chromosome duplication

The disease ataxia telangiectasia, which causes nervous system defects and a high frequency of cancer in affected individuals, results from a mutation in the gene for the protein a. ABS. b. Akt. c. MCM. d. ATM.

d. ATM.

Which of the following is not a key property of stem cells in tissues? a. Dividing to produce one cell that then differentiates b. Exhibiting self-renewal c. Dividing to produce one daughter cell that remains a stem cell d. Dividing within each tissue to maintain a set number of cells

d. Dividing within each tissue to maintain a set number of cells

24. Which of the following is not an intermediate filament protein? a. Vimentin b. Nestin c. Lamin A d. Fibronectin e. Desmin Textbook Reference: Intermediate Filaments, p. 497

d. Fibronectin

2. Actin exists in cells in two major forms called a. monomers and dimers. b. -actin and -actin. c. G actin and D actin. d. G actin and F actin. e. actin 1 and actin 2.

d. G actin and F actin

A major pathway that signals cell survival and inhibits cell death is the _______ pathway. a. TNF b. Wnt c. Hedgehog d. PI 3-kinase/Akt

d. PI 3-kinase/Akt

A major pathway that signals cell survival and inhibits cell death is the _______________ pathway a. Hedgehog b. Wnt c. TNF d. PI 3-kinase/Akt

d. PI 3-kinase/Akt

45. The cargo carried by kinesin along microtubules binds to kinesin on which region? a. Head b. Neck c. Coiled-coil d. Tail e. None of the above Textbook Reference: Microtubule Motors and Movement, p. 515

d. Tail

23. Vimentin is the major intermediate filament protein of _______ cells. a. epithelial b. striated muscle c. nerve d. fibroblast e. None of the above Textbook Reference: Intermediate Filaments, p. 497

d. fibroblast

45. The cargo carried by kinesin along microtubules binds to kinesin on which region? a. Head b. Neck c. Coiled-coil d. Tail e. None of the above

d. tail

Cancer is usually caused by a. X rays. b. an inherited oncogene. c. a cancer virus. d. the stepwise breakdown of normal cell regulatory processes.

d. the stepwise breakdown of normal cell regulatory processes.

Desmocollins

desmosomes

The amount of DNA in a G2 somatic cells is? (assuming the haploid cell of this organism is 3n)? a. 6n b. 3n c. 9n d. 1n e. 12n

e. 12n

If a cell is in G2 and has 10 chromosomes, how many pairs of homologous pairs of chromosomes are present? a. 2.5 b. 20 c. 10 d. 40 e. 5

e. 5

12. Duchenne's muscular dystrophy is characterized by a. X-chromosomal inheritance. b. childhood onset. c. abnormal dystrophin function. d. All of the above e. None of the above Textbook Reference: Structure and Organization of Actin Filaments, p. 483

e. None of the above

Nuclear envelope breakdown occurs at the _______ of _______.

end; prophase

Cdc42·GTP locally activates

formins

Apoptotic cells produce "eat me" signals, which include _______ of cell surface _______.

gain; phosphatidylserines

Connexin

gap junctions

Require the alignment of connexons in the plasma membranes of two adjacent cells.

gap junctions (G)

telophase events are triggered by

inactivation of Cdks due to APC/C and activation of phosphatases

Multipotent hematopoietic stem cells: Divide symmetrically

increase stem cell number

Suppose you were to fuse a tumor cell with a nontumor cell in culture, grow the daughter cells of the hybrid clone in culture, and then inject them into mice with defective immune systems. Tumors would likely develop in _______ of the mice.

less than 1%

Cells that die as the result of acute injury undergo

lysis

during cellular respiration, carbon atoms (from glucose) are (oxidized/reduced) as they lose energy

oxidized

motor proteins are activated by

phosphorylation

G0 phase

resting state When environmental conditions are not favorable

wo sea urchin proteins were named cyclin A and B because during the embryonic cell cycle they were periodically

synthesized and degraded

Two sea urchin proteins were named cyclin A and B because, during the embryonic cell cycle, they were periodically

synthesized and degraded.

insufficient activity of an enzyme called hexosaminidase a hallmark of _______ disease.

tay-sachs

some cancer cells have "re-activated"

telomerase activity, which keep the telomeres from shortening. making these cells "immortal"

the centrosomes and microtubules of animal cell are located in

the cytoplasm

assembly of the contractile ring results from

the local formation of new actin filaments stimulated by formin proteins

the overlapping arrays of actin and mysoin II filaments contract to generate

to generate a force that divides the cytoplasm in 2

Transcytosis is a type of

transcellular transport in which various macromolecules are transported across the interior of a cell.

What is Sec61, describe its functional role in the translocon (as a gated channel)

translocator in the ER membrane (actually core of translocator) -A heterotrimer that forms a dynamic gated channel

Bi-orentation is achieved by

trial and error

M-Cdks

triggers M phase entry and mitosis

S-Cdks

triggers chromosomal replication

Metaphase-Anaphase Transition

triggers chromosomal segregation

Re-formation of the nuclear envelope occurs as the result of cyclin B destruction, which allows phosphatases to dephosphorylate nuclear envelope lamins. true or false

true

symmetric division

two daughter cells are essentially identical to each other and to the parent cell

G0 phase

"Resting state". State of cells no longer dividing. (some cells permanently/terminally differentiated-RBCs and neurons.

Microglia (support cells in the brain) are connected by gap junctions. When the fluorescent dye Lucifer yellow is injected into individual microglia that are part of a large group of cells, dye passes to other cells. When microglia are treated with the calcium ionophore, 4Br-A23187, there is a dramatic decrease in dye passage between cells.

"The passage of molecules between cells can be regulated by the intracellular Ca2+ content. When the Ca2+ concentration is increased in an individual cell, the movement of fluorescent molecules into that cell is increased, suggesting that gap junctions are open under these conditions.

_______________ happens because the chromosome is moving back & forth as the microtubules are pulling resulting them settling in the middle

"Tug of War"

G1/S checkpoint

"start" or "restriction point" controls whether conditions favorable for divisoin

7 ml of 0.1 % solution using 10% solution which is in a 100 ml bottle

( 7ml) (0.1)= (x) (10) x= 0.07 ml add 0.07 ml of the 10 % solution then dissolve with some water then fill to the 7 ml mark with water

15 ml of a 1mM solution from a 10 mM solution?

(15 ml)(1mM)=(X)(10mM) X=1.5 ml add 1.5 ml of the concentrated 10 mM solution and fill the flask to the 15ml mark

20 ml of a 2mM solution from 1 M solution

(20 ml) (0.002M )= (X)(1M) x= 0.04 ml 1/0.002=500 Dilution Factor 20/500= 0.04 ml 1M solution (0.04) 499=19.96 ml water

30 ml of 3M solution of H2O2

(3 mol/L) (0.3 L)= 0.09 mol H2O2 (34g/mol) (0.09 mol) = 3.06 g of H2O2 + 30 ml solvent

30 ml of 2M solution of H2O2

(34 g/mol)/ (1M) = (x)/ (2M) (68 g/mol)/ (1000 ml) =( x)/(30 ml) 2.04 g/mol H2O2

Targeting proteins to the ER

- In mammalian cells, most proteins enter the ER co-translationally - both co-translational and post-translational pathways are used in yeast.

LOTS of proteins help ___________

- Maintain structure of chromosome - Control gene's activity

Rough ER

- covered by ribosomes on its outer (cytosolic) surface - functions in protein processing

Apoptosis

-programmed cell death pathway. -A neat and tidy way of killing cells and getting rid of them. Other types of cell death (lysis, necrosis) are messy. -Phagocytic cell can engulf the apoptotic cell and chew it up in little pieces and sending it to the lysosome to be digested. -A normal role in development & maintenance in multicellular organisms. ex. helps eliminate the tail during the metamorphosis of a tadpole into a frog.

"The Cdk inhibitor, p16, binds specifically to Cdk4,6/Cyclin D complexes (thus inhibiting Cdk4,6/Cyclin D function). What would be the predicted effect of overexpression of p16 on cell cycle progression?"

. Cells would be unable to exit the G1 phase

prepare 40 ml of 0.3M solution from 0.5 M solution

0.04/0.03=1.67 50ml/1.67= 29.9 sodium chloride 50 ml- 29.9 = 20.1 H2O

M Phase takes about _ hour

Of the offspring that result from the reproductive cloning of mammals by somatic nuclear transfer, _______% are viable.

1-3

Direct Binding of CDK Inhibitors to Regulate CDK

1. As soon as the Cyclin-CDK complex is made, they are immediately bound by the inhibitor protein (P27), so we which keeps the complex inactive. 2. G1/S cyclin-CDK phosphorylates p27. When p27 is phosphorylated, it's recognized by a protein called SCF: a ubiquitin ligase that adds a ubiquitin chain onto its substrates and targets them for degradation. 3. When p27 is degraded, we have active S-phase cyclin-CDK. This triggers the initiation of DNA replication. **G1-S Transition and DNA Replication are the same thing.

(STEPS) Co-translational Targeting of Secretory Proteins to the ER

1. As the signal sequence emerges from the ribosome, it is recognized and bound by the signal recognition particle (SRP) 2. The SRP escorts the complex to the ER membrane where it binds to the SRP receptor. 3. The SRP is released, the ribosome binds to the translocon, and insertion of the signal sequence opens the translocon. 4. Translation resumes and the signal sequence is cleaved by signal peptidase. 5. Continued translation drives translocation of the growing polypeptide chain across the membrane. 6. The completed polypeptide chain is released within the ER lumen.

List three major products of the light reactions of photosynthesis

1. NADPH 2. ATP 3. O2

initiation of DNA replication requires 2 steps

1. licensing (pre-replicative complex, Pre-RC) 2. Pre-initiation complex formation

A hemoatopoietic stem cell may give rise to which of the following differentiated cells?

1. macrophages 2. granulocytes 3. erythrocytes

Construct the sequence of events leading from a dietary vitamin C deficiency to symptoms such as bruising and breakdown of supporting tissues.

1. tissue levels of ascorbic acid is low 2. enzyme prolyl hydroxylase is inactive 3. proline is not hydroxylated 4. the triple helix is inadequately stabilized . 5. collagen breaks down 6. defects in tissues that depend on collagen 7. tissues that depend on collagen are subject to breakdown and bruising

S Phase takes about _ hours

10-12 (1/2 of cycle)

Apoptosis is also active in the adult, where about

1010-1011 cells die every day.

If a cell normally has 12 chromosomes, how many chromosomes are present in each cell during anaphase 2?

Let 12n represent the amount of DNA present in a somatic cell of a eukaryotic organism. How much DNA would you expect to find in a cell in prophase of Meiosis II?

12n

How many chromosomes do alga (somatic cells) have?

148

in a given homologous chromosome pair, how many recombinant chromatids are generated by a single crossover event?

Microtubules are approximately ________ in diameter

25 nm

Microtubules are approximately ___________ in diameter

25 nm

microtubules are approximately ____ in diameter.

25 nm

microtubules are approximately ___________ in diameter

25 nm

there are over _____ general cell types in the human body

250

In the absense of crossing over, which formula best represents the number of possible different arrangements of chromosomes generated by independent assortment?

2^n, where n represents the number of homologous chromosome pairs per cell entering meiosis

4 ml of 0.7 M solution from 3 % H2O2 solution

3 %= 3g/100 ml 3g/100= 3/34 0.088/100 mol 0.088 mol/ 0.1 L = 0.88 M 0.88/0.7 =1.26 4 ml/1.26 =3.17 (20)(3.17)=0.825

10 ml of 0.5 M solution from 3 % H2O2 solution

3 g/100 ml 3gx 1/34=0.0882 0.0882 / 100 ml = X/1000 ml x= 0.882M 0.882/0.5 = 1.76 DF 10/1.76 = 5.68 ml 3 % H2O2 soln +4.32 ml H2O

5 ml of 0.3% solution using 3% solution which is in a 100 ml bottle?

3%/0.03%= 10 Df 5/10 = 0.5 ml concentrate +4.5 ml H20

G2 Phase takes about __ hours

4-6

How many chromosomes do chimpanzees (somatic cells) have?

Which of the following represents the amount of DNA in a typical G2 cell?

G1 Phase takes about - hours

5-6

30 ml of 5 % of H2O2

5g/100 mlx 30 ml= 1.5 g + 30 ml of water

If a normal diploid cell has 12 chromosomes, how many chromosomes are present in each daughter cell following the conclusion of meiosis 1?

In a diploid organism with 12 chromosomes, how many different arrangements of chromosomes can be generated by independent assortment?

Let 12n represent the amount of DNA present in a somatic cell of a eukaryotic organism. How much DNA would you expect to find in a cell resulting from Meiosis II?

each centiole is comprised of ______________ of microtubules

9 X 3 + 0 formation = total 27 microtubules

the formula for microtubule arrangement in cilia and flagella is

9 x2+ 2

each centriole comprised of _______ of microtubules.

9 x3+ 0

the microtubules of centriol are organized in characteristic _________ pattern

9 x3+0

How many chromosomes do hedgehogs(somatic cells) have?

During all 3 Phases of interphase = __________________

A cell grows by producing proteins and cytoplasmic organelles (mitochondria, endoplasmic reticulum)

What are the essential processes of the cell cycle triggered by?

A central controller, kinase

ER (Endoplasmic Reticulum)

A network of membrane-enclosed tubules and sacs (cisternae) that extends from the nuclear membrane throughout the cytoplasm. - enclosed by a continuous membrane - largest organelle of most cells - rough ER / smooth ER (membrane domains) - site of protein folding, assembly of multi-subunit proteins, disulfide bond formation, N-linked glycolisation, and the addition of glycolipid anchors to some plasma membrane proteins.

Genome of Eukaryotic cells:

A number of DNA molecules, Enormous, 2 copies

Genome of Prokaryotic cells:

A single DNA molecule

BiP

A specific Hsp70 chaperone

A tubule: complete 13 protofilament microtubule B tubule: incomplete 10−11 protofilament microtubule sidearms: generates force to slide microtubules past one another radial spokes: project inward at each doublet nexin: links adjacent doublets

Regulation of entry into S phase

A-CDK2 is inhibited by a small protein p27KIP1. IN late G1 phase this inhibitor becomes phosphorylated by late G1 cyclin-CDK complex (Cyclin E-CDK2), which triggers polyubiquitination and subsequent proteolysis of the inhibitor. -Additional level or regulation through dephosphorylation of CDK2 itself. A specific phosphatase is required to remove an inhibitory phosphate from CDK2, allowing activation of cyclin-CDK2 complexes. Once the inhibitor is degraded and CDK2 is dephosphorylated, DNA replication can begin.

In which phase of meiosis do homologous chromosomes initiate pairing? A. prophase I B. telophase I C. metaphase I D. anaphase I E. metaphase II

A. prophase I Pairing of homologous chromosomes begins in prophase I of meiosis, and homologous chromosomes will remain paired until anaphase I.

What effects would you predict on a sperm flagellum to which AMPPNP was added? In your explanation, please be specific about what molecule's function would be inhibited and what the effect on overall flagellar function would be.

AMPPNP would inhibit flagellar dynein, causing cessation of flagellar bending.

The overlapped region is reduced as motor protein---microtubules walk AWAY from each other using _____ during Anaphase

ATP

list the three major products of the light reaction of photosynthesis

ATP O2 NADPH

which of the following is not a product of the Krebs cycle

Acetyl CO2

UPR (Unfolded Protein Response)

Activated if an excess of unfolded proteins accumulates in the ER. - activation leads to expansion of the ER and production of additional chaperones to meet the need for increased protein folding, as well as a decrease in the amount of newly synthesized proteins entering the ER. - sustained activity of the UPR leads to programmed cell death, thereby eliminating cells that are unable to properly fold proteins from the body.

M phase/mitosis

Actual division of cell into two identical daughter cells. Comprised of -prophase, prometaphase, metaphase, anaphase and telophase

Which of the following experimental data would support the hypothesis that gap junction function in cardiomyocytes (heart muscle cells) is dependent on the gap junction proteins being phosphorylated?

Addition of phosphatase inhibitors to cultures of heart muscle cells results in the cells not beating together, and is correlated to connexin proteins no longer being phosphorylated.

Provide a brief justification for the following false answer: An algal cell contains neither tubulin nor actin.

Algae are eukaryotes and therefore possess the same kinds of cytoskeletal components as other eukaryotic cells.

Which of the following is evidence for the single-cell origin of a tumor?

All cells in one tumor from a female have the same X chromosome inactivated.

In yeast, START triggers the progression from G1 to S. Which of the following are involved in regulating START? Nutrients Mating factors Cell size All of the above

All of the above

Which of the following statements about the stimulation of muscle cells is true?

An action potential in a muscle cell ultimately results in the release of calcium ions into the cell.

Ligase

An enzyme that connects two fragments of DNA to make a single fragment

PDI (Protein Disulfide Isomerase)

An enzyme that facilitates disulfide bond formation in the ER lumen. - Disulfide bonds generally do not form in the cytosol (reducing environment) - ER lumen (oxidizing environment) promotes disulfide bond formation.

mitogen

An extracellular signal molecule that stimulates cell proliferation.

At the end of _____: - Duplicated groups of chromosomes are at OPPOSITE ENDS -Nuclei reform during Telophase -Cytokinesis begins at _____ or Telophase -The Spindle DISAPPEAR by depolymerize of microtubules

Anaphase

The 4th stage of mitosis, where the Chromatids of each CHROMOSOME have separated & daughter chromosomes are moving to the POLEs of the cells

Anaphase

The shortest stage of Mitosis

Anaphase

During which phases of meiosis do homologous chromosomes separate?

Anaphase 1

APC

Anaphase Promoting Complex. A ubiquitin ligase that promotes anaphase and the degradation of cyclin. It works by covalently attaching ubiquitin to its substrate. Once the substrate has been ubiquitinated, the substrate is targeted for degradation by the proteosome.

Binds to adapter protein

Apaf-1 (forms apoptosome).

Oct4 and Sox2

Are core transcriptional regulators of pluripotency and activate many target genes necessary for this activity: Including, but not limited to histone and cytosine demethylases (decondense chromatin regions containing pluripotent genes.

Different Cyclin-Cdk Complexes Trigger Different Steps in the Cell Cycle

As the diff. cyclins appear and disappear, we have different kinase activities. -When the cyclin associates with kinase, it's the interaction of both proteins within the kinase complex that is binding to the substrate. -The substrates for the different CDK complexes are different. -Diff proteins get phosphorylated by diff CDK complexes at diff. times in the cell cycle. Mammalian cells: multiple CDKs. Multiple cyclins. Association of different cyclins with different CDKs that give us important transitions.

Maturation promotion factor (MPF), discovered by Masui and Markert, is the factor that a. is missing in the cdc2 mutant in yeast. b. induces entry into meiosis when injected into frog oocytes. c. fluctuates in amount during early cleavages of sea urchin eggs. d. fluctuates in amount during the cell cycle of mammalian cells.

Nuclear envelope breakdown occurs at the _______ of _______. a. beginning; prophas b. end; prophase c. end; prometaphase d. beginning; anaphase

Tetraploid cells can be seen in the field labeled?

The G1 checkpoint in animal cells is called a. START. b. the restriction point. c. the decision point. d. the G1/S boundary.

The diversity of haploid daughter cells is increased by the independent assortment of chromosomes at anaphase and by a. crossing over and recombination. b. somatic mutation. c. chromosome elimination. d. the selection of the fittest sperm.

The progression from metaphase to anaphase is triggered by a. activation of protein kinases by MPF. b. ubiquitin-mediated proteolysis of key proteins. c. binding of an inhibitory protein to MPF. d. depolymerization of the mitotic spindle.

The spindle assembly checkpoint monitors the alignment of chromosomes in the mitotic spindle during mitosis to insure an even distribution of chromosomes to each of the daughter cells. If the chromosomes do not align properly, the spindle assembly checkpoint will arrest cells in what phase of mitosis? a. Prophase b. Metaphase c. Anaphase d. Telophase

The structure that associates homologous chromosomes and keeps them aligned during meiotic prophase is called a a. chiasma. b. synaptonemal complex. c. centromere. d. pachytene complex.

To become active, Cdk1 must a. bind cyclin. b. bind cyclin and be phosphorylated on tyrosine 15 and threonines 14 and 161. c. bind cyclin and be phosphorylated on tyrosine 15, and be dephosphorylated on threonines 14 and 161. d. bind cyclin and be phosphorylated on threonine 161, and be dephosphorylated on threonine 14 and tyrosine 15.

The signal-recognition particle (SRP) ... A.is permanently attached to the cytosolic face of the ER membrane, thus bringing the ribosomes into close proximity of the translocon. B.transiently inhibits translation and polypeptide elongation by binding to elongationfactor binding site on ribosome C.accompanies the nascent polypeptide all the way into the ER lumen. D. functions as an ATPase E. All of the above are correct

B. not A bc SRP not permanently attached to ER membrane

If a cell normally has 12 chromosomes, how many chromosomes are present in each cell during anaphase II? A. 6 B. 12 C. 24 D. more than 12 but fewer than 24 E. None of the above

B. 12 Although a cell entering meiosis II would have six chromosomes, each of these chromosomes would consist of two double-stranded DNA molecules (sister chromatids). During anaphase, the sister chromatids separate resulting in 12 chromosomes until the completion of telophase II when each daughter cell would have six chromosomes, each consisting of a single DNA molecule.

The distinct series of changes that characterizes programmed cell death is called: Select one: a. Necrosis. b. Apoptosis. c. Sepsis. d. Execution.

B. Apoptosis

The 2 Origin of Replication end up in opposite sides by

Being anchored by one or more proteins -polymerization -tubulin help pinching the plasma membrane inward

MPF is a general regulator of the transition from a. G1 to S. b. S to G2. c. G2 to M. d. metaphase to anaphase.

Passage of animal cells through the cell cycle is regulated primarily by a. the availability of nutrients. b. intracellular second messengers. c. extracellular growth factors. d. direct cell surface interactions.

Skin fibroblasts arrested in G0 are stimulated near a wound to enter G1 by _______ growth factor. a. epidermal b. fibroblast c. platelet-derived d. keratinocyte

The G2 cell cycle checkpoint detects a. the binding of the MCM proteins to origins of replication. b. chromosome misalignment. c. unreplicated or damaged DNA. d. levels of p53.

Fertilization of a frog egg triggers the resumption of meiosis by an increase in

Ca2+

You are considering treatment of a leukemic patient with TNF. Upon further analysis you determine that the leukemic cells have an inactivating mutation of caspase-8. Will treatment with TNF be an effective therapy for this patient?

Caspase-8 is the initiator caspase downstream of TNF receptors, so cells with inactive caspas-8 will not undergo apoptosis with treatment of TNF and be an ineffective treatment.

APC/C cant recognize its target proteins without

Cdc20

Cdc20 regulation

Cdc20 increases as the cell approaches mitosis. Phosphorylation of APC/C by M-Cdk mediates interaction with Cdc20.

A pair of ____ located at the center of CENTROSOME, not essential for cell division - it is NOT PRESENT in Plant cells where they can also form MITOTIC SPINDLES

Centrioles

Each sister chromatid has a ______ in a duplicated chromosome, the region on each sister chromatid where it's closely attached to its sister chromatid by protein---centromeric DNA

Centromere

________ have repetitive sequence in chromosomal DNA

Centromere

A structure present in the Cytoplasm of Animal cells that functions as: -microtubule - organizing center -important during cell division - has 2 centrioles / centrosome

Centrosome

The complex of DNA + Proteins making up the eukaryotic chromosomes

Chromatin

A cellular structure made of 1 DNA molecule + associated protein molecules

Chromosomes

The REPLICATION & DISTRIBUTION of DNA are manageable because DNA molecules are in _________

Chromosomes

Draw a schematic scheme of the LDL (indicate what is found in the outmost and inner layers)

Circle with phospholipids and cholesterol on the outer layer and Apoprotein B100 surrounding the LDL, cholesteryl esters inside.

The ____ deepens until the parent cells is pinched into 2

Cleavage Furrow

After______ each cell has: - own nucleus -cytosol -organelles -other subcellular structures

Cleavage furrow

Signal Peptidase

Cleaves the signal sequence of mRNA as it is being translated and moving through the translocon, allowing the release of a polypeptide into the lumen of the ER.

Protein---- Centromeric DNA = other proteins ____ the DNA giving it a narrow "waist"

Condense

The passage of a cell through the stages of the cell cycle is controlled by protein kinases that phosphorylate many different proteins at appropriate times. What are these protein kinases called? Tyrosine kinases Cdk activating kinases Cyclin-dependent kinases Cyclins

Cyclin dependent kinases

Cyclin-dependent kinases

Cyclin-dependent kinases are serine/threonine kinases that form complexes and function in association with regulatory subunits called cyclins. CDKs regulate progression through the cell cycle with different CDK/cyclin complexed active at different stages. Regulation of cycle via phosphorylation of different protein targets. Each cyclin is synthesized at a specific point in the cell cycle and then degraded by ubiquitin-dependent proteolysis once function has been accomplished. Control of CDK kinases involves phosphorylation, dephosphorylation and action of specific CDK inhibitors.

Which of the following events is not part of apoptosis? Select one: a. Fragmenting of chromosomal DNA. b. Fragmenting of the nucleus. c. Fragmenting of the cell. d. Lysis of cell fragments and release of their contents.

D. Lysis of cell fragments and release of their contents

If a cell normally has 12 chromosomes, how many chromosomes would be present in each cell at the end of meiosis II if a single pair of homologous chromosomes failed to separate during anaphase I? A. Two daughter cells will each have six chromosomes, one daughter cell will have five chromosomes, and one daughter cell will have seven chromosomes. B. Two daughter cells will each have six chromosomes and two daughter cells will each have seven chromosomes. C. All four daughter cells will have six chromosomes. D. Two daughter cells will each have five chromosomes and two daughter cells will each have seven chromosomes. E. All four daughter cells will have five chromosomes.

D. Two daughter cells will each have five chromosomes and two daughter cells will each have seven chromosomes. If a single pair of homologous chromosomes failed to separate in anaphase I, one of the daughter cells would inherit an extra chromosome (seven chromosomes), and the other daughter cell would be missing a chromosome (five chromosomes). As each of these initial two daughter cells entered meiosis II, the sister chromatids would separate normally in anaphase II resulting in two cells having seven chromosomes and two cells having five chromosomes at the end of meiosis.

During which type of cell division does each daughter cell contain half the amount of DNA as did the cell just prior to cell division? A. meiosis I B. meiosis II C. mitosis D. meiosis I, meiosis II, and mitosis E. meiosis I and meiosis II

D. meiosis I, meiosis II, and mitosis The amount of DNA is reduced by half in mitosis, meiosis I, and in meiosis II.

Cohesion also results from

DNA catenation which is the intertwining of sister DNA molecules

Early prophase I sets the stage for

DNA crossover

ES cells pluripotency is controlled by multiple factors, including the state of

DNA methylation, chromatin regulators, certain micro-RNAs, and the transcription factors Oct4, Sox2, and Nanog.

Centromeres are

DNA repeats recognized by proteins of the large kinetochore complex

Dividing cells replicate ______, distributing to ___ copies of opposite ends of cells, and _____ into daughter cells

DNA, 2, Splits

when is the signal sequence removed?

DURING translational, not after big distinction from mitochondrial import (post-translational)

Tumor necrosis factor

Dead receptor involved in extrinsic apoptosis pathway.

