Exam 2
about _____ of your neurons energy goes towards the sodium-potassium pump
2/3
During one cycle, the sodium-potassium pump binds and moves how many of each compound
3 Na and 3 K
What is the source of energy used to power the sodium-potassium pump? A) breakdown of ATP B) formation of ATP C) transport of ATP by the pump D) breakdown of GTP E) transport of GTP by the pump
A
What are diploids?
A cell that has 2 sets of chromosomes (2n) one from each parent
What is cotransport?
a substance that has been pumped across a membrane can do work as it diffuses back across the membrane
What is an electrogenic pump?
a transport protein that generates voltage across a membrane
The positive charge on the outside of the cell favors movement of __________ out of the cell
anions
If cells detach from their substance then they under go a type of programmed cell death called ______
anoikis
Avoidance of programmed cell death is also called _________________
apoptosis
Normal cells can usually repair DNA damage, but if not, will 'sacrifice' themselves through a process called
apoptosis
Water molecule must pass through __________ single file by turning sideways to move through the membrane
aquaporin
What has occurred at the end of G2?
chromosomes already have duplicated and aren't, visible and the centrosome has divided into 2
What happens during the S phase in interphase
chromosomes are duplicated
The most abundant component of the extracellular matrix in animals is
collagen
What are alleles?
different versions of genes
When the oxygen concentration is higher on the outside of the cell than the inside oxygen ______ rapidly into the cell. Conversely CO2 build up within the cell as a waste product of cellular respiration then later __________ of the cell
diffuses, diffuses
Which of the following statements about genes is incorrect?
each different type of cell within an organism has a unique set of genes
When does crossing over begin?
early in meiosis 1
Chemical and electrical forces work together to constitute an ________________________
electrochemical gradient
"into the cell"
endocytosis
sex cells/gametes are diploid/haploid
haploid
Cyanide binds with at least one molecule involved in producing ATP. If a cell is exposed to cyanide, most of the bound cyanide is likely to be localized within the ________
mitochondria
____________ is the original source of genetic variation among organisms
mutations
What are 2 organelles involved in the detoxification of harmful substances?
peroxisomes, smooth ER
Which of the following are found in both eukaryotic and prokaryotic cells?
plasma membrane, ribosomes, DNA, protein
In plants, adjacent cells are connected to each other through
plasmodesmata
concentration and electrical gradients favor the movement of _________________________ ions into the cell
positively charged ions
What important functions does the plasma membrane do
structural support, regulation of what move in and out of the cell, recognition between cells, communication between cells, binding of cells to other cells to form tissues and organs
Why does active transport use no energy from the cell
substances are moving from high to low concentrations
What is the most common cancer treatment?
surgery
What are the treatments of cancer?
surgery, radiation, chemotherapy
synaptonemal complex occurs during _____________
synapsis
What does chemotherapy do?
targets ant cells that are dividing
In eukaryotes, cellular respiration occurs primarily in
the mitochondria
What is active transport?
the movement of solutes with the input of energy from the cell
In humans, how many sister chromatids are there per cell at the conclusion of Meiosis I?
1
What is telomerase?
An enzyme that adds more of the protective telomerase cap.
Which of the following molecules can pass through the plasma membrane most easily? CO2 H+ water K+ glucose
CO2
Which of the following occurs in both mitosis and meiosis? Click ALL that apply. -Chromosome replication -Synapsis of chromosomes -Production of daughter cells -Alignment of chromosomes at the equator -Condensation of chromatin -Exchange of DNA between homologous nonsister chromatids -Reduction in DNA from diploid to haploid
Chromosome replication, Production of daughter cells, Alignment of chromosomes at the equator, condensation of chromatin
__________ are molecules that activate Cdk's. Their concentration fluctuates throughout the cell cycle
Cyclins
The parent cell that enters meiosis is diploid, whereas the four daughter cells that result are haploid. Which statement below correctly describes how cellular DNA content and ploidy levels change during meiosis I and meiosis II?
DNA content is halved in both meiosis I and meiosis II. Ploidy level changes from diploid to haploid in meiosis I, and remains haploid in meiosis II.
Which of the following are present in eukaryotes but NOT prokaryotes? DNA, DNA enclosed in a nuclear envelope, cell wall composed primarily of peptidoglycan, ribosomes, multicellularity, membrane bound organelles such as mitochondria and Golgi apparatus
DNA enclosed envelope, multicellularity, membrane bound organelles such as mitochondria and Golgi apparatus
Which of the following are present in BOTH plant AND animal cells? DNA enclosed in a nuclear envelope ribosomes chloroplasts large central vacuole mitochondria cell wall composed primarily of cellulose cell membrane microtubules
DNA enclosed in a nuclear envelope, ribosomes, mitochondria, cell membrane, microtubules
major function of the nucleus in all eukaryotic organelles
DNA storage
Which of the following are present in BOTH eukaryotes AND prokaryotes? DNA, DNA enclosed in a nuclear envelope, cell wall composed primarily of peptidoglycan, ribosomes, multicellularity, membrane bound organelles such as mitochondria and Golgi apparatus
DNA, ribosomes
Lysosomes function
Digestion and recycling
major function of the Mitochondrion in all eukaryotic organelles
Energy production
Once the system reaches equilibrium, will the two solutions have the SAME solute concentrations, this is because
Glucose will move out of the cell until it is in equal concentration inside and outside, Fructose will move into the cell until it is in equal concentration inside and outside, Water will move into the cell until the concentration of sugars (including sucrose) is the same on both in the inside and the outside
what is a tight junction?
Membranes of neighboring cells are pressed together, preventing leakage of extracellular fluid
What are cyclins?
Proteins that activate cyclin-dependent kinases (Cdks) via allostene regulation
What happens during telophase?
