Cell Biology Questions

Post ID: 2841827

Overview

Of the following, which is a cell cycle phase found within interphase, in a plant cell?

A. M
B. S
C. mitosis
D. cytokinesis
E. Answers (A) and

2 Culture medium for mammalian cells often contains serum, which the clear fluid that remains after blood has clotted. What is the major class of molecules within serum (but not whole blood) that is essential for cell proliferation?

A. Basic amino acids
B. Glucose
C. Acidic amino acids
D. Vitamins
E. Growth factors

3 Which of the following best describes a primary culture of mammalian cells that has passed the Hayflick Limit?

A. The cells within the culture will enter a state of senescence.
B. The cells within the culture will enter a terminal G0 state.
C. The cells within the culture will enter a state of quiescence.
D. Answers (A) and (B)
E. None of the above

4 Budding yeast (S. cerevisiae) cultures are asynchronous. What technique might you use to separate physically cells in G2 phase from cells in M phase?

A. Fluorescence in situ hybridization (FISH)
B. Light microscopy
C. Cell fractionation
D. Flow cytometry
E. Answers (C) and (D)

5 For a mammalian cell culture that has a mitotic index of 0.1, a known generation time of 35 hours, and an S phase of 6.5 hours, what is the approximate length of G1 phase of the cell cycle?

A. 10 hours
B. 25 hours cna you share your notes yeah i shared them! I didnt get umm all the notes on their though some are coming from my notes on the slides
C. 3.5 hours
D. Unknown, insufficient data to determine
E. 35 hours

6 Your friend, Dr. X. Pression, has developed a ground breaking method to transform cardiomyocytes. What has your friend actually accomplished?

A. Dr. Pression developed a method that enables these cells to express GFP (green fluorescent protein)-tagged proteins.
B. Dr. Pression developed a method that drives the cells into crisis.
C. Dr. Pression developed a method that further differentiates the cells.
D. Dr. Pression developed a method that introduces DNA into the cells.
E. Dr. Pression developed a method that creates an immortal cell line from these cells.

7 START defines the point at which _________________________.

A. a mammalian cell commits to the cell cycle, no longer requiring the presence of growth factors
B. a mammalian cell commits to the cell cycle, after sensing it is of the correct size
C. a fungal cell exits M phase and enters G1 phase
D. a fungal cell commits to the cell cycle, no longer requiring the presence of growth factors
E. a fungal cell commits to the cell cycle, after sensing it is of the correct size

8 Which one of the following choices describes an INCORRECT statement with regard to the cell cycle?

A. For some cells, growth is not required before entering the cell cycle.
B. Fungi, frogs, and humans utilize the same master kinase to regulate progression through the cell cycle.
C. A cell can return to metaphase if chromosomes mis-segregate during anaphase.
D. A cell in G0 can re-enter the cell cycle only at a point within in G1.
E. Prokaryotes and eukaryotes display a cell cycle.

9 Of the following, which enzyme dephosphorylates substrates phosphorylated by M-phase promoting factor (MPF)?

A. MAP kinase
B. Protein phosphatase 2A
C. Wee1 kinase
D. Cdc25 phosphatase
E. Ubiquitin ligase

10 Drs. Rao and Johnson have analyzed more heterokaryons formed after cell-cell fusion. In this experiment, they measured, at varying times after cell fusion, the mitotic index of heterokaryons formed from the fusion of G1 and G2 cells. In the same manner, they also measured the mitotic index of G2/G2 and G1/G1 homokaryons as well as the mitotic index of G1 and G2 cells with a single nucleus. Rao and Johnson's data are presented in the attached figure. Assume for homo- and heterokaryons that both nuclei are in mitosis when scored as "mitotic." Of the following, which one of the following is the most plausible interpretation of the data?

picture unavailable currently for this

A. An M-phase promoting factor exists.
B. G1/G2 heterokaryons never enter mitosis.
C. A checkpoint exists at the end of G2.
D. A S-phase promoting factor exists.
E. A checkpoint exists at the end of G1.

11 Of the following, which is structure represents an self-organized pattern within a cell?

A. Mitotic spindles
B. Golgi
C. Viral coats
D. Answers (A) and (B)
E. Answers (A), (B), and (C)

12 The oscillation of cell cycle, represented by periodic transitions between interphase and M-phase, is due to which of the following?