DBRP = Destruction Box Recognizing Protein

Destruction Box = 9 amino acid sequence near the amino terminus —Arg—Thr—Ala—Leu—Gly—Asp—Ile—Gly—Asn— Ubiquitin = small protein covalently attached to proteins as a marker of degradation (or can be signalling something else) Proteasome = Large protein complex that degrades proteins back to amino acids

M =

Divides

what does SRP bind to?

ER signal sequence through signal-sequence binding pocket -wraps around large subunit of ribosome -one end binds to signal sequence -other end blocks elongation factor binding site->halts translation so we can have co-translational translocation , ensures ribosome has enough time to get to ER, we dont want protein to start folding yet

The first step of N-linked glycosylation is the transfer of a common oligosaccharide consisting of 14 sugar residues to asparagine residue within a conserved sequence. Before being transferred, the oligosaccharide is assembled within _______ on lipid carrier ____

ER, dolichol - in the ER membrane

In which of the following cell types do G1 and G2 not take place? Typical proliferating human cells Skin fibroblasts Early embryonic cells Budding yeast cells

Early embeyonic cells

What are the potential advantages of embryonic stem cells as compared to adult stem cells for therapeutic applications?

Embryonic stem cells are easier to isolate and culture and are capable of giving rise to all differentiated cell types in an adult organism.

G2/M checkpoint

Ensure all DNA has been replicated and that environment remains favorable for division -ATM kinase detects replication forks, activates a checkpoint kinase that inhibits phosphatase and prevents dephosphorylation of A/B-CDK1 complexes needed to enter mitosis.

Studying protein import into ER

Er breaks into fragments, fragments reseal to form closed vesicles called microsomes

In ____________ and ___________: most cell division involves the distribution of identical genetic material DNA ---> 2 daughter cells

Eukaryotes, Prokaryotes

Metaphase/anaphase transition point

Evaluates whether all chromosomes are attached to mitotic spindle -anaphase is dependent upon association of all chromosomes with the spindle. -protein factors recognize the kinetochores that are not associated with the spindle and initiate a sequence of events leading to inhibition of anaphase promoting complex.

An algal cell contains neither tubulin nor actin.

The energy required for tubulin and actin polymerization is provided by hydrolysis of a nucleoside triphosphate.

The minus end of microtubules and microfilaments is so named because subunits are lost and never added there.

A mutant cyclin B that is resistant to degradation by protease, but is otherwise active, would block the metaphase-to-anaphase transition. true or false

False

Cancer patients with mutant p53 can be treated effectively with radiation therapy. True of False

False

Each of the three cell types in the adult intestinal epithelium is derived from a different stem cell. True or False

False

In Meiosis I and Mitosis, the nuclear material is aligned at the metaphase plate exactly the same. True or False

False

In animal cells, Cdk2/cyclin A act to drive cells through the restriction point in G1. True of False

False

Rb is a tumor suppresor protein that acts by inhibiting phosphorylation of Cdk true or false

False

Rb is a tumor suppressor protein that acts by inhibiting phosphorylation of Cdk. True or False

False

The metaphase-to-anaphase transition in animal cells is triggered by the breakdown of cyclin B. true or false

False

True or false? Myofibrils are the alternating light-dark units that produce the banded appearance of muscle fibers.

False

Caspases (cysteine-aspartate proteases)

Family of proteases responsible for apoptosis of cell. Present in inactive precursors until apoptotic signal is received. Initiator caspases activated then in turn activate executional caspases, which hydrolyze cellular proteins and trigger DNA fragmentation.

What hypothesis was being tested with the Δformin strain?

Formin is required for the signal transduction pathway leading to shmoo formation.

Can you guess why sailors are no longer susceptible to scurvy?

Fresh fruits (vitamin C source) are available now.

A model helps scientists form testable hypotheses. What hypothesis was being tested with the ΔFus3 strain?

Fus3 is required for the signal transduction pathway leading to shmoo formation.

The ________ were misnamed as "gaps" because they were observed as inactive, but they were wrong because INTENSE METABOLIC ACTIVITY & GROWTH occur throughout interphase

G Phases

Allow the exchange of metabolites between the cytoplasms of two adjacent cells.

G and P

Cells in the quiescent phase of the cell cycle are said to be in the _______ phase.

In which cell cycle phase are cells metabolically active but will never divide again are likely to be in this phase

Most cells in adult animals are in the _______ stage of the cell cycle.

In the absence of growth factor, most animal cells will stop the cell cycle at a restriction point in what stage? G1 phase S phase G2 phase M phase

G1 Phase

The 1st gap OR growth phase of cell cycle consisting the portion of interphase BEFORE DNA synthesis begins

G1 Phase

____ is most variable in lengths of Different types of cells

G1 Phase

The length of time it takes for the cells labeled during DNA synthesis to begin to enter mitosis is a good estimate of the length of the _______ phase(s). S G1 M G2

The length of time it takes for the cells labeled during DNA synthesis to enter mitosis is a good estimate of the length of the _______ phase.

The oocytes in a normal 7-year-old female (prepubertal) would be expected to be arrested in which stage of the cell cycle, until they are hormonally stimulated? G1 G0 Correct G2 Interphase

The genetic material of an organism or virus. The complete complement of organism's or virus's gene + noncoding nucleic acid sequences

Genome

The reduced cofactors transfer their electrons to O2 to produce H2O via a set of four membrane-bound complexes pump _____ across the _____ membrane. The H gradient across the inner mitochondria membrane is a driving force to ________

H+ inner mitochondriea the production of ATP by ATP synthases

The reduced cofactors transfer their electrons to O2 to produce H2O via four membrane-bound complexes that pump ________ across the _________ membrane. The H gradient across the inner mitochondrial membrane is the driving force to __________

H+, inner, synthesize ATP

Glycosylation

Helps prevent protein aggregation in the ER and provides signals that promote protein folding and subsequent sorting in the secretory pathway.

Provide a brief justification for the following false answer: The energy required for tubulin and actin polymerization is provided by hydrolysis of a nucleoside triphosphate.

Hydrolysis of the ATP bound to actin and the GTP bound to tubulin usually occurs during monomer polymerization, but the polymerization process still occurs even if the ATP or GTP is replaced by a nonhydrolyzable analogue.

Symmetric and asymmetric divisions may occur simultaneously in stem cell population to:

Increase stem cell number Increase differentiated cell number

Meiosis 2 is often considered to be similar to mitosis. which of the following features is shared by both meiosis 2 and mitosis?

Individual chromosomes align on the metaphase plate and sister chromatids separate at anaphase in both mitosis and meiosis 2

Maturation promotion factor (MPF), discovered by Masui and Markert, is the factor that induces entry into meiosis when injected into frog oocytes. is missing in the cdc2 mutant in yeast. fluctuates in amount during the cell cycle of mammalian cells. fluctuates in amount during early cleavages of sea urchin eggs.

Induces entry into meiosis when injected into frog oocytes

Wee1

Inhibitory kinase that phosphorylates CDK at Tyrosine 15 and inhibits CDK activity.

How does cardiac muscle differ from the other types of muscle?

It contains branched cells.

Both Fibronectin and Laminin

It has multiple domains that allow to attach to other ECM proteins.

how does familial hypercholesterolemia promotes development of atherosclerosis?

It is a disease in which there is too much cholesterol in the blood which causes atherosclerosis

Rb phosphorylation for cell cycle progression

Key event in initiation of cell cycle in G1 phase is phosphorylation of Rb (retinoblastoma protein) by Cyclin D-CDK4/6 complex. E2F protein activate transcription and ready the cell for entry into S phase. When Rb is bound to E2F, function as transcriptional repressors, because Rb also binds histone deacetylase and methylase complexed (promote chromatin condensation). Once phosphorylated by cyclin D-CDK4/6, Rb dissociates from E2F proteins liberating E2F to activate transcription and ready cell for entry into S phase. Cyclin E-CDK2, produced by E2F can also phosphorylate Rb, making it independent of cyclin D-CDK4/6 activity and allowing progression through cell cycle in absence of growth factors. -INK4s compete with cyclin D for binding CDK4/6 and can inhibit Rb phosphorylation.

Based on your knowledge of the directionality of microtubule motors and the information in part B, where would you predict that the plus ends of flagellar microtubules are? State your reasoning.

Kinesins transport cargoes toward the plus ends of microtubules, so the plus ends should be at the tip of the flagellum.

Fas ligand

Ligand involved in extrinsic apoptosis pathway. Produced by natural killer cells and cytotoxic T-lymphocytes (immune response)

A special type of eukaryotic cell division that can produce SPERM & EGGS

Meiosis

In _______, the overlapping & interacting of Nonkinetochore microtubules from opposite sides

Metaphase

The 3rd phase of mitosis, which the Spindle is complete and the chromosomes----microtubules at their Kinetochore are all ALINGED at the Metaphase Plate

Metaphase

A plane that is equidistant from spindle's two poles

Metaphase Plate

An imaginary structure located at a plane midway between the 2 poles in Metaphase

Metaphase Plate

What would be the outcome or effect on mitosis if MPF fails to phosphorylates microtubules?

Metaphase and anaphase would fail to occur

Provide a brief justification for the following false answer: All microtubules within animal cells have their minus ends anchored at the centrosome.

Most do, but not all. In addition, in ciliated or flagellated cells, the minus ends of microtubules can be anchored at the basal body, which also serves as a microtubule-organizing center.

Which molecules form the thick filaments of sarcomeres?

Myosin

Which of the following interactions is the molecular basis of muscle contraction?

Myosin and thin filaments.

orientation of N-terminal signal single pass TM protein

N terminal is inside lumen, C in cytosol maintains topological equivalence, when it gets to plasma membrane, the N terminal side will be in the extracellular space, and the C terminal side will be in the cytosol

Describe how single pass TM proteins are inserted into ER membrane (N-terminal signal)

N-terminal signal sequence opens translocator stop transfer sequence (hydrophobic segment) interacts with binding site within the pore and stops translocation -causes release of both signal sequence and polypeptide translocator opens at the lateral seam -signal sequence is cleaved and mature protein is released laterally into bilayer -stop-transfer sequence anchors the protein

name the two energy storing molecules that are produced during the light dependent reactions of photosynthesis

NADPH and ATP

name the two energy storing molecules that are produced during the light-dependent reactions of photosynthesis

NADPH and ATP

"The Cdk inhibitor, p16, binds specifically to Cdk4,6/Cyclin D complexes (thus inhibiting Cdk4,6/Cyclin D function). Would overexpression of p16 affect a tumor cell lacking functional Rb protein?"

Each eukaryotic species = a characteristic # of chromosomes in each cell's __________

Nucleus

What would be the outcome or effect on mitosis if nuclear lamins are unable to bind to heterochromatin?

Nucleus would not reform during telophase

what atom serves as the terminal electron acceptor during aerobic respiration in humans?

electron transferred to molecule of ________ via a series of protein complexes and lose their energy which is used to create________

O2 PH gradient ( energy is used to move H+ from matrix to intermembrane space creating PH gradient )

Electrons are transported to a molecule of ____________ via a series of protein complexes and lose their energy which is used to create a ______________

O2, proton gradient

three master transcription factors

Oct4, Sox2, and Nanog

A major pathway that signals cell survival and inhibits cell death is the _______ pathway.

PI3K/Akt

Small vesicles containing pigment inside of pigmented fish epidermal cells aggregate or disperse in response to treatment with certain chemicals. When nocodazole is added to cells in which the pigment granules have been induced to aggregate, the granules cannot disperse again.

Pigment granule dispersal is a microtubule-dependent process.

What enhances MPF activation?

Positive and negative feedback loops.

during what phase of meiosis does recombination between maternal and paternal chromosomes occur?

Prophase I

The 2 Centrosomes move APART during _____ & _____ as spindles grow out of them

Prophase, Prometaphase

Post-translational Translocation

Proteins are translocated into the ER after their synthesis. - requires BiP not SRP - process driven by BiP

Co-translational Translocation

Proteins are translocated into the ER during their synthesis. - requires SRP - process driven by protein synthesis

KDEL Retrieval Sequences

Proteins marked by these sequences are exported from the ER to the Golgi, and are recognized by a recycling receptor in the ERGIC or the Golgi and selectively returned to the ER.

The G1 checkpoint in animal cells is called the decision point. the G1/S boundary. START. the restriction point.

Restriction point

____ localizes to the cortical actin cytoskeleton where it

Rho-GEF exchanges a GDP for a GTP that activated RhoA kinase

The cytoplasmic side of the furrow = contractile ring of actin microfilaments + myosin protein causing ___

Ring to contract

The Synthesis Phase of cell cycle, where DNA is replicated (Sister chromatids)

S Phase

You perform an experiment by incubating a radiolabeled nucleotide into the medium of a culture of cells. The cells that take up the radiolabel would be expected to be in what phase of the cell cycle? S phase G1 G2 M phase

S phase

The G1 checkpoint in budding yeast cells is called

START

G2 subphase of interphase

Second period of growth that precedes cell division

Anaphase begins suddenly when the coheins holding together the sister chromatids of each CHROMOSOMES are CLEAVED by an enzyme called ______

Separase

DNA copied & Replicated

Separated for each daughter cell

In meiosis I, sister chromatids:"

Share a single kinetochore

Signal Sequence

Short stretch of hydrophobic amino acids that are cleaved from the polypeptide chain during its transfer into the ER lumen. - role: targeting proteins to their appropriate locations within the cell.

-After replicating DNA -Condense as a part of cell division Chromosomes are _______________

Shorter, thick (coiled and folded chromatins)

Growth Factors

Signaling molecules that stimulate cell proliferation and growth. Typically be specific combination of growth factors, indicating a relatively small number of growth factors can selectively regulate growth and proliferation in many cell types.

What are the signals to start another round of the cell cycle?

Signals (mitogens) binding to cell surface receptors and initiating a signal transduction pathway that results in transition across the restriction point (START).

Co-translational translocation

Simultaneous transport of a secretory protein into the endoplasmic reticulum as the nascent protein is still bound to the ribosome and being elongated

The chromosomes of prokaryotic cells are _______

Single, CIRUCULAR chromosomes in NUCLEOID

Each duplicated chromosome have ___________________

Sister Chromatids

Microsomes

Small vesicles made of disrupted rough ER. - because vesicles derived from the rough ER are covered with ribosomes, they can be separated from similar vesicles derived from the smooth ER (or other membranes). - large amounts of RNA within ribosomes increases the density of the membrane vesicles derived from the rough ER (rough microsomes) by equilibrium centrifugation in density gradients.

Any cell in multicellular organism, except sperm/eggs/precursors

Somatic cells

blastocyst (64 cells) formation

Some cell-cell adhesions diminish locally. Fluid inflow fills an internal blastocoel cavity.

How can the wave-like motion seen in the beating of sperm flagella be created?

Some dynein molecules must be exerting force while those on the opposite side of the tail must be inactive.

GPI Anchor (Glycosyl-phosphatidylinositol)

Some proteins are attached to the plasma membrane by glycolipids rather than by membrane-spanning regions of the polypeptide chain. These membrane- anchoring glycolipids contain phosphatidylinositol. - anchors are assembled in the ER membrane. - added to (C)-terminus of proteins retained in the membrane by a hydrophobic sequence. - (C)-terminal sequence of the protein is cleaved and exchanged for the GPI anchor, so these proteins remain attached to the membrane only by their associated glycolipid. - like transmembrane proteins, they are transported to the cell surface as membrane components via the secretory pathway. - GPI-anchored proteins are exposed on the outside of the cell with the GPI anchor mediating their attachment to the plasma membrane.

Which of the following are the three core transcription factors that can reprogram adult somatic cells into induced pluripotent cells?

Sox2, Oct4, and Nanog

G2/M transition

Spindle assembly checkpoint commitment to mitosis Ensures that there is no chromosomal damage and that the spindles are attached to sister chromatids

How can signals outside the cell induce cell apoptosis?

T cell interacts physically with target cell via protein-protein interactions, this triggers a program of events inside the cell that leads to the activation of the caspase cascade that causes apoptosis of the target cell.

the image below shows the separation of DNA fragments of varying length by gel electrophoresis. each lane of the gel (A,C,G,T) contains fragments of DNA which include "chain terminating" dideoxy analogues of the four nucleotides: ddATP, ddCTP, ddGTP, and ddTTP. the smallest fragments have traveled furthest down the gel from the negative to the positive end. your task is to determine the DNA sequence for the original DNA strand used as template for sequencing.

TACGGTCAT

Activated TNFα receptor recruits

TRADD (TNF receptor-associated death domain protein) and FADD (Fas-associated death domain protein) adapter proteins.

How would the drug taxol affect the in vitro dynamic instability and treadmilling experiments?

Taxol would stabilize the microtubules in both experiments, leading to polymerization without catastrophe.

insufficient activity of an enzyme called hexosaminidase A is a hallmark of _______ disease.

Tay- Sachs

Insufficient activity of an enzyme hexosaminidase A is a hallmark of _______________ disease

Tay-Sachs

Translocation of a gene can produce a fusion product with uncontrolled protein kinase activity. An example of this type of fusion protein is

Tel/PDGFR

During which phase of meiosis do diploid cells first become haploid?

Telophase 1

-Motor proteins on the Kinetochores "walk" the chromosome along their microtubules -Depolymerizing the Kinetochore ends - The "PacMan" analogy

The 1/2 mechanisms of how the kinetochore microtubules function the poleward movement of chromosome

Chromosomes are "reeled in" by motor proteins at the Spindle Poles & the microtubules depolymerize after they pass these motor proteins at poles

The 2/2 mechanisms of how the kinetochore microtubules function the poleward movement of chromosome

The H zone is a specific portion of the A band. If the H zone of each A band decreases in length from 1.2 to 0μm as the sarcomere length contracts from 3.2 to 2.0μm, what can you deduce about the physical meaning of the H zone?

The H zone corresponds to that portion of the thick filament length that is not overlapped by thin filaments.

What's the remarkable thing about cell division?

The accuracy where DNA passed from 1 generation of cells to ANOTHER

What would be the likely outcome if the radial spokes inside cilia were destroyed and the cilia attempted to move?

The bending of the cilia would cease, and the microtubules inside the cilia would slide past one another.

How does the cell stop and fix a problem in the cycle?

The cell can pause the cell cycle if it senses problem with itself or the environment.

"If an abnormal, indestructible form of Cyclin B were introduced into cells, what affect would this have on the cell:"

The cell would immediately enter M phase and would remain in M phase (unable to get past M phase

When an animal cell is treated with colchicine, its microtubules depolymerize and virtually disappear. If the colchicine is then washed away, the MTs appear again, beginning at the centrosome and elongating outward at about the rate (1μm/min) at which tubulin polymerizes in vitro.

The centrosome serves as a microtubule-organizing center in vivo, and all of the microtubules radiating from the centrosome apparently have the same polarity.

What is the critical property of stem cells?

The critical characteristic of stem cells is their capacity for self-renewal. They divide to produce one daughter cell that remains a stem cell and one that differentiates.

What makes the cell cycle move forwards and not in reverse?

The degradation of specific proteins at specific times. (Can't reverse degradation of protein).

What can you say about the distance from the Z line to the edge of the H zone during contraction?

The distance remains constant during contraction.

Extracts from nondividing frog eggs in the G2 phase of the cell cycle were found to contain structures that could induce the polymerization of tubulin into microtubules in vitro. When examined by immunostaining, these structures were shown to contain γ-tubulin.

The extracts appear to contain structures that are functionally equivalent to centrosomes (as evidenced by the presence of γ-tubulin), which nucleate micro-tubule growth.

Frog skeletal muscle consists of thick filaments that are about 1.6μm long and thin filaments about 1μm long. Part A What is the length of the A band and the I band in a muscle with a sarcomere length of 3.2μm?

The length of the A band is 1.6μm, and the length of the I band is also 1.6μm.

Describe what happens to the length of both bands as the sarcomere length decreases during contraction from 3.2 to 2.0μm.

The length of the A band remains fixed at 1.6μm, and the length of the I band decreases from 1.6μm to 0.4μm.

You have contructed a Bad mutant in which the Akt phosphorylation site has been mutated such that Akt no longer phosphorylates it. How would expression of this mutant affect cell survival?

The mutant Bad would not be maintained in an inactive state and would act to induce apoptosis.

Somatic nuclear transfer:

The nucleus of a fully differentiated cell is transferred into an enucleated egg (ovum). The nucleus can undergo reprogramming to initiate animal development and give rise to all of the cells of a mature organism.

Fus3 kinase and formin proteins are generally distributed evenly throughout a yeast cell. Based on the model in the diagram, why does the shmoo projection emerge on the same side of the cell that bound the mating factor?

The only formin molecules that get phosphorylated and thus activated are those near the G protein-coupled receptor that binds mating factor.

retrotranslocation

The passage of a protein from the ER to the cytosol because of incorrect folding to be degraded by proteasome mannosidase (trimming of particular mannose) recognized by ER lectins

Which step constitutes the power stroke of muscle contraction?

The phosphate ion is released, and the myosin head moves back to its original position.

What is the difference between the plus and minus ends of the microtubule in in vitro experiments?

The plus end has a lower critical concentration for tubulin heterodimers.3

You have isolated a polypeptide from a toxic plant, which localizes to mitochondria after endocytosis by mammalian cells. How will treatment with this polypeptide affect mammalian cells in culture?

The polypeptide will lead to the release of cytochrome c from mitochondria and induce apoptosis of treated cells.

Provide a brief justification for the following false answer: The minus end of microtubules and microfilaments is so named because subunits are lost and never added there.

The rate of loss is greater than the rate of addition at the minus end over time. There is no absolute absence of addition at the minus end.

Provide a brief justification why the following answer can be either true or false: As long as actin monomers continue to be added to the plus end of a microfilament, the MF will continue to elongate.

The statement is true if the monomer concentration is above the overall critical concentration but false otherwise.

Which of the following accurately describes the nucleotide dependence of cilia and flagella structure and function?

The structures of cilia and flagella are dependent on GTP, whereas the functions of cilia and flagella are dependent on ATP.

The translocator is gated in two directions, explain the significance of this.

The translocator is gated in two directions: 1) it can open to form a pore across the membrane to let the hydrophilic portions of proteins cross the lipid bilayer 2) it can open laterally within the membrane to let hydrophobic portions of proteins partition into the bilayer. This lateral gating mechanism is crucial for the insertion of transmembrane proteins into the lipid bilayer, as we discuss next.

When designing an experiment, scientists make predictions about what results will occur if their hypothesis is correct. One of their hypotheses was that Fus3 kinase is required for the signal transduction pathway leading to shmoo formation. If this hypothesis is correct, what result should be observed in the ΔFus3 strain?

The ΔFus3 strain should not form shmoos, and the cells should not have a red zone in their walls.

One of their hypotheses was that formin is required for the signal transduction pathway leading to shmoo formation. If this hypothesis is correct, what result should be observed in the Δformin strain?

The Δformin strain should not form shmoos, and the cells should not have a red zone in their walls.

Which of the following would result if an inhibitor of myosin light-chain kinase (MLCK) were added to a culture of smooth muscle cells?

There would be no muscle contraction.

Stress fibers of nonmuscle cells contain contractile bundles of actin and myosin II. For stress fibers to contract or develop tension, how would actin and myosin have to be oriented within the stress fibers?

There would have to be regions of antiparallel actin filaments (with some actin filaments attached to myosin in the opposite orientation).

Many adult tissues contain terminally differentiated cells that are incapable of proliferation. However, these tissues can regenerate following damage. What gives these tissues their regenerative capabilities?

These tissues contain stem cells that retain the ability to proliferate and replace differentiated cells.

How apoptosis controlled?

Through the activation of the caspase cascade (cleavage of proteins) Active caspase can cleave another caspase (cleaving to form a different caspase). That caspase can activate other caspases. Looks like kinase cascade. Proteins that are proteases and the X activate many copies of the Y which can activate copies of the Z.

How does the cell exit M phase?

Through the inactivation of MPF.

Why do you need to add inhibitory phosphate group?

To allow for a more controlled activation of MPF. Remember that MPF activation is very dramatic and sudden, which causes the entry into M phase. By putting on inhibitor, the cell can get ready to immediately activate. All it needs to do is remove Y15.

The retinoblastoma protein (Rb) binds to and inhibits

Transcription factor Ef2

p53 involvement in transcription

Transcription factor that is normally unstable and therefore does not reach high concentrations within the cell to impact transcription. Can be phosphorylated/stabilized via ATM/ATR complex. -targets p21CIP1, which is an inhibitor of cyclin-dependent kinase, inhibiting both cyclin/CDK1 and cyclin/CDK2 kinase complexes.

M-G1 Transition

Transition in which cell exit M phase.

G2-M transition

Transition in which the cell enters M phase

G1-S Transition

Transition in which the cell enters S phase.

A mutant bcl-2 gene can be an oncogene True or False

True

ATM and ATR recognize damaged or unreplicated DNA and initiate signals that arrest cells at cell cycle checkpoints. True of False

True

Acute promyelocytic leukemia results from a mutated retinoic acid receptor, effectively blocking cell differentiation and allowing leukemic cells to continue proliferation. True or false

True

All of the protein subunits of intermediate filaments are encoded by genes in the same gene family.

True

As a causal factor in the development of tumors, the inability of cancer cells to undergo apoptosis is as significant as their uncontrolled proliferation. True or False

True

BRCA1 and BRCA2 prevent breast cancer by maintaining the integrity of the genome. True of False

True

Goblet cells and enteroendocrine cells have the same stem cells as absorptive epithelial cells. True or False

True

In normal, nonapoptotic cells, antiapoptotic members of the Bcl-2 protein family bind to proapoptotic members and inhibit their activity. True or False

True

In normal, nonapoptotic cells, antipoptotic members of the Bcl-2 protein family binds to propototic members and inhibit their activity True or False

True

Programmed cell death plays an important role in development. true or false

True

Rb is a member of the family of tumor suppressor genes. True or False

True

Reproductive cloning of humans raises ethical concerns. True or False

True

SV40, papillomaviruses, and adenoviruses induce transformation by producing proteins that interact with the tumor suppressor proteins p53 and Rb. true or false

True

Satellite cells are located beneath the basal lamina of muscle fibers. True or Flase

True

Several oncogenes encode antiapoptiotic proteins that promote cell survival true or false

True

Several oncogenes encode antiapoptotic proteins that promote cell survival. true or false

True

The clinical application of adult stem cells is limited by difficulties in isolating and culturing the appropriate stem cell populations. True or False

True

The sensitivity of tumors to inhibition of activated oncogenes is called oncogene addiction. True of False

True

Transcription ceases as chromosome condensation occurs. True False

True

Transformation can be assayed in cell culture. True of False

True

Microtubules lengthen somewhat by the addition of _________________ to their overlapping ends

Tubulin Subunits

Cyclins

Undergo a cycle of protein synthesis and degradation • Essential regulators of CDK activity • Are also regulated • Animals have 10 cyclins • Can be divided into G1/S cyclins, S-cyclins and G2/M cyclins

_____________ developed dye to see the mitosis and cytokinesis

Walther Flemming

What would happen if Rb was mutated and non-functional?

We would no longer need an active signal. The cell could just move forward in the absence of a stimulatory signal. This could be bad, since this causes unregulated cell division. Cancer in many cases is unregulated cell division.

M-Cdk is held inactive by

Wee1 (inhibitory phosphorylation)

Phosphorylation of Cdk includes

Wee1 inhibits Cdk activity Cdc25, a phosphatase, increases Cdk activity

The micrographs shown below were taken of wild-type, ΔFus3, and Δformin cells after they were stained green, exposed to mating factor, and then stained red. For each micrograph, drag the labels to answer the questions. Labels may be used once, more than once, or not at all.