The nuclear envelope, one at each end, reforms from fragments of the orginal envelope and chromosomes become less condensed. At this point mitosis is considered complete and cytokinesis (division of the cytoplasm) are underway.
What occurs in the G1 phase of interphase?
a cell grows by producing proteins and cytoplasmic organelles
What are Haploids?
a cell with a single set of chromosomes (n)
In a normally functioning cell, the ras gene produces the Ras protein, which signals the presence of a growth factor, stimulating cell division. The ras gene is most accurately described as
a proto-oncogene
crossing over between a maternal and paternal chromosome results in
a recombinant chromosome
What are autosomes?
all chromosomes except sex chromosomes (in humans 1-22 are autosomes)
Which of the following are functions of the cell membrane? Click all that apply. -structural support -regulation of what moves in and out of cell -recognition between cells -communication between cells -binding of cells to other cells to form tissues and organs
all of them
Mutations create different _______
alleles
What do both prokaryotic and eukaryotic cells have?
cell membrane, cytosol within the cell, DNA, and ribosomes
Which of the following are present in prokaryotes but NOT eukaryotes? DNA, DNA enclosed in a nuclear envelope, cell wall composed primarily of peptidoglycan, ribosomes, multicellularity, membrane bound organelles such as mitochondria and Golgi apparatus
cell wall composed primarily of peptidoglycan
The Mitochondria is the cite for what
cellular respiration
What occurs during telophase 2 of meiosis 2?
cytokinesis is occurring at the same time, the nuclear envelope reforms and the cell pinches in 2
At high temperatures, the presence of cholesterol ___________ the fluidity of the cell membrane. At low temperatures, it _____________ fluidity.
decreases, increases
What are the major functions of vacuoles?
digestion, water balance, storage, disposal, growth
Somatic cells are dipolid/haploid
diploid
where does passive transport occur
directly across the membrane or with the help of a transport protein
What is sister chromatids?
duplicated chromosomes
Sister chromatids are separated from each other
during anaphase of meiosis II
Telomerase is present in what cells?
embryonic
At what phase are sister chromatids no longer identical
end of prophase 1
Some of the monomers will be used within the cell while what isn't needed is expelled through secretion, or ________________
exocytosis
Proteins that are embedded in cell membrane are _____________ proteins, while proteins that are attached to either the inner or outer face of the cell membrane are _____________ proteins.
integral, peripheral
The solutions in the two arms of this U-tube are separated by a membrane that is permeable to water and glucose but not to sucrose. Side A is half filled with a solution of 2 M sucrose and 1 M glucose. Side B is half filled with 1 M sucrose and 2 M glucose. Initially, the liquid levels on both sides are equal.Initially, in terms of tonicity, the solution in side A with respect to that in side B is
isotonic
Suppose there is a single cell in an aqueous environment with dissolved solutes. In a(n) ______________ environment, water will enter and leave a cell at the same rate. In a(n) ______________ environment, water will leave the cell, and the cell will undergo plasmolysis. In a(n) _________________ environment, water will enter the cell, causing it to swell and possibly burst.
isotonic, hypertonic, hypotonic
Water passes quickly through cell membranes because
it moves through aquaporins in the membrane
If a cell failed to pass a checkpoint between the S and G2 phases
it would have double the amount of DNA that it should have
Selective permeability refers to which aspect of the cell membrane?
its ability to regulate what enters and exits the cell
Sister chromatids are attached to each other through _____________
kinetochore proteins
What do prokaryotes have that eukaryotes don't?
lack a true nucleus, DNA consists of single circular chromosomes not enclosed in the nucleus, no linear membranes, cell wall made out of peptiodoglycan, single celled only
Main function of microtubules
maintenance of cell shape (compression resisting), cell motility (cilia and flagella), chromosome movements in cell division, and organelle movements
A ___________ neoplasm can spread through a process called ________________ .
malignant, metastasis
What does the cytoskeleton/cells skeleton provide
mechanical support, motility, regulation, and maintaining a cells shape
Somatic cells/ sex cells are formed through ____________
meiosis
The voltage, specially referred to as _______________, is electrical potential energy, acting as a battery
membrane potential
The M phase checkpoint ensures that all chromosomes are attached to the mitotic spindle. If this does not happen, cells would most likely be arrested in __________.
metaphase
what is the longest phase in mitosis?
metaphase (lasting up to 20 min)
During _____ chromosomes align single file along the equator of a haploid cell
metaphase II
If cells escape their home tissue and survive and divide in foreign sites then they __________
metastasize
During cytokinesis in animal cells, a cell pinches in half due to the formation of a cleavage furrow that is formed mainly by
microfilaments
The mitotic spindle is composed primarily of
microtubules
What 3 structures are present in eukaryotic cytoskeleton
microtubules, microfilaments, intermediate filaments
The mitotic phase includes what?
mitosis (division of the nucleus), cytokinesis (division of cytoplasm)
Cell division takes place during the ___________ phase
mitotic
Many events of mitosis depends on the __________________
mitotic spindle
What are the major functions of the Golgi apparatus?
modification of proteins and phospholipids, synthesis of polysaccharides, sorting and packaging of molecules
What is anchorage dependence?
most normal cells need to be attached to a substance be able to survive and divide
Is there energy expenditure in facilitated diffusion?
no
Maturation-promoting factor, or MPF, is a cyclin-dependent kinase that promotes a cell's entrance into mitosis from the G2 phase by activating a number of proteins important during mitosis, including several that contribute to the breakdown of the nuclear envelope. Based on this information, you know that MPF is most active during
prophase
what do extracellular matrix do in animal cells?
provide support, adhesion, movement, and regulation
a cell englufs particles by wrapping ___________ around it and forming a vesicle
pseudopodia
The G1 is frequently the most important checkpoint, hence, it was dubbed the ________________
restriction point
In eukaryotic cells, what is produced in the region known as the nucleolus?
