Cell Biology Final Exam Questions

Why is meiosis special?

1.) One DNA Replication follows two rounds of nuclear division that results in haploid cells (gametes) 2.) Long complex prophase I when DNA Recombination occurs 3.) Products are genetically different

Plant Cell vs Animal Cell: What do plant cells contain that animal cells do not? (Exam 1)

Cell Wall, Vacuoles, Plasmodesmata, & Chloroplasts

True or False: A symport would function as an antiport if its orientation in the membrane were reversed (i.e. If the portion of the molecule normally exposed to the cytosol faced the outside of the cell instead). (Exam 2)

False

True or False: Actin filaments are made up of dimers, consisting of alpha-actin and beta-actin subunits. (Lecture 21)

False

True or False: Because the two strands of DNA are complementary, the mRNA of a given gene can be synthesized using either strand as a template. (Cumulative)

False

True or False: Minus end-directed microtubule motors (like dyneins) deliver their cargo to the periphery of the cell, whereas plus end-directed microtubule motors (like kinesins) deliver their cargo to the interior of the cell. (Exam 3)

False

True or False: Plants and Animal cells use totally different signaling mechanisms for cell communication (Exam 3)

False

True or False: The cytosol contains membrane-enclosed organelles, such as lysosomes. (Cumulative)

False

True or False: The differences between multicellular organisms are largely explained by different kinds of genes carried on by their chromosomes. (Exam 1)

False

True or False: The replication fork is asymmetrical because it contains two DNA Polymerase molecules that are structurally distinct. (Exam 1)

False

Meiosis Prophase I: Steps of Cells

Leptotene, Zygotene, Early Pachytene, Late Pachytene, Diplotene, Diakinesis

When does the formation of bivalents start?

Prophase I

Process of Meiosis I:

Prophase I, Metaphase I, Anaphase I, Telophase I

Process of Meiosis II:

Prophase II, Metaphase II, Anaphase II, Telophase II

True or False: It is possible for a coding region of a gene to be present in a genomic library prepared from a particular tissue, but not to be represented in a cDNA library prepared from the same tissue (Exam 2)

True

True or False: Lipids in a lipid bilayer do not flip-flop readily from one lipid monolayer to the other (Exam 2)

True

True or False: MAP Kinase cascade is an important (and widespread) signal transduction pathway involved in the regulation of transcription, replication, and translation. (Exam 3)

True

True or False: Nucleic acid hybridization is used to isolate or identify specific DNA fragment by base-pairing between complementary DNA or RNA probes and the DNA of interest (Exam 2)

True

True or False: Of the molecule-transporting membrane proteins, only carriers are capable of active transport. (Exam 2)

True

True/False: In meiosis, duplicated homologous chromosomes pair before lining up on the spindle

True

True/False: Mitosis and Meiosis both begin with a round of chromosome duplication

True - Mitosis has chromosome duplication, followed by a single round of cell division to yield two diploid nuclei; Meiosis, chromosome duplication followed by TWO rounds of division (no DNA Replication) to produce four haploid nuclei

For each statement below, which one is FALSE? (Exam 1) a.) All highly conserved stretches of DNA in the genome are transcribed into RNA b.) To find functionally important regions of the genome, it is most useful to compare species whose last common ancestor lived 100 million years ago rather than 5 million years ago. c.) Most mutations and genome alterations have neutral consequences d.) Proteins required for growth, metabolism, and cell division are more highly conserved than those involved in development and in response to the environment.

a.) All highly conserved stretches of DNA in the genome are transcribed into RNA

Which of the following organisms would you expect to have the HIGHEST percentage of unsaturated phospholipids in their membrane: (Cumulative) a.) Antarctic Fish b.) Cactus c.) Humans d.) Bacteria from thermal hot springs

a.) Antarctic Fish

Passive Transport of ions can mostly be driven by: (Exam 2) a.) Concentration Gradients b.) Light Energy c.) Hydrolysis of ATP d.) High energy electrons

a.) Concentration Gradients

If running out of GTP microtubules will: (Exam 3) a.) continue shrinking and eventually disappear b.) continue shrinking and growing c.) continue growing, but stop shrinking d.) all of the above could happen

a.) Continue shrinking and eventually disappear

The gene encoding DNA Polymerase involved in DNA Replication can be inactivated by a mutation in a cell. The cell attempts to replicate its DNA. What will most likely happen in the absence of DNA Polymerase? (Exam 1) a.) No replication can take place at all. RNA Primers will be laid down at the origin of replication. b.) The lagging DNA Strand will consist of newly synthesized fragments with both DNA and RNA. c.) The rate of DNA Replication will be greatly slowed down. d.) Some new DNA will be synthesized

a.) No replication can take place at all. RNA Primers will be laid down at the origin of replication.