A. Activation of a cyclin-dependent kinase
B. Destruction of mitotic cyclin
C. Activation of a checkpoint in G2
D. Answers (A) and (B)
E. Answers (A), (B), and ©

13 Dr. Bunsen Honeydew (as a fond farewell to the class) developed a compound known as Fin3000, which competitively inhibits Wee1-type kinase, blocking its ability to interact with cyclin-dependent kinase/cyclin B complexes. Which one of the following graphs (attached) most likely describes the effect of Fin3000 when added to a frog egg extract in early G2? The arrow indicates the position of metaphase. Addition of the compound occurs at time zero in the experiment.picture unavailable currently for thisA. Graph A

B. Graph B
C. Graph C
D. Graph D
E. Graph E

14 In the context of the cell cycle, cyclin-dependent kinase activity is conceptualized as a switch that maintains the cell in one of two stable steady-states. Of the following, which is a CORRECT statement in regard to this switch?

A. The switch is viscoelastic (easy to activate, but slower to inactivate).
B. The switch is hysterical.
C. The switch is regulated principally by Cdc25 phosphatase and Wee1 kinase.
D. The switch is regulated principally by Cdk complexed with G1 cyclins.
E. None of the above

15 Of the following, which is an accurate description of a basement membrane?

A. It is a selectively permeable barrier between epithelial and connective tissue cell layers.
B. It is an impermeable barrier between epithelial and connective tissue cell layers.
C. It is only present after tissue injury, providing a scaffold for cell growth.
D. It is an unusually thin ( < 4.5 nm) biomembrane with a low lipid:protein ratio.
E. It is an unusually thick ( >20 nm) biomembrane with a high lipid:protein ratio.

16 Cells within connective tissues are the source of which one of the following tumor types?

A. Carcinoma
B. Sarcoma
C. Lymphoma
D. Leukemia
E. None of the above

17 Complete the following sentence. An immortalized human cell ____________________.

A. has low levels of telomerase activity
B. cannot exit the G0 phase of the cell cycle
C. has elevated levels of telomerase activity
D. has lost its telomeres
E. is in crisis

18 Of the following choices, which best represents a mutation that confers on a cell the cancer hallmark of "insensitivity"?

A. A mutation that decreases telomerase expression
B. A mutation that activates tyrosine kinase receptors in the absence of ligand
C. A mutation that enhances binding of Transforming Growth Factor beta (TGFbeta) to a cell surface serine/threonine kinase
D. A mutation that decreases Smad complex formation
E. A mutation that results in a loss of Bcl-2 function

19 Activation of the mitotic spindle assembly checkpoint requires which of the following?

A. Phosphorylation of Sic1 by S-phase Promoting Factor (SPF)
B. Attachment of microtubules to kinetochores
C. Release of Cdc20 from Bub protein complexes
D. Answers (B) and (C)
E. None of the above

20 Of the following, which event potentially represents the conversion of a proto-oncogene to an oncogene?

A. Acquisition of a mutation that results in an increase in gene product activity
B. Acquisition of a point mutation that results in loss of function of the gene product
C. Loss of telomeric DNA sequences
D. Answers (A) and (B)
E. None of the above

21 When Dr. Bunsen Honeydew (yes, he's back!) treats a culture of mammalian cells with the drug Muppetin165 in early G1, he finds the cells arrest before S phase. In contrast, untreated cells progress normally into S phase. Of the following, which is the most plausible mechanism for this arrest?

A. Muppetin165 inhibits DNA polymerase
B. Muppetin165 inhibits mitotic cyclin activity
C. Muppetin165 stimulates Rb binding to E2F
D. Muppetin165 promotes expression of Myc, Jun, and Fos
E. None of the above

22 Each choice below contains a series of genes, which from left to right represent a temporal order of mutation. The leftmost gene acquires a mutation first; the rightmost gene acquires a mutation last. Assuming each mutation contributes to the development of cancer, which choice most likely represents the temporal order of mutation during the process of tumorigenesis?

A. p53 - Ras - PTEN - Bcl2 - Rheb - Rho
B. Rho - p53 - Ras - PTEN - Bcl2 - Rheb
C. Rheb - Rho - p53 - Ras - PTEN - Bcl2
D. Bcl2 - Rheb - Rho - p53 - Ras - PTEN
E. All of the choices are equally valid.

23 As part of a study on cell growth and proliferation, you measured mTOR kinase activity in normal and mutant cells. In mutant cells, which exhibit a high rate of growth and proliferation, you found a significantly higher level of mTOR kinase activity, relative to normal cells. Which one of the following mutations is most likely to produce a higher level of mTOR kinase activity?

A. A mutation that increases the affinity of AMP for AMP kinase.
B. A mutation that blocks signaling from tyrosine kinase receptors bound to growth factors.
C. A mutation that blocks mTOR kinase from binding the GTP-bound form of the Ras-like GTPase Rheb.
D. A mutation that increases the affinity of GTP for mTOR kinase.
E. A mutation that decreases the activity of a GAP for the Ras-like GTPAse Rheb.