ribosomes
A protein that is to be secreted from the cell would pass through the structures below in what order?
rough ER, Golgi apparatus, transport vesicle, plasma membrane
Once the system reaches equilibrium, will the two solutions have the SAME or DIFFERENT solute concentrations?
same
Which of the following proteins are produced by bound ribosomes? nuclear proteins cytosolic proteins secreted proteins endomembrane proteins
secreted proteins and endomembrane proteins
Passive transport relies on
the presence of a concentration gradient
the ability of a solution to cause a cell to gain to lose water is referred to as
tonicity
what are microtubule fibers made of?
tubulin
RB1 is a gene that produces retinoblastoma protein. This protein must be made inactive in order for a cell to proceed from the G1 to S phase of the cell cycle. Based on this information, RB1 can be classified as
tumor suppressor
BRCA1 and BRCA2 are what kind of gene?
tumor supressor
What is a chromatin?
uncondensed DNA
One reason cells need to maintain higher concentrations of certain substances within the cell than outside the cell is to maintain a ________ across their plasma membrane
voltage
What is Pinocytosis?
when a cell "drinks" extracellular fluid and dissolved solutes by forming infolds of the plasma membrane
What is phagocytosis?
when a cell "eats" particulate substances or small organisms
What are alternation generations?
when a cells can go back and fourth between a multicellular haploid and their diploid phase
What is contact inhibition/density-dependent inhibition?
when cells dont divide when touching eachother
are transport proteins specific to a particular substance
yes
A sperm and egg fuse to form _____________
zygote
Put the major events of meiosis in the correct order. Note that not all events are included. DNA is duplicated DNA is exchanged between sister chromatids pairs of homologous chromosomes converge on the metaphase plate homologous chromosomes are separated sister chromatids converge on the metaphase, as in mitosis plate sister chromatids are separated cytokinesis occurs, resulting in two daughter cells with a haploid set of duplicated chromosomes cytokinesis occurs, resulting in two daughter cells with a haploid set of non-duplicated chromosomes
1- DNA is exchanged between sister chromatids(prophase1). In this stage pair of homologous chromosome after forming bivalent exchange their DNA forming chismata.It is the 1st phase of prophase1 (pachytene) 2-Pairs of homologous chromosomes converge on the metaphase plate.(metaphase 1) All the pairs of homologous chromosomes are aligned in the middle of the cell and a fibre start attaching to the centromere of the cell called spindle fibre. 3-Homologous chromosomes are separated.(anaphase 1) during this stage the spindle fibre which are previously attached to the centromeres of the chromosomes started decreasing their length and pull the chromosomes towards the pole breaking their homologous attachment. 4-Cytokinesis occurs, resulting in two daughter cells with a haploid set of non-duplicated chromosomes.(Telophase)It is the last stage of meiosis 1 . After the sets of chromosomes reaching the poles a cleavage of cytoplasm starts dividing the cytoplasm in to two different cells.
If there are 20 chromatids in a cell, how many centromeres are there?
10
For a species with a diploid number of 8 chromosomes, how many different combinations of maternal and paternal chromosomes are possible for the gametes?
16
In a cell undergoing meiosis, there are 16 sister chromatids in the cell after the S phase of interphase. How many different outcomes are possible for the gametes?
16
What is crossing over?
2 homologous chromatids exchange DNA
What is sexual reproduction?
2 parent organisms combining genetic material to create diverse offspring. Having a unique combination of genes due to behavior of chromosomes
What is the average limit a cell can divide?
20-50
In a cell undergoing meiosis, there are 32 sister chromatids in the cell after the S phase of interphase. How many different outcomes are possible for the gametes?
256
For each cycle of the sodium-potassium pump ____ sodium ion(s) __________ the cell, and ___ potassium ion(s) ________ the cell, making the inside of the cell negatively charged relative to the outside of the cell
3, leave, 2, enter
During mitosis, if there are 8 sister chromatids in a cell at metaphase, how many chromosomes are there in each daughter cell following cytokinesis?
4
If there are 92 sister chromatids in a cell at metaphase of mitosis, how many chromosomes are there in each daughter cell following cytokinesis?
46
If there are 16 sister chromatids in a cell at metaphase, how many chromosomes are there in each daughter cell following cytokinesis?
8
he sodium-potassium pump functions to pump A) sodium ions out of the cell and potassium ions into the cell. B) sodium ions into the cell and potassium ions out of the cell. C) sodium and potassium ions into the cell. D) sodium and potassium ions out of the cell. E) sodium and potassium ions in both directions across the cell membrane
A
Which of the following most accurately describes apoptosis?
A damaged cell's DNA and organelles are fragmented, the cell shrinks and forms blebs, and it self-digests
What is binary fission?
A form of asexual reproduction in which the parent divides into two approximately equal parts
What is immunotherapy?
A form of cancer treatment that takes blood cells from a patient and fuses the blood with an antibody that is specifically designed to seek out and destroy the cancer cell.
What is the cyotskeleton?
A network of fibers extending throughout the cells cytoplasm
Match the major events of mitosis with the correct stages: A. the nuclear envelopes (one at each end of the cell) reform from fragments of the original envelope and chromosomes become less condensed B. the sister chromatids are cleaved apart, and each daughter chromosome is pulled toward a pole by kinetochore microtubules C. the nuclear envelope fragments; microtubules invade the nuclear area; chromosomes continue to condense, and two sister chromatids become visible D. chromosomes converge in the middle of the cell, guided by the mitotic spindle E. the mitotic spindle begins to form; centrosomes pull apart, lengthening the microtubules with them; and the chromosomes condense and become visible
A. telophase B. Anaphase C. prometaphase D. metaphase E. prophase
The sodium potassium exchange pump is an example of. A) diffusion. B) facilitated diffusion. C) active transport. D) osmosis. E) filtration.