The hybridization between mRNAs and DNA probes is called: (Cumulative) a.) Northern blotting b.) Southern blotting c.) Eastern blotting d.) Western blotting

a.) Northern blotting

Let's assume that solute A is moving against its concentration and electrical gradients via a carrier protein that does not use ATP (or a similar energy carrying molecule). Which statement could be true? (Cumulative) a.) Solute B is moving with its chemical and/or electrical gradient. b.) Solute B is moving against its chemical and/or electrical gradient. c.) Without using ATP, this carrier protein should not be expected to be able to transport A. d.) Solute A is providing the energy needed for the protein to undergo a conformational change.

a.) Solute B is moving with its chemical and/or electrical gradient.

The replacement of GDP with GTP in G-Protein Trimeric Complex. The dissociated subunits can relay the signal to the downstream target. What is the consequence if the GDP affinity for the alpha-subunit is reduced by a mutation? (Exam 3) a.) The mutant G protein would be almost continuously activated b.) The activation of the G protein is still dependent on the activation of G-protein-linked receptor c.) The activation of the mutant G protein stays normal d.) None of the above

a.) The mutant G protein would be almost continuously activated

Which of the following is a limitation on the use of PCR to detect and isolate genes? (Exam 2) a.) The sequence at the beginning and end of the DNA to be amplified must be known b.) It also produces large numbers of copies of sequences beyond the 5' to 3' end of the desired sequence c.) It cannot be used to amplify cDNAs d.) It will amplify only sequences present in multiple copies in the DNA sample

a.) The sequence at the beginning and end of the DNA to be amplified must be known

A mutation in DNA generates a UGA stop codon in the middle of an RNA. A second mutation in the cells leads to a single nucleotide change in a tryptophan (Trp) tRNA anticodon that allows the continuation of translation by pairing the UGA stop codon. The codon for Trp is 5' UGG 3'. What are the normal and mutated anticodons of the Trp-tRNA? (Cumulative) a.)5' CCA 3' and 5' ACU 3' b.) 5' CCA 3' and 5' UCA 3' c.) 5' ACC 3' and 5' UCA 3' d.) 5' ACC 3' and 5' ACU 3'

b.) 5' CCA 3' and 5' UCA 3'

Homologous recombination is an important mechanism in which organisms use a "backup" copy of the DNA as a template to fix double-strand breaks without loss of genetic information. Which of the following is not necessary for homologous recombination to occur? (Cumulative) a.) 3' DNA strand overhangs b.) 5' DNA strand overhangs c.) A long stretch of sequence similarity d.) Nucleases

b.) 5' DNA strand overhangs

The products of the light reactions of photosynthesis are: (Exam 2) a.) ATP and NAD+ b.) ATP and NADPH c.) Glucose d.) Sucrose

b.) ATP and NADPH

A gated ion channel: (Exam 2) a.) Stays continuously open when stimulated b.) Opens more frequently in response to a given stimulus c.) Opens more widely, the stronger the stimulus d.) Remains closed if unstimulated

b.) Opens more frequently in response to a given stimulus

Which of the following mutational changes would you expect to be the most harmful to an organism? (Exam 1) a.) Insertion of a single nucleotide near the end of the coding sequence b.) Removal of a single nucleotide in the beginning of the coding sequence c.) Deletion of three consecutive nucleotides in the middle of the coding sequence d.) Substitution of one nucleotide for another in the end of the coding sequence.

b.) Removal of a single nucleotide in the beginning of the coding sequence

Cholesterol is the extremely insoluble molecule that is needed by cells. Cholesterol is taken up by cells via receptor-mediated endocytosis. The cholesterol molecules can bind to low-density lipoproteins (LDL). Which sentence is wrong in describing the cholesterol endocytosis? (Cumulative) a.) The cholesterol- LDL complex binds to the LDL receptor. b.) Under the basic conditions in the lysosome, the LDL receptor releases cholesterol. c.) The LDL receptor is recycled by the vesicular transport. d.) The endocytosis system allows cells to take up cholesterol efficiently.

b.) Under the basic conditions in the lysosome, the LDL receptor releases cholesterol.