Wild Type: Red Green - Asym - Y - Y - Y ΔFus3: Yellow - Sym - N - Y - Y Δformin: Yellow - Sym - N - Y - Y

family proteins polymerization is very fast.

With Arp2/3 and WASP

family proteins polymerization is very slow.

Without Arp2/3 or WASP

What have been powerful tools for studying the cell cycle?

Xenophus (Frog) and Sea Urchin Eggs

Which of the following stem cells have the capacity to give rise to all the differentiated cell types of adult organisms? a. Embryonic stem cells b. Endothelial cells c. Satellite cells d. Epithelial cells

Oncogenes were first discovered in

a chicken retrovirus

mulitpotent stem cells can only give rise to

a few different cell types that have some of the same basic features. "adult stem cells".

the ability of M-Cdk to promote Cdc20-APC/C activity creates

a negative feedback loop

A proto-oncogene is a normal gene from which an oncogene can arise. expressed normally in tumor cells. one that has been picked up by an oncogenic virus. evolving into an oncogene.

a normal gene from which an oncogene can arise

incorrect attachments are corrected by

a system of trial and error

During synapsis? a. homologues pair all along their length b. sister chromatids pair all along their length c. sister chromatids pair at the centromeres d. homologues repel each other except at the ends

a. homologues pair all along their length

Crossing over occurs during which phase of meiosis? a. prophase 1 b. metaphase 1 c. anaphase 2 d. anaphase 1 e. metaphase 2

a. prophase 1

A major pathway that signals cell survival and inhibits cell death is the _______ pathway. Select one: a. PI 3-kinase/Akt. b. Hedgehog. c. TNF. d. Wnt.

a. PI 3-kinase/Akt.

You preform an experiment by incubating a radiolabeled nuclotide into the medium of a culture of cells. The cells that take up the radiolabeled would be ecpected to be in what phase of the cell cycle? a. S phase b. M phase c. G2 phase d. G1 phase

a. S phase

a tumor of an epithelial cell is a a. carcinoma b. sarcoma c. leukemia d. lymphoma

a. carcinoma

5. ADF/cofilin plays a role in a. the disassembly of microfilaments. b. stimulation of actin filament formation. c. the nucleation of microfilaments. d. the disassembly of microtubules.

a. the disassembly of microfilaments

Mammalian embryonic stem cells are cultured from cells taken from a. the inner cell mass. b. the four-cell embryo. c. amnion cells. d. trophoblast cells.

a. the inner cell mass.

16. Whether a microtubule shrinks or grows is determined by a. the rate of GTP-bound tubulin addition relative to the rate of tubulin GTP hydrolysis. b. the phosphorylation state of β-tubulin. c. the rate of ATP hydrolysis relative to the rate of ATP-bound tubulin addition. d. the presence or absence of γ-tubulin.

a. the rate of GTP-bound tubulin addition relative to the rate of tubulin GTP hydrolysis.

What generates the force for cytokinesis?

actin and myosin II

Myosin V motor transports secretory vesicles toward

actin filament (+) ends.

RhoA kinase activation promotes

actin filament formation, myosin II assembly, and ring contraction

Formins nucleate and elongate

actin filaments with (+) ends oriented toward Cdc42·GTP at membrane.

G1/S Cdks

activate late in G1, trigger expression through start.

Positive autoregulatory loop -

activates transcription of each of these genes

DNA damage initiates a signaling pathway by

activating a pair of protein kinases known as ATM and ATR

There remains concern that such cells may not possess

all of the qualities of embryonic stem cells, and there remains a risk that such cells, once transplanted, may grow uncontrollably and produce tumors.

Effector caspases cleave

all of these (DNase inhibitor, cytoskeletal proteins, nuclear lamins)

S- and M- cyclins are inactivated in anaphase to

allow phosphatases to dephosphorylate Cdk targets that are required for the completion of mitosis and cytokines

MAP kinase leads to

an increase in the production of transcription regulatory proteins, including Myc

role of dolichol

associates oligosaccharide with lipid membrane

Cell polarity involves the

asymmetric distribution of proteins, lipids, and other macromolecules in the cell

Which of the following products would result from caspase cleavage of a protein with the amino acid sequence AVEELCSTWYYDLLCHMRTL? a. AVEELCS + TWYYDLLCHMRTL b. AVEELCSTWYYD + LLCHMRTL c. AVEELCSTWYYDLLCH + MRTL d. AVEELC + STWYYDLLC + HMRTL

The Cdk inhibitor, p16, binds specifically to Cdk4,6/cyclin D complexes. Would over expression of p16 affect a tumor cell lacking functional Rb protein? a. yes b. no

b no

1. Actin filaments are approximately _______ in diameter. a. 5 Å b. 7 nm c. 11 nm d. 25 nm e. 50 nm Textbook Reference: Structure and Organization of Actin Filaments, p. 473

b. 7 nm

2. The approximate diameter of an actin filament is a. 8-12 nm. b. 7 nm. c. 25 nm. d. 5 mm.

b. 7 nm

2. The approximate diameter of an actin filament is a. 8-12 nm. b. 7 nm. c. 25 nm. d. 5 mm. Textbook Reference: Structure and Organization of Actin Filaments, p. 473

b. 7 nm.

1. Actin filaments are approximately _______ in diameter. a. 5 Å b. 7 nm c. 11 nm d. 25 nm e. 50 nm

b. 7nm

18. Intermediate filaments are typically _______ in diameter. a. 5-7 nm b. 8-11 nm c. 16-22 nm d. 24-26 nm e. 32-36 nm

b. 8-11nm

Members of the Bcl-2 family of proteins are: Select one: a. All caspases. b. Either antiapoptotic or proapoptotic. c. All antiapoptotic. d. All proapoptotic.

b. Either antiapoptotic or proapoptotic.

22. Keratin filaments are found in what cell types? a. Fibroblasts b. Epithelial cells c. Muscle cells d. Neurons e. All of the above Textbook Reference: Intermediate Filaments, p. 497

b. Epithelial cells

Most cells in adult animals are in the _______ stage of the cell cycle. a. G2 b. G0 c. G1 d. S

b. G0

32. Which nucleotide triphosphate is hydrolyzed during a cycle of microtubule assembly and disassembly? a. ATP b. GTP c. CTP d. UTP e. TTP Textbook Reference: Microtubules, p. 505

b. GTP

what is the fate of the LDL receptors after the fusion described in the above question?

because of the low ph ( acidic conditions) in the early endosomes the LDL is separated from B receptor and it is recycled to the plasma membrane through a vessicle or the LDL is dissociated from its receptor & the receptor is spit out into the cytoplasm & is recycled or LDL receptors dssosiate and get recycled back to the plasma membrane

G1 phase

between M and S phase cells grows in size and protein synthesis occurs

G2 phase

between S phase and M phase DNA repair mechanisms are busy during this time.

To become active, Cdk1 must

bind cyclin and be phosphorylated on threonine 161, and be dephosphorylated on threonine 14 and tyrosine 15.

G1-Cdks activate E2F proteins, which

bind to promoters of genes that code proteins required for S phase entry

Cells require trophic factors that

bind to surface receptors to repress apoptosis for survival.

transforming growth factor-B (TGF-B)

blocks cell cycle progression in G1/S

Describe two populations of ribosomes

bound vs free just depends on what proteins they are making at a certain time ex. hydrophobic sequence-> ribosome bound to ER population associated with ER constantly changes, no one ribosome stays on ER or stays free, all are on both at different times between free ribosome cycle and membrane-bound cycle

Plant stem cells persist for the life of the plant and can give rise to a

broad spectrum of cell types.

In reference to stem cells, which of the following statements is false? a. Stem cells divide to form one daughter cell that remains a stem cell and a second cell that proliferates and then differentiates. b. Stem cells are a subpopulation of less differentiated self-renewing cells present in most adult tissues. c. Stem cells in organs can only differentiate into the tissue in which they are located. d. Stem cells in tissues are typically found in G0, unless they are called on to differentiate.

Which of the following is NOT a mechanism for regulation of the cell cycle? a. synthesis of cyclin proteins b. ubiquitinylation of protein c. proteolysis of cdk/cdc protein kinases d. proteolysis of cyclin proteins e. protein phosphorylation

c. proteolysis of cdk/cdc protein kinases

In a cell with 8 chormosomes, how many total sister chomatids are visible at the beginning of mitosis? a. 4 b. 8 c. 16 d. 25 e 32

c. 16

c. 9 doublet; in a circle around a central pair of microtubules

During prophase, Cdk1/Cyclin B (MPF) directly phosphorylates all of the following except a. condensins. b. lamins. c. APC/C. d. microtubule-associated proteins.

c. APC/C.

Bax and Bak act by: Select one: a. Interacting with Apaf-1 to initiate a proapoptotic signal. b. Interacting with Ced-9 to initiate a proapoptotic signal. c. Forming oligomers in the mitochondrial outer membrane that release cytochrome c. d. Interacting with Apaf-1 to block an apoptotic signal.

c. Forming oligomers in the mitochondrial outer membrane that release cytochrome c.

c. G proteins, regulated by bound GTP or GDP.

Which of the following microtubules are attached to chromosomes? a. Interphase microtubules b. Interpolar microtubules c. Kinetochore microtubules d. Astral microtubules

c. Kinetochore microtubules

1. Which of the following is not one of the functions of the cytoskeleton? a. To provide a structural framework for the cell b. Cell locomotion c. Protein translocation into the ER d. Intracellular movement of organelles and other structures Textbook Reference: Introduction, p. 473

c. Protein translocation into the ER

Intermediate filaments

can be composed of the protein vimentin.

M-Cdk can activate its own activator, which

can remove the inhibitory phosphorylation

The dramatic increase in cancer incidence with age suggests that

cancer develops as a consequence of multiple abnormalities that accumulate over many years.

The gene ced-3 of C. elegans codes for a proteolytic enzyme that is a(n)

caspase

centrosome duplication begins as the

cell enters S phase

VEGF is secreted by

cells deprived of oxygen

terminally differentiated

cells do not divide. Where do the replacement cells come from?

Apoptosis involves activation of

cellular caspase proteases that cleave cellular proteins.

kinetochores are found at the

centromeric region on each sister chromatid

spindle poles originate from

centrosomes

lipids rafts are clusters of sphingolipids and

cholesterol

S-phase requires production of

chromatin proteins (histones)

The M phase checkpoint detects:

chromosome alignment and attachment of mitotic spindle

M phase

chromosome segregation and cell division mitosis and cytokenesis

In many people, the ingestion of ethanol produces a dose-dependent leakage of interstitial fluid from the intestinal wall into the lumen of the intestine, giving rise to diarrhea. Which of the following proteins is likely inhibited or compromised in function to produce this ethanol-induced diarrhea?

claudins

Describe the type of translocation involved in protein import into the ER

co-translational translocation

anaphase I of meiosis

cohesion is removed from the chromosome arms of the homologs and not from the regions near the centromeres

Genomic equivalence:

concept that each cell in the body has the same genetic material and therefore all the information necessary to create a complete organism

Sister chromatids must be _____ for segregation without breakage

condensed

Kinetochore microtubules

connect the spindle poles to the kineotchores of the sister chromatids

blastocyst

consists of two primary cell types: 1) inner cell mass (embryoblast) which is the source of embryonic stem cells and give rise to all structures of the organism; 2) trophoblast (aka trophectoderm) - layer of cells surrounding the embryoblast that ultimately forms the placenta

actin and myosin II assemble in the

contractile ring

SCF polyubiquitylates CKI proteins in late G1 to help

control the activation of S-Cdks and DNA replication

Mitosis

copied chromosomes are distributed into a pair of daughter nuclei

In addition to the independent assortment of chromosomes at anaphase, the diversity of haploid daughter cells is increased by the process of

crossing over

Which process results in sister chromatids that are no longer identical?

crossing over

Vertebrate polarized epithelial cells -

cues from adjacent cells and the extracellular matrix orient polarization axis

"To become active, Cdk1 must bind"

cyclin and be phosphorylated on threonine 161 and dephosphorylated on threonine 14 and tyrosine 15.

p21 inhibits cell cycle progression by binding to and inhibiting

cyclin-dependent kinases.

most mitochondrial proteins are synthesized on

cytoplasmic ribosomes using nuclear mRNA

Most mitochondrial proteins are synthesized on

cytoplasmic ribosomes; they are imported after they are completely synthesized

Most mitochondrial proteins are synthesized on

cytoplasmic ribosomes; they are imported after they are completely synthesized.

M-Cdk functions

cytoskeletal changes chromosomal condensation spindle formation spindle kinetochore attachment nuclear envelope fragmentation golgi break-up

12. Duchenne's muscular dystrophy is characterized by a. X-chromosomal inheritance. b. childhood onset. c. abnormal dystrophin function. d. All of the above e. None of the above

d. all of the above

10. Actin filaments are bound into bundles of parallel filaments by the proteins a. filamin and spectrin. b. troponin and tropomyosin. c. profilin and thymosin. d. α-actinin and fimbrin. e. All of the above Textbook Reference: Structure and Organization of Actin Filaments, p. 480

d. α-actinin and fimbrin.

42. Rings of the protein _______ in the pericentriolar material nucleate microtubule assembly. a. centrin b. pericentrin c. α-tubulin d. γ-tubulin e. β-tubulin Textbook Reference: Microtubules, p. 508

d. γ-tubulin

Which of the following steps arrest cells in G2 preventing progression to M phase? a. Phosphorylation of Cdc2 b. Phosphorylation of Cdk 4/6 c.Phosphorylation of CAK d.Phosphorylation of Cdc25 e.Phosphorylation of Wee 1

d.Phosphorylation of Cdc25

Stem cells regenerate differentiated tissue cells that are

damaged, sloughed, or aged.

in order to organize the sisters, they are

decatenated and some of the cohesions are removed

which of the following best describes the order in which western blotting is performed?

denature --> SDS gel --> transfer --> blocking --> primary antibody --> secondary antibody --> development

What activates M-Cdk?

dephosphorylation by Cdc25

Cdks bind to cyclin and are activated by

dephosphorylation by Cdc25 protein phosphatase.

3 mechanisms that generate the forces that produce tension

depolymerization at kinetochore end microtubule flux polar ejection force

The primary role of _____ is to bind animal cells together.

desmosomes

the destruction of _____ at the end of metaphase _____, which is then _____

destruction of securin releases separase, which is then free to cleave cohesion, separating the two sister chromatids

differentiated cells do not lose any of their genetic information as

development/differentiation occurs.

Crossing over shuffles alleles on....?

different homologous chromosomes

cell differentiation is driven by

differential gene expression

induced pluripotent stem cells (iPS cells)

differentiated somatic cells are dedifferentiated into a stem cell state:

MPF is a

dimer of Cdk1 and cyclin B

MPF is a

dimer of Cdk1 and cyclin B.

ER signal sequence

directs transmembrane and water soluble proteins to ER membrane signal sequence varies in amino acid sequence has eight or more nonpolar amino acids at its center binds to SRP

major events of telophase include

disassembly of the mitotic spindle followed by the reformation of the nuclear envelope

The beating of cilia and flagella occurs by means of ____- based______.

dynein, microtubule sliding

the beating of cilia and flagella occurs by means of ________-based ___________

dynein; microtubule sliding

27. Expression of a shortened skin keratin gene in place of the normal keratin gene in transgenic mice resulted in a phenotype in which mice had a. thick skin. b. no hair. c. fragile, easily blistered skin. d. white hair. e. Both b and c Textbook Reference: Intermediate Filaments, pp. 502-503

e. Both b and c

How does Cdk 4/6 and Cyclin D promote cell cycle progression? a. Through phosphorylation of p53 b. Through phosphorylation of Cdk 4/6 c. Through phosphorylation of p21 d. Through phosphorylation of E2F e. Through phosphorylation of Rb

e. Through phosphorylation of Rb

Which of the following enzymes involved in G2 to M phase translation inactivates MPF? a. Cdc2 b. Cdk 4/6 c. Cdc25 d. CAK e. Wee 1

e. Wee 1

Meiosis differs from Mitosis in that Meiosis: a. has a longer prophase b. involved two cell division c. produces haploid cells from tetraploid cells d. creates recombinants e. all of the above

e. all of the above

Meiosis differs from mitosis in that meiosis: a. involves two cell divisions b. produces haploid cells from diploid cells. c. has a longer prophase d. both and b e. all of the above

e. all of the above

The type of cell is potentially a(n)?

egg

Members of the Bcl-2 family of proteins are

either antiapoptotic or proapoptotic.

progenitors

either multipotent or unipotent

The reduced cofactors transfer their electrons to O2 to produce H2O via a set of four membrane bound complexes collectively called the ____. These complexes pump _____ across the _____ membrane.

electron transport chain ( of oxidative phosphorylation) , H + (protons), inner mitochondrial membrane (from matrix into inter-membranous space)

what is protein glycosylation reaction as it transfers all different sugar monomers at once

end block transfer

Reinforcement -

endocytic cycle constantly returns diffusing polarity factors such as membrane-associated Cdc42 back along the actin filaments to the signal site

Cell Cycle Checkpoints

ensure that specific steps are completed properly before the cell moves onto the next phase.

M-Cdk drives

entry into mitosis

mammalian embryo initial division yields

equivalent totipotent cells; subsequent divisions give rise to the blastocyst inner cell mass and surrounding trophectoderm as the first differentiation event.

Par complex:

essential for asymmetric cell division and polarized growth

Cdc42-GTP is required to

establish cell polarity

intrinsic polarity program

establishes asymmetry in cells before asymmetric cell division that yields cells with different fates.

While all cells of an organism contain the exact same complement of genes, only a subset of those genes are

expressed at an given time. This differential gene expression provides each cell with a unique identity and function by producing different proteins and functional RNA molecules.

apoptosis initiated by

external stimuli

Which of the following aspects of collagen would be directly affected by a defect in procollagen peptidase?

extracellular assembly

Passage of animal cells through the cell cycle is regulated primarily by

extracellular growth factors

After development, liver cells stop cycling and stay in G1. True or false

false

the number of cells in the different phases of a population can be determined most early by measuring the amount of DNA per cell in a large sample of cells with a

flow cytometer

Repress genes that are silenced in undifferentiated ES cells and that encode proteins and micro-RNAs essential for the

formation of many differentiated cell types

What happens to the Golgi?

fragmented and distributed to opposite ends of the spindle ensuring that each daughter cell inherits materials to reconstruct the Golgi

A proto-oncogene is a gene

from a normal cell from which an oncogene can arise

interpolar microtubules

from the 2 poles interlock at the spindle equator

Just a few transcription factors are sufficient to induce

fully differentiated cells to adopt a ES like fate

With the correct timing of specific differentiation and growth factors, ES and iPS cells can be stimulated to differentiate into

functional human cells under cellular culture conditions.

glycan trimming

further removal and addition of sugars occurs in the Golgi apparatus involves glycosidase and glycosyltransferase

Which of the following proteins would be a good drug target for interfering with microfilament network breakdown?

gelsolin

Cells have an intrinsic program that can

generate polarity through feedback loops.

Cohesions form

giant ringlike structures that surrounds the sister chromatids

multipotent somatic stem cells

give rise to both stem cells and multiple types of differentiated cells.

mesoderm (middle layer)

gives rise to somites, notochord, and mesenchyme (muscles, circulatory and excretory systems)

endoderm (internal layer)

gives rise to the inner cell linings of the digestive tract, respiratory passages, and linings of all glands including and the liver and pancreas

ectoderm (external layer)

gives rise to the skin, epithelial layer of certain structures (nose, mouth), lens of the eye, the retina and nervous system

list the major product of the dark reaction of photosynthesis

glucose

What happens when a protein is improperly folded?

glycosyl transferase adds sugar monomer again, and goes through cycles of glucose trimming and glucose addition until properly folded

In meiosis I, sister chromatids

go to the same poles.

This karyotype is from a human cell. The source of the cell is?

haploid

Mice lacking plakoglobin have skin defects but usually die from

heart failure.

partial junctions that connect intracellular keratin intermediate filaments of epithelial cells to extracellular matrix are called _____________

hemidesmosomes

which cell can be stimulated to divide if there is damage

hepatocytes, fibroblasts

Which of the following is characteristic of the first division of meiosis but not mitosis?

homologous chromosomes pair

crossovers hold

homologs together

embryonic stem cells therapeutic challenge

host tissue immune rejection

symmetric division yields

identical daughter cells that may have different fates if exposed to different external signals

Spindle Assembly Checkpoint

if you used MT depolymerizing drugs to depolymerize the spindle MTs, the cell does not exit M phase. It doesn't initiate the degradation or cleavage of cohesin either. -able to sense whether there is a chromosome with lack of tension. Kinetochores of unattached chromosomes are sending a WAIT signal. The wait signal occurs in part because they are not under tension. (When they are under tension, proteins become dephosphorylated which affects the activity at the kinetochore.) As long as the kinetochores are not under tension, there are proteins that are phosphorylated, and we are sending out a WAIT signal, which keeps the CDC20-APC INACTIVE until all the sister chromatids are attached. Any chromosome that has not achieved bipolar attachment is sending out an inhibitory signal that can bind to CDC20-APC. Until there is no more inhibitory signal in the cell, which occurs after everybody is lined up at the metaphase plate. Then, CDC20-APC becomes activate, securin is ubiquitinated, separate activated, cohesin cleaved, the sister chromatids segregate to opposite poles. **operates in every cell cycle to monitor whether cell ready to enter anaphase or not

cohesion

in anaphase I, cohesion is removed from the chromosome arms and not from the regions near the centromere

What are the two processes in meiosis that create genetic differences among cells?

independent assortment and crossing over

As proliferating precursor cells move away from the stem cell population they are

induced to terminally differentiate as Goblet or absorptive cells within the villus. (Other precursor cells migrate downward and adopt a different fate known as Paneth cells).

what does clathrin do

induces the budding off of vesicles from the plasma membrane. it causes buckling of the membrane due to its shape, forming pits in the membrane which assist in receptor mediated endocytosis. receptors lie in the pits and are transported along with their cargo into the cell. the actual budding off is due to dynamin.

The normal function of Rb is to:

inhibit Ef2

The normal function of the tumor suppressor protein Rb is to

inhibit progression through the G1 restriction point.

Ced-9 functions directly to _______ Ced- _______.

inhibit; 4

Angiogenesis inhibitors are useful for inhibiting tumor growth because

inhibiting angiogenesis prevents growing tumors from developing a blood supply, thereby starving tumor cells.

Grim and Reaper act by _______ the activity of _______.

inhibiting; inhibitors of apoptosis (IAPs)

blastulation

initiated during early cleavage stages and results in the formation of the blastula

Describe how single pass TM proteins are inserted into ER membrane (internal signal sequence)

internal start-transfer sequence -we doNOT need stop-transfer sequence bc this serves as anchor itself) positively-charged aa cluster, upstream if the start-transfer sequence (NH2 side) -causes this region to remain on cytoplasmic side, while hydrophobic start-transfer sequence and C-terminus are passed across membrane

In what phase of cell cycle does the DNA chromatin become visible?

interphase

midbody is made up of

interpolar microtubules which act like a tether between the daughter cells

To establish cell polarity, locally activated receptors initiate an

intracellular signaling pathway.

Ndc80 complex

is anchored in the kinetochore at one end and interacts with microtubules at the other, thereby, linking the microtubules to the kinetochore but still allowing instability at the plus ends

second major step in spindle formation

is the attachment of the array to kinetochores

what does clathrin do?

it coats vesicles as they bud off from the plasma by fxming invaginated pits on the in Clathrin performs critical roles in shaping rounded vesicles in the cytoplasm for intracellular trafficking. Clathrin-coated vesicles (CCV) selectively sort cargo at the cell membrane, trans-Golgi network, and endosomal compartments for multiple membrane traffic pathways During the first steps of endocytosis, clathrin-coated pits are internalized to form clathrin-coated vesicles which transport proteins from organelle to organelle.

what is the function of lysosomes in receptor mediated endocytosis

it fuses whit vesicles containing LDL particles and digest the particle

what is the function of lysosomes in receptor mediated endocytosis

it fuses with structures containing LDL particles and digests the particle

How does familiar hypercholesterolemia promote development of atherosclerosis?

it involves mutations that affect the LDL receptors. this causes LDLs and the cholesteryl esters within now to be transported properly and removed through receptor mediated endocytosis. This causes too much LDL to accumulate in the blood, which can increase the risk of blood clots.

Polar microtubules

keep the spindles separated.

the major intermediate filaments in epithelial cells are made of

keratin

the major intermediate filaments in epithelial cells are made of _________

keratin

The intermediate filaments in epithelial cells are made of

keratins

the intermediate filaments in epithelial cells are made of

keratins

The GTP-binding protein Cdc42 is a

key regulator of the polarity program in many systems.

Flow of vesicles from the ER to the Golgi involves all of these structures EXCEPT __________.

kinesin

3 types of kinesins

kinesin-5 kinesin-14 kinesin-4/10

Which phase of microtubule polymerization in vitro would be affected most by adding short microtubules to unpolymerized GTP-tubulin?

lag phase

For a cancerous tumor to move from tissue to tissue in metastasis, which proteins of the basal lamina must it be able to degrade or pass through?

laminins and type IV collagen

the intermediate filaments in the nucleus are made of keratins lamins desmin none of the above; intermediate filaments are all cytosolic

lamins

a major mitogenic pathway acts through the monomeric GTPase Ras, which

leads to the activation of a mitogen-activated protein kinase (MAP kinase)

Which of the following could you use experimentally to help you determine which carbohydrates are present on a cell's surface?

lectins

the morphological changes that occur during homolog pairing are the basis for dividing meiotic prophase into 5 stages

leptotene zygotene pachytene diplotene diakinesis

Transient amplifying cells: Produce

lineage-restricted progenitor cells - Divide and produce specific differentiated cells Cannot undergo self-renewal divisions

where is smooth ER found

liver (detoxification) and muscle cells (SR)

What triggers assembly and contraction of the contractile ring

local activation of RhoA

Intestinal epithelium turns over every 3-5 days. Intestinal epithelial cells are

lost constantly and must be replaced by stem cells.

Cell polarity determinants -

mRNAs, proteins, and lipids:

The intestinal epithelium generates

macrovilli - long protrusions into the lumen of the gut in order to increase surface area.

the inner compartment of mitochondria is called the

matrix

the mitochondrial protein pre-sequence is cleaved off by a protease called

matrix-processing protease

fetal growth

maturation of developing organ systems and anatomical structures; terminated by birth

Phosphorylation of the Golgi matrix proteins by Cdk1 during mitosis

mediates breakdown of the Golgi apparatus into vesicles.

During which type of cell division does each daughter cell contain half the amount of DNA as did the cell just prior to cell division?

meiosis 1, meiosis 2, and mitosis

central components of the cell cycle control system are

members of a family of protein kinases known as Cdks

Polarized cytoskeleton transports

membrane-trafficking organelles and macromolecular complexes including fate and polarity determinants to one end of cell.