C
Which of the following describe(s) cyclin-dependent kinase (Cdk)?
Cdk is present throughout the cell cycle, Cdk is active, or 'turned on,' in the presence of cyclin.If a cell failed to pass a checkpoint between the S and G2 phases
Ribosomes can be either free (in the cytosol) or bound (attached to the rough ER). Consider the list of proteins below and determine which would be synthesized by a free ribosome. Hint #1: Remember that free ribosomes synthesize proteins that will remain in the cytosol or travel to the nucleus. Bound ribosomes synthesize proteins that will be used within the endomembrane system or be secreted from the cell - for example proteins destined for the cell membrane, the extracellular matrix, or for destinations outside the cell (e.g., hormones, neurotransmitters). Hint #2: Look up the functions of the proteins below and determine their destination. tubulin chemokine serotonin CFTR protein RNA polymerase elastin
DNA polymerase, CFTR protein,
what does radiation do for cancer?
Depending on the location. High energy radiation damages DNA in cancerous cells much more than cells, triggering cell death in cancerous cells, where normal cells are able to recover
__________ fasten cells together into strong sheets, like rivets, allowing tissues to withstand mechanical stress.
Desmosomes
Which of the following statements about genes is incorrect? Genes correspond to segments of DNA. Many genes contain the information needed for cells to synthesize enzymes and other proteins. During fertilization, both the sperm and the ovum (egg) contribute genes to the resulting fertilized egg. Each different type of cell within an organism has a unique set of genes. All of the above statements are correct.
Each different type of cell within an organism has a unique set of genes
Interphase has 3 phases, what are they?
G1, S, G2
What is the protein that phosphorylates RB?
G1-S cyclin
Ribosomes can be either free (in the cytosol) or bound (attached to the rough ER). Consider the list of proteins below and determine which would be synthesized by a bound ribosome. Hint #1: Remember that free ribosomes synthesize proteins that will remain in the cytosol or travel to the nucleus. Bound ribosomes synthesize proteins that will be used within the endomembrane system or be secreted from the cell - for example proteins destined for the cell membrane, the extracellular matrix, or for destinations outside the cell (e.g., hormones, neurotransmitters). Hint #2: Look up the functions of the proteins below and determine their destination. GLUT2 BRCA1 primase topoisomerase LDLR collagen
GLUT2, LDLR, collagen
The sodium-potassium pump is called an electrogenic pump because it contributes to the membrane potential of a cell. What are the two basic functions of membrane potential? Click two options. It allows cells to store high concentrations of sodium ions. It allows a cell to function as a battery, providing power for a variety of cellular functions. It allows cells to bind to adjacent cells. It allows cells to import harmful ions and neutralize them. It is used for transmitting signals from one part of an excitable cell to another. It creates an electrical field that protects the cell from attacks.
It allows a cell to function as a battery, providing power for a variety of cellular functions, It is used for transmitting signals from one part of an excitable cell to another
Which of the following statements is correct about diffusion?
It is a passive process in which molecules move from a region of higher concentration to a region of lower concentration.
Why does the rough ER appear rough?
It is studded with ribosomes
major function of the Peroxisome in all eukaryotic organelles
Lipid Destruction; contains oxidative enzymes
major function of the Smooth Endoplasmic Reticulum (SER) in all eukaryotic organelles
Lipid production; Detoxification
Maturation-promoting factor, or MPF, is a cyclin-dependent kinase that promotes a cell's entrance into mitosis from the G2 phase by activating a number of proteins important during mitosis, including several that contribute to the breakdown of the nuclear envelope. Based on this information, which of the following must occur in order for MPF to become active?
MPF must bind to cyclin
Main function of Intermediate Filaments
Maintenance of shape (tension-baring element), anchorage of the nucleus and certain other organelles, formation of nuclear lamina
Which cells can only be single celled?
Prokaryotes
________________ must have a ________ surface area to volume ratio
Prokaryotes, high
Meiosis 2 has what 4 phases in it?
Prophase 2, Metaphase 2, Anaphase 2, and telophase 2
major function of the Lysosome in all eukaryotic organelles
Protein destruction
__________ are molecules that activate or inactive other molecules by phosphorylating them
Protein kinases
major function of the Golgi apparatus in all eukaryotic organelles
Protein modification and export
major function of the Rough Endoplasmic Reticulum (RER) in all eukaryotic organelles
Protein production; in particular for export out of the cell
_______________________ are genes normal genes that, under normal circumstances, stimulate cell division. When mutated, they can turn into ____________________ , which can cause the production of too much protein, or produce a protein that is more active than usual. _______________________ are genes that normally detect damaged DNA and stop cell division.
Proto-oncogenes, oncogenes, Tumor suppressor genes
What is random fertilization?
Random nature of gamete selection during fertilization.
With respect to the sodium-potassium pump, which of the following statements correctly describe(s) the driving forces for the diffusion of Na+ and K+ ions through their respective channels. Click all that apply. Hint: Due to membrane potential, the movement of cations into the cell and anions out of the cell are favored. -The diffusion of Na+ ions into the cell is facilitated by the Na+ concentration gradient across the plasma membrane. -The diffusion of Na+ ions into the cell is impeded by the electrical gradient across the plasma membrane. -The diffusion of K+ ions out of the cell is impeded by the K+ concentration gradient across the plasma membrane. -The diffusion of K+ ions out of the cell is impeded by the electrical gradient across the plasma membrane. -The electrochemical gradient is larger for Na+ than for K+.
