MCB 252 Final

Which type of tissue described in lecture is involved in support, connecting body parts, and cushioning? A. Muscle B. Epithelial tissue C. Connective tissue D. Nervous tissue

C

What is the most typical form of cytoplasmic dyneins that move along interphase cytoplasmic microtubules? A. They are dimers. B. They are monomers. C. They are tetramers. D. They are trimers.

A

Which of the following proteins is most likely a transmembrane protein? A. Occludin B. ZO-2 C. Zonula Occludins-1 (ZO-1) D. All of the above

A

In which part of dynein is the microtubule binding site located? A. The stalk B. The head C. The stem D. None of the above

A

MPF drives (or regulates) which transition in the cell cycle? A. G2 → M B. G1 → S C. S → G2 D. M → G1

A

Ras is a(n): A. Oncogene B. Tumor suppressor gene

A

As shown in this figure, the G1 Cdks phosphorylate Whi5 and Rb thereby inactivating Whi5 and Rb. Which of the following proteins activates Whi5 and Rb? A. Cdc14 B. the APC C. Cdc25 D. the M Cdks E. SCF

A

In lecture we discussed a version of the figure shown below. Figure A: unorganized red and green cells Figure B: red cells on outside, green cells on inside This experiment involves a type of tissue culture cell that normally has very little or no adhesive properties. You express a single type of cadherin in these cells. In one set of cells you express a higher level of cahdherin and label those cells with one color. In another set of cells you express a lower level of cahdherin and label those cells with a second color. Which cells are which? A. The green cells have a higher level of cadherin than the red cells. B. The red cells have a higher level of cadherin than the green cells.

A

In which part of dynein is the ATPase activity located? A. The head B. The stalk C. The stem D. None of the above

A

Which of the following techniques was used in the experiment we discussed in lecture that determined the step size of a dynein motor protein? A. Electron microscopy B. A sliding filament assay C. Fusion of dynein to GFP D. An optical trap E. X-ray crystallography

A

Which subunit of a heterodimeric Cdk is the regulatory subunit? A. The cyclin subunit B. The kinase subunit

A

Which type of junction effectively connects the actin cytoskeleton of one cell to the extra-cellular matrix (ECM)? A. Focal adhesion B. Desmosome C. Adherens junction D. Hemidesmosome

A

Which type of reaction best describes microtubules that are undergoing dynamic instability in vitro- steady state or equilibrium (assuming GTP is always available)? A. Steady state B. Equilibrium

A

You are studying a cell line in in which one cell cycle takes approximately 24 hours. You perform FACS analysis on a population of your dividing cells. Your cells are growing asynchronously meaning different cells are in different stages of the cell cycle. Your FACS analysis indicates that 1/3 of your cells have a DNA content of 2n. How long is the G1 phase in these cells? A. 8 hours B. 4 hours C. 1 hour D. 2 hours E. 24 hours

A

You are studying a particular protein we'll call YFP (for Your Favorite Protein). You hypothesize that YFP binds tightly to other proteins in the cell and wish to identify those proteins. Which technique discussed in lecture will most directly allow you to achieve your goal? A. A Co-immunoprecipitation experiment B. A domain swapping experiment C. Deletion analysis D. Screening an expression library

A

Cdc25 is a phosphatase that activates the M-Cdk(s). What activates Cdc25? A. Cdc25 B. One or more M Cdks C. One or more S Cdks D. One or more G1 Cdks E. Cdc14

B

Immunoprecipitation can be used in conjunction with which technique to identify the protein that is recognized by a specific antibody? A. RNAi B. Mass spec C. Transfection D. Electron microscopy E. Immuno-fluorescent microscopy

B

In lecture we talked about a Xenopus egg extract that can undergo cell cycles in vitro. We saw that addition of an RNAase resulted in degradation of the mRNAs in this extract and blocked the ability of the extract to undergo cell cycles in vitro. Based on this assay, answer the following two questions. After inhibiting the RNAase in the previous question one can add back different versions of the cyclin mRNA. As described above, addition of the wild-type version results in multiple rounds of cycling. Addition of no mRNA results in replication of the DNA but the extract does not enter mitosis. You next add back a version of the cyclin mRNA that lack the region that codes for the N-terminal 90 amino acids of cyclin. This mRNA codes for a version of the cyclin protein that does not get degraded. You find that addition of this mRNA to your extract allows your extract to enter M-phase but not exit M-phase. Do these results support the conclusion that cyclin synthesis is required for entry into M-phase and that cyclin degradation is required for exit from M-phase? A. No, these results are not consistent with this conclusion. B. Yes, these results support this conclusion.