During which phase of meiosis do homologous chromosomes line up at the metaphase plate?

metaphase 1

During which phase of meiosis does independent assortment occur?

metaphase 1

When a Xenopus oocyte is stimulated with the hormone progesterone, it enters meiosis and arrests at ______, awaiting fertilization by a sperm.

metaphase II

translation-translocation in vitro system consists of isolated mRNA, ribosomes, microsomes. Mostly short chain IgG light chains produced. If complete, oversized light chains added AFTER microsome, signal sequence is not cleaved, why?

microsome must be added before first 70 amino acids are polymerized in order for protein to be processed in microsome proteins must be translated during translation (co-translation)

TCA cycle takes place in

mitochondria matrix

Proapoptotic proteins stimulate

mitochondria to leak proteins, mostly cytochrome c

A signal sequence on the polypeptide chain targets all but _________ proteins ro the rough ER surface

mitochondrial

3 major classes of extracellular signal molecules that regulate cell growth, division, and survival

mitogens growth factors survival factors

Cell polarity determinants - mRNAs, proteins, and lipids: asymmetrically localized in

mother cell

what drives centrosome separation

motor proteins

you need to visualize p53 protein in cells. Your primary antibody was raised in mice. your secondary antibody was raised in rabbits. HRP - is an enzyme that breaks down H2O2 with the production of a colored product. Your cells should be incubated with the following antibodies.

mouse anti-p53 antibody followed by HRP- conjugated rabbit anti mouse antibody.

Most animal stem cells are

multipotent and can undergo symmetric or asymmetric self-renewal divisions.

Sox2 expressed in

multipotent neural stem cells that give rise exclusively to neuronal and glial cell types

Most tissue type contain populations of undifferentiated self-renewing cells known as

multipotent stem cells (referred to as tissue-specific stem cells or adult stem cells).

which cells can remain in G0 for forever

muscle cells, nerve cells

Cell fate determinants

must be deposited at one side of the cell that will divide

accumulated mutations lead to

mutations in the p53 gene results in loss of p53 function mutation of ATM

Commitment point

near the end of G1 known as "start"

Crossing over results in?

new genetic combination

after chromosomes visible under the microscope during interphase? yes or no

Crossing over occurs between?

nonhomologous chromosome

Crossing over occurs between?

nonidentical sister chromatids

apoptosis is crucial for

normal development

microtubules

not all associated with a centrosome

These are distinct from embryonic pluripotent stem cells in that they are

not capable of generating any type of differentiated cell type. Their developmental potential is restricted by the expression of tissue-specific sets of transcriptional regulators and they can produce a limited number of cell types, specific to the tissue in which they reside.

What DOES NOT happen during interphase in the cell cycle?

nuclear divison

the completion of spindle assembly in animal cells require

nuclear-envelope breakdown

y-tubulin complex which is responsible for

nucleating microtubules

what determines sides of N and C termini in multipass TM proteins?

number and position of start and stop transfer sequences

centrosome maturation is when the

number of y-tubulin ring complexes increases and therefore increases the ability of centrosome to nucleate new microtubules.

Bax and Bak act by oligomerizing with Apaf-1 to block an apoptotic signal. interacting with Ced-9 to initiate a proapoptotic signal. interacting with Apaf-1 to initiate a proapoptotic signal. oligomerizing in the mitochondrial outer membrane, forming pores that release cytochrome c.

oligomerizing in the mitochondrial outer membrane, forming pores that release cytochrome c

Prevention of new preRC assemblies ensures replication occurs

once during the cycle

S-Cdk initiates DNA replication ....

once per cycle

cell-cycle control system

operating like a timer, it is programmed to provide a fixed amount of time for the completion of each cell-cycle event

Apoptosis is an

ordered process involving cell shrinkage, loss of adhesion to other cells, dissection of chromatin, and engulfment by phagocytosis.

polar microtubules

overlap in the center of the spindle.

What three events occur during the light reactions of photosynthesis

oxidation of water, reduction of NADP+, formation of ATP

what three events occur during the light reactions of photosynthesis?

oxidation of water, reduction of NADP+, formation of ATP

during cellular respiration, carbon atoms (from glucose) are________ as they lose energy

oxidized

peroxisomes contain the enzyme

peroxin

apoptotic cells are cleared by

phagocytosis

which of the following movements is not tubulin related?

phagocytosis

CDC25

phosphatase that removes the inhibitory phosphate on Tyr-15. It activates CDK.

To prevent cells with unreplicated DNA from passing through the G2 checkpoint, Chk1 and Chk2 _______ and _______ protein phosphatase Cdc25.

phosphorylate; inhibit

When in the absence of or low tension, Aurora-B...

phosphorylates several components of the microtubule attachment site which decreases the sites affinity for a microtubule plus end

DNA damage leads to

phosphorylation of p53, which dissociates from Mdm2, and thus it can stimulate gene transcription that leads to cell cycle arrest

Cell activity can be suppressed in 2 ways

phosphorylation of the Cdk subunit Binding of Cdk inhibitor proteins

which step is the beginning of photosynthesis

pigments in photosystem II absorb light

receptor-mediated endocytosis is a form of

pinocytosis

which of the following is a protein that can link intermediate filaments with actin filaments and microtubules

plakins

Annulus

plasmodesmata

desmosomes

plasmodesmata

Found exclusively in plant cells.

plasmodesmata (P)

Fibroblasts are stimulated to exit G0 and proliferate by _______ growth factor.

platelet derived

first mitogen identified

platelet-derived growth factor (PDGF)

which of the following is a protein that can link intermediate filaments with actin filaments and microtubules

plektin

Embryonic blastocyst inner mass cells are

pluripotent and give rise to all differentiated cell types of the organism.

SSEA-1 (CD15) is a marker that can be used to identify which type(s) of cells?

pluripotent stem cells (embryonic or induced)

plus ends are embedded in the

plus ends of kinetochore microtubules with the help of the Ndc80 complex

Describe how multipass TM proteins are inserted into ER membrane

polypeptide chain passes back and forth repeatedly across the lipid bilayer as hydrophobic alpha helices so hydrophobic internal start-transfer sequence opens translocator last hydrophobic stop-transfer sequence stops translocation

The APC works by

polyubiquitinates specific target proteins, resulting in their destruction in proteosomes.

Cell polarity determinants - mRNAs, proteins, and lipids: mitotic spindle

positioned so that polarity determinants are segregated differentially into daughter cells during cell division

CapZ

prevents assembly and disassembly at microfilament plus ends.

Smooth ER

primary site of ER vesicle budding, transitional zones in specialized cells the SER is involved in lipid metabolism, and steroid biosynthesis (so cholesterol is abundant here bc it is precursor) detoxification of lipid soluble drugs (ex. liver and alcohol)

Cell fate depends on the balance between

pro- and anti-apoptotic signals regulated by Bcl-2 family proteins.

blastula

produced by cleavage of the fertilized ovum to produce a spherical layer of cells with a large fluid filled space (blastocoel); leads to the formation of the blastocyst.

Start

progression beyond this point that is governed by ser/thr protein kinase

external signals can also inhibit

progression through the cell cycle

M-Cdk initiates spindle assembly in

prophase

During which phase of meiosis does crossing over occur?

prophase 1

progression through metaphase to anaphase is triggered by

protein destruction

Studies on cell cycle mutants in budding and fission yeasts demonstrated that cdc2 and cdc28 both encode a

protein kinase

tension sensing mechanism depends on the

protein kinase Aurora-B

Biosynthetic pathway -

proteins and lipids destined for the apical and basolateral domains - sorted in the Golgi complex and transported to their respective surfaces

microtubule bipolarity is essential in order to

pull the sister chromatids apart

+4 stem cells are

quiescent stem cells ("back up" stem cells)

you are using mouse anti-P53 antibody. which of the secondary antibodies would you use to detect your primary antibody

rabbi anti-mouse

astral microtubules

radiate out from the poles into the cytoplasm

The most frequently encountered oncogene in human tumors is

ras

phosphorylation of Rb proteins

reduce their binding affinity to E2F

during photosynthesis, carbon atoms (from glucose) are (oxidized/reduced) as they gain energy

reduced

during photosynthesis, carbon atoms from carbon dioxide are _________ as they gain energy

reduced

when bi-orientation occurs, the resulting tension

reduces phosphorylation by Aurora-B, thereby increasing the affinity of the attachment site.

Back-to-back orientation of kinetochores

reduces the likelihood that both kinetochores can face the same spindle pole

Cytokine types and amounts -

regulate HSC self-renewal divisions and proliferation and differentiation of the precursor cells for various blood-cell lineages

G1-Cdks

regulate early G1 events

Endocytic pathways -

regulate protein and lipid abundance and sorting on each surface by transcytosis

The viral raf oncogene produces a constitutively active protein because the

regulatory domain has been replaced by viral sequences and the protein cannot be turned off.

What happens to the ER?

remains largely intact and is cut in two

Addition of ATP to isolated axonemes causes localized bending. What can be done to the isolated axonemes to cause the outer doublets to slide past each other unrestrained, lengthening the overall structure instead of causing bending?

remove the interdoublet nexin links

glycosidase

removes sugars through hydrolysis of glycosidic bonds

In adult organisms, cell death must be balanced by cell

renewal

The G2 cell cycle checkpoint detects chromosome misalignment. the binding of the MCM proteins to origins of replication. unreplicated or damaged DNA. levels of p53.

replicated or damaged DNA

Klf4

represses p53: repression of p53 promotes proliferation

in the absence of mitogens,

retinoblastoma protein (Rb) binds to E2F factors which block transcription of S phase products

The RNA viruses that most commonly pick up cellular oncogenes are the

retroviruses

Secretory Pathway

rough ER --> golgi --> secretory vesicles --> cell exterior. - not limited to proteins destined for secretion. - plasma membrane, nuclear envelope, peroxisomal and lysosomal proteins travel from ER--> golgi and then to their final destinations. - proteins destined to remain in the cytosol or to be incorporated into mitochondria, chloroplasts, or the interior of the nucleus or peroxisomes are synthesized on free ribosomes and released into the cytosol when their translation is complete.

In muscle cells, calcium is being released from the _______ and interacts with ______ complex shifting the position of the complex and exposing _______ binding sites on ________

sarcoplasmic reticulum, troponine/tropomyosin , myosin, actin filaments.

The stem cells of skeletal muscle are called

satellite cells

what happens to secretory protein if we add protease:

secretory proteins have to pass through ER first before being secreted inside microsome: protected by microsome and NOT digested outside microsome: digested

2 major targets of the APC

securin (seperation of sister chromatids) S- and M-cyclin (depo4 of many proteins from S phase to early mitosis)

Transient amplifying cells: Divide rapidly and undergo limited

self-renewal divisions

Growth signals within the crypt maintain the stem cells as

self-renewing and non-differentiated.

the APC/C complex initiates sister-chromatid

separating by ubiquitylating several mitotic regulatory proteins

the carrier molecules nicotinamide adenine dinucleotide (NAD) and flavin adenine dinucleotide (FAD) are important in cellular respiration because these molecules can:

serve as transporters and short- term storage sites for high energy electrons

The carrier molecules nicotinamide adenine dinucleotide (NAD) and flavin adenine dinucleotide (FAD) are important in cellular respiration because these molecules can

serve as transporters and short-term storage sites for high energy electrons

what is a cellular function of pericitrin

serves as an anchor for proteins and protein complexes in the cell

the kinetochores initially bind to the ____, but then,

side of microtubules the plus ends of the microtubule captures the kinetochores in the correct end-on oreintation

Cancers initiate from a

single cell

success of mitosis demands that

sister chromatids attach to opposite poles of the mitotic spindle (bi-orientation)

unipolar kinetochore attachment

sister kinteochores in a homolog must attach to the same spindle pole

Rough ER

site of protein synthesis, maturation, and transport primary site of protein synthesis of ALL integral transmembrane proteins and "soluble" secreted proteins studded with ribosomes

An autoimmune disorder in which an immune response targets Type V collagen fibers is most likely to affect the

skin

What controls opening and closing of Sec61? Closed vs Open

small alpha helix plug Closed: plug in channel core Open: plug displaced from channel core, growing polypeptide chain in core, signal peptide in lateral seam

microsome

small versions of ER, retain functionality of ER

Which of the following is most likely to increase the likelihood of contracting cancer?

smoking a pack of cigarettes a day

Glicerol phopholipids are synthesized in _________ from ____________ and ________________

smooth ER, fatty acids, glycerol-3- phosphate

differentiating between smooth and rough microsomes

smooth microsomes: (top) have low density and stop sedimenting and float at low sucrose concentration -difficult to distinguish smooth ER rough microsomes (bottom): have high density and stop sedimenting and float at high sucrose concentration

Why is a halt in protein synthesis necessary?

so we can have co-translational translocation ensures ribosome has enough time to get to ER we dont want protein to start folding yet

Induced pluripotent stem (iPS) cells can be formed from

somatic cells by expression of combinations of key transcription factors.

in multicellular organisms, tissue/organ formation and cell replacement depends on

specific patterns of mitotic cell divisions

lipid rafts are clusters of _____________ and _____________

sphingolipids, cholesterol

Apoptotic cell death occurs without

spilling cellular contents to prevent inflammation, compared to necrosis.

The stem cell niche provides the appropriate source of signals to maintain

stem cells in their proliferative and self-renewing state.

What are the substrates for MPF?

still an active area of research. MPF phosphorylates: 1. Proteins required for chromosome condensation 2. Microtubule binding proteins (phosphorylated and disassociates from the MTs which increases dynamic instability) 3. Nuclear lamins, which leads to nuclear envelope breakdown 4. Other proteins that become ACTIVE during M phase. NOT ALL ENZYMES HAVE A SINGLE KINASE. MPF is an enzyme that binds a specific recognition sequence, this kinase can phosphorylate these multiple substrates.

growth factors

stimulate cell growth by promoting protein and macrolide synthesis

damage ends of chromosomes (due to shortening of telomeres)

stimulate p53 leading to sensence and death

M-Cdk stimulates ______ of microtubules by inhibitory phosphorylation of ____

stimulates instability phosphorylation of motor proteins

p53

stimulates trascription of p21

mitogens

stimulation cell division by triggering a wave of G1/S-Cdk activity

the calvin cycle takes place in the

stroma

Cohesin is made up of

structural maintenance of chromosomes (SMC) proteins

survival factors

suppress apoptosis

Antiapoptotic proteins promote

survival.

Cells undergoing necrosis or necroptosis (uncontrolled cell death) exhibit very different morphological changes:

swell and burst release intracellular contents that can damage surrounding cells and cause inflammation

instability of microtubules just means

switching between shortening and lengthening

Mutations that lead to overexpression of Ras and Myc can promote

the development of cancer

Attachment of sister-chromatid pairs to the spindle requires the removal of

the double membrane barrier of the nuclear envelope

Most cellular lipids are synthesized in

the endoplasmic reticulum

What drives ATP synthesis by ATP synthase?

the harnessing of the energy release that occurs by the flow of H+ back through the ATP synthase, to relieve the H+ gradient, to reach an equilibrium on both sides of the membrane- chemiosmosis. The released energy is used to synthesize higher energy ATP from ADP.

early prophase I of meiosis

the homologs begin to associate along their length via complementary DNA sequences

Mammalian embryonic stem cells are cultured from cells taken from

the inner cell mass

Organogenesis

the process by which the ectoderm, endoderm, and mesoderm develop into the internal organs of an organism

Signal Hypothesis by Blobel

the short N-terminal sequence of the nascent secretory polypeptide chain, now dubbed signal sequence, would be recognized by cellular recognition factors and would be targeted to the ER, where it would open a protein-conducting channel in the ER. nascent membrane proteins would contain a signal sequence to initiate translocation and a subsequent "stop transfer sequence" that would open the protein conducting channel laterally, toward the lipid bilayer, yielding integration of the nascent transmembrane protein into the lipid bilayer. Hence the asymmetric integration of membrane proteins into the lipid bilayer is not a "spontaneous" event but is catalyzed and dictated by sequence elements of the membrane protein that are decoded by the protein conducting channel

the SNARE hypothesis states that

there are two protein complexes- V-SNARE and T-SNARE on the transport vesicle and the target membrane respectively. their function is to assist the vesicle in finding its proper target membrane.

Myc

thought to promote cell cycle entry by stimulating genes that increase G1-Cdk activity and increase cell growth

Claudins

tight junctions

Which of these cell junctions form a barrier to the passage of materials?

tight junctions

Sites of membrane fusion are limited to abutting ridges of adjacent membranes. Seal membranes of two adjacent cells tightly together.

tight junctions (T)

APC/C is activated by binding

to Cdc20

In addition to testing shmoo formation in the two mutant strains of yeast, the scientists also tested shmoo formation in wild-type yeast. What is the purpose of including wild-type yeast cells in the experiment?

to show normal shmoo formation under the experimental conditions

LGR5+ cells are the main multipotent stem cells and give rise to

transient-amplifying cells.

Intestinal stem cells may give rise to all of the following terminally differentiated cell types in the intestinal epithelium except _______ cells.

transit-amplifying

When stem cells of the intestinal epithelium and epidermis divide, they give rise to two different cells: one stem cell and one _______ cell.

transit-amplifying

when a striated muscle is stimulated to contract, calcium is and interacts with a group of three thin filament proteins called the ___ which in turn causes the long, thin protein __ to move away from cross-bridge binding sites on the ___ molecules. this allows the cross-bridge cycle to occur

troponin tropomyosin complex , tropomyosin, actin

when a striated muscle is stimulated to contract, calcium is released and interacts with a group of three thin-filament proteins called the ______________, which in turn cause the long, thin protein _________ to move away from the cross-bridge binding sites on the ___________ molecules. this allows the cross-bridge cycle to occur

troponin-complex, tropomyosin, actin

The spindle assembly checkpoint monitors the alignment of chromosomes on the mitotic spindle.

true

true/false mitochondrial DNA are similar to the ones of bacteria

true

true/false the electron flow from photosystem I mostly produces NADPH

true

Loss-of-function mutations can be oncogenic if the mutant gene codes for a

tumor suppressor protein

Some cells reposition their spindle to divide asymmetrically to produce

two cells that differ in size or in the cytoplasmic contents they inherit.

asymmetric cell division

two daughter cells may differ in size, shape, protein composition, gene expression and have different fates

asymmetric cell division yields

two different types of daughter cells with different fates

The progression from metaphase to anaphase results from phosphorylation mediated by Cdk2. ubiquitin-mediated proteolysis of key regulatory proteins. activation by Wee1. phosphorylation mediated by Polo-like kinase.

ubiquitin-mediated proteolysis of key regulatory proteins.

Proposed model of unattached kinetochores

unattached kinetochores stimulate a conformational change of Mad2 so that Mad2 can bind and inhibit Cdc20-APC/C

Explain role of glycosylation in protein folding

unfolded glycosylated protein inside ER undergoes glucose trimming, and is left with one glucose monomer this monomer at the end of protein associates with calnexin, and is held there glucosidase removes this terminal glucose either: 10% looks good and is able to exist ER 90% improperly folded/incomplete, and is sent through a another round with glycosyl transferase

3 features of meiosis I that distinguish it from mitosis

unipolar kinetochore attachment crossing over cohesion

The pattern of cell replacement varies from one tissue to another and for each tissue

unique physical locations, known as the stem cell niche, house the stem cells.

embryonic stem cells therapeutic affect

using such knowledge to develop treatments for injury or loss of cell types

What happens to mitochondria and chloroplasts

usually present in large enough numbers to be safely inherited

quality control in retrotranslocation

very strict, makes sure right proteins are sent out fails in diseases like CF, where CFTR protein is sightly misfiled, but gets rapidly degraded because of very strict quality control (if it got to plasma membrane, it would function)

intermediate filaments in fibroblasts are polymers of

vimentin

Cell cycles of early embryonic animal cells are unusual because they have

virtually no G1 or G2.

dyneins

walk towards the minus end

kinesins

walk towards the plus end

simplified view of protein translocation in ER

we have to have ribosomes associate with translator bc this is co-translational translocation as ribosome is associated with translocator, the signal sequence remains attached to the same part of the translocator as the polypeptide chain grows signal peptidase is associated with translocator, and cleaves signal peptide in membrane to yield a mature polypeptide chain in the ER lumen -signal sequence stays in membrane -translocator closes

leptotene

when homologs condense, pair, and genetic recombination begins

nondisjunction

when homologs faily to separate properly, leading to an abnormal amount of chromosome

When is SRP and its receptor released from ribosome complex?

when nascent protein attached ribosome transfers from SRP to membrane translocator -here, translation continues and translocation begins GTP hydrolysis drives the disassembly and recycling of SRP and SRP receptor through conformational changes

pachytene

when the assembly process is complete and the homologs are synapsed along their entire lengths

Diakinesis

when the separation of homologous chromosomes is complete and crossing over has occurred

diplotene

when the synaptomeal complex disassembles and the chromosomes condense and shorten the homologs at this point are held together by inter homolog connections known as chiasmata

zygotene

when the synaptonemal complex begins to assemble at sites where the homologs closely associate.

"If mammalian cells were grown in the absence of growth factors, the cells would most likely:"

would remain in G0

found in the matrix of the pericentriolar matrix is the

y-tubulin ring complex

is genetic material (i.e, chromatin) visible under the light microscope during interphase? yes or no

yes

Which of the following is true about the structure of the microtubule wall?

α-β-tubulin heterodimers are arranged with the same orientation in each protofilament, and protofilaments are arranged with same polarity in the microtubule wall

Mechanism 2: Controlled degradation of cyclins

• Highly controlled, precisely timed, protein degradation (proteolysis)

Glycoprotein Folding by Calnexin

- As the glycoprotein exists the translocon, 2 glucose residues are removed, allowing calnexin to bind and assist in folding. - removal of the remaining glucose residue terminates the interaction with calnexin, releasing a glycoprotein. - a protein folding sensor then assesses the extent of folding of the glycoprotein by monitoring exposed hydrophobic regions. If none are found, the glycoprotein is correctly folded and proceeds to exit the ER. - If the glycoprotein is incorrectly folded, the folding sensor (a glucosyltranferase) will add back a glucose residue, allowing the glycoprotein to again bind calnexin for another attempt at correct folding. - If there are too many hydrophobic regions exposed and the protein cannot be properly folded, it is recognized by EDEM1 which removes mannose residues (from oligosaccharide). - this prevents the protein from being bound by calnexin and the protein is targeted back to the cytosol through a ubiquitin ligase complex in the ER membrane. - ubiquitylated at the cytosolic side of this complex and degraded in the proteasome.

Co-translational Pathway

- association of the ribosome-mRNA complex with the ER - ribosomes are targeted for binding to the ER membrane by the amino acid sequence of the polypeptide chain being synthesized, rather than the intrinsic properties of the ribosome itself. - free and bound ribosomes are functionally indistinguishable - protein synthesis usually initiates on ribosomes that are free in the cytosol. - ribosomes engaged in the synthesis of proteins destined for secretion are targeted to the ER by a signal sequence at the (N)-terminus of the growing polypeptide chain.

Integral / Trans-Membrane Proteins

- embedded in the membrane by hydrophobic sequences that span the phospholipid bilayer. - membrane-spanning portions of these proteins are usually a-helical regions (20-25 hydrophobic amino acids). - a-helixes maximize hydrogen bonding between peptide bonds and the hydrophobic amino acid side chains interact with the fatty acid tails of the phospholipids in the bilayer. - can span the membrane multiple times. - inserted into the ER membrane via SRP/Sec61 co-translational pathway. - many are directly inserted into the membrane by internal transmembrane sequences that are recognized and brought to the translocon by SRP, but not cleaved by signal peptidase. - transmembrane a-helices exit the translocon laterally and anchor proteins in the ER membrane. DIAGRAMS: p.408/9

Quality Control in the ER

- many proteins synthesized in the ER are rapidly degraded because they fail to fold properly; protein folding in the ER is slow and inefficient. - mis-folded proteins are removed from the ER by a process called ER-associated degradation (ERAD). - mis-folded proteins are identified, returned to the cytosol, and degraded by the ubiquitin-proteasome system. - chaperones and protein processing enzymes in the ER lumen often act as sensors of mis-folded proteins. - Calnexin = ER lumen - Calreticulin = ER membrane - both recognize partially-processed oligosaccharides (2 residues removed)

Vesicular Transport From the ER to the Golgi

- proteins and lipids are carried from the ER to the Golgi in transport vesicles that bud from ER exit sites (ERES), fuse to form the vesicles and tubules of the ER-Golgi intermediate compartment (ERGIC), and then are carried on to the Golgi. - lumenal ER proteins targeted for the Golgi are bound by transmembrane proteins that are selectively packaged into vesicles. - resident ER proteins (destined to remain) are marked by KDEL retrieval sequences at their (C)-terminus. * Transmembrane proteins that are targeted for transport from the ER to the Golgi have a variety of peptide and carbohydrate signals that direct their packaging into transport vesicles at ER exit sites. *Topological orientation is maintained during transport. *Unmarked proteins in the ER can also be packaged into vesicles and transported to the Golgi by a default pathway which does not require specific signals for protein packaging.

List steps involved in translocation of soluble protein to ER lumen (include start transfer signal)

1) Er signal sequence binds to a specific binding site in the pore -serves as the start-transfer signal that opens the pore and starts translocation 2) signal sequence remains bound to Sec 61 complex during translocation 3) 4) signal peptidase cleaves signal sequence, mature protein released into lumen -alpha helix plug closes translocator

process from emerging ER sequence to translocation in membrane

1) SRP binds to signal sequence emerging from ribosome on both ends 2) conformational change in SRP exposes a binding site for SRP (on ER membrane) -allows SRP to associate with SRP receptor -allows ribosome to be brought to membrane 3) SRP-ribosome complex is brought to unoccupied translocator

Advantage of Sea Urchin

1. Can fertilize eggs in a petri dish 2. Synchronous and cleavage division: undergoing cell division to create smaller and smaller cells. Cells don't grow before division.

Advantage of Xenophus

1. Can fertilize eggs in petri dish 2. Synchronous division: all the cells are undergoing cell division at the same time. When one cell is in M phase, they all in M phase. Useful for isolating molecules involved in M phase. 1mm. Can see with naked eye. Can generate large extracts of them.

How does cohesin hold the sister chromatids together?

1. Embrace model: most popular. Cohesin holds sisters in the ring. 2. Handcuff model: one sister in one ring, another sister in another ring. The two rings are held together.

Phases of Mitotic Cell Division in correct order:

1. G0 2. G1 3. S 4. G2 5. Prophase 6. Metaphase 7. Anaphase 8. Telophase 9. Cytokinesis

phases of meiosis in order

1. G0 2. G1 3. S 4. G2 5. Prophase 1 6. Metaphase 1 7. Anaphase 1 8. Telophase 1 9 Cytokinesis 1 10. Prophase 2 11. Metaphase 2 12. Anaphase 2 13. Telphase 2 14. Cytokinesis 2

What is the biochemical basis of MPF activity?

1. Going through cleavage divisions, saw protein called cyclin they could see early on, then disappeared. Named it cyclin, since it was cycling during cell cycle. Cyclin activity correlates with MPF activity.

3 Signalling Molecules of UPR

1. IRE1 (only sensor in yeast) results in cleavage and activation of the mRNA encoding a transcription factor called XBP1 on the cytosolic side of the ER membrane. - this factor then induces expression of genes involved in the unfolded protein response, including chaperones, enzymes involved in lipid synthesis, and ERAD (ER-associated degradation) proteins. 2. ATF6 (transcription factor) - unfolded proteins signal the transport of ATF6 to the Golgi, where it is cleaved to release the active form of ATF6 into the cytosol. -It then translocates to the nucleus and induces the expression of additional unfolded protein response genes. 3. PERK - protein kinase that phosphorylates and inhibits translation initiation factor eIF2, resulting in a general decrease in protein synthesis, and a reduction in the load of unfolded proteins entering the ER. - eIF2 inhibition leads to the preferential translation of some mRNAs and transcription factor ATF4. DESCRIPTION: p417.