The diffusion of Na+ ions into the cell is facilitated by the Na+ concentration gradient across the plasma membrane, The diffusion of K+ ions out of the cell is impeded by the electrical gradient across the plasma membrane, The electrochemical gradient is larger for Na+ than for K+
A patient has had a serious accident and lost a lot of blood. In an attempt to replenish body fluids, distilled water, equal to the volume of blood lost, is transferred directly into one of his veins. What will be the most probable result of this transfusion? It will have no unfavorable effect as long as the water is free of viruses and bacteria. The patient's red blood cells will shrivel up because the blood fluid is hypotonic compared to the cells. The patient's red blood cells will swell because the blood fluid is hypotonic compared to the cells. The patient's red blood cells will shrivel up because the blood fluid is hypertonic compared to the cells. The patient's red blood cells will burst because the blood fluid is hypertonic compared to the cells.
The patient's red blood cells will swell because the blood fluid is hypotonic compared to the cells.
The solutions in the two arms of this U-tube are separated by a membrane that is permeable to water and glucose but not to sucrose. Side A is half filled with a solution of 2 M sucrose and 1 M glucose. Side B is half filled with 1 M sucrose and 2 M glucose. Initially, the liquid levels on both sides are equal.After the system reaches equilibrium, what changes are observed?
The water level is higher in side A than in side B, The molarity of sucrose and glucose are equal on both sides
Assume that a species exists in which crossing over does not occur, but that all other steps in meiosis occur normally. With respect to meiosis, which of the following would be true for this species? Click ALL that apply. -There would be less genetic variation among gametes. Independent assortment of chromosomes would not occur. -The daughter cells of meiosis I would be diploid, but the daughter cells of meiosis II would be haploid. -The four daughter cells produced in meiosis II would all be different. -The two sister chromatids of each replicated chromosome would no longer be identical. -The two daughter cells produced in meiosis I would be identical.
There would be less genetic variation among gametes
_____________ play a major role in the growth of plant cells, enlarging their vacuoles as water is absorbed, enabling the cell to become bigger without having to spend a lot of energy on new cytoplasm
Vacuoles
Using the diagram above, answer the following question. As the system reaches equilibrium, which of the following will occur? Click all that apply. Water will move into the cell. Water will move out of the cell. Sucrose will move into the cell. Sucrose will move out of the cell. Glucose will move into the cell. Glucose will move out of the cell. Fructose will move into the cell. Fructose will move out of the cell.
Water will move into the cell, Glucose will move out of the cell, Fructose will move into the cell
what is a genome?
a cells DNA
What 2 forced drive the diffusion of ions across a membrane?
a chemical and electrical force
How is a clevage forrow formed?
a contractile ring of microfilaments pinching the 2 ends of the cell
what is the fluid mosaic model
a membrane is a fluid structure with a "mosaic" of various proteins embedded in it attached to a phospholipid bilayer
What is meiosis?
a type of cell division that produces gametes with half the normal amount of chromosomes
What is the synaptonemal complex?
a zipper like protein structure that physically connects 2 sister chromatids
Spherocytosis is a human blood disorder associated with a defective cytoskeletal protein in the red blood cells (RBCs). What do you suspect is the consequence of such a defect?
abnormally shaped RBCs
what is necessary when a substance needs to be moved against its concentration gradient?
active transport
The energy for most active transport is provided by the molecule ________________________, or _________
adenosine triphosphate, ATP
What are somatic cells?
all cells except sex cells
Which of the following is/are true about microtubules? -They are responsible for the beating of flagella and cilia that project from some cells. -They are dynamic, polymerizing and depolymerizing as needed. -They serve as tracks along which motor proteins can move. -They grow out of a region of the cell known as the centrosome. -They are hollow tubes composed of the protein tubulin.
all of them
In order for a protein to be an integral membrane protein it would have to be which of the following? hydrophilic hydrophobic amphipathic completely covered with phospholipids exposed on only one surface of the membrane
amphipathic
What is Retinoblastoma protein (RB)?
an important protein in the G1 checkpoint that is a type of eye cancer in children. Though it is a normal protein until mutated
The ras gene normally signals the presence of a growth factor, which stimulates cell division. If it mutates, it may stimulate cell division even in the absence of a growth factor. This hyperactive, mutant version of ras can be classified as
an oncogene
What is the shortest phase of mitosis?
anaphase
Cancer cells may emit growth factors to attract blood vessels, a process called
angiogenesis
cancer cells emit growth factors to attract blood vessels through __________________
angiogenesis
examples of channel proteins
aquaporins and ion channels
Lysosomes play a role in recycling the cells organelles and macromolecules, this recycling is called
autophagy
a specialized arrangment of microtubules is responsible for
beating cilia and flagella
tumors can be _________ or ____________ in size
benign, malignant
Bacteria divide through a process called
binary fission
What has to be done to activate protein kinases?
bind to a protein called cyclin, making them cyclin-dependent kinases of Cdks
What is metastasis?
blood vessels not only allow the tumor to grow, but provides a pathway that allows cancer cells to leave the tumor and travel to other parts of the body
Proteins that change shape to shuttle a substance across the membrane, such as those involved in facilitated diffusion, are
carrier proteins
The effect of membrane potential favors the movement of what into the cell, since the inside of negatively charged?
cations
The effect of a cell's membrane potential is that the movement of ___________ into the cell is favored, while the movement of __________ out of the cell is favored.
cations, anions
What happens during the S phase of interphase?
cell duplicates its DNA
What does hypotonic mean?
cell gains water
What does hypertonic mean?
cell loses water
Which of the following are present in prokaryotic cells but not eukaryotic cells? cell wall composed primarily of peptidoglycan plasma membrane circular DNA chloroplasts ribosomes smooth endoplasmic reticulum
cell wall composed primarily of peptidoglycan, circular DNA
Plants, prokaryotes, fungi, and some protists construct ______________ outside the cell membrane. The composition depends on the organism
cell walls
HeLe cells are
cells used to research cervical cancer that they took from a woman without her family or anyone knowing for years
Sister chromatids are located in what region
centromere
In animals, microtubule assembly begins at the __________, the microtubule organizing center
centrosome
In animal cells what do microtubules grow from?