The role of calcium in muscle contraction is: (Lecture 21) a.) To detach myosin heads from actin b.) to bind to troponin complex to include the change of tropomyosin, exposing actin filaments to myosin heads c.) to maintain the structure of the myosin filament d.) All of the above

b.) to bind to troponin complex to include the change of tropomyosin, exposing actin filaments to myosin heads

Which of the following statements is NOT correct: (Exam 2) a.) During photosynthesis, electrons are removed from one water and two protons and 1/2 O2 are yielded b.) High energy electrons travel through electron transport chains in both mitochondria and chloroplasts, which results in the establishment of H+ gradients c.) Mitochondria are not required during daylight hours in chloroplast-containing cells to supply cells with ATP derived by oxidative phosphorylation. Therefore, plants can live without mitochondria d.) The photosynthesis products not only include NADPH and sugars, but also ATPs

c.) Mitochondria are not required during daylight hours in chloroplast-containing cells to supply cells with ATP derived by oxidative phosphorylation. Therefore, plants can live without mitochondria

The two strands of the DNA double-helix can be separated by heating (the heat provides enough energy to break the bonds that hold DNA complementary strands together). If you gradually increase the temperature, in what order would you expect the following DNA strands to "melt". (Cumulative) 1.) 5'-GCGGGCCAGCCCCGAGTGGGTAGCCAGG-3' 3'-CGCCCGGTCGGGGCTCACCCATCGGTCC-5' 2.) 5'-TATAAAATATTTAGATACTATATTTACAA-3' 3'-ATATTTTATAAATCTATGATATAAATGTT-5' 3.) 5'-AGAGCTAGATCGAT-3' 3'-TCTCGATCTAGCTA-5' a.) 3, 1, 2 b.) 2, 3, 1 c.) 3, 2, 1 d.) 1, 3, 2

c.) 3, 2, 1

Assume you use the EcoR I restriction nuclease to digest the human genomic DNA which contains 3x10^9 nucleotide pairs, principally how many DNA fragments would you expect to obtain? The EcoR I restriction nuclease can recognize a sequence of 6 nucleotide pairs. (Cumulative) a.) 3x10^9 /6 b.) 3x10^9 /4 c.) 3x10^9 /4^6 d.) 3x10^9 /6^4

c.) 3x10^9 /4^6

Which statement is not true about ATP Synthase? (Exam 2) a.) ATP Synthase can run in either direction b.) The ATP Synthase should stall when the energy that it can draw from the proton gradient is just equal to the free energy change required to make ATP c.) ATP Synthase does not consume energy from ATP Hydrolysis to pump protons against their electrochemical gradient. d.) The running directions of ATP Synthase depend on the ration of ATP/ADP in the mitochondrial matrix

c.) ATP Synthase does not consume energy from ATP Hydrolysis to pump protons against their electrochemical gradient.

Which of the following is not a type of mRNA modification/processing that occurs in eukaryotes? (Exam 1) a.) 3' poly-A-tail b.) Splicing c.) Acetylation d.) 5' Capping

c.) Acetylation

Dr. Cute found the extract from an endangered tree in Tibet could inhibit the tumor growth in mouse. Suppose the expression of numerous genes are changed after the treatment with this tree extract, Dr. Cute wants to figure out what those genes are, which experiment do you suggest him to do? (Cumulative) a.) Making a genomic DNA library b.) Northern Blotting c.) DNA Microarray d.) In situ hybridization

c.) DNA Microarray

The local mediator nitric oxide stimulates the intracellular enzyme guanylyl cyclase by: (Exam 3) a.) Way of a G-Protein-Mediated Mechanism b.) Way of a receptor tyrosine kinase c.) Diffusing into cells and stimulating the cyclase directly d.) Way of a cell surface receptor linked to an intracellular signaling pathway

c.) Diffusing into cells and stimulating the cyclase directly

Which of the following statements regarding membrane proteins is false? a.) Membrane proteins can be dissociated from membranes using a gentle detergent b.) Cells can restrict the movement of membrane proteins c.) In transmembrane proteins that form an aqueous pore through the membrane, the pore is lined with hydrophobic amino acid side-chains d.) The plasma membrane is reinforced by the cell cortex. The main component of red blood cell cortex is the protein spectrin

c.) In transmembrane proteins that form an aqueous pore through the membrane, the pore is lined with hydrophobic amino acid side-chains

Which is not true in the following statements about gated protein transport (transport through nuclear pores) and protein transport across membranes? (Cumulative) a.) The energy supplied by GTP hydrolysis drives nuclear transport. b.) The signal sequence is required for both protein transports. c.) Proteins are imported into the nucleus after they are correctly folded, it doesn't matter that proteins are folded or not for the protein transport across membranes d.) All above are correct

c.) Proteins are imported into the nucleus after they are correctly folded, it doesn't matter that proteins are folded or not for the protein transport across membranes

Describe the consequences that would arise if a eukaryotic chromosome lacked one or both telomeres. (Exam 1) a.) The rate of DNA Replication would severely limit the rate of cell division b.) Many mutations would occur during DNA Replication c.) The chromosome ends would gradually shrink. Eventually, essential genes would be lost leading to cell death. d.) Newly replicated chromosomes could not be partitioned accurately between two daughter cells.

c.) The chromosome ends would gradually shrink. Eventually, essential genes would be lost leading to cell death.