Job of controller

1. Make events happen 2. Allow events to happen once 3. Make sure events happen in right order

Putting together G and S Pathways Together

1. Mitogen binds to Receptor Tyrosine Kinase, which initiates Signal Transduction Pathway. 2. Transcription of G1 cyclins and G1 CDKs, which associate with one another. 3. Rb is substrate of G1 Cyclin-CDK. Rb bound to transcription factor E2F (keeps txn inactive and prevents progression of G1). 4. G1 cyclin-CDK becomes active and phosphorylates Rb. 5. Rb undergoes conformational change and lets go of E2F. 6. E2F active, and promotes the transcription (DNA copied into RNA) of the G1/S Cyclin-CDK protein, and S phase Cyclin-CDK. 7. These transcripts become translated into proteins. As soon as S phase Cyclin-CDK complex forms, p27 (CDK inhibitor) binds to the complex. 8. Enough G1-S Cyclin-CDK activity phosphorylates p27 targets p27 to become a substrate of SCF. 9. SCF ubiquitinated p27 and targets it for degradation 10. p27 degraded = active S phase Cyclin-CDK. 11a. Allows entry into S phase = origin fires and DNA replication begins. 11b. Phosphorylates CDC6, targeted to SCF for ubiquitination and degradation = prevention of firing more than once.

How does MPF become activated?

1. Mitotic cyclin synthesis. 2. As cyclin synthesizes, it associates with the CDK subunit. MPF still inactive. 3. Once cyclin associates with CDK, there are 2 diff. kinases that phosphorylate the CDK subunit: -WEE1: adds an inhibitory phosphate group, has Tyrosine15 (Y15) as its substrate -CAK (CDK Activating Kinase): adds activating phosphate, its substrate is T161 (tyrosine161) 4. Phosphatase Cdc25 removes Tyrosine 15 and activates MPF

Key Parts of Controller

1. Proteins that rise and fall with stages of cell cycle 2. Regulated degradation of proteins 3. Regulated phosphorylation and dephosphorylation 4. Regulation of inhibitor proteins

Purification of MPF to discover CDK

1. Purified MPF by running 6 diff chromatographic columns 2. Assayed fractions for activity (injecting into G2 oocyte and seeing if undergo M phase). 3. SDS-PAGE of fractions from final column. 4. In fraction 12, 85% of oocytes broke down nuclear envelope, condensed chromosomes, built spindle. They entered M phase. The proteins on the column: 1. MPF 2. Cyclin: the larger protein 3. CDK: Cyclin-Dependent Kinase. The kinase only active when bound to cyclin protein.

G1-S Signal Pathway

1. Signal (Growth Factor/Mitogen) binds to the receptor and activates the signal transduction pathway. 2. G1 cyclins and G1CDKs become transcribed. 3. G1-CDK associated, are phosphorylated and activated. Rb is G1-CDK substrate. 4. When G1-CDK phosphorylated, Rb is phosphorylated as well. Rb undergoes a conformational change & lets go of the transcription factor, E2F. Rb inactivated. 5. Now, Active E2F promotes the expression of proteins required for DNA replication, including G1/S & S phase cyclins and CDKs. Phosphorylation of Rb is necessary for cell to pass the Restriction Point and enter S phase.

(STEPS) Post-translational Targeting of Secretory Proteins to the ER

1. Signal sequences are recognized by the Sec62/63 receptor protein complex associated with the translocon in the ER membrane. 2. Cytosolic Hsp70 and Hsp40 chaperones are required to maintain the polypeptide chains in an unfolded confirmation so they can enter the translocon. 3. BiP pulls the polypeptide chain through the channel and into the ER by binding to it. This prevents it from sliding backwards. - coupled t o ATP hydrolysis (ATP --> ADP)

How was the controller discovered?

1. Take cytoplasm from a Xenophus M phase cell. Embryos undergo synchronous mitotic division. 2. Inject cytoplasm into oocyte (that is in G2). 3. G2 Oocyte now enters M phase. We can see using microscope that the oocye is in G2 since chromosomes condensed, nuclear envelope has broken down, the spindle has assembled. We then assay for entry in M phase. If inject cytoplasm from an interphase cell into the G2 oocyte, nothing happens. The oocyte doesn't enter M phase. This tells us that there's an MPF, M-phase Promoting Factor in the cytosol that can trigger the G2-M transition.

Insertion of Membrane Proteins

1. W/ internal transmembrane sequences - transmembrane sequence directs insertion of the polypeptide such that its amino (N) terminus is exposed on the cytosolic side. - transmembrane sequence exits the translocon to anchor the protein in the lipid bilayer (laterally) and the remainder of the polypeptide chain is translocated to the ER as translation proceeds. 2. W/ cleavable signal sequences and ITS - signal sequence is cleaved as the polypeptide chain crosses the membrane, so the (N) terminus of the polypeptide chain is exposed in the ER lumen - translocation of the polypeptide chain across the membrane is halted when the translocon recognizes an internal transmembrane sequence. - protein exists the translocon laterally and becomes anchored in the ER membrane. - continued translation results in a membrane-spanning protein with its (C) terminus on the cytosolic side. 3. Some proteins with a transmembrane sequence at their (C)-terminus are inserted into the ER membrane by an alternative post-translational pathway. These proteins cannot be recognized by the SRP because their (C)-terminal domain does not emerge from the ribosome until translation is terminated and the completed polypeptide chain is released from the ribosome. - domains of proteins are recognized by a targeting factor (TRC40 or GET3) once translation is complete. - TRC40 then escorts the protein to the ER membrane, where it is inserted via the GET1-GET2 receptor.

Let 12n represent the amount of DNA present in a somatic cell of a eukaryotic organism. How much DNA would you expect to find in a somatic cell in G0?

12n

How would expression of siRNA targeted against 14-3-3 proteins affect apoptosis?

14-3-3 proteins sequester proapoptotic proteins in an inactive state, so cells expressing siRNA against 14-3-3 proteins will therefore have an increased rate of apoptosis.

"In a cell with 8 chromosomes, how many total sister chromatids are visible at the beginning of mitosis?"

How many chromosomes do cabbage plants (somatic cells) have?

each centriole is comprised of _____________ of microtubules

9X3+0

the microtubules of centrioles are organized in a characteristic ____________ pattern

9x3+0

Cdks bind to cyclin and are activated by a. phosphorylation by Wee1. b. dephosphorylation by Cdc25 protein phosphatase. c. the binding of Ink4. d. the binding of Cip.

Cell cycle checkpoints ensure that complete genomes are transmitted to daughter cells. DNA damage checkpoints are found in all of the following phases except a. M phase. b. G1 phase. c. G2 phase. d. S phase.

Cell cycles of early embryonic animal cells are unusual because they have a. no G1 or G2. b. an elongated G1 and G2. c. a short S. d. a much shortened M.

Cells in the quiescent phase of the cell cycle are said to be in the _______ phase. a. G0 b. G1 c. G2 d. M

Chromosomes are attached to spindle microtubules by a. centromeres. b. kinetochores. c. centrioles. d. centrosomes.

Damaged DNA is sensed by a complex of proteins that activate the protein kinase a. ATM or ATR. b. ABS. c. Akt. d. MCM.

Fertilization by multiple sperm is blocked by a. the exocytosis of secretory vesiclesthat coat the egg. b. a hardening of the plasma membrane. c. a hyperpolarization of the plasma membrane. d. the release of spermicidal jelly.

In which of the following cell types do G1 and G2 not take place? a. Early embryonic cells b. Budding yeast cells c. Typical proliferating human cells d. Skin fibroblasts

Most cells in an adult animal are a. in G0, or quiescent, phase. b. actively proliferating. c. stem cells. d. undergoing meiosis.

Studies on cell cycle mutants in budding and fission yeasts demonstrated that cdc2 and cdc28 both encode a a. protein kinase. b. protein phosphatase. c. ubiquinating enzyme. d. growth factor.

The G1 checkpoint in budding yeast cells is called a. START. b. the restriction point. c. the decision point. d. the G1/S boundary.

The eukaryotic cell cycle is composed of four phases in the following order: a. G1; S; G2; M b. G1; G2; S; M c. G1; M; G2; S d. S; G1; G2; M

The p21 and p15 proteins are examples of a. Cdk inhibitors. b. cyclins. c. oncogenes. d. growth factors.

The retinoblastoma protein (Rb) binds to and inhibits a. transcription factor E2F. b. oncogenes. c. cyclin-dependent kinase. d. p53.

Which of the following are not phosphorylated by the Cdk1/cyclin B complex during mitosis? a. Histone H3 b. Golgi matrix proteins c. Nuclear lamins d. Condensins

p21 inhibits cell cycle progression by binding to and inhibiting a. cyclin-dependent kinases. b. p53. c. ATM. d. Rb protein.

During prophase, Cdk1/Cyclin B (MPF) directly phosphorylates all of the following except

APC/C

Damaged DNA is sensed by a complex of proteins that activate a protein kinase called

ATM

Damaged DNA is sensed by a complex of proteins that activate the protein kinase

ATM or ATR

Active and Inactive MPF

Active MPF (CDK-Cyclin Complex): Mitotic CDK activity going up really dramatically, which causes G2-M transition. Some kinase active, we're in M-phase, the chromosomes condense, spindles assembly, nuclear envelope breakdown. Inactive MPF: CDK activity turns off, causes cell to exits M phase. Chromosomes de-condense, spindles dis-assemble, nuclear envelope re-forms.

Meiosis differs from Mitosis in that Meiosis : a) has a longer prophase. b) involves two cell divisions. c) produces haploid cells from tetraploid cells. d) creates recombinants e) All of the above

All of the above

An apoptosome is a complex containing multiple subunits of

Apaf-1, caspase-9, and cytochrome c.

Apical surface is the surfaces of intestinal epithelial cells that face the lumen of the intestine. basolateral surface is the surfaces of intestinal epithelial cells that face the circulatory system. Fibronectins occur widely throughout supporting tissues and body fluids, whereas laminins are found mainly in the basal laminae. The glycocalyx is a carbohydrate-rich zone juxtaposed between the plasma membrane and the ECM of many types of animal cells. Collagen is responsible for the strength of the ECM, whereas elastin imparts elasticity and flexibility to the ECM. The groups mediate cell-cell recognition and adhesion; the two groups of proteins can be distinguished from each other functionally because of the calcium requirement of cadherins but not IgSFs. These are transmembrane proteins that serve as receptors for ECM proteins such as collagen, fibronectin, and laminin; selectin is the best-characterized integrin.

What occurs if damage is too severe?

Apoptosis, programmed cell death, is initiated. For multi-cellular organisms, having a mechanism to recognize that things have gone terribly wrong in a specific cell and being able to induce the suicide of that cell is highly advantageous for the organism as a whole.

Why is cell death via apoptosis more advantageous to multicellular organisms than cell death via acute injury?

Apoptotic cells are removed via phagocytosis. Cells that die by injury release their contents into extracellular space causing inflammation.

Is the association of cyclin with CDK necessary and sufficient for activation of MPF?

Association of cyclin with CDK is necessary for activation of MPF, but not sufficient. In order for MPF to be active, there needs to be association. But just associating does NOT activate MPF.

In Metaphase, the microtubules of ____ have grown and are in contact with plasma membrane

Asters

The shorter microtubules extend from centrosomes

Asters

_____ extend from each centrosome

Asters

multipotent somatic stem cell self-renewal divisions

At least one daughter usually becomes a stem cell like the parent cell. Stem cell number - stays constant or increases during the organism's lifetime

At fertilization, the sperm binds to a receptor on the surface of the egg and fuses with the plasma membrane, initiating the development of a new diploid organism. Which of the following statements about fertilization is false? a. Binding of a sperm to its receptor on the egg induces an increase in cytoplasmic calcium. b. The progression of metaphase II to anaphase is triggered by the activation of MPF. c. Eggs are arrested at metaphase II of meiosis and fertilization leads to anaphase progression. d. Once fertilized, secretory vesicles are exocytosed, leading to an alteration in the extracellular coat of the egg to prevent additional sperm entry.

DNA content can be determined using a method of flow cytometry that can determine 2n or 4n states of cells based on cell counting and fluorescent labeling of DNA. Which of the following phases would be identified through flow cytometry as 2n? a. M phase b. G1 phase c. G2 phase b. S phase

Fertilization of a frog egg triggers the resumption of meiosis by an increase in a. ATP. b. Ca2+. c. cAMP. d. PIP2.

In a typical cycling mammalian cell, _______ of the cell cycle is spent in interphase. a. 99% b. 95% c. 75% d. 50%

In meiosis I, sister chromatids a. go to opposite poles. b. go to the same poles. c. have kinetochores facing in opposite directions. d. synapse with each other during the zygotene stage.

Interphase is defined as a. the G1 and G2 phases. b. the G1, G2, and S phases. c. G0, the quiescent phase. d. M phase. happens only after interphase, during which cell growth and DNA replication occur.

To prevent cells with unreplicated DNA from passing through the G2 checkpoint, Chk1 and Chk2 _______ and _______ protein phosphatase Cdc25. a. phosphorylate; stimulate b. phosphorylate; inhibit c. dephosphorylate; stimulate d. dephosphorylate; induce the degradation of

Two sea urchin proteins were named cyclin A and B because, during the embryonic cell cycle, they were periodically a. activated and inactivated by phosphorylation and dephosphorylation. b. synthesized and degraded. c. bound and released by another protein. d. ubiquitylated and non-ubiquitylated.

Which of the following is not one of the phases of mitosis? a. Prophase b. S phase c. Metaphase d. Anaphase

During which phase of meiosis do homologous chromosome pairs line up on the metaphase plate? A. metaphase II B. metaphase I C. anaphase I D. anaphase II E. prophase I

B. metaphase I Homologous chromosome pairs, that first joined in prophase I, line up on the metaphase plate in metaphase I. These chromosome pairs separate during anaphase I, whereas chromosomes line up on the metaphase plate individually during metaphase II, and centromeres joining sister chromatids divide creating new chromosomes during anaphase II.

During which phase of meiosis do diploid cells first become haploid? A. telophase II B. telophase I C. prophase I D. anaphase I E. metaphase II

B. telophase I When a cell completes meiosis I, during telophase I, the cell divides and each daughter cell nucleus contains half the number of chromosomes that were present in the original cell that entered prophase I.

You suspect that an elderly patient's skin blistering is caused by an autoimmune disorder. If you are correct, the patient's serum likely contains antibodies directed against

BPAG2

Healthy cells - Bcl-2/Bcl-xL anti-apoptotic protein binding blocks

Bak/Bac oligomerization-pore formation in the outer mitochondrial membrane

Regulators of apoptosis

Bcl-2 family: PUMA, BID and BAX. -Bcl-2 (antiapoptic and inhibits BAX at outer MM) -Bax forms a channel in outer MM, releases cytochrome c into cytoplasm where will form apoptosomes (association with Apaf-1) which then recruits caspase (apoptosis initiators and executioners) -BID AND PUMA stimulate BAX

The cytostatic factor that holds the oocytes at the arrest point is called a. Fos. b. Kos. c. Mos. d. Boss.

The length of time it takes for the cells labeled during DNA synthesis to begin to enter mitosis is a good estimate of the length of the _______ phase(s). a. G1 b. S c. G2 d. M

The phase of the cell cycle that corresponds to the interval between mitosis and initiation of DNA replication is referred to as the a. M phase. b. S phase. c. G1 phase. d. G2 phase.

The sequence of DNA on each chromosome where the sister chromatids are held together is called the a. centrosome. b. kinetochore. c. centromere. d. centriole.

Which cyclin(s) is/are required to pass the G1 restriction point in animal cells? a. Cyclin A b. Cyclin A and Cyclin B c. Cyclin D d. Cyclin D and Cyclin E

Which of the following represents the amount of DNA in a typical G2 cell? a. n b. 2n c. 4n d. 8n

Which of the following statements regarding cyclin D is false? a. It is required for cell cycle progression. b. It is activated by growth factors. c. It is always present and its activity is regulated by fluctuating levels of Cdk4 and Cdk6. d. It is rapidly degraded following removal of appropriate growth factors.

Meiosis II is often considered to be similar to mitosis. Which of the following features is shared by both meiosis II and mitosis? A. Both mitosis and meiosis II immediately follow an interphase where DNA was replicated. B. Within a given species, a cell entering mitosis or meiosis II will have equivalent numbers of chromosomes. C. Individual chromosomes align on the metaphase plate and sister chromatids separate at anaphase in both mitosis and meiosis II. D. Within a given species, a cell entering mitosis or meiosis II will have equivalent amounts of DNA. E. All of the above features are common between mitosis and meiosis II.

C. Individual chromosomes align on the metaphase plate and sister chromatids separate at anaphase in both mitosis and meiosis II. DNA is not replicated between meiosis I and meiosis II. Also, since a cell entering meiosis II is haploid, the number of chromosomes in a cell entering meiosis II is half the number in a cell entering mitosis. Also, a cell entering meiosis II will contain half the amount of DNA compared to a cell entering mitosis. Therefore, the only correct answer is "C" because individual chromosomes line up on the metaphase plate in both mitosis and meiosis II.

During development, 50% of neurons die; those that survive are those that: Select one: a. Generated axons. b. Received epithelial growth factor. c. Made correct connections with their target cells. d. Did not receive an extracellular cell death signal.

C. Made correct connections with their target cells

List the major product of the dark reaction of photosynthesis

C6H12O6 (glucose)

Positive and Negative Feedback Loop of MPF Activation

CDC25 is a substrate for active MPF. Wee1 also substrate for MPF. Positive: 1. As soon as MPF activates just a little bit, MPF can phosphorylate CDC25. 2. When CDC25 phosphorylated, there's more CDC25. 3. These CDC25 can dephosphorylate (remove inhibitory phosphate) on the inactive MPF, which activates MPF. 4. When MPF activates, it phosphorylates CDC25. Negative: At the same time as positive loop, 1. MPF adds a phosphate on Wee1. 2. Wee1 no longer active and cannot add inhibitory phosphates onto Tyr-15. At the same time of accelerating the removal of the inhibitory phosphate, also preventing the addition of inhibitory phosphate from any complexes that form subsequent to MPF activation.

G2 and M phase

CDK1 most important driver of events leading to mitosis. Works in cooperation with cyclin A (present in early S phase) and B (late S phase through G2 and peaks M). Cyclin/CDK1 inactive due to inhibitory phosphorylation of CDK1 subunit. Once DNA is replicated (S phase), cyclin/CDK1 complex is activated via dephosphorylation. Once active, phosphorylate other protein substrates and initiate chromosome condensation, formation mitotic spindle, and disassembly of nuclear membrane. Once chromatids are separated, anaphase promoting complex polyubiquitinates cyclin A and B. Dephosphorylation reversed effects of cycline/CDK1, leading to reassembly of nuclear membrane and cytokinesis. Anaphase promoting complex inactivated, Rb dephosphorylated and cell cycle is complete.

What moleular mechanisms regulate caspase activity?

Caspases are synthesized as long inactive precursors that are activated in complexes or converted to active enzymes by proteolytic cleavage. Cells also contain IAP's that associate caspases and inhibit their activity.

Entry into mitosis occurs because

Cdk1/Cyclin B (MPF) get activated.

How would siRNA against Ced-3 affect the development of C. elegans?

Ced-3 is the only caspase in C. elegans. Mutating it leads to the survival of all the cells that would normally die by apoptosis during development.

Microtubules pushed apart = Spindle poles push apart = elongating __

Cell

A membrane-bound, flattened sac located in the middle of a DIVDING plant cell, inside which the new cell wall forms during Cytokinesis

Cell Plate

Mechanism #1: Cell receives external cue.

Cell polarizes Fate determinants - become segregated before cell division Division - produces one stem cell and one differentiating cell

During Interphase in animal cells, the single _____ duplicates forming 2 ___ (same word)__ near the nucleus

Centrosome

The assembly of Spindle Microtubules starts at the ___________

Centrosome

The spindle includes: - - -

Centrosomes, the Spindle Microtubules, Asters

Cytokinesis occur by a process of _____ (1) the process of Cytokinesis in animal cells, pinching of PLASMA MEMBRANE. (2) The succession of RAPID cell division with out growth that converts the zygote of the ball of cell

Cleavage

________________ the first sign of cleavage in animal cells, a shallow groove around the cell in the cell surface near the old metaphase plate

Cleavage Furrow

How do we release sister cohesion?

Cleave subunit, rings open, the sister move away from each other. APC also promotes degradation of the cohesion regulator Securin. 1. When cells enter M-phase, MPF associates with accessory factor APC. 2. APC is inactive, thus securin is bound to separase, which keeps securin inactive. 3. APC becomes active and ubiquitinates securin, which targets securin for degradation. 4. Securin is degraded. 5. The separase is now free & and active & cleaves the cohesin rings. 6. The ring opens, and the sister chromatids can move apart. This is the metaphase-anaphase transition.

Active caspase-8:

Cleaves-activates effector caspases-3, -6, and -7. Generates the tBid fragment that binds to Bcl-2 on the outer mitochondrial membrane, leading to release of cytochrome c. Cyt c activates the intrinsic apoptosis pathway.

What are the sister chromatids held together by?

Cohesin protein complex, hold sister chromatids together from the time of their synthesis until anaphase onset.

Securin

Cohesion regulator. Its sole job is to bind an enzyme called separase. Separase is the enzyme that cleaves cohesin.

Entire Cell Cycle in terms of Control Regulator

Controller in all cases is a CDK, but there are different CDKs that are active at different times of the cell cycle and drive different transitions. 1 Early G1: DNA pre-replication complexes assemble at origins. Exits M phase, no longer have s phase or m phase CDk activity. CDC6 no longer phosphorylated. CDC6 can recruit proteins necessary for DNA replication. 2. G1 cyclin-CDK inactivates APC to stop degrading regulators during G1. 3. G1 cyclin CDK that becomes induced in the presence of a positive signal. That CDK by phosphorylating Rb and causing the activation of E2F, activates the expression of the G1 S and S phase cyclin CDK components. 4. G1/S Cyclin CDK phosphorylates S-phase inhibitor (p27). p27 degraded, we have active S-phase cyclin CDK. 5. Entry in to S phase. 6. During G2, we get accumulation of the mitotic CDK and mitotic cyclin. When we get dephosphorylation of the inhibitory phosphate by CDC25, this allows the cell to enter M-phase. 7. At M-phase, we get spindle assembly, chromosome condensation, NE breakdown. 8. Activate APC in M-phase in order to get Securin degraded. When Securin is degraded, this allows anaphase to happen. Need APC-Cdh1 to get rid of mitotic cyclins in order to exit M phase and re-enter early G1.

Which of the following drugs blocks the assembly of actin filaments?

Cytochalasin

Many stimuli that trigger cell death release the molecule _______ from mitochondria to bind to Apaf-1.

Cytochrome c

The DIVISION of Cytoplasm happen by late Telophase so the 2 daughter cells appear shortly after end of mitosis. -Cleavage furrow in animal cells

Cytokinesis

_______ is the division of CYTOPLASM forming 2 separate daughter cells immediately after -mitosis -meiosis I -meiosis II

Cytokinesis

-Vesicles - cell wall materials -Collect up in cell plate - Enlarges until reaching Plasma Membrane - Cell wall arises

Cytokinesis steps of Cell Wall

Mitotic spindle begins to form in the ______ during Prophase (#1)

Cytoplasm

Cells are restricted to one round of DNA replication per cycle by origin of replication binding proteins called a. ATMs. b. Akts. c. Oris. d. MCMs.

During mitosis, the rate of microtubule turnover a. decreases. b. stays the same. c. doubles. d. increases five- to tenfold.

During prophase, Cdk1/Cyclin B (MPF) directly phosphorylates all of the following except a. condensins. b. lamins. c. APC/C. d. microtubule-associated proteins.

During what phase of meiosis does recombination between maternal and paternal chromosomes occur? a. Anaphase I b. S phase c. Prophase II d. Prophase I

Entry into mitosis occurs because a. cyclin is destroyed at the beginning of mitosis. b. cyclin is phosphorylated at the beginning of mitosis. c. sufficient cyclin-dependent kinase is synthesized to trigger mitosis. d. Cdk1/Cyclin B (MPF) get activated.

For how long can human oocytes remain arrested in the diplotene stage of the first meiotic division? a. 1 month b. 9 months c. 10 years d. 50 years

Growth-factor stimulation of the Ras/Raf/ERK pathway initially stimulates the synthesis of cyclin a. A. b. B. c. C. d. D.

Growth-factor stimulation of the Ras/Raf/ERK pathway initially stimulates the synthesis of cyclin ___.

Growth-factor stimulation of the Ras/Rat/ERK pathway initially stimulates the synthesis of cyclin

In the absence of growth factor, most animal cells will stop the cell cycle at a restriction point in what stage? a. S phase b. M phase c. G2 phase d. G1 phase

In yeast, START triggers the progression from G1 to S. Which of the following are involved in regulating START? a. Nutrients b. Mating factors c. Cell size d. All of the above

MPF is a a. monomeric protein kinase. b. dimer of two molecules of Cdk1. c. dimer of Cdk1 and cyclin A. d. dimer of Cdk1 and cyclin B.

Meiosis differs from mitosis in that during meiosis a. the nuclear envelope remains intact. b. haploid cells are produced from diploid cells. c. there are two S phases. d. two haploid daughter cells are produced.

The G2 checkpoint prevents entry into _______ if _______. a. G1; DNA synthesis is not complete and/or DNA is damaged b. S; DNA synthesis is not complete and/or DNA is damaged c. G2; DNA synthesis is not complete and/or DNA is damaged d. M; DNA synthesis is not complete and/or DNA is damaged

The beginning of anaphase occurs when cohesins holding the sister chromatids together are degraded by a. anaphase-promoting complex. b. ATM. c. proteasome. d. separase.

S-phase cyclin-CDK ensures that origins fire only ONCE.

DNA replication is tightly regulated so that it occurs only once per cell cycle. At S-phase, when the S-phase cyclin-CDK becomes active, one of the proteins it phosphorylates CDC6. When CDC6 phosphorylated, it becomes degraded (targeted for SCF ubiquitination). After cell enters S-phase, no more CDC6. CDC6 unable to recruit any machinery to the origins. Can't fire from the origin again. As long as S phase or M phase cyclin/CDKK remains active, CDC6 will be phosphorylated and degraded. Without CDC6, no new pre-replicative can form. After M phase exit, CDC6 protein no longer phosphorylated (no more M-phase cyclin CDK activity), CDC6 becomes stable and can facilitate the formation of pre-replicative complexes.

How does S-phase cyclin CDK intiate DNA replication?

DNA replication starts at specific origins. The origin is recognized by the ORC (origin recognition complex). 1. ORC bound to origin 2. CDC6 (came out of yeast strains) is bound to ORC which is bound to origin. 3. Early in G1, CDC6 recruits a DNA helicase (protein that unwinds the DNA helix) to the ORC. The enzyme that catalyzes the synthesis of DNA can't do so until the two strands are separated. The critical point: when the active S phase cyclin CDK phosphorylates several proteins which associate with the pre-replicative complex. Facilitates the phosphorylation of the helicase by another kinase activates it. DNA polymerase is recruited to the origin and replication begins. S-phase cyclin-CDK complex ESSENTIAL to open up the origin and allow replication to start. You only want to fire the origin once, since you only want to make 2 copies of the chromosomes.