centrosomes
Which of the following form a tunnel through the cell membrane through which hydrophilic substances can pass?
channel proteins
The areas of overlap during crossing over are called
chiasmas or chiasmata
Fungal cell walls are composed of mainly
chitin
Which of the following are present in plant cells but NOT animal cells? DNA enclosed in a nuclear envelope ribosomes chloroplasts large central vacuole mitochondria cell wall composed primarily of cellulose cell membrane microtubules
chloroplasts, large central vacuole, cell wall composed primarily of cellulose
The fluidity of the membrane is affected by the number of unsaturated hydrocarbons, as well as by the presence of ______________________
cholesterol
_______________ can either be increased or decreased membrane fluidity depending on the temperature
cholesterol
In a non-dividing cell, DNA and its associated proteins are in an uncondensed form called
chromatin
What happens during metaphase?
chromosomes convert the metaphase plate or equator and spindle fibers continue to jerk around the sister chromatids until they are lined up in the middle
The side of the Golgi apparatus closest to the endoplasmic reticulum is the _______ side. Molecules travel through the Golgi apparatus, where they undergo modification and bud off of a vesicle from the _____ side.
cis, trans
specialized receptors that bind to a specific substance are embedded in the plasma membrane, clustered together in a _______________
coat pit
What causes cells to result in recombinant chromosomes?
crossing over
Proteins that are involved in the regulation of the cell cycle, and that show fluctuations in concentration during the cell cycle, are called
cyclins
Which of the following proteins are produced by free ribosomes? nuclear proteins cytosolic proteins secreted proteins endomembrane proteins
cytosolic proteins and nuclear proteins
What is passive transport?
diffusion of a substance across a membrane with no energy input from the cell
What is Osmosis?
diffusion of water across a selectively permeable membrane
Sister chromatids are separated from each other during what phase?
during anaphase of meiosis II
What are microtubules responsible for?
during cell division, forming the mitotic spindles, or spindle apparatus
What are protein kinases?
enzymes that activate or inactive other proteins by phosphorylating them (adding a phosphate group).
"out of the cell"
exocytosis
During synaptic signaling, neurons release a chemical messenger called a neurotransmitter from a vesicle inside the cell into a region outside the cell called the synaptic cleft. The name of this process is
exocytosis
The release of molecules from a cell through the fusion of a vesicle with the plasma membrane is
exocytosis
What do animal cells have instead of cell walls?
extracellular matrix (ECM)
What do desmosomes do?
fasten cells together into strong sheets, much like rivits
What do channel proteins do
form a tunnel through the membrane, through which hydrophilic substances can pass
What is angiogenesis?
formation of new blood vessels
Meiosis II typically produces ______ cells, each of which is ______
four, haploid
what is the "gold standard" for treating cancer?
gene therapy
What is independent assortment?
genes for different traits can segregate independently during the formation of gametes
BRCA1 and BRCA2 genes
genes that are major risk factors for breast and ovarian cancer
What are tumor suppressor genes?
genes that code for proteins that inhibit the cell cycle and promote apoptosis
What are proto-oncogenes?
genes that normally code for proteins that stimulate cell growth and division
Carrier proteins prodice
glucose transporters
What is the primary component of extracellular matrix
glycoproteins
collagen account for ________ the protein in the human body
half
Normal cells have a limit to the number of times they can divide, called _________________
hayflick limit
Genetics is the study of
heredity and hereditary variation
What are genes?
heredity units that encode information, located on chromosomes
Passive transport occurs when substances naturally move from ___________________________ concentration, and requires _____________________________
high to low, no energy expenditure from the cell .
In a concentration gradient substances naturally defused from areas of __________ concentrations to areas of _______ concentration
high, low
What occurs in Anaphase 1 of meiosis?
homologous chromosomes are separated, so the paurs of sister chromatids are moved to the poles as spindle fibers shorten
Celery stalks that are immersed in fresh water for several hours become stiff and hard. Celery stalks left in a salt solution become limp and soft. From this we can deduce that the cells of the celery stalks are
hypertonic to fresh water but hypotonic to salt solution
An artificial cell consisting of an aqueous solution enclosed in a selectively permeable membrane is immersed in a beaker containing a different solution. The membrane is permeable to water and to the simple sugars glucose and fructose, but impermeable to the disaccharide sucrose. Which of the following describes the solution outside of the artificial cell relative to the inside to the cell?
hypotonic
When vacuoles enter a ___________________, water will move into the cell
hypotonic environment
Where are desmosomes/anchoring junctions found?
in the tissues of organs that have a lot of mechanical stress on them (heart, urinary bladder, female uterus)
The fluidity of a cell's membrane is essential to life. Many cold-hardy plants can survive cold temperatures because they are able to maintain the fluidity of their cell membranes at very low temperatures. Which of the following would increase the fluidity of a cell membrane at low temperatures?
increasing the number of unsaturated fatty acids in the cell membrane, increasing the amount of cholesterol in the cell membrane
Many __________ proteins are found to be often transmembrane proteins
integral
Proteins found in the lipid bilayer can be divided into what 2 groups?
integral proteins, peripheral proteins
________________ proteins are embedded in the protein bilayer, _______________ proteins are attracted to the inner or outer surface of the membrane, _______________ proteins often fo all the way across the membrane
integral, peripheral, transmembrane
Cells spend a majority in their life in what phase
interphase
If cells escape their home tissue they are _____________
invasive
Why does smooth er look smooth
lack in ribosomes
What molecules cannot pass freely or at least not quickly and require the aid of a transport protein
large, charged, polar
At ________ temps, cholesterol prevents the phospholipids from packing together tightly, increasing fluidity
low
Active transport occurs when substances are moved move from ___________________ concentration, and requires ____________________________
low to high, energy expenditure from the cell
The higher the concentration of dissolved solutes, the ___________ the concentration of free water molecules. The lower the concentration of dissolved solutes, the ____________ the concentration of free water molecules.