B

Microtubules are: A. Not polar B. Polar

B

The genetic screen outlined below was designed to identify what type of genes? S + G2 = 35 minutes -> Mitosis All cells alive S + G2 = 35 minutes -> Mitosis Before Replication Complete All cells dead Genetic Scree: Look for cells (colonies) that can grow on media lacking HU but not on media containing HU A. Genes that are required for the G2-to-M transition B. Genes required for an S-phase checkpoint C. Genes that are required for the S-to-G2 transition D. Genes that are required for the G1-to-S transition E. Genes that are required for the M-to-G1 transition

B

Tubulin hydrolyses which nucleotide? A. ATP B. GTP C. UTP D. All of the above E. None of the above

B

What specific type of experiment demonstrated that cadherins were sufficient to mediate cell-cell adhesion? A. Using an antibody to block cadherin function B. Expression of a cadherin gene in cells that do not normally adhere to each other (or have low adhesion function) C. RNAi inhibition of cadherin function in developing frog embryos D. Cloning by screening an expression library

B

Which family of protein are found in (and make up) GAP junctions? A. Desmoglein family members B. Connexins C. Occludins D. Claudins E. None of the above

B

Which of the following proteins binds to the GTP cap and stabilizes that cap? A. MAP2 B. EB1 C. Kinesin-13 D. All of the above

B

Which type of junction prevents transmembrane proteins in the apical part of the plasma membrane from diffusing into the basolateral part of the plasma membrane? A. Equatorial junctions B. Tight juctions C. Adherens junctions D. Gap junctions

B

γ-TURC plays a role in which of the following processes? A. Capping of the plus end of microtubules B. Nucleation of microtubules C. Elongation of microtubules D. Elongation of microtubules and capping of the plus end of microtubules E. All of the above

B

In which of the following time frames do we think that LUCA existed? A. 5.6 to 6.1 billion years ago B. 1.6 to 2.1 billion years ago C. 3.6 to 4.1 billion years ago D. 1.6 to 2.1 million years ago E. 3.6 to 4.1 million years ago

C

The microtubules that attach to the chromosomes at the centromere/kinetochore attach to what? A. The centromeric DNA B. The inner layer of the kinetochore C. The outer layer of the kinetochore

C

What is responsible for shutting off the M-Cdks in M-phase? A. Sic1 B. The M Cdks C. The APC D. Cdc25 E. None of the above because the M Cdks remain active throughout all of M-phase

C

When dynein is in the "apo" form, what is the form of the "nucleotide" that is bound to the dynein? A. ADP B. ATP C. ADP + Pi D. no nucleotide

D

Which family of cell-cell adhesion molecules has approximately 750 family members in humans and is thought to play a role in wiring of the human brain? A. Cadherins B. Intergrins C. Selectins D. Ig-CAMs

D

Which of the following are advantages to genetic analysis of the cell cycle in yeast, relative to humans or most other eukaryotes? A. You can tell what stage of the cell cycle a yeast cell is in by looking at the morphology of that cell; whereas you cannot tell what stage of the cell cycle a human cell (or most other eukaryotic cells) is in by looking at the morphology of that cell. B. You can isolate loss-of-function mutants in haploid cells. C. The time to complete the cell cycle is longer in yeast than in humans, therefore it is easier to watch the cell cycle events unfold in yeast relative to humans D. You can tell what stage of the cell cycle a yeast cell is in by looking at the morphology of that cell; whereas you cannot tell what stage of the cell cycle a human cell (or most other eukaryotic cells) is in by looking at the morphology of that cell, and you can isolate loss-of-function mutants in haploid cells. E. All of the above

D

Which of the following is a ubiquitin ligase? A. Sic1 B. SCF C Sic1 and SCF D. SCF and the APC E. All of the above

D

Which one of the following terms most specifically describes the type of allele of the CDC genes that Lee Hartwell isolated in order to study the cell cycle in the bakers/brewers yeast S. cerevisiae? A. Gain of Function B. Dominant C. Recessive D. Conditional/temperature sensitive E. Loss of Function

D

Which part of dynein contacts the Arp1? A. The stalk B. The head C. The stem D. None of the above