In a relaxed muscle, the myosin heads of the sarcomeres' thick filaments are extended and ready to bind to the actin strands of the thin filaments. But this binding does not occur until an action potential is triggered in the muscle cell. An action potential results in the release of Ca2+ ions from the sarcoplasmic reticulum into the cytosol of the muscle cell. As the concentration of Ca2+ rises in the cytosol, so does the concentration of Ca2+ in the sarcomeres. In response to changes in the Ca2+ concentration in the sarcomeres, two protein components of the thin filaments, troponin and tropomyosin, control access to actin's myosin-binding sites. In this way, Ca2+ concentration in the cytosol and sarcomeres regulates muscle contraction. Which of the following statements correctly describe(s) the relationship between Ca2+ concentration in the cytosol and the response in the sarcomere? Select all that apply.

Decreasing Ca2+ concentration causes dissociation of Ca2+ from troponin. Increasing Ca2+ concentration causes movement of tropomyosin, exposing myosin-binding sites on actin.

which of the following best describes the order in which western blotting is preformed?

Denature -> SDS gel -> Transfer -> blocking -> primary antibody -> secondary antibody -> development.

________________ = crucial for eventual division of cell occurs entirely during the S Phase

Duplication of Chromosomes

Some cells needs survival factors to stay alive

During development, if cells do not receive a survival signal, they will undergo apoptosis. Pruning: getting rid of specific neurons. Orchestrating the attachments neurons make during development.

The APC is an

E3 ubiquitin ligase

Emery-Dreifuss muscular dystrophy is caused by mutations in ____________________ genes

EMD and LMNA

N-linked oligosaccharides are added in the

ER and modified in the Golgi.

Along a secretary pathway, proteins that function within the ER are selectively retrieved from_______ and returned to_____

ER-Golgi intermediate, ER

multiple factors control

ES cell pluripotency

Oct4 and Nanog expressed only in

ES cells

eight-cell stage embryo

Each cell is totipotent to give rise to a complete animal when implanted into the uterus of a pseudopregnant animal. Divides to form the 16-cell morula - cell affinities for one another increase substantially to compact embryo

Describe key experiment (Blobel) that led to the discovery of a signal sequence

Evidence for Signal Hypothesis: 1. mRNA encoding for the secretory IgG light chain is translated in an in vitro translation system in the absence or presence of microsomes Result: SDS-PAGE analysis shows that translation in the presence of microsomes results in a slightly smaller polypeptide Conclusion: In presence of microsomes, a leader sequence of the precursor protein directs it to the ER, where it is cleaved off by a signal peptidase following transport into ER

Describe the structure of F actin

F actin is made from globular actin globular actin forms trimers which come together to form F actin. F actin has two poles barbed end (+)and pointed end (-).

In meiosis I versus meiosis II, the nuclear material is aligned at the metaphase plate exactly the same. True or False

False

Injured muscle cells regenerate by division of muscle fibers to form myoblasts that proliferate and fuse to form new muscle fibers. True or False

False

Leukemias arise from cells of the immune system. True of False

False

3 phases of interphase are - - -

G1 phase, S phase, G2 phase

The eukaryotic cell cycle is composed of four phases in the following order: G1; S; G2; M. G1; G2; S; M. G1; M; G2; S. S; G1; G2; M.

G1, s, G2, M

Interphase is comprised of _____ and take ____ hour(s)

G1,S,G2 23 hours

mitogens stimulate

G1-Cdk and G1/S-Cdk activities

Four classes of Cyclin-Cdk complexes

G1-Cdks G1/S Cdks S-Cdks M-Cdks

When does the cell make a decision that it's going to undergo cell division?

G1.

centrosome duplication is initiated by

G1/S-Cdk this also triggers cell cycle entry

The eukaryotic cell cycle is composed of four phases in the following order:

G1; S; G2; M

The 2nd gap, or growth phase of cell cycle, the portion of interphase after DNA synthesis occurs

G2 Phase

MPF is a general regulator of the transition from

G2 to M

MPF is a general regulator of the transition from G1 to S. metaphase to anaphase. S to G2. G2 to M.

G2 to M

Signaling complexes and cascades (MAP kinase cascade)

GRB2 binds phosphotyrosine, then binds Sos, brining Sos to the cell membrane. Sos then interacts with G-protein, Ras, and promotes exchange of GDP to GTP in Ras, leading to Ras activation. Ras activates Raf, which activates MAP kinase kinase which then activates MAP kinase. -Activation of the MAP kinase cascade can stimulate c-Fos transcription, which can in turn overcome restriction point of the cell cycle.

What causes catastrophe of the microtubule in vitro?

GTP hydrolysis

What is the role of GTP in microtubule polymerization?

GTP stabilizes the tip of the microtubule, allowing more monomers to be added.

A haploid reproductive cell (eggs/sperms) formed by Meiosis or descendant of cells formed by meiosis

Gametes

______ = (eggs/sperms) variation of cell division - meiosis 1 set of chromosome = yielding daughter cells 1/2 as many as parent cells

Gametes

__________ unite during sexual reproduction producing diploid zygote

Gametes

_____ aid in the coordination of the activities of adjacent animal cells.

Gap (communicating) junctions

Rise and Fall of Cyclin During Cell Cycle

High cyclin levels correlate with high MPF activity. Cyclin increases gradually. MPF occurs and disappears all of a sudden. MPF disappears when cyclin disappears.

Scurvy is a disease that until the nineteenth century was common among sailors and others whose diets were deficient in vitamin C (ascorbic acid). Individuals with scurvy suffer from various disorders, including extensive bruising, hemorrhages, and breakdown of supporting tissues. Ascorbic acid serves as a reducing agent responsible for maintaining the activity of prolyl hydroxylase, the enzyme that catalyzes hydroxylation of proline residues within the collagen triple helix, which is required for helix stability. Part A Based on this information, postulate a role for hydroxyproline in collagen triple helices.

Hydroxylated proline residues, but apparently not non-hydroxylated proline residues, but apparently not unhydroxylated proline residues, stabilize the collagen triple helix. The hydroxyl groups of this amino acid form interchain hydrogen bonds that help stabilize the assembled triple-stranded helix.

Most likely to remain when cells are treated with solutions of nonionic detergents or solutions of high ionic strength

Temperature-sensitive mutations in a kinesin II required for intraflagellar transport (IFT) have been identified in Chlamydomonas. Such mutations only lead to defects when the temperature is raised above a certain threshold, called the restrictive temperature. When algae with fully formed flagella are grown at the restrictive temperature, their flagella degenerate. What can you conclude about the necessity of IFT from this experiment?

IFT seems to be necessary for ongoing maintenance of flagellar structure.

Normal Cell Proliferation Compared to Cancer Cell Proliferation

In cancer, in large part, unregulated cell division. All of the mechanisms can be disrupted in different types of cancer cells.

Contact inhibition

In general, interactions between the cell and the extracellular matrix will promote cell division, while interactions between neighboring cells inhibit cell division. Loss of contact inhibition between neighboring cells is characteristic of cancer cells.

The period in cell cycle, where the cell is NOT DIVIDING cellular metabolic activity is HIGH. -Chromosomes and Organelles are DUPLICATED causing cell size to increase

Interphase

The microtubules that overlap in the center of the mitotic spindle are called _______ microtubules. interpolar minus-end astral kinetochore

Interpolar

p53 involvement in apoptosis

Intrinsic pathway. Activation of p53 as result of DNA damage can trigger entry into apoptosis.

Fibronectin

It can bind to fibrin (important during blood clot formation), and can bind to collagen or heparin sulfate proteoglycans for attaching it to the ECM. The RGD-containing cell-binding domain is crucial for allowing cells to attach to this molecule, because this is the site that is bound by integrins on the cell surface.

Which of the following is FALSE about cyclin B?

It cycles between active and inactive states in the cell cycle (but is always present).

Each of the 2 Sister Chromatids pf a duplicated chromosome has a _____

Kinetochore

Specialized protein structure

Kinetochore

The ____ acts as a coupling device attaching the motor of spindle --> chromosome

Kinetochore

During Prometaphase (#2), some of the Spindle microtubules ---- kinetochore are called __________________________

Kinetochore Microtubules

Emery-Dreifuss Muscular Dystrophy is caused by mutations in ______ genes

LMNA and EMD (enesin)

give an example of a mitochondrial disease

Leber's Optic Atrophy- degeneration of the retinal ganglion cells, leading to an acute or subacute loss of central vision

mammalian embryo cell initial cleavages

Little cell growth - cells become progressively smaller Lead to the first differentiation events

-Cell not dividing -Replicating DNA The chromosomes are_____

Long, thing chromatin fibers

Which of the following events is not part of apoptosis?

Lysis of cell fragments and release of their contents

The G2 checkpoint prevents entry into _______ if DNA synthesis is incomplete and/or the DNA is damaged. G1 S G2 M

Cell cycle checkpoints ensure that complete genomes are transmitted to daughter cells. DNA damage checkpoints are found in all of the following phases except G1 phase. G2 phase. M phase. S phase.

M phase

___ and __ phosphorylate kinesin motors to stimulate them to ______

M-Cdk and Aurora-A stimulates them to drive centrosome separation.

What initiates the breakdown of the envelope?

M-Cdk phosphorylates nuclear pore complexes and nuclear lamin

prepare 20 ml of 0.5 M solution (MW of sodium chloride is 58.4)

M= moles/L 58.4/2= 29.2 g 29.2g/1000 ml x x/20 ml 584/1000= 0.584g/20 ml

Cells are restricted to one round of DNA replication per cycle by the origin of replication binding proteins called

MCM helicases

Cells are restricted to one round of DNA replication per cycle by origin of replication binding proteins called

MCMs

More important for cytokinesis than for chromosome movements in animal cells.

give an example of a mitochondria disease

MIDD (meternally innerited diabetes of a seas) DAD LHON (lebehans optical neurology )

Involved in the movement of cilia and flagella

More important for chromosome movements than for cytokinesis

The fundamental repeating subunit is a dimer.

MT IF

Play well-documented roles in cell movement

MT MF

Their subunits can bind and catalyze hydrolysis of phosphonucleotides

MT MF

Can be detected by immunofluorescence microscopy.

MT MF IF

Structurally similar proteins are found in bacterial cells.

MT MF IF

Negative signal that blocks Cdc20/APC-C activation depends on

Mad2

Stem cells exhibit several patterns of cell division - must meet three objectives:

Maintain the stem-cell population Sometimes increase stem cell number Produce cells that differentiate

As long as actin monomers continue to be added to the plus end of a microfilament, the MF will continue to elongate.

Maybe

What's the one exception of cell division that doesn't involved the distribution of identical genetic material DNA into 2 daughter cells

Meiosis

calnexin

Membrane-bound ER chaperone protein which binds to the carbohydrate domains of unfolded ER proteins, preventing the proteins from leaving the ER. a lectin

The other _____ of the cytoplasm partially DISASSEMBLE so the materials can be used to construct the spindle

Microtubules

______ conserves the chromosomes # by allocating replicated chromosomes EQUALLY to each daughter nuclei

Mitosis

Sister chromatids eventually SPLITS at ______ or ______

Mitosis, Mitosis II

The phase of cell cycle includes mitosis and cytokinesis

Mitotic (M) Phase

The shortest part of cell cycle (10%)

Mitotic (M) Phase

An ASEEMBLAGE of MICROTUBULES and associated PROTEINS that is involved in the movement of chromosomes during mitosis

Mitotic Spindle

Most event of mitosis depends on _______

Mitotic Spindle

Bacterias don't have _______ or microtubules

Mitotic Spindles

Mechanism #2: Stem cells interacting with a stem-cell niche.

Mitotic spindle oriented with one end toward stem cell niche Cell division yields - Stem cell associated with the niche Differentiating cell displaced from the niche

Some cells in a _________________ don't DIVIDE at all, if they do it's a little. Spending their time in G1 (relating to G0) doing their jobs Ex: Cells of pancreas

Multicellular Organisms

The chromosomes of eukaryotic cells are __________________

Multiple, LINEAR chromosomes in NUCLEUS+ LOTS of proteins

What occurs if Wee1 cannot function?

Mutants isolated in CDC Yeast Screens: 1. Grow Wee1 Mutant at the restrictive temperature that does not function properly 2. Wee1 no longer can inhibit CDK activity 3. CDK activity becomes active too soon 4. Cells divide too early (before they have grown, when they are "wee")

What do you predict would happen if the yeast had a mutation that prevented the G protein from binding GTP?

No shmoo would form in response to mating factor.

The ______ are responsible for elongating the whole cell during Anaphase

Nonkinetochore Microtubules

The microtubules that aren't attached to the Kinetochores elongating

Nonkinetochore Microtubules

embryonic stem cells ethical challenge

Obtaining such cells requires the generation of human embryos and the harvesting of the ICM cells for such research.

Multipotent hematopoietic stem cells: Divide asymmetrically

One daughter cell - remains multipotent like parent stem cell One daughter - generates either lymphoid progenitors or myeloid progenitors (capable of limited self-renewal but committed to one of the two major hematopoietic lineages).

When should APC become activated?

Only after all the chromosomes are lined up on the metaphase plate and have bipolar attachments.

Bacteria: The process of cell division is initiated when the DNA of the bacterial chromosome begins to REPLICATE at a specific plate of chromosome called _______________ site where DNA molecule beings, consisting of a specific sequence pf nucleotides

Origin of Replication

Meiosis occur in the special cells: _________ and ____________ -reduces chromosome # from 46 --> 23

Ovaries, Testes

Example of ER resident protein

PDI (protein disulfide isomerase)

Which of the following is not phosphorylated by Akt?

PI3K

S subphase of interphase

Period during which DNA is replicated (only once). At conclusion of S phase, each chromosome comprises two identical sister chromatids linked at the centromere.

To prevent cells with unreplicated DNA from passing through the G2 checkpoint, Chk1 and Chk2 _______ protein phosphatase Cdc25. phosphorylate and inhibit dephosphorylate and induce the degradation of phosphorylate and stimulate dephosphorylate and stimulate

Phosphorylate and inhibit

Mechanism 1: Phosphorylation of CDKs

Phosphorylation of Thr160 in the T-loop activates the CDK by allowing target binding; Phosphorylation of Tyr15, near the amino terminus, inactivates CDK2 by blocking the ATP binding site with its negatively charged

What drives the activation and inactivation of CDK?

Phosphorylation. CDK is phosphorylated by another kinase. There's more than 1 kinase that regulates MPF.

Cytokinesis in ______: -No cleavage furrow - in Telophase, the VESICLES from GA move along the microtubules to middle of cell where they coalesce -making cell plate

Plant Cells

which of the following is a protein that can link intermediate filaments with actin filaments and microtubules?

Plectin

When the microtubules capture the chromosome's kinetochore, the chromosomes moves toward the ______ the microtubules are extending from

Pole

2 additional families that help M-Cdk

Polo-like kinases Aurora kinases

Asymmetric divisions

Produce one stem cell and one differentiating cell Maintains constant stem cell number

Apoptotic changes are activated by proteolytic enzymes, caspases, which target:

Protein kinases, some of which cause detachment of cells. Lamins, which line the nuclear envelope. Proteins of the cytoskeleton Caspase activated DNase (CAD)

ER resident proteins

Proteins that are retained and function within the ER -contain ER retention signal as opposed to "En Route" ER proteins", which are en route to other destinations

Retinoblastoma

Rare autosomal disease in which cancer forms in retinal cells in both eyes. Not usually fatal, but often results in loss of vision, and sometimes removal of an eye. Rb was the first Tumour Suppressor Gene cloned. It is involved in many 'sporadic' tumours all over the body.

Ataxia-telangiectasia

Rare disorder caused by mutations in the gene encoding ATGM. Response of cell to double stranded breaks in DNA is impaired (no inhibition at G2/M checkpoint) -progressive difficulty in coordination of movement that is experienced and "telangiectasia" refers to appearance of small, widened blood vessels on the skin. Often suffer immune deficiencies, chronic lung infections, and increased incidence of cancer. High sensitivity to radiation exposure, neurologic complications and deficits.

Transformation of human cells by the SV-40 virus results in inactivation of the tumor suppressor protein

G1 subphase of interphase

Represents period of growth that precedes DNA synthesis

pre-initiation complex formation

S phase S-Cdk phosphorylates initiator proteins that activates the DNA helicase and recruits DNA synthesis machinery.

How do you prevent a new preRC from forming?

S-Cdk inhibits the ORC and Cdc6 proteins by phosphorylation. inactivation of APC/C in late G1 helps turn off preRC assembly by inhibiting Cdt1 activity

How can cells be induced to die from the inside?

Series of events where the cell can sense that something is wrong (apoptotic stimulus), which triggers events that begin at the mitochondria. Cytochrome C (in the ETC) is released from the mitochondria, which triggers the assembly of proteins which triggers the caspase cascade that leads to apoptosis.

________ are typically attach all along their lengths by Protein Complexes called cohesions

Sister Chromatid Cohesion

2 copies of chromosome attached to each other by PROTEINS at the Centromere/arms becoming 1 chromosome. Have DNA wrapped around Histones. Identical DNA molecule.

Sister Chromatids

What would be the outcome or effect on mitosis if degradation of securin is not accomplished?

Sister chromatids would be unable to separate despite being pulled to opposite poles of the cell

SRP structure

Six protein subunits and one RNA subunit -translational pause domain -hinge -signal-sequence binding pocket, lined with Methionines (nonpolar) -RNA

Which muscle type is involved in the function of the digestive tract and blood vessels?

Smooth

transitional zone

Smooth ER also serves as a transitional area for vesicles that transport ERproducts to various destinations. primary site of ER vesicle budding

The G1 checkpoint in budding yeast cells is called the G1/S boundary. the restriction point. Correct START. the decision point.

Start

1. Begins when the Cohesin Proteins are CLEAVED allowing the Sister Chromatids of each pair to PART Each Chromatid --> Independent Chromosome

Step 1 of Anaphase

1. The CENTROSOMES are at OPPOSITE POLES of cell

Step 1 of Metaphase

The 2nd stage of mitosis 1. The nuclear envelope fragments and the Spindle microtubules---kinetochores of chromosome

Step 1 of Prometaphase

1 st stage of mitosis, where 1. the CHROMATIN condenses into discrete chromosomes visible with he LM

Step 1 of Prophase

1. Daughter nuclei are forming and Cytokinesis begun

Step 1 of Telophase

2. Daughter chromosomes are moving to the POLES of the cell by the MICROTUBULES---- centromere region are pulling ahead of arms

Step 2 of Anaphase

2. The CHROMOSOMES arrived at the Metaphase plane - The CENTROMERES lies at the Metaphase plate

Step 2 of Metaphase

2. The MICROTUBULES from each centrosome INVADE the nuclear area

Step 2 of Prometaphase

2. The nucleolus disappears, but the NUCLEUS remains

Step 2 of Prophase

2. Nuclear Envelopes form from fragment of the parent cell's Nuclear Envelopes & other portions

Step 2 of Telophase

3. The cell elongates as the Non Kinetochore Microtubules lengthen

Step 3 of Anaphase

3. The Kinetochores of each Sister Chromatid are attached to each Kinetochore Microtubules from OPPOSITE POLE

Step 3 of Metaphase

3. The CHROMOSOMES have become even more CONDENSED

Step 3 of Prometaphase

3. Each duplicated chromosome (sister chromatids) joined at their CENTROMERES / along their arms by Cohesins (Sister Chromatid Cohesion)

Step 3 of Prophase

3. Nucleoli Reappear

Step 3 of Telophase

4. At the end, 2 ends of cells have equivalent & complete collection of Chromosomes

Step 4 of Anaphase

4. The Kinetochore formed at the CENTROMERE of each Chromatid

Step 4 of Prometaphase

4. The MITOTIC SPINDLE begins to form

Step 4 of Prophase

4. Chromosomes become LESS condensed

Step 4 of Telophase

5. Becoming Kinetochore Microtubules - jerking the chromosome back & forth

Step 5 of Prometaphase

The Centrosomes MOVE AWAY from each other propelled partly and have MICROTUBULES between them

Step 5 of Prophase

5. The remaining Spindle Microtubules are DEPOLYMERIZED

Step 5 of Telophase

6. Nonkinetochore Microtubules interact with those from OPPOSITE POLES of the spindle, lengthening the cell

Step 6 of Prometaphase

6. Mitosis the division of 1 nucleus --> 2 genetically identical nuclei is complete

Step 6 of Telophase

Genetic Approach: Temperature-Sensitive Mutations to discover CDK

Temperature Sensitive Mutations that Could Disrupt Cell Cycle Progression 1. Grow mutant yeast with two types of yeast: -Fission yeast: cell grows then divides into two equal daughter cells -Budding yeast: divides by growing a bud and ultimately cell divides into 2 cells, a mother and daughter (mother larger cell) 2. Perform screen with mutagenized yeast. -Grow mutant yeast at permissive temp, look for mutations that allowed cell to go through cell cycle. -Grow mutant yeast at restrictive temperature, look for mutations that halted the cell cycle. One mutation that blocked cell cycle progression disabled CDK.

Protein Folding in the ER

The Hsp70 chaperone BiP binds to polypeptide chains as they cross the ER membrane and facilitates protein folding and assembly within the ER. - correctly assembled proteins are released from BiP and are available for transport to the Golgi. - abnormally folded or improperly assembled proteins are targets for degradation.

What would happen in the treadmilling experiment if a non-hydrolyzable analogue of GTP were used?

The microtubule would treadmill until the new tubulin, with non-hydrolyzable GTP, reached the minus end, and then it would only extend at the plus end.

You have expressed mutants of nuclear lamins in human fibroblasts. The Asp residue in the caspase cleavage site has been mutated to Glu in these lamins. How would these mutant lamins affect the progression of apoptosis?

The mutated lamins will not be cleaved by caspases, so theirexpression will block nuclear fragmentation.

Lumenal ER Proteins

The primary role of lumenal ER proteins is to assist the folding and assembly of newly translocated polypeptides. - proteins are translocated across the ER membrane as unfolded polypeptide chains while their translation is still in progress. - proteins therefore, fold into their 3D conformations within the ER, assisted by molecular chaperones that facilitate the folding.

differentiation

The process by which cells become specialized in order to perform specific functions, examples: pancreatic b-cells, white blood cells , or neurons.

Target proteins of CDKs

There are 100s of proteins that are phosphorylated by CKDs Example 1. Mitosis - nuclear lamins Example 2. Mitosis - condensins Example 3. G1 to S checkpoint release - Rb First, the checkpoints

How do Proteins Span a Membrane Multiple Times?

They are inserted as a result of a series of transmembrane sequences with alternating orientations. - (N) on cytosolic side - translation proceeds until a second transmembrane sequence is encountered. - secondary, tertiary, (etc.) transmembrane sequences cause the polypeptide chain to form a loop within the lumen of the ER; translation continues in the cytosol. - tertiary transmembrane sequences trigger reinsertion of polypeptide chain into the translocon and forming a loop in the cytosol.

Interphase usually consists of G1, S, and G2, but in some cells it consists only of S. True or False

True

Latrunculin A treatment would block intracellular movements of Listeria.

True

Microtubules, microfilaments, and intermediate filaments all exist in a typical eukaryotic cell in dynamic equilibrium with a pool of subunit proteins.

True

Most tissues maintain a balance between cell proliferation and cell death. True or False

True

Summary questions:

What is a CDK? What other protein is required to bind to it for activity? • How many CDKs and cyclins do animals have? • True or False: The abundance of CDK proteins cycles with the cell cycle, while the abundance of cyclin proteins is stable. • True or false: The activity of CDKs cycles with the cell cycle. • What is the T-loop, and what does it do during regulation of CDK activity? • What reversible protein modification (and on what aa) is required to activate CDK, and what reversible protein modification (and on what aa) then inactivates it? • What is the importance of the Destruction box? What recognises this sequence and what happens when it binds it? • List the four mechanisms that regulate CDK/cyclin activity. • Does the binding of p21 activate or inhibit the activity of CDK? • Give three examples of target proteins of CDKs. For all three, which phase of the cell cycle is it phosphorylated, and what happens when it is phosphorylated? • What is the role of the protein Rb? • What is a checkpoint? Give several examples. • What is the mechanism by which a double stranded break causes a cell cycle arrest? How is this arrest relieved once the break is repaired? • What is Knudson's two-hit hypothesis? How does this explain the formation of tumours in the retinas of people with Rb? • What is the cell cycle phase G0?

How is MPF Inactivated?

When the cyclin subunit is poly-ubiquitinated and degraded. 1. During late anaphase, APC gets activated which causes polyubiquitination (chains of ubiquitin are covalently attached to the cyclin subunit) 2. This targets the cyclin for degradation 3. When cyclin is degraded by the proteosome, the CDK is no longer active. 4. Cell exits M-phase. 5. Cell enters Interphase. 6. Later, in G2, cyclin synthesizes, CDK activates, which drives the cell into M-phase.

Historically, an important strategy for disrupting the adhesion of integrins to their ligands is by using a synthetic peptide that mimics the binding site on the ECM molecule to which the integrin attaches. In the case of fibronectin, the amino acid sequence is arginine-glycine-aspartate (when written using the single letter designation for each amino acid, this sequence becomes RGD). Explain why addition of such synthetic peptides would disrupt binding of cells to their normal substratum.

When the integrins are bound to RGD peptides, their receptors will be unavailable for binding to FN (or LN), and thus cells will be inhibited from binding to the ECM.

With Arp2/3 polymerization increases, but not as much as with Arp2/3 and WASP family proteins.

With Arp2/3 with Arp2/3 and WASP

Wrap-Up

Within the cell cycle, we have important controllers that are all cyclin-CDKs. We have controller, kinase that is triggering certain events that is needed for the next transition. We also have checkpoints/signals that allow the cell to orchestrate the activation or inactivation of the controller.

Propagation of an action potential in a skeletal muscle cell links the signal from a motor neuron to contraction of the muscle cell. An action potential in a muscle cell is propagated by the same mechanism as in neurons, the sequential opening and closing of voltage-gated Na+ and K+ channels in the plasma membrane. However, in muscle cells, the topography of the plasma membrane is quite different than in neurons, and this difference is critical to the function of muscle cells. Which of the following statements correctly describe(s) T tubules and their role in conducting action potentials in muscle cells?

Without T tubules, the muscle cell would not be able to contract. T tubules carry action potentials into the interior of the muscle cell via voltage-gated Na+ and K+ channels. T tubules are infoldings of the plasma membrane that encircle the myofibrils and are in contact with the sarcoplasmic reticulum.

What is the best rationale for the use of therapeutic cloning to replace defective cells or tissues in a patient? a. The transplanted cells are identical to those of the recipient who donated the adult nucleus, so complications of immune rejection are avoided. b. Embryos do not have to be destroyed, so ethically there is little controversy. c. It is a very efficient process for generating the tissues that need to be replaced. d. We already know how to fully differentiate the embryonic stem cells into all the major cell types.

Within a given species, which two types of cells have the equivalent amounts of DNA?

a cell in G1 of interphase and a cell in metaphase 2 of meiosis

Sister chromatid cohesion depends on

a large protein complex called choesin

at the end of S phase, each replicated chromosome consists of

a pair of identical sister chromatids "glued" together along their length.

MPF

a protein complex, kinase, enzyme that contains the mitotic cyclin and mitotic CDK that controls entry into M-Phase. The kinase subunit cannot function unless the cyclin subunit is bound to it. MPF must be active for cell to enter M-Phase.

9. Branching of actin filaments can be initiated by a. Arp2/3 b. formin c. ADR/cofilin d. fibrin e. none of the above

a. Arp 2/3

9. Branching of actin filaments can be initiated by a. Arp2/3. b. formin. c. ADF/cofilin. d. fimbrin. e. None of the above Textbook Reference: Structure and Organization of Actin Filaments, p. 478

a. Arp2/3.