Which microscope is the most suitable one to observe the fine structure of chloroplasts? (Cumulative) a.) Phase-Contrast Microscope b.) Fluorescence Microscope c.) Transmission-Electron Microscope d.) Confocal Fluorescence Microscope

c.) Transmission-Electron Microscope

The hydrolysis of GTP to GDP that is carried out by tubulin molecules: (Exam 3) a.) Provides the energy needed for tubulin to polymerize b.) Occurs because the pool of free GDP has run out c.) Tips the balance in favor of microtubule assembly d.) Allows the behavior of microtubules called dynamic instability

d.) Allows the behavior of microtubules called dynamic instability

Ion channels: (Exam 2) a.) Only open in response to a signal of some kind b.) Requires input of energy in order to function c.) Is not selective for different kinds of ions d.) Are not continuously open

d.) Are not continuously open

Which of the following organisms would you expect to have the lower percentage of unsaturated phospholipids in their membrane? (Exam 2) a.) Antarctic Fish b.) Cactus c.) Human d.) Bacteria from thermal hot springs

d.) Bacteria from thermal hot springs

What will be the possible effect if the dividing cells are exposed under strong radiation? (Lecture 22) a.) The cell division will be halted b.) The checkpoint mechanism will be activated to repair the DNA damage c.) Cell will be divided at a faster pace d.) Both A and B

d.) Both A and B

Electron transport is coupled to ATP synthesis in mitochondria and chloroplasts. Which of the following are likely to affect the coupling of electron transport in both systems? (Cumulative) a.) A potent inhibitor of cytochrome oxidase b.) The removal of oxygen c.) The absence of light d.) Dinitrophenol (permeabilizes membranes to protons)

d.) Dinitrophenol (permeabilizes membranes to protons)

Why do action potentials only propagate one way? (Exam 2) a.) All electrical signals start at the neuron cell body, so there is only one direction for the action potential to move b.) The channels become desensitized over time c.) The higher concentration of Na+ in the extracellular domain forced the action potential to go in one direction d.) Inactivation of channels prevents the signal from going backwards

d.) Inactivation of channels prevents the signal from going backwards

Second generation sequencing differs from Sanger Sequencing because: (Exam 2) a.) Second-Generation sequencing does not depend on chain-terminator dNTPs b.) Second-Generation sequencing does not require DNA Polymerase c.) For the cost per base sequenced, second-generation sequencing is much more expensive than Sanger sequencing d.) Second-Generation sequencing can sequence tens of millions of pieces of DNA at the same time on a single glass slide

d.) Second-Generation sequencing can sequence tens of millions of pieces of DNA at the same time on a single glass slide

Levels of cyclin-dependent kinase (Cdk) activity change during the cell cycle as a result of: (Lecture 22) a.) The Cdks phosphorylating each other b.) The Cdks activating other cyclins c.) the level of production of Cdks changing throughout the cell cycle d.) the Cdks binding different cyclins to become active

d.) the Cdks binding different cyclins to become active

Crossing over occurs between which chromosomes in each bivalent?

duplicated maternal and paternal chromosomes

Meiosis generates _________________ cells, whereas Mitosis produces _____________ cells.

four non-identical haploid cells; two identical diploid cells

Asexual Reproduction vs Sexual Reproduction

Asexual offspring are identical; Germ-Line cells have half the chromosomes as somatic cells; Sexual Reproduction allows for wide variety of gene combinations; Zygotes can ONLY be produced through sexual reproduction

When a mutation arises, it can have three possible consequences: a.) Beneficial to the individual b.) Selectively neutral c.) Detrimental Order the above in the order that is most-likely to spread to following generations to the least likely to be spread to the following generations. (Exam 1) 1.) A, C, B 2.) A, B, C 3.) B, C, A 4.) C, B, A

2.) A, B, C

If you took away all membrane enclosed organelles in an animal cell, what would you be left with? (Exam 1)

Cytosol

List the following compounds in order of from high membrane permeability to low membrane permeability. (Cumulative) 1.) Ca2+ , 2.) Glucose, 3.) N2, 4.) Ethanol a.) 1, 2, 3, 4 b.) 4, 3, 2, 1 c.) 1, 4, 3, 2 d.) 3, 4, 2, 1

d.) 3, 4, 2, 1

The cell surface receptors can rapidly relay the signal to the nucleus by activating latent gene regulatory proteins such as STATs at the plasma membrane. Why do most cell-surface receptors not use the shortcut, but use long, indirect cascades to influence gene transcription in the nucleus? (Exam 3) a.) Amplify the signal b.) Integrate signals from different pathways c.) Spread the signal along divergent paths d.) All of the above

d.) All of the above