24 Activation of tyrosine kinase receptors by growth factors results in the inhibition of apoptosis. Which one of the following represents an intermediate step in this process?

A. Increasing cytochrome c leakage from mitochondria
B. Increasing apoptosome levels
C. Conversion of PIP3 to PIP2
D. Decreasing Bcl-2 levels
E. Activation of Akt kinase

25 Which one of the following statements about an individual adult stem cell is TRUE?

A. It will only produce two daughter stem cells, with each cell division.
B. It may be multipotent.
C. It may be totipotent.
D. It will only produce a daughter stem cell and a daughter differentiated cell, with each cell division.
E. Answers (C) and (D)

26 With respect to the Warburg Effect, which of the following is a TRUE statement?

A. The Warburg Effect is associated with high levels of PI(4,5)P uptake.
B. The Warburg Effect is often described as aerobic glycolysis.
C. The Warburg Effect is associated with high levels of glucose uptake.
D. The Warburg Effects increases lipid production in cells.
E. Answers (B), (C), and (D).

27 Beaker, Dr. Honeydew's very able assistant, is performing his last experiment for BIOL3000. In this experiment, Beaker notices that cells infected with human papillomavirus (HPV) are no longer destroyed by killer lymphocytes after the cells are treated with Compound Q. Of the following, which protein(s) is most likely inhibited by Compound Q?

A. MPF
B. SCF complex
C. Zds1 and Zds2
D. Caspases
E. Mad and Bub proteins

28 Of the following cellular events, which is directly promoted by the Anaphase Promoting Complex (APC) in embryonic frog cells?

A. Nuclear envelope breakdown
B. Sequestration of separase
C. Condensation of chromosomes
D. Cleavage of cohesin
E. Activation of securin

29 British mathematician and theoretical biologist Alan Turing conceptualized that a reaction-diffusion system can generate a self-organized pattern. These Turing patterns can either be spatial or temporal. Of the following, which most accurately describes an attribute of Turing's reaction-diffusion system?

A. The reaction product is a short range activator and a long range inhibitor.
B. The reaction product is a long range activator and a short range inhibitor.
C. The pattern produced by the reaction product can be altered by diffusion instabilities.
D. Answers (A) and (C)
E. Answers (B) and (C)

30 Of the following choices, which represents an example of templated formation of a new intracellular structure?

A. DNA synthesis
B. Spindle assembly in the absence of chromatin
C. Formation of a ribosome
D. Formation of the plasma membrane
E. All of the above

31 Among the following choices, which is/are required to fully understand how a cellular process functions?

A. Determination of the in vivo spatial positions of the molecules associated with the process
B. Determination of the in vitro concentration of molecules associated with the process
C. Reconstitution of the process in vitro using purified molecules or cell fractions
D. Answers (A) and (C)
E. Answers (B) and (C)

32 Of the following, which is NOT a common characteristic of a cancer cell?

A. Density-dependent growth
B. Prominent nucleoli
C. Anchorage-independent growth
D. Aneuploidy
E. Unstable karyotypes

33 Of the following, which is the rate limiting step of tumor growth at primary or secondary sites?

A. Intravasation
B. Epithelial-Mesenchymal Transition
C. Mesenchymal-Epithelial Transition
D. Angiogenesis
E. Breach of the basement membrane

34 Of the following, which characterizes the mesenchymal-epithelial transition (MET) of metastatic carcinoma cells?

A. Invadopodia formation
B. Gain of hemi-desmosomes
C. Expression of death receptors
D. Expression of metalloproteases
E. Answers (A) and (B)

35 Of the following, cell death serves which function?

A. Remodeling tissues during development
B. Removing cells damaged by radiation
C. Removing cells infected with viruses
D. Removing immune cells that recognize self
E. All of the above

36 Which combination of drugs will most effectively treat a tumor with "evasion" and "immortality" as its two main cancer hallmarks?

A. Caspase inhibitor + TGFbeta inhibitor
B. Cytochrome C inhibitor + p53 inhibitor
C. Bcl-2 inhibitor + p53 inhibitor
D. Bcl-2 inhibitor + telomerase inhibitor
E. Caspase inhibitor + p53 inhibitor

37 Of the following, which is an attribute of an apoptotic cell?

A. Nuclear fragmentation
B. Leakage of cytochrome C from mitochondria into the cytoplasm
C. Phosphatidylserine flipping from the inner to outer leaflet of the plasma membrane
D. Answers (A) and (B)
E. All of the above

38 Which one of the following describes the experimental evidence that a mitotic cyclin must be destroyed for a cell to exit mitosis?