10. The major cation responsible for regulating actin-myosin contraction is a. Ca2+ b. H+ c. K+ d. Na+ Textbook Reference: Actin, Myosin, and Cell Movement, pp. 491-492

a. Ca2+

10. The major cation responsible for regulating actin-myosin contraction is a. Ca2+. b. H+. c. K+. d. Na+.

a. Ca2+

Which of the following components of MPF is responsible for the actual phase transition of G2 to M? a. Cdc2 b. Cyclin E c. Cdk 4/6 d. Cdc 25 e. Cyclin B

a. Cdc2

30. The evolutionary ancestor of eukaryotic tubulins appears to be a protein similar to the bacterial protein a. FtsZ. b. Arp2/3. c. prototubulin. d. coli-tubulin. e. archae-tubulin. Textbook Reference: Microtubules, p. 504

a. FtsZ.

54. The drug taxol stabilizes microtubules so they cannot shorten. If taxol were added during anaphase of mitosis, what effect would you expect it to have on anaphase movements? a. It would stop all movements. b. It would stop anaphase A but not anaphase B. c. It would stop anaphase B but not anaphase A. d. It would have no effect. e. None of the above Textbook Reference: Microtubule Motors and Movement, p. 521

a. It would stop all movements.

The drug taxol stabilized microtublues so they cannot shorten. If taxol were added during anaphase of mitosis, what effect it to have on anaphase movements? a. It would stop anaphase A but not anaphase B b. it would stop all movements c. It would have no effect d. it would stop anaphase B not anaphase A

a. It would stop anaphase A but not anaphase B

Cell cycle checkpoints ensures that complete genomes are transmitted to daughter cells. DNA damage checkpoints are found in all of the following phases except a. M phase b. S phase c. G1 phase d. G2 phase

a. M phase

A proto-ocogene is a. a normal gene from which an oncogene can arise b. expressed normally in tumor cells c. evolving into an oncogene d. one that has been picked up by an oncogenic virus

a. a normal gene from which an oncogene can arise

13. Actin filaments are anchored at junctions called a. adherens junctions. b. tight junctions. c. desmosomes. d. gap junctions. e. hemidesmosomes.

a. adherens junctions

13. Actin filaments are anchored at junctions called a. adherens junctions. b. tight junctions. c. desmosomes. d. gap junctions. e. hemidesmosomes. Textbook Reference: Structure and Organization of Actin Filaments, p. 484

a. adherens junctions.

The distinct series of changes that characterizes programmed cell death is called a. apoptosis. b. execution. c. sepsis. d. necrosis.

a. apoptosis.

12. Myosin II is found in skeletal muscle and the contractile ring. It is a two-headed myosin with tails that can form thick filaments. Other myosins such as myosin I or myosin V do not form thick filaments and yet are still capable of producing movement along actin filaments. To what do the tail(s) of myosin I or myosin V bind? a. Cargo such as membrane vesicles or intermediate filaments b. Centrosomes c. Chromosomes d. Tubulin

a. cargo such as membrane vesicles or intermediate filaments

The DNA region to which proteins bind to form the kinetochore and spindle fibers attach for segregation of the chromosomes is called the a. centromere. b. chiasma. c. synaptonemal complex. d. origin.

a. centromere.

During the spindle fiber checkpoint, degradation of _______ allows for separation of the sister chromatids. a. cohesin b. separase c. kinetochore d. cyclin B

a. cohesin

The ras proto-oncogene can become an oncogene by a single point mutation that alters its protein product to have _______ activity. a. constitutive Raf-activation b. more GTPase c. greater nucleotide exchange d. less nucleotide exchange

a. constitutive Raf-activation

Many stimuli that trigger cell death release the molecule _______ from the intermembrane space of mitochondria so they can bind to Apaf-1. a. cytochrome c b. ATP synthase c. ubiquinone d. citric acid

a. cytochrome c

52. The beating of cilia and flagella occurs by means of _______-based _______. a. dynein; microtubule sliding b. kinesin; microtubule sliding c. myosin; microfilament sliding d. tubulin; microtubule contraction e. dynein; microtubule contraction

a. dyne; microtubule sliding

a. dynein; microtubule sliding

Apoptotic cells produce "eat me" signals, which include _______ of cell surface_________ a. gain; phosphatidylserines b. loss; carbohydrates c. loss; phosphatidylserines d. gain; phosphatidylethanolamines

a. gain; phosphatidylserines

a. it would stop all movements

Phosphorylation of the Golgi matrix proteins by Cdk1 during mitosis a. mediates breakdown of the Golgi apparatus into vesicles. b. causes microtubules to pull the Golgi into two parts. c. inhibits association of the Golgi with microtubules. d. activates proteins to degrade the Golgi proteins.

a. mediates breakdown of the Golgi apparatus into vesicles.

40. At the end of interphase, the part of the microtubule farthest from the centrosome is the _______ end. a. plus b. minus c. pointed d. barbed e. capped Textbook Reference: Microtubules, p. 507

a. plus

40. At the end of interphase, the part of the microtubule farthest from the centrosome is the _______ end. a. plus b. minus c. pointed d. barbed e. capped

a. plus

14. Which of the following statements is true about intermediate filaments? a. Rather than consisting of a single type of protein, they can be made up of a number of different proteins. b. They are involved in cell movement. c. The basic structure of an intermediate filament protein is a globular head and a long α- helical tail. d. Like microfilaments, they exhibit treadmilling.

a. rather than consisting of a single type of protein, they can be made up of a number of different proteins

The viral raf oncogene produces a constitutively active protein because the a. regulatory domain has been replaced by viral sequences so the protein cannot be turned off. b. GTPase activity is deficient and the protein is always in the GTP form. c. kinase domain is mutant and cannot be competitively inhibited. d. gene is always on.

a. regulatory domain has been replaced by viral sequences so the protein cannot be turned off.

The beginning of anaphase occurs when cohesins, holding the sister chromatids together, are degraded by: a. separase b. ATM c. proteasome d. anaphase-promoting complez

a. separase

What would be the outcome or effect on mitosis if degradation of securin is not accomplished? a. sister chromatids would be unable to separate despite being pulled to opposite poles of the cell b. nucleus would not reform during telophase c. the Er and Golgi Apparatus would fail to distribute evenly between the two new daughter cells d. the chromoses would not condense e. metaphase and anaphase would fail to occur

a. sister chromatids would be unable to separate despite being pulled to opposite poles of the cell

15. During muscle contraction, the A band a. stays the same width and the I bands and H zone shorten. b. and H zone stay the same width and the I bands shorten. c. shortens and the I bands and H zone stay the same. d. and H zone shorten and the I bands stay the same. e. and H zone shorten and the I bands elongate. Textbook Reference: Actin, Myosin, and Cell Movement, p. 489

a. stays the same width and the I bands and H zone shorten.

Two sea urchin proteins were named cyclin A and B because, during the embryonic cell cycle, they were periodically a. synthesized and degraded. b. ubiquitylated and nonubiquitylated. c. activated and inactivated by phosphorylation and dephosphorylation. d. bound and released by another protein.

a. synthesized and degraded.

5. ADF/cofilin plays a role in a. the disassembly of microfilaments. b. stimulation of actin filament formation. c. the nucleation of microfilaments. d. the disassembly of microtubules. Textbook Reference: Structure and Organization of Actin Filaments, p. 478

a. the disassembly of *microfilaments.*

19. Like myosins, kinesins and dyneins are both families of proteins. Which of the following statements is true of all kinesins and dyneins? a. They are microtubule-dependent motors. b. They are minus-end-directed motors. c. The motor activity of the proteins resides in their light chains. d. They are plus-end-directed motors.

a. they are microtubule-dependent motors

Intestinal stem cells may give rise to all of the following terminally differentiated cell types in the intestinal epithelium except _______ cells. a. transit-amplifying b. absorptive epithelial c. goblet d. enteroendocrine

a. transit-amplifying

death signals murder cells by

activating apoptosis

Which of the following experimental treatments would NOT be a potentially effective strategy to inhibit or prevent cell-cell adhesion?

adding an antagonist to prevent integrin function

what happens to secretory protein

addition of protease

glycosyl transferase

adds sugars

Associated with filaments that confer either contractile or tensile properties.

adhesive junctions (A)

Hematopoietic stem cells can give rise to

all blood cells and macrophages

Hematopoietic stem cells (HSCs) form

all blood cells.

pluripotent stem cells can give rise to

all cell types in the body

totipotent stem cells can give rise to

all cell types in the body, as well as the extraembryonic cells (placenta). Can differentiate into a complete organism.

The distinct series of changes that characterizes programmed cell death is called

apoptosis

Release of apoptotic mitochondrial proteins irreversibly commits the cell to

apoptosis.

Once in the cytosol, cytochrome c forms part of a multiprotein complex called the

apoptosome (Apaf-1), that also includes several molecules of procaspase-9.

intermediate filaments

associated with basolateral cell-cell adhesion junctions (desmosomes-hemidesmosomes) and ends of microvili actin bundles

Axonemal dyneins are

associated with cilia and flagella.

Intestinal epithelial stem cells are located _______ the crypt.

at the bottom of

How is the cycle reset?

at the end of mitosis, APC/C activation leads to: activation of ORC and Cdc6 via dephosphorylation and Cdt1 activation. this allows the preRC assembly to prepare the cell for the next phase.

32. Which nucleotide triphosphate is hydrolyzed during a cycle of microtubule assembly and disassembly? a. ATP b. GTP c. CTP d. UTP e. TTP

b. GTP

47. Cytoplasmic dynein plays a key role in the positioning of which organelle? a. Nucleus b. Golgi apparatus c. Lysosome d. Mitochondrion e. Peroxisome Textbook Reference: Microtubule Motors and Movement, p. 516

b. Golgi apparatus

47. Cytoplasmic dynein plays a key role in the positioning of which organelle? a. Nucleus b. Golgi apparatus c. Lysosome d. Mitochondrion e. Peroxisome

b. Golgi apparatus

Crossing over results in? a. Gametes b. New genetic combinations c. New species d. Cancerous growths

b. New genetic combinations

one function of the tumor suppressor protein p53 is to a. stimulate cell cycle progession b. activate synthesis of p21, a Cdk inhibitor c. phosphorylate cyclin-dependate kinases on an iinhibitory site d. inhibit phosphodiesterase

b. activate synthesis of p21, a Cdk inhibitor

3. ATP is hydrolyzed by actin a. in the process of assembly into a filament. b. after assembly but before disassembly. c. in the process of disassociation. d. after disassociation from the filament. e. None of the above

b. after assembly but before disassembly

b. after assembly but before disassembly.

Hematopoietic stem cells can give rise to a. all blood cells, macrophages, and skin cells. b. all blood cells and macrophages. c. erythrocytes and lymphocytes. d.erythrocytes.

b. all blood cells and macrophages.

Peroxisomes contain the enzyme _________ which breaks down H2O2 into H2O and O2 a. peroxin b. catalse c. peroxigen d. plasmalogen

b. catalase

The mechanism of cytokinesis in plants involves the formation of the a. plasma membrane bridge. b. cell plate. c. contractile ring. d. Aurora belt.

b. cell plate.

50. The basal bodies of cilia and flagella are similar in structure to (and can form from) a. centromeres. b. centrioles. c. centrosomes. d. kinetochores. e. kinetomeres.

b. centrioles

50. The basal bodies of cilia and flagella are similar in structure to (and can form from) a. centromeres. b. centrioles. c. centrosomes. d. kinetochores. e. kinetomeres. Textbook Reference: Microtubule Motors and Movement, p. 518

b. centrioles.

which of the following movements is not actin based a. cell migration (crawling) over surfaces b. chromosome movement c. cytokinesis of animal cells d. phagocytosis e. none of the above- all are actin based

b. chromosome movement

which of the following movments is not actin-based a. cell migration (crawling) over surfaces b. chromosome movement c. cytokinesis of animal cells d. phagocytosis e. none of the above; all are actin-based

b. chromosome movement

14. Which of the following movements is not based on actin-myosin interactions? a. Cell migration (crawling) over surfaces b. Chromosome movement during anaphase A c. Cytokinesis of animal cells d. Phagocytosis e. None of the above

b. chromosome movement during anaphase A

6. Actin may be cross-linked into either parallel or _______ bundles. a. antiparallel b. contractile c. networks of actin filament d. orthogonal filament Textbook Reference: Structure and Organization of Actin Filaments, pp. 480-481

b. contractile

6. Actin may be cross-linked into either parallel or _______ bundles. a. antiparallel b. contractile c. networks of actin filament d. orthogonal filament

b. contractile

4. The concentration of actin monomers at which the rate of polymerization into filaments equals the rate of depolymerization is called the _______ concentration. a. equilibrium b. critical c. steady-state d. treadmilling e. dynamic Textbook Reference: Structure and Organization of Actin Filaments, p. 474

b. critical

The passage of cell through the stages of the cell cycle is controlled by protein kinases that phosphorylate many different proteins at appropiate times. what are these protein kinases called? a. tryosine kinases b. cyclin dependent kinases c. Cdk activating kinases d. cyclins

b. cyclin dependent kinases

p21 inhibits cell cycle progression by binding to and inhibiting a. Rb protein. b. cyclin-dependent kinases. c. ATM. d. p53.

b. cyclin-dependent kinases.

7. Which of the following drugs blocks the assembly of actin filaments? a. Colchicine b. Cytochalasin c. Phalloidin d. Taxol e. Both b and c

b. cytochalasin

8. The association between actin filaments and the plasma membrane is mediated by all of the following except a. catenin links to cadherins. b. direct interaction between actin and plasma membrane proteins. c. myosin I-calmodulin linkages. d. talin links to integrins.

b. direct interaction between actin and plasma membrane proteins

b. direct interaction between actin and plasma membrane proteins.

36. The microtubule behavior in which some microtubules are rapidly depolymerizing and some are growing is called a. an equilibrium state. b. dynamic instability. c. treadmilling. d. recycling. e. directional transport.

b. dynamic instability

b. dynamic instability.

Membranes of the Bcl-2 family of proteins are a. all antipoptotic b. either antiapoptotic or proapoptotic c. all propoptotic d. all caspases

b. either antiapoptotic or proapoptotic

22. Keratin filaments are found in what cell types? a. Fibroblasts b. Epithelial cells c. Muscle cells d. Neurons e. All of the above

b. epithelial cells

Which of the following statements about mammalian mitosis is NOT true? a. nuclear envelope breakdown coincides with onset of prometaphase b. homologous chromosomes pair up at prophase c. onset of anaphase is inhibited until all chromosomes are aligned at the metaphase plate d. during prophase, each chromosome has two chromatids e. daughter nuclei are genetically identical to the parent nucleus

b. homologous chromosomes pair up at prophase

p53 causes the cessation of the cell cycle upon detection of DNA damage by causing transcription of p21, which leads to: a. phosphorylation of chomatin b. inhibition of Cdk4/6 c. transcription of DNA polymerase d. transcription of ChK 1 and ChK2 e. phophorylation of Rb

b. inhibition of Cdk4/6

b. it requires ATP

polar microtubules a. are attached to the cell membranes b. keep the spindles separated c. are attached to kinetochores d. pull kinetochores poleward

b. keep the spindles separated

20. The intermediate filaments in the nucleus are made of a. keratins. b. lamins. c. desmin. d. vimentin. e. None of the above; intermediate filaments are all cytosolic.

b. lamins

20. The intermediate filaments in the nucleus are made of a. keratins. b. lamins. c. desmin. d. vimentin. e. None of the above; intermediate filaments are all cytosolic. Textbook Reference: Intermediate Filaments, p. 497

b. lamins.

18. Kinesin and dynein are a. intermediate filament proteins. b. microtubule motor proteins. c. proteins within centrosomes that mediate nucleation of microtubules. d. microfilament motor proteins.

b. microtubule motor proteins

What would be the outcome or effect on mitosis if nuclear laminis are unable to bind to heterochormatin? a. sister chomatids would be unable to separate despite begin pulled to opposite poles of the cell b. nucleus would not reform during telophase c. the ER and Golgi Apparatus would fail to distribute evenly between the two new daughter cells d. The chomosomes would not condense e. methaphase and anaphase would fail to occur

b. nucleus would not reform during telophase

The key protein involved in "deciding" whether a cell with DNA damage should delay its cell cycle or undergo apoptosis is a. p15. b. p53. c. Akt. d. pRB.

b. p53.

As the cell enters M phase, the condensins are activated as a result of a. dephosphorylation by cyclin dependent and Aurora B phosphatases. b. phosphorylation by both Cdk1 and Aurora B kinase. c. ubiquitylation by cyclin dependent ubiquitin ligases. d. proteolytic cleavage by checkpoint proteases.

b. phosphorylation by both Cdk1 and Aurora B kinase.

Receptor mediated endocytosis is a form of a. phagocytosis b. pinocytosis c. autophagy d. none of the above

b. pinocytosis

53. The microtubules that overlap in the center of the mitotic spindle are called _______ microtubules. a. astral b. polar c. kinetochore d. central e. minus-end Textbook Reference: Microtubule Motors and Movement, p. 521

b. polar

53. The microtubules that overlap in the center of the mitotic spindle are called _______ microtubules. a. astral b. polar c. kinetochore d. central e. minus-end

b. polar

19. Intermediate filaments function in a. cell motility. b. providing mechanical strength for cells. c. nuclear pore structure. d. All of the above e. None of the above

b. providing mechanical strength for cells

19. Intermediate filaments function in a. cell motility. b. providing mechanical strength for cells. c. nuclear pore structure. d. All of the above e. None of the above Textbook Reference: Intermediate Filaments, p. 496

b. providing mechanical strength for cells.

In meiosis I, sister chomatids a. go to opposite poles b. share a single kinetochore c. synapse with each other d. do not exist

b. share a single kinetochore

38. The anticancer drug taxol acts to a. block microtubule organizing centers. b. stabilize microtubules and thus inhibit disassembly. c. block microtubule assembly by binding to free tubulin. d. accelerate microtubule disassembly by binding to tubulin in microtubules, causing those molecules to exit the microtubule more quickly. e. Both a and c

b. stabilize microtubules and thus inhibit disassembly

b. stabilize microtubules and thus inhibit disassembly.

The retinoblastoma protein (Rb) binds to and inhibits a. oncogenes. b. transcription factor E2F. c. p53. d. cyclin-dependent kinase.

b. transcription factor E2F.

C-myc becomes an oncogene in Burkitt's lymphoma and several plasmacytomas by a a. deletion of a regulatory sequence. b. translocation to the immunoglobulin heavy chain locus. c. duplication. d. point mutation.

b. translocation to the immunoglobulin heavy chain locus.

recombination complex

binds the matching DNA sequence in the nearby homolog and helps reel in its partner

G1 Damaged DNA Checkpoint

breaks in your chromosomes, important to fix in G1 before you enter S-phase and start replicating DNA. In the case of damage, double-strand break... 1. A protein kinase becomes active and phosphorylates p53. 2. Phosphorylated p53 becomes stable and active, and becomes a transcription factor (in an unphosphorylated state, it's targeted by degradation). 3. Active p53 binds to upstream regulatory regions of different genes and promotes transcription. 4. One of the genes is the p21 gene: CDK inhibitor protein is transcribed and translated. 5. p21 binds to G1/S and S-phase cyclin-CDK complexes and inhibits them. As long as there's damage, p53 is active, which promotes the production of p21, which inhibits the G1/S and S-phase cyclin-CDKs from becoming active. Will NOT enter S phase as long as this signaling pathway is active. **Similar pathway operates if damage occurs during G2, which inhibits Cdc25, so cell can't activate M-phase CDK-cyclin.

Inhibitors of apoptosis (IAPs) regulate caspases. Which of the following statements about IAPs is false? a. IAPs were discovered in virus-infected insect cells as viral proteins that inhibit apoptosis of the host cell in response to viral infection. b. IAPs target caspases for ubiquitination and degradation in the proteasome. c. IAPs are activated through the p53 pathway. d. IAPs interact directly with caspases.

The Bcl-2 family of proteins is divided into three functional groups that contain and share as many as four Bcl-2 homology domains (BH domains). Which of the following is common to all members of the Bcl-2 family? a. BH1 b. BH2 c. BH3 d. BH4

The PI 3-kinase pathway is important in countering apoptosis in healthy cells and promotes cell survival. Which of the following statements about the PI 3-kinase pathway is false? a. PI 3-kinase is activated by a receptor tyrosine kinase. b. PIP3 activates Akt, a serine/threonine kinase. c. Activated Akt phosphorylates and activates Bad. d. PI 3-kinase phosphorylates PIP2 to form PIP3.

Which of the following statements about caspases is false? a. They cleave target proteins after aspartic acid residues in their substrate proteins. b. They inhibit DNAse which, when activated, fragments nuclear DNA. c. They predominantly break up Golgi membranes, which in turn release other caspases to cleave nuclear lamins and cytoskeleton proteins. d. They contain cysteine residues in the active site.

Which of the following statements is true in reference to Bax and Bak, two members of the Bcl-2 family? a. Bax and Bak are antiapoptotic proteins that function to repress apoptosis in cells. b. Bax and Bak act as ligands to the apoptosome in activation caspases. c. When activated, Bax and Bak form oligomers in the outer membrane of mitochondria, leading to the release of cytochrome c. d. Bax and Bak directly activate caspase-9.

Which of the following are the three core transcription factors that can reprogram adult somatic cells into induced pluripotent cells? a. Oct4, c-Myc, and Klf4 b. Sox2, c-Myc, and Nanog c. Sox2, Oct4, and Nanog d. Sox2, Oct4, and Hedgehog

c. Sox2, Oct4, and Nanog

11. Short actin filaments bind to tetramers of which protein to form the cytoskeleton of erythrocytes? a. Myosin b. α-actinin c. Spectrin d. Ankyrin e. Arp2/3 Textbook Reference: Structure and Organization of Actin Filaments, p. 482

c. Spectrin

21. The desmin filaments in muscle cells connect a. actin filaments to the Z line. b. actin filaments to the plasma membrane at the ends of myofibrils. c. Z lines of adjacent myofibrils. d. myosin filaments to the Z line. e. tropomyosin filaments to the Z line.

c. Z lines of adjacent myofibrils

c. Z lines of adjacent myofibrils.

A tumor is a. a benign growth. b. a cancerous growth. c. any abnormal growth of cells. d. a malignant growth.

c. any abnormal growth of cells.

37. Both colchicine and colcemid a. block microtubule organizing centers. b. block microtubule disassembly by binding to microtubule ends. c. block microtubule assembly by binding to free tubulin. d. accelerate microtubule disassembly by binding to tubulin in microtubules, causing those molecules to exit the microtubule more quickly. e. Both a and b

c. block microtubule assembly by binding to free tubulin

c. block microtubule assembly by binding to free tubulin.

39. The major microtubule-organizing center in most animal cells is the a. kinetochore. b. centriole. c. centrosome. d. centromere. e. kinetosome.

c. centrosome

39. The major microtubule-organizing center in most animal cells is the a. kinetochore. b. centriole. c. centrosome. d. centromere. e. kinetosome. Textbook Reference: Microtubules, p. 507

c. centrosome.

The M phase checkpoint detects: a. the presence of MCM activity b. ending or completion of G2 phase c. chromosome alignment and attachment of mitotic spindle d. Chromosome alignment e. spindle attachment of telomeres

c. chromosome alignment and attachment of mitotic spindle

which of the following is not tubuline related a. beating of a cilia b. chromosome movement c. cytokinesis d. vesicle transport e. none of the above, all are based on actin - myosin interaction

c. cytokinesis ( also phagocytosis)

43. Microtubules are not involved in a. movement of chromosomes during mitosis. b. transport of membranous vesicles in the cytoplasm. c. cytokinesis of animal cells. d. movement of cilia and flagella. e. positioning of Golgi in cells.

c. cytokinesis of animal cells

c. cytokinesis of animal cells.

Most mitochondrial proteins are synthesized on a. mitochondrial ribosomes from nuclear mRNAs b. cytoplasmic ribosomes; they are imported cotranslationally as they are being synthesized c. cytoplasmic ribosomes; they are imported after they are completely synthesized d. mitochondrial ribosomes from mitochondrial mRNAs

c. cytoplasmic ribosomes; they are imported after they are completely synthesized

The cell cycle checkpoints in G1 and G2, which are similar, detect? a. chromosome misalignment b. levels of cyclin D c. damaged DNA d. levels of Chk1/2 e. levels of p53

c. damaged DNA

25. Keratin filaments are anchored to junctions called a. adherens junctions. b. tight junctions. c. desmosomes. d. gap junctions. e. neuromuscular junctions.

c. desmosomes

25. Keratin filaments are anchored to junctions called a. adherens junctions. b. tight junctions. c. desmosomes. d. gap junctions. e. neuromuscular junctions. Textbook Reference: Intermediate Filaments, p. 501

c. desmosomes.

31. Microtubules are assembled from a. alpha-tubulin dimers. b. beta-tubulin dimers. c. alternating alpha-tubulin dimers and beta-tubulin dimers. d. dimers of alpha- and beta-tubulin. e. trimers of 2 alpha- and 1 beta-tubulin

c. dimers of alpha- and beta- tubulin

48. A male patient at a medical clinic presents with infertility due to nonmotile sperm and an inability to clear mucous from his respiratory tract. Other tissues are normal. You suspect that these symptoms may be caused by mutant a. tubulin. b. kinesin. c. dynein. d. tau protein. e. MAP 1.

c. dynein

c. dynein.

Apoptotic cells produce "eat me" signals, which include _______ of cell surface _______. a. loss; phosphatidylserines b. gain; phosphatidylethanolamines c. gain; phosphatidylserines d. loss; carbohydrates

c. gain; phosphatidylserines

Using approaches similar to those of Takahashi and Yamanaka, scientists have now reprogrammed adult fibroblasts to become a. red blood cells. b. platelets. c. heart muscle cells. d. adipocytes.

c. heart muscle cells.

Ced-9 functions directly to a. stimulate Ced-3. b. inhibit Ced-3. c. inhibit Ced-4. d. stimulate Ced-4.

c. inhibit Ced-4.

41. The role of the centrosome is to a. determine the center of the cell. b. determine the position of the nucleus. c. initiate microtubule growth. d. adhere to the plus ends of microtubules. e. add tubulin dimers to the minus ends of microtubules.

c. initiate microtubule growth

c. initiate microtubule growth.

The microtubles that overlap in the center of the mitotic spindle are called _________ microtubles a. kinetochore b. astral c. interpolar d. minus-end

c. interpolar

21. Which of the following classes of microtubules is attached to chromosomes? a. Astral microtubules b. Interphase microtubules c. Kinetochore microtubules d. Polar microtubules

c. kinetochore microtubules

Polar microtubules a. are attached to kinetochores. b. are attached to the contractile ring. c. overlap in the center of the spindle. d. pull kinetochores poleward.

c. overlap in the center of the spindle.

c. protein translocation into the ER

The most frequently encountered oncogene in human tumors is a. fos. b. src. c. ras. d. myc.

c. ras.