lower, higher
Cell digestion events, such as phagocytosis and autophagy, are performed by
lysosomes
The cells in humans immune system helping to defend the body by phagocytosing and destroying pathogens, as well as debris around the cell
macrophages
Main function of microfilaments
maintenance and changing of cell shape, (tension-bearing element), muscle contraction, movement of cytoplasm, cell motility, animal cell division
Which of the following are composed of the protein actin and responsible for cellular locomotion (ameboid movement), muscle contractions, and the formation of a cleavage furrow during cell division? microfilaments Intermediate filaments microtubules plasmodesmata proteoglycans
microfilaments
Which of the following serve as tracks for motor proteins, form the mitotic spindle, and are responsible for the movement of cilia and flagella?
microtubules
Put microtubules, microfilaments, and intermediate filaments in order from thickest to thinnest
microtubules, intermediate filaments, microfilaments
What is active transport require energy to do?
move substances from low to high concentration
Cancer is a single/multi step process?
multi step
A cell has the following molecules and structures: enzymes, DNA, ribosomes, plasma membrane, and mitochondria. It could be a cell from
nearly any eukaryotic organism
what is a neoplasm
new growth
Do animal cells have cell walls?
no
Can water pass through the hydrophobic core of the lipid bilayer
no (not easily at least)
What does isotonic mean?
no affect on the water passage in the cell
Is pinocytosis specific or nonspecific process?
nonspecific
Determine whether each of the following traits is generally a characteristic of normal cells or cancerous cells. -die if they leave their home tissue? -can divide in the absence of a growth factor, or produce their own growth factors? -may not undergo apoptosis if DNA is damaged? -do not divide when they are touching neighboring cells? -can divide if not attached to a substrate? -can reactive an enzyme called telomerase to rebuild chromosomes? -stay anchored to their neighbors through cell adhesion molecules?
normal, cancerous, cancerous, normal, cancerous, cancerous, normal
What do eukaryotes have that prokaryotes don't?
nucleus, membrane bound organelles, multiple linear chromosomes, single or multicellular
What are homologous chomosomes?
offspring receive 1 chromosomes from each parents, being the same length, same centromere position, and same genes
Why is S phase important for mitosis to work properly?
once it copies its DNA its committed to cell division
If proto-oncogenes mutate they become_____________
oncogenes
Which of the following processes are passive? Click all that apply. -simple diffusion -facilitated diffusion -receptor-mediated endocytosis -pinocytosis -osmosis
osmosis, facilitated diffusion, simple diffusion
Which of the following genes are tumor suppressor genes? ras p53 Rb BRCA1 BRCA2
p53, Rb, BRCA1, BRCA2
What do integral proteins do?
penetrate the hydrophobic interior of the lipid bilayer
_____________ proteins are not embedded in the membrane, but loosely bound to the surface
peripheral
A specialized process in which a cell takes in solid material is
phagocytosis
What process is it when many single celled eukaryotes eat by engulfing smaller organism
phagocytosis
When pathogenic bacteria appear in tissues of many organisms, they are engulfed by specialized white blood cells through a process called
phagocytosis
Which of the following processes require energy input from the cell? facilitated diffusion phagocytosis osmosis pinocytosis cotransport
phagocytosis, pinocytosis, cotransport
Which of the following modes of transport are considered bulk transport? Click all that apply. -phagocytosis -pinocytosis -receptor-mediated endocytosis -facilitated diffusion -exocytosis
phagocytosis, pinocytosis, receptor-mediated endocytosis, exocytosis
Cells take in dissolved solutes through the process of
pinocytosis
Receptor-mediated endocytosis is a specialized type of __________________
pinocytosis
Mitochondria are found in _____.
plant and animal cells
What are the major differences between plant and animal cells
plant cells have large central vacuoles for storage that has many functions on lysosomes in animal cells (using it for growth-they can fill it up and expand it when needed). Plant cells have cell walls made of cellulse, a polymer of a glucose molecule. Plant cells contain chloroplast (an organelle that allows them to make their own food)
What is the function of the blood-brain barrier
preventing blood born pathogens from infecting the brain and spinal cord
What kind of molecules cannot preform binary fission?
prokaryotes
what does Maturation promoting factor (MPF) do?
promotes mitosis by phosphorylating several different proteins that help break down the nuclear envelope during pro metaphase
What are the 4 phases that occur during meiosis 1?
prophase 1, metaphase 1, anaphase 1, and telophase 1
Synapsis occurs during _____
prophase I of meiosis
During ______, a spindle forms in a haploid cell
prophase II
What are the 5 stages of Mitosis?
prophase, prometaphase, metaphase, anaphase, telophase
Collagen fibers are embedded in a network of _____________, small proteins with many carbohydrate chains covalently attatched
proteglycan
What are the important regulatory molecules?
protein kinases, cyclins
What is the function of the ribosome in Eukaryotic organisms?
protein synthesis
Large numbers of ribosomes are present in cells that specialize in producing which of the following molecules?
proteins
what are glycoproteins?
proteins with a carbohydrate component, especially collagen fibers
a proton pump creates a ________________
proton gradient
What is the main electrogenic pump of plants, fungi, and bacteria?
proton pump
The membranes regulation of what enters and exits the cells id referred to as __________________
selective permability
What is the purpose of meiosis 2?
separate sister chromatids and is basically identical to mitosis
What occurs during meiosis 1?
separates homologous chromosomes
many single celled eukaryotes have a cell wall made out of
silicon
simple, hydrophobic molecules such as oxygen and carbon dioxide can pass through the cell membrane through ______________
simple diffusion
During cell division, each chromosome makes a copy of itself, forming
sister chromatids
What occurs during anaphase 2 of meiosis 2?
sister chromatids are pulled apart
Increased telomerase levels may _______________________, too much telomerase activity can cause cells _______________________
slow down the aging process, become cancerous cells
What kinds of molecules pass through a cell membrane most easily?
small and hydrophobic
what molecules can freely pass through the membrane
small, nonpolar, lipid soluble
The liver is involved in detoxification of many poisons and drugs. Based on this information, which of the following structures would you expect to be abundant in liver cells?
smooth E
An action potential arriving at the presynaptic terminal causes. -sodium ions to diffuse into the cell. - sodium ions to diffuse out of the cell. -calcium ions to diffuse into the cell. -acetylcholine to diffuse into the cell. -ligand-gated sodium channels to open
sodium ions to diffuse out of the cell.