D

Which type of junction effectively connects the actin cytoskeleton of one cell to the intermediate filament cytoskeleton of an adjacent cell? A. Desmosome B. Hemidesmosome C. Focal adhesion D. Adherens junction

D

Which type of junction effectively connects the intermediate filament cytoskeleton of one cell to the intermediate filament cytoskeleton of an adjacent cell? A. Focal adhesion B. Adherens junction C. Hemidesmosome D. Desmosome

D

You have carried out a genetic screen in S. pombe and identified a hypothetical recessive allele we'll call cdc252-. The phenotype of a haploid cdc252- strain is that cells are smaller than wild-type. You identify an allele we'll call cdc252D. Haploid cdc252D strains produce cells with a larger size than wild-type cells. Which of the following most likely describes the function of the cdc252+ gene? A. cdc25+ is required for cell cycle progression, but is not likely to be a regulator of cell cycle progression. In this case, cdc252+ is an activator of cell cycle progression. B. cdc252+ is required for cell cycle progression, but is not likely to be a regulator of cell cycle progression. In this case, cdc252+ is an inhibitor of cell cycle progression. C. cdc252+ is a regulator of cell cycle progression. In this case, cdc252+ is an activator of cell cycle progression. D. cdc252+ is a regulator of cell cycle progression. In this case, cdc252+ is an inhibitor of cell cycle progression.

D

Kinetochores send a signal that inhibits which protein until microtubules are properly attached to the kinetochores? A. Sic1 B. the M Cdks C. Wee1 D. SCF E. the APC

E

Which of the following are hallmarks of cancer cells? A. Metastasis B. Unregulated proliferation C. Genomic instability D. Unregulated proliferation and metastasis E. All of the above

E

Which of the following techniques was used in Lee Hartwell's primary screen for cdc mutants? A. Replica plating B. Mutagenizing cells C. Plating for single cells D. Plating for single cells and replica plating E. All of the above

E

True or false? As discussed in lecture, microtubules that are anchored in a centrosome are nucleated by and are extensions of the microtubules that comprise the centrioles.

False

True or false? All the genes identified in Hartwell's secondary cdc screen are regulators of the cell cycle.

False

True or false? As discussed in lecture, when cloning a yeast gene by complementation you make the genomic library from cells that have a mutation in your gene of interest.

False

True or false? As discussed in lecture, within a centrosome the two centrioles are identical to each other.

False

True or false? Kinesins are minus end directed motors proteins.

False

True or false? As described in lecture, kinetochore microtubules treadmill in M-phase prior to anaphase.

True

In lecture we talked about a Xenopus egg extract that can undergo cell cycles in vitro. We saw that addition of an RNAase resulted in degradation of the mRNAs in this extract and blocked the ability of the extract to undergo cell cycles in vitro. Based on this assay, answer the following two questions. Inhibition of the RNAase followed by addition of the mRNA for cyclin restored cell cycling. As a result we can conclude that cyclin is required for progression through the cell cycle and that cyclin is the only protein that needs to be translated in these extract to get cycling to occur. True or false?

True

True or false? As described in lecture, S and M Cdks are made ahead of when they are needed but are held in an inactive form until the appropriate time; at that time a switch is thrown and a large pool of those proteins become rapidly activated.

True

True or false? As described in lecture, kinetochore microtubule begin to pull on the sister chromatids prior to anaphase.

True

True or false? As described in lecture, when one is studying yeast and plates for single cells, all cells within a given colony are expected to be genetically identical.

True

True or false? As discussed in lecture, it takes greater than 1 full cell cycle for a centriole to mature from being "born" (or its initial formation) until it matures into a fully functional mother centriole.

True

True or false? As discussed in lecture, the cell cycle is regulated by a series of (irreversible) switches.

True

True or false? As discussed in lecture, the progenitor of the AAA ATPase family of proteins existed before the eubacteria, the archaebacteria and the eukaryotes diverged from each other.

True

True or false? As discussed in lecture, when cloning a yeast gene by complementation you transform your library into cells that have a mutation in your gene of interest.

True

True or false? Dr. Rivier's "definition" of "regulation" is biological decision making. Specifically, doing something at one time, in one place, or in response to one condition, but not doing that thing at a different time, in a different place, or in response to a different condition.

True

True or false? In the early part of mitosis, prior to anaphase chromosomes are moved to the center of the cell; whereas, in anaphase the sister chromatids move toward the spindle poles away from the center of the cell.

True

True or false? MPF function is conserved from frogs to humans.

True