11. Short actin filaments bind to tetramers of which protein to form the cytoskeleton of erythrocytes? a. Myosin b. alpha-actinin c. Spectrin d. Ankyrin e. Arp2/3

c. spectrin

What would be the outcome or effect on mitosis if MPF does not phosphorylate GM130? a. sister chomatids would be unable to separate despite being pulled to opposite poles of the cell b. nuclues would not reform during telophase c. the ER and Golgi Apparatus would fail to distribute evenly between the two new daughter cells d. the chromsomes would not condense e. metaphase and anaphase would fail to occur

c. the ER and Golgi Apparatus would fail to distribute evenly between the two new daughter cells

9. The basis for muscle contraction is a. rotation of myosin fibers around actin fibers. b. expansion of the sarcomere. c. the sliding of myosin and actin fibers past one another. d. movement of the Z discs away from one another. Textbook Reference: Actin, Myosin, and Cell Movement, p. 489

c. the sliding of myosin and actin fibers past one another.

c. the sliding of myosin and actin fibres past one another

20. Which of the following statements about cilia is false? a. They are about 10 micrometers in length, and cells that have them usually have many of them. b. They can be used to move fluids over the cell surface or to move the cell through fluids. c. They are projections of the plasma membrane supported by microfilaments. d. Their movement relies upon the motor activity of axonemal dynein.

c. they are projections of the plasma membrane supported by microfilaments

Early experiments by Takahashi and Yamanaka showed that a set of four genes introduced by retroviral expression are capable of transforming somatic cells into induced pluripotent stem cells. The four proteins encoded by these genes were all a. calcium-binding proteins. b. tyrosine kinases. c. transcription factors. d. G-protein coupled receptors.

c. transcription factors.

When stem cells of the intestinal epithelium and epidermis divide, they give rise to two different cells: one stem cell and one _______ cell. a. goblet b. crypt c. transit-amplifying d. G0

c. transit-amplifying

35. The microtubule behavior in which tubulin adds at the plus end, fluxes through a constant-length microtubule, and comes off the minus end is called a. an equilibrium state. b. dynamic instability. c. treadmilling. d. recycling. e. directional transport.

c. tread milling

6. The phenomenon that takes place at a concentration of free actin at the midpoint between the critical concentrations of the barbed and pointed ends of an actin filament is called a. assembly. b. dynamic instability. c. treadmilling. d. disassembly. e. walking.

c. tread milling

c. treadmilling.

44. Kinesin 1 is a motor protein molecule consisting of a. two heavy chains. b. one heavy chain and two light chains. c. two heavy chains and two light chains. d. two heavy chains and four light chains. e. four heavy chains and four light chains.

c. two heavy chains and two light chains

c. two heavy chains and two light chains.

13. In cell movement, branched actin filament growth pushes against the cell membrane. Proteins involved in this process include all of the following except a. Arp2/3 b. profilin c. vinculin d. WASP/Scar

c. vinculin

if mammalian cell were grown in the absence of growth factors, the cell would most likely a. progress through the cell cycle normally b. die c. would remain in G0 d. would become stuck in M phase e. would push quickly to G2

c. would remain in G0

FADD recruits and activates initiator

caspase-8. (activated by dimerization rather than proteolysis)

Apoptosome dimerizes-activates initiator

caspase-9

Procaspases convert other procaspases to

caspases.

Peroxisomes contain the enzyme

catalase

peroxisomes contain the enzyme ______, which breakes down H2O2 into H2O and oxygen.

catalase

protein glycosylation reaction -mediated by what?

catalyzed by oligosaccharyl transferase -mediates transfer of oligosaccharide to the ASN reside on the protein (N-linked protein glycolsylation) -enzyme is closely associated with the SEC61 complex so protein modifications occur relatively quickly following translocation into lumen

PDI (protein disulfide isomerase)

catalyzes disulfide bond formation, one of the most abundant proteins in the ER since oxidizing environment allows S-S linkages catalyzes oxidation of -SH groups on Cysteines to form disulfide bonds (S-S) promotes disulfide bonds in ER since cytosol is a reducing environment that breaks all disulfide bonds

Ultraviolet radiation increases the likelihood of a cell's becoming malignant primarily because UV radiation

causes mutations in DNA

Mutation of ATM

causes xray sensitivity and increased rates of cancer. known as ataxia telengiectasia

SCF is controlled by

changes in the phosphorylation state of its target proteins

Protein folding in the ER is assisted by

chaperones

which of the following drugs blocks the assembly of actin filaments

cytochalasin

which of the following drugs blocks the assembly of actin filaments colchicine cytochalasin phalloidin taxol

cytochalasin

Bone marrow transplants are used to treat patients with which of the following diseases? a. Aplastic anemia b. Hemoglobin disorders c. Immune deficiencies d. All of the above

TNF and related cytokines can directly induce apoptosis. Which of the following statements about TNF-mediated induction of apoptosis is true? a. TNF binds a trimeric receptor complex on the surface of the cell membrane. b. Upon receptor binding, caspase-8 is activated through an adaptor protein. c. Caspase-8 activates Bid, which in turn activates Bax and Bak and then feeds into the mitochondrial pathway. d. All of the above

Which of the following cells cannot develop from hematopoietic stem cells? a. Macrophages b. Platelets c. B lymphocytes d. Satellite cells

Which of the following diseases represents an ideal target for therapeutic cloning? a. Diabetes b. Parkinson's disease c. Spinal cord injury d. All of the above

Which of the following events occurs during apoptosis? a. Fragmentation of chromosomal DNA b. Condensation of chromatin c. Breaking up of the cell nucleus d. All of the above

Which of the following represents a viable source of stem cells? a. Umbilical cord blood b. Bone marrow c. An embryo d. All of the above

Which of the following statements about cloning by somatic cell nuclear transfer is false? a. The nucleus of an adult somatic cell is transferred to an enucleated unfertilized egg. b. Somatic cell nuclear transfer was first carried out in frogs in the 1950s. c. In the laboratory, the cloned egg is cultured to an early embryo stage and then transferred to a foster mother. d. The cloned embryo is genetically identical to the foster mother.

46. What cell components are kinesins able to transport along microtubules? a. Membranous vesicles and mitochondria b. Endoplasmic reticulum c. mRNAs d. All of the above e. None of the above Textbook Reference: Microtubule Motors and Movement, pp. 515-516

d. All of the above

A hematopoietic stem cell may give rise to which of the following differentiated cells? Select one: a. Erythrocytes. b. Macrophages. c. Granulocytes. d. All of the above. Page 1 of 3

d. All of the above.

7. In red blood cells, which of the following cytosolic proteins is the link between the plasma membrane and the spectrin/actin network beneath the cell surface? a. Band 3 b. Glycophorin c. Dystrophin d. Ankyrin Textbook Reference: Structure and Organization of Actin Filaments, pp. 482-483

d. Ankyrin

An apoptosome is a complex containing multiple subunits of: Select one: a. Apaf-1. b. Apaf-1 and caspase-9. c. Apaf-1 and caspase-3. d. Apaf-1, caspase-9, and cytochrome c.

d. Apaf-1, caspase-9, and cytochrome c.

34. When does the GTP bound to β-tubulin hydrolyzed to GDP and Pi? a. During formation of the α-β dimer b. During polymerization of dimers onto microtubules c. During depolymerization of dimers from microtubules d. Following polymerization but before depolymerization e. Following depolymerization of dimers from microtubules Textbook Reference: Microtubules, p. 505

d. Following polymerization but before depolymerization

2. Actin exists in cells in two major forms called a. monomers and dimers. b. α-actin and β-actin. c. G actin and D actin. d. G actin and F actin. e. actin 1 and actin 2. Textbook Reference: Structure and Organization of Actin Filaments, p. 474

d. G actin and F actin.

17. Myosin _______ is present in muscle sarcomeres. a. I b. II c. III d. IV e. V

d. II

11. Which of the following is true about myosin I? a. It is involved in muscle contraction. b. It has a long α-helical tail through which it forms homodimers. c. It does not act as a molecular motor. d. It links the actin bundles to the plasma membrane in the microvilli of intestinal cells.

d. It links the actin bundles to the plasma membrane in the microvilli of intestinal cells.

26. Which of the following is a protein that can link intermediate filaments with actin filaments and microtubules? a. α-actinin b. β-catenin c. Integrin d. Plectin e. Laminin Textbook Reference: Intermediate Filaments, p. 501

d. Plectin

Which of the following is not a key property of stem cells in tissues? Select one: a. They divide to produce one daughter cell that remains a stem cell. b. They divide to produce one cell that then differentiates. c. They exhibit a property of self-renewal. d. They divide within each tissue to maintain a set number of cells.

d. They divide within each tissue to maintain a set number of cells.

46. What cell components are kinesins able to transport along microtubules? a. Membranous vesicles and mitochondria b. Endoplasmic reticulum c. mRNAs d. All of the above e. None of the above

d. all of the above

The unfolding response involves a. general inhibition of protein synthesis b. increased synthesis of chaperons c. increased activity of proteosomes d. all of the above e. non of the above

d. all of the above

10. Actin filaments are bound into bundles of parallel filaments by the proteins a. filamin and spectrin. b. troponin and tropomyosin. c. profilin and thymosin. d. -actinin and fimbrin. e. All of the above

d. alpha-actinin and fimbrin

7. In red blood cells, which of the following cytosolic proteins is the link between the plasma membrane and the spectrin/actin network beneath the cell surface? a. Band 3 b. glycophorin c. dystrophin d. ankyrin

d. ankyrin

16. The barbed (fast growing) end of actin filaments is located in muscle a. at the AI junction. b. near the M line of a contracted sarcomere c. at the inner margin of the AI zone d. at the Z disc e. none of the above

d. at the Z disc

16. The barbed (fast growing) end of actin filaments is located in muscle a. at the A/I junction. b. near the M line of a contracted sarcomere. c. at the inner margin of the A/I zone. d. at the Z disc. e. None of the above Textbook Reference: Actin, Myosin, and Cell Movement, p. 490

d. at the Z disc.

To become active, Cdk1 must a. bind cyclin. b. bind cyclin and be phosphorylated on tyrosine 15 and be dephosphorylated on threonines 14 and 161. c. bind cyclin and be phosphorylated on tyrosine 15 and threonines 14 and 161. d. bind cyclin and be phosphorylated on threonine 161 and be dephosphorylated on threonine 14 and tyrosine 15.

d. bind cyclin and be phosphorylated on threonine 161 and be dephosphorylated on threonine 14 and tyrosine 15.

The gene ced-3 of C. elegans codes for a proteolytic enzyme that is a a. chymotrypsin. b. ubiquitin-targeted protease. c. serine protease. d. caspase

d. caspase.

VEGF is secreted by a. injured endothelial cells. b. injured smooth muscle cells. c. platelets. d. cells deprived of oxygen.

d. cells deprived of oxygen.

31. Microtubules are assembled from a. α-tubulin dimers. b. β-tubulin dimers. c. alternating α-tubulin dimers and β-tubulin dimers. d. dimers of α- and β-tubulin. e. trimers of 2 α- and 1 β-tubulin. Textbook Reference: Microtubules, p. 505

d. dimers of α- and β-tubulin.

Members of the Bcl-2 family of proteins are a. all caspases. b. all proapoptotic. c. all antiapoptotic. d. either antiapoptotic or proapoptotic.

d. either antiapoptotic or proapoptotic.

Passage of animal cells through the cell cycle is regulated primarily by a. intracellular second messengers. b. the availability of nutrients. c. direct cell surface interactions. d. extracellular growth factors.

d. extracellular growth factors.

23. Vimentin is the major intermediate filament protein of _______ cells. a. epithelial b. striated muscle c. nerve d. fibroblast e. None of the above

d. fibroblast

24. Which of the following is not an intermediate filament protein? a. Vimentin b. Nestin c. Lamin A d. Fibronectin e. Desmin

d. fibronectin

34. When does the GTP bound to -tubulin hydrolyzed to GDP and Pi? a. During formation of the -dimer b. During polymerization of dimers onto microtubules c. During depolymerization of dimers from microtubules d. Following polymerization but before depolymerization e. Following depolymerization of dimers from microtubules

d. following polymerization but before depolymerization

42. Rings of the protein _______ in the pericentriolar material nucleate microtubule assembly. a. centrin b. pericentrin c. alpha-tubulin d. gamma-tubulin e. beta-tubulin

d. gamma-tubulin

Which of the following is charctersitc of the first division of mesios but mitosis? a. chromosomes are duplicated prior to division b. sister chromatids are attached to each other at the centromere c. nuclear membrane and nucleolus disappear in phropase d. homologous chromosomes pair e. spindle fibers form and attach to kinetochores

d. homologous chromosomes pair

A tumor promoter is a type of carcinogen that a. induces apoptosis of healthy cells. b. immortalizes cancer cells. c. decreases chromosomal stability. d. increases cell proliferation.

d. increases cell proliferation.

During mitosis, the rate of microtubule turnover a. doubles. b. decreases. c. stays the same. d. increases five- to tenfold.

d. increases five- to tenfold.

Drugs that inhibit general expression or function of an oncogene will a. kill tumor cells as well as normal cells. b. kill tumor cells only. c. inhibit division of tumor cells only. d. inhibit cell division of tumor cells and normal cells.

d. inhibit cell division of tumor cells and normal cells.

Which of the following is FALSE about cyclin B? a. it is expressed in G2 b. is required for the activation of Cdc2 c. is a component of MPF d. it cycles between active and inactive states in the cell cycle (but is always present) e. its destruction is cause by APF/APC

d. it cycles between active and inactive states in the cell cycle (but is always present)

Cells that die as the result of acute injury undergo a. sepsis. b. apoptosis. c. execution. d. lysis.

d. lysis.

Crossing over between maternal and paternal chromosomes takes place during? a. mitosis b. meiosis II c. fertilization d. meiosis I e. interphase

d. meiosis I

4. Actin-binding proteins have all of the following functions except a. filament initiation and polymerization. b. end capping. c. filament severing/depolymerization d. microfilament incorporation into the extracellular matrix

d. microfilament incorporation into the extracellular matrix

4. Actin-binding proteins have all of the following functions except a. filament initiation and polymerization. b. end capping. c. filament severing/depolymerization. d. microfilament incorporation into the extracellular matrix. Textbook Reference: Structure and Organization of Actin Filaments, p. 476

d. microfilament incorporation into the extracellular matrix.

What type of cell division is responsible for the repair of your skin following a sunburn? a. fertilization b. meiosis c. both mitosis and meiosis d. mitosis

d. mitosis

28. Lou Gehrig's disease (ALS) can result from a mutation in the gene for the intermediate filament protein a. keratin. b. vimentin. c. glial fibrillary acidic protein. d. neurofilament protein. e. desmin.

d. neurofilament protein

51. Adjacent microtubule doublets in cilia and flagella produce a bending movement because a. tubulin is contracting on one side of the microtubules. b. dynein is contracting on one side of the microtubules. c. kinesin is contracting on one side of the microtubules. d. nexin links between microtubule doublets convert a sliding movement into a bending movement. e. dynein heads move in a plus-end direction. Textbook Reference: Microtubule Motors and Movement, p. 518

d. nexin links between microtubule doublets convert a sliding movement into a bending

d. nexin links between microtubule doublets convert a sliding movement into a bending movement

branching of actin filaments can be initiated by a. capping proteins b. formin c. ADF/cofilin d. none of the above

d. none of the above

branching of actin filaments can be initiated by a. capping proteins b. formin. c. ADF/ cofilin d. none of the above

d. none of the above (Arp2/3)

26. Which of the following is a protein that can link intermediate filaments with actin filaments and microtubules? a. alpha-actinin b. beta-catenin c. Integrin d. Plectin e. Laminin

d. plectin

Studies on cell cycle mutants in budding and fission yeasts demonstrated that cdc2 and cdc28 both encode a a. protein phosphatase. b. growth factor. c. ubiquitin ligase. d. protein kinase.

d. protein kinase.

The stem cells of skeletal muscle are called a. myo-stem cells. b. myocytes. c. myoblasts. d. satellite cells.

d. satellite cells.

Mitosis does NOT produce which of the following? a. epithelial cells b. white blood cells c. liver cells d. sex cells

d. sex cells

Tumor initiation occurs in a a. single protein molecule. b. few cells. c. single tissue. d. single cell.

d. single cell.

A scientist notices that cells being grown in culture have ceased to divide. Further investigation demonstrates the cells have abnormally segregated chromosomes. which checkpoint are these cells likely arrested at? a. DNA damage checkpoints b. Restriction checkpoint c. START d. spindle assembly checkpoint

d. spindle assembly checkpoint

17. A centrosome is a. a cylindrical structure made up of nine triplets of microtubules. b. a chromosomal region that connects sister chromatids during mitosis and attaches them to the spindle. c. a protein structure that binds centromeres and mediates the attachment of chromosomes to the spindle. d. the major microtubule-organizing center in animal cells.

d. the major microtubule-organizing center in animal cells.

15. The discovery that the intermediate filament protein keratin is essential for mechanical strength of epithelial cell layers was made in a. cell cultures. b. organ cultures. c. small invertebrates. d. transgenic mice.

d. transgenic mice

8. Actin filaments are stabilized by a. cofilin. b. gelsolin. c. thymosin. d. tropomyosin. e. fimbrin.

d. tropomyosin

8. Actin filaments are stabilized by a. cofilin. b. gelsolin. c. thymosin. d. tropomyosin. e. fimbrin. Textbook Reference: Structure and Organization of Actin Filaments, p. 476

d. tropomyosin.

desmin keeps muscle myofibrils in register nucleation formation of tubulin oligomers myosin subfragment 1 (S1) decorates actin microfilaments gelsolin breaks and caps actin filaments microvilli increase cell surface area treadmilling assembly and disassembly on opposite ends of the same filament tropomodulin prevents loss of subunits from filament minus end lamin forms scaffold underlying nuclear envelope MAPs stabilizes and organizes microtubules EB1 binds to microtubule plus ends plectin crosslinks microtubules to intermediate filaments axonemal microtubules is in cilia and flagella phosphoinositides binds to profilin and CapZ filamin connects crisscrossing actin filaments into 3D networks Arp2/3 complex nucleates actin filament branches

Actin filaments -

distinct arrangements associated with the apical and basolateral membranes

cleavage

division of cells in the early embryo; rapid cell division producing a cluster of cells approximately the same size as the original zygote; dividing cells are referred to as blastomeres

Cytokenesis

division of the cytoplasm to form two separate daughter cells

centrosomes and microtubules are separated from the chromosomes by the

double-membrane barrier of the nuclear envelope

e. both b and c

e. desmin.

following internalization, clathrin-coated vesicles shed their coats and fuse with what structures?

early endosomes

dissociation of the LDL receptor from the LDL particle takes place in ______________ and is caused by _____________

early endosomes, acidic pH

dissociation of the LDL receptor from the LDL particle takes place in ________ and is caused by _________

easy endosome, low PH

The reduced cofactors transfer their electrons to O2 to reduce H2O via a set of four membrane-bound complexes collectively called the ______. These complexes pump _______ across the ______membrane.

electron transport chain, H+, inner mitochondrial membrane

the reduced cofactors transfer their electrons to O2 to produce H2O via a set of membrane-bound complexes known collectively as ___________. some complexes pump __________ across the _______________.

electron transport chain, protons, inner mitochondrial membrane

Differentiation occurs during

embryogenesis, as well as when stem cells produce progeny that will replace older or damaged cells in tissues.

The ability to induce fully differentiated cells to adopt pluripotent stem cell qualities overcomes both the

ethical and immune rejection challenges of stem cell work.

The types of cells division that created sperm and egg cells is called mitosis true or false

false

true/false about 50% of mitochondrial proteins are coded by mitochondrial DNA

false

true/false cadherins mediate the adhesions of cells to extracellular matrix

false

true/false krebs cycle is major process of ATP production in eukaryotic cells

false

true/false most mitochondria use the universal genetic code

false

true/false only a small percentage of mitochondrial diseases are inherited from father

false

Brown and Goldstein discovered the mechanism of cholesterol uptake by studying fibroblasts from children with what disease

familial hypercholesterolemia

The key insights came from studies of patients with the inherited disease known as __________________

familial hypercholesterolemia

the key insights came from studies of patients with the inherited disease known as

familial hypocholesterolemia (FH)

Which of the following is not associated with the bundle of microfilaments supporting each microvillus in small intestine mucosal cells?

fascin

You discover a dog suffering from an autoimmune response. On further investigation, you find that the cells of various tissues are loosely arranged and do not have characteristic shapes, and the animal is prone to hemorrhaging because of poor blood clotting. Based on these results, the target of the autoimmune response is most likely to be

fibronectins.

When researchers incubated purified vesicles, nerve cytosol from squid giant axons, and MTs in the presence of AMPPNP, the vesicles bound tightly to the microtubules but did not move. Scientists then used AMPPNP to promote its tight binding to MTs, and the MTs with bound proteins were collected by centrifugation. The main protein purified in this way promotes movement of vesicles away from the cell body, where the nucleus resides. What was this protein?

kinesin

Translation of secrtary protein mRNA on free ribosomes yielded proteins that were slightly_________ then when microsomes (ER partials) were added. The reason for that is that _____________________

longer, signal peptidase in the ER cleaves the signal peptide on the secretery P larger, in microsomes the signal sequence is cleaved off. or When microsomes were added to the system, the growing polypeptide chains were incorporated into the microsomes and the signal sequences were removed by proteolytic cleavage.

Differentiated cell can be transplanted into

mutant/disease-susceptible individuals as therapeutic treatment:

Mutations in p53

occur is 1/2 of all human cancers

Licensing

occurs in early G1 ORC Cdc6 and Cdt1 combine with the ORC to load inactive DNA helicase (Mcm) around the DNA next to origin, this forms the preRC and the origin is now licensed for replication

Signaling pathway directs

organization/ orientation of the cytoskeleton (microtubules and/or microfilaments, depending on the system).

Describe structure of ER

organized into netlike labyrinth of branching tubules and flattened sacs that extends through the cytosol, continuous with nucleus ER and nuclear membrane form continuous sheet enclosing a single internal space, ER lumen

ATM and ATR localize to the site of damage and phosphorylate

other target proteins that lead to cell cycle arrest

During apoptosis, a phospholipid "scramblase" moves phosphatidylserine molecules to the

outer leaflet of the plasma membrane where they are recognized as an "eat me" signal by specialized macrophages.

Bak/Box oligomerization generates pores in

outer mitochondrial membrane and releases cytochrome c

what atom serves as the terminal electron acceptor on the electron transport chain

oxygen

The key protein involved in "deciding" whether a cell with DNA damage should delay its cell cycle or undergo apoptosis is

p53

How does p53 activation in response to DNA damage affect cell cycle progression and cell survival?

p53 activation leads to expression of its target genes including p21 causing cell cycle arrest and BH3-only Bcl-2 family members inducing apoptosis.

Transient amplifying cells: Signals these cells received from their environment directs them down

pathways of terminal differentiation

centrosome is made up of

pericentriolar matrix with paired centrioles

gastrulation

phase of early development in which the morphology of the embryo is dramatically restructured by cell migration; purpose of gastrulation is to position the three embryonic germ layers

As well as providing the physical context for signals that will be received by

proliferating precursor cells to receive the signals that will promote their differentiation.

Activate genes encoding proteins and micro-RNAs important for the

proliferation and self-renewal of ES cells

for an animal cell to proliferate, it must

receive stimulation from a mitogen

SRP

signal recognition particle rodlike nucleoprotein, part protein part RNA -6 polypeptides -1 RNA recognizes and targets specific proteins to the ER recognizes signal sequence as it emerges from ribosome, causes a pause in translation, delivers ribosome with mRNA and partial polypeptide to SRP receptor in ER membrane, composed of an RNA molecule with 6 protein subunits, GTPase

Translation and translocation process at translocator

signal sequence functions to open translocation channel signal sequence bound to translocator while rest of protein is threaded through like a loop after all protein is in lumen, signal peptidase cleaves signal sequence from protein signal sequence released from translocation channel to lipid bilayer, where it is rapidly degraded

Stem cells are formed in niches that provide

signals to maintain a population of undifferentiated stem cells but prevent excess proliferation.

Apoptosis is needed during embryonic development to form

structure, organs and tissues (e.g. spaces between the digits, pruning unneeded nerve cells).

Asymmetric distribution of Par proteins in cleaving cells dictates

structures of organisms and stem cell fates.

SCF only recognizes

substrates that are phosphorylated

Cells have intrinsic apoptosis pathways for

suicide without the release of cytosolic contents.

how does the kinetochore sense a correct attachment?

tension-sensing (tension is checked during the spindle checkpoint)

At the base of each macrovillus lies a specialized compartment known as

the Intestinal Crypt: the stem cell niche for intestinal epithelial cells.

what is the fate of the LDL receptors after the fusion described in the above question?

the LDL is released from the receptors because of the acidic pH in the endosome. It is then recycled to the plasma membrane.

Residual midbody components mark

the cleavage site that helps to orient the spindle in future cell divisions

what drives ATP synthesis by ATP synthase

the energy from the electron transport chain creates a ph gradient across the inner mitochondrial membrane (from matrix to intermembrane space). the flow of protons back into the matrix (dowr) the concentration gradient though ATP synthases drives ATP synthesis ( makes the ATP)

the cleavage furrow narrows

the form a midbody

cell senscence seems to be caused by

the shortening of telomeres with every cell division.

Kinetochores attach sister chromatids to

the spindle

Cancer is usually caused by

the stepwise breakdown of normal cell regulatory processes

F-box protein

the subunit of SCF that binds phosphorylated targets. contains WD-repeats that mediate protein:protein interactions

a student you are tutoring comes to you carrying two centrifuge tubes, each with a pellet at the bottom. he knows that one tube contains a pellet of mitochondria and the other a pellet of chloroplasts, but he has them mixed up and cannot remember which is which. can you help him?

the tube with the green pellet is the chloroplasts because of the chlorophyll making it green. the other tube is the mitochondria pellet.

fertilization

the union of sperm and egg (haploid cells) to produce a zygote (diploid cells)

cell lineage

traces the birth order of cells progressively becoming more restricted in developmental potential and differentiating into specialized cell types

The ability to reprogram somatic cells into other types of differentiated cells (other than induced pluripotent stem cells) is referred to as

trans differentiation

The retinoblastoma protein (Rb) binds to and inhibits

transcription factor E2F.

Bind to the

transcription-control regions of many genes

If a cell normally has 12 chromosomes, how many chromosomes would be present in each cell at the end of meiosis 2 if a single pair of homologous chromosomes failed to separate during anaphase 1?

two daughter cells will each have five chromosomes and two daughter cells will each have seven chromosomes.

Mad 2 is recruited to

unattached kinetochores

Cyclin - dependent kinases (CDKs)

• Family of protein kinases • Activity of the kinase activity is cyclical • Regulates the proteins that carry out cyclical cellular functions • Are heavily regulated • Require binding to a cyclin for activity • Stable protein levels across cell cycle • Animals have 8 CDKs

apoptotic cell morphological changes

•Dense chromatin condensation at nuclear periphery •Cell body shrinkage (most organelles remain intact) •Nucleus and cytoplasm fragmentation - •Forms membrane-enclosed apoptotic bodies •No loss of intracellular contents into extracellular milieu •Apoptotic bodies phagocytosed by surrounding cells.

Cell Bio Final

Related study sets

ABP yr 2

marketing chapter 1

MNGMT CH. 9

Chapter 2: Overview of the Financial System

1.3 Conditional Probability

GLO-BUS Quiz 1

Chapter 5-6 official test questions

Chapter 17 Textbook Questions

A Guide to Computer User Support Ch.11

Pharmacology- Adaptive Quiz

Mental Health EAQ

TestOut 6.1-6.5 Review

International Business Quiz 8

Equation for Photosynthesis

Ch, 10 leading, managing and delegating

The 7 Habits of Highly Effective People

Pharmacology Exam 3 PrepU and ATI Questions

Psychology Final Part 4

ANS Pharm Questions

Govt 8