What is the major electrogenic pump of animal cells?
sodium-potassium pump
What are aquaporins?
special types of channel proteins meant for water
What are the major functions of smooth ER?
synthesis of lipids, storage of calcium ions, detoxification of harmful substances
Normal cells have a limit to the number of times they can divide, called the Hayflick limit, which is somewhere between 20-50 times. This is because structures called __________ at end of chromosomes break off each time a cell divides and thus, chromosomes shorten, limiting the life of a cell.
telomeres
At the end of _____ and cytokinesis, haploid cells contain chromosomes that each consist of two sister chromatids.
telophase I
At the end of _____ and cytokinesis there are four haploid cells
telophase II
What does amphipathic mean?
that they both have a hydrophilic and a hydrophobic region
What are sex chromosomes?
the 23rd chromosome to determine the sex
A cell duplicates its DNA during
the S phase of interphase
What is receptor-mediated endocytosis?
the bulk movement of specific substances into a cell via vesicle formation
What happens during the G2 phase of interphase?
the cell grows more and completes prep for cell division
What happens during cytokinesis?
the cell pinches in 2 giving rise to 2 new daughter cells
What is n or a ploidy number?
the certain number of chromosome characteristics of their species
What is facilitated diffusion?
the diffusion of a substance across a membrane with the help of a carrier protein
What occurs in metaphase 1 of meiosis?
the duplicated chromosomes line up in the middle at the metaphase plate after being around by spindle fibers
What does membrane sidedness refer to
the fact that each side of the membrane is different from the other
What does blood-brain barrier refer to
the fact that there are many tight junctions between the cells of blood vessels in the central nervous system
Tay-Sachs disease is a human genetic abnormality that results in cells accumulating and becoming clogged with very large and complex lipids. Which cellular organelle must be involved in this condition?
the lysosome
What happens during prophase?
the mitotic spindles begin to form, centrosomes are pulled apart while the microtubules are lengthening and the chromosomes are condensing and becoming visible
What occurs during prophase 2 of meiosis 2?
the nuclear envelope disassembles and spindle apparatus are formed
What happens in prophase 1 of meiosis?
the nuclear envelope dissembles and the spindle apparatus starts to form
What happens during prometaphase?
the nuclear envelope fragments and microtubules invade the nuclear area and chromosomes continue to condense. Sister chromatids become visible, each with a kinetochore protein at the centromere. The kinetochores get captured by microtubules from each end and are jerked back and fourth
What is asexual reproduction?
the production of new organisms without fertilisation. The offspring have exactly the same genes as the parent - so there's no genetic variation.
what is exocytosis?
the secretion of molecules from a cell by the fusion of vesicles (which contain molecules) with the plasma membrane
What happens during anaphase?
the sister chromatids are pulled apart and each daughter chromosome is pulled towarda poleby kinetochore microtubules. The cell elongates at the end, the 2 ends of each cell have a complete collection of chromosomes
What occurs during metaphase 2 of meiosis 2?
the sister chromatids line up in the middle
What is gene therapy?
the transplantation of normal genes into cells in place of missing or defective ones in order to correct genetic disorders.
what does it mean if a tumor is malignant?
the tumor can spread throughout the body through metastasis
what does it mean if a tumor is benign?
the tumor remains in place and is not spreading
What is cancer?
the uncontrolled division of cells, which results in a mass of tissue known as tumor or neoplasm
What is endocytosis?
the uptake of molecule or particulate matter by the formation of vesicles form the plasma membrane
At the end of Meiosis 1, what has happened?
there are 2 haploid cells, but sister chromatids are still in contact. Each cell has just 1 copy of each chromosome, but are duplicated
What are carcinogens?
things that cause damage to the DNA
What are the 3 types of intercellular junctions in animal cells?
tight junction, desmosomes, and gap junctions
Why do cells use exocytosis?
to get rid of waste and secrete biological molecules
What is the primary function of the sodium-potassium pump?
to maintain membrane potential
What do carrier proteins do
"carry" a molecule, changing shape to shuttle a substance across the membrane
What is apoptosis?
"neat" death for cells
cells maintain a membrane potential of ________ to __________ millivolts
-50, -200 (negative meaning that the inside of the cell is negatively charged, relative to the outside)
Cellular respiration produces what?
ATP
The energy for active transport in a cell is supplied primarily by
ATP
For a species with a haploid number of 23 chromosomes, how many different combinations of maternal and paternal chromosomes are possible for the gametes?
About 8 million
What are sex cells/gametes?
specialized cells for reproduction having half as many chromosomes as somatic cells
Active transport moves substances from an area of high concentration to an area of low concentration of that substance .A) True B) False
B
Which of the cells are haploid?
C and D
What is the longest phase in interphase?
G1
what are the 3 major checkpoints?
G1, S, G2
What occurs in telophase 1 of meiosis?
the nuclear envelope reforms and the cells undergoes cytokinesis
Vacuoles can have what functions?
water balance, storage, digestion, growth, disposal