A. The addition of sperm nuclei to Xenopus egg extracts initiated a cyclical replication, condensation, and de-condensation of DNA. Decondensation does not occur when mRNA encoding a non-degradable mitotic cyclin is the only mRNA present in the extract.
B. Synchronously fertilized sea urchin eggs were radio-labeled with 35S-methionine and portions of the sample (aliquots) were collected every 10 min for analysis by SDS-PAGE and autoradiography. The level of a mitotic cyclin was observed to be lowest during the cleavage of the fertilized egg and highest at the onset of mitosis.
C. When fertilized Xenopus eggs are treated with cycloheximide, an inhibitor of protein synthesis, cell division arrests until the fertilized eggs were injected with cytoplasm from mammalian cells in M-phase.
D. The addition of sperm nuclei to Xenopus egg extracts initiated a cyclical replication, condensation, and de-condensation of DNA. These cyclical events occur even after the addition of a DNA synthesis inhibitor.
E. The addition of sperm nuclei to Xenopus egg extracts initiated a cyclical replication, condensation, and de-condensation of DNA. The level of mitotic cyclin was shown to peak just prior to onset of DNA condensation and fall shortly afterwards.

39 Of the following methods, which would be most useful for identifying the location of a protein of interest in a living cell?

A. Expressing a chimeric protein in which GFP (Green Fluorescent Protein) is non-covalently bonded to a protein of interest, the observing the cells with a fluorescence microscope.
B. Indirect immunofluorescence microscopy, using an antibody to probe the location of the protein within a cell.
C. Thin section-transmission electron microscopy, using heavy metal stains to detect the protein of interest.
D. Cryo-electron microscopy, to detect the protein of interest in vitreous ice.
E. None of the above.

40 Dr. Bunsen Honeydew has introduced a mutation into the primary amino acid sequence of a GAP, a GTPase Activating Protein. This mutation inactivates the GAP. Which of the following occurs when this mutant GAP is isolated and subsequently mixed with its cognate G protein, GTP, and Protein J, the target (effector) of the G protein.

A. The G protein binds Protein J.
B. The G protein does not bind Protein J.
C. The G protein rapidly hydrolyzes GTP.
D. The G protein rapidly releases GDP and inorganic phosphate.
E. The G protein rapidly exchanges GDP for GTP.

41 Dr. Bunsen Honeydew's assistant Beaker developed an ingenious method for manipulating the pH of intracellular compartments. After applying his technique to an eukaryotic cell, Dr. Meyer was able to measure the pH of individual cellular compartments using a pH-sensitive dye (which does not kill the cells.) His data from the cells he treated are summarized below. Of the following, which is most likely to be observed in these cells?

Lumen of endoplasmic reticulum 7.0

Lumen of the cis-Golgi network 6.7

Lumen of the trans-Golgi network 6.2

Lumen of early endosomes 4.8

Lumen of late endosomes 5.5

Lumen of lysosomes 4.8

A. Absence of acid hydrolases in the lysosome.
B. Absence of V-class pumps in the lysosomal membrane.
C. Absence of P-class pumps in the lysosomal membrane.
D. Absence of F-class pumps in the lysosomal membrane.
E. None of the above answers are plausible.

42 Epidermal growth factor (EGF) receptors are internalized at plasma membrane sites known as ___________________.

A. Coated cavities
B. Caveolae
C. Cavisomes
D. Cav-mans
E. Coated pits

43 Which one of the following about the cytoplasm is TRUE?

A. It will deform rapidly under high shear stress and return slowly to a less deformed state.
B. It has high microviscosity.
C. It has low macroviscosity.
D. Answers (B) and (C)
E. None of the above

44 Of the following choices, which one best describes the structure or function of the nucleolus?

A. Nucleoplasmic reticulum surrounds the nucleolus.
B. Translation of ribosomal proteins occurs in the nucleolus.
C. Transcription of rDNA occurs in the nucleolus.
D. Answers (A) and (B)
E. Answers (A), (B), and (C)

45 For approximately the past 150 years, the experimental approaches of cell biology have been based on which one of the following philosophies?

A. Fallibilism
B. Reductionism
C. Holism
D. Vitalism
E. Bonism

46 In this course, we encountered many biologists and their discoveries. Of the following, who discovered the cellular processes known as intraflagellar transport?

A. Barbara McClintock
B. Randy Sheckman
C. Elizabeth Blackburn
D. George Palade
E. Keith Kozminski