Cyclin B1, a key cell cycle regulatory protein in vertebrates, is mostly cytosolic before
mitosis. Early in mitosis, however, the protein is phosphorylated by certain protein
kinases and consequently accumulates in the nucleus. How can phosphorylation bring
about nuclear accumulation of this protein?
A.Phosphorylation within the nuclear localization signal inhibits the function of the
signal.
B.Phosphorylation within the nuclear export signal enhances the function of the signal.
C.Phosphorylation within the nuclear export signal interferes with the function of the
signal.
D.Phosphorylation elsewhere on the protein enhances binding to cytosolic proteins.
Which of the following groups of living organisms has the highest variation in haploid
genome size?
A.Mammals
B.Fish
C.Fungi
D.Protozoa
E.Prokaryotes
After reaching sexual maturity, the nematode Caenorhabditis elegans normally doubles
in size within about two weeks. This doubling is mainly due to …
A.cell division.
B.DNA replication without cell division.
C.reduced cell death.
D.deposition of extracellular matrix.
In the following schematic drawing of a polarized neutrophil engaged in chemotaxis, in
what region (a or b) does Rac activity dominate? What other member of the Rho family
dominates at the other region?
A.Region (a); Rho
B.Region (a); Cdc42
C.Region (b); Rho
D.Region (b); Cdc42
Which group of factors is thought to impede iPS cell generation from a differentiated
cell, inasmuch as the reprogramming efficiency is increased when the activity of the
factors is decreased?
A.Histone acetyl transferases
B.Histone deacetylases
C.Chromatin remodelers
D.DNA demethylases
E.All of the above
In addition to fibroblasts themselves, the fibroblast family of connective-tissue cells
includes all of the following EXCEPT …
A.Smooth muscle cells
B.Chondrocytes
C.Osteoblasts
D.Adipocytes
E.Macrophages
What are the advantages of monoclonal antibodies over antisera?
A.They can be produced in higher quantities.
B.They can be produced with higher purity.
C.They have a more uniform specificity.
D.They can be made against molecules that constitute only a minor component of a
complex mixture.
E.All of the above.
A piece of DNA has been sequenced by Ion Torrent¢ sequencing. The result
corresponding to a six-nucleotide segment of this DNA is presented in the graph below,
in which pH change is recorded after the addition of each of the four nucleotide
triphosphates in cycles. What is the sequence of this segment? All sequences are written
from 5′ to 3′.
A.TACGTA
B.CGTACG
C.CCGTAA
D.CGGTTA
E.ATTGGC
Which of the following is NOT correct regarding cryoelectron microscopy?
A.It does not require shadowing or negative staining.
B.It involves obtaining images from many-sometimes tens of thousands of-individual
molecules that may or may not all be in the same orientation.
C.Subnanometer resolutions (e.g. 0.5 nm or better) can be achieved by this technique.
D.It can only be used to see the exterior surface of molecules and complexes.
E.Atomic models obtained from x-ray crystallography can be fitted into the density
envelope obtained from this technique.
Consider two proteins A and B with equal transcription and translation rates. The mean
lifetime of A, however, is twice as long as that of B. Starting with no protein, the time it
takes for a protein to reach 99% of its steady-state concentration is ___
A.the same for proteins A and B.
B.two times longer for A compared to B.
C.two times longer for B compared to A.
D.less than twofold longer for A compared to B.
E.less than twofold longer for B compared to A.
This model organism is particularly well suited for studying developmental processes in
higher animals. It develops from a fertilized egg to an adult in only two to three months,
and its body is transparent for the first two weeks, making it easy to observe cell
behavior during development. Which of the following describes this organism?
A.It is a vertebrate.
B.It is well suited for genetic analysis.
C.Its early stages of development occur outside of the mother’s body.
D.Its genome size is almost half that of humans.
E.All of the above.
Two transcription activators cooperate to recruit a coactivator to a cis-regulatory
sequence and activate transcription of a nearby gene. If each of the activators increases
the affinity of the coactivator for the reaction site (and therefore the rate of
transcription) by 100-fold, how much would you expect the affinity to increase when
both activators are bound to DNA compared to when none is bound?
A.10-fold
B.100-fold
C.200-fold
D.10,000-fold
The cell can change the pH of its internal compartments using membrane transport
proteins that pump protons into or out of a compartment. How many protons should be
pumped into an endocytic vesicle that is 10-15 liters in volume and has a neutral pH in
order to change the pH to 5? Avogadro’s number is 6 x 1023. Omit complications such
as the membrane potential, buffers, and other cellular components.
A.6000
B.60,000
C.120,000
D.600,000
E.6,000,000
Which of the following is NOT correct regarding M6P receptors and KDEL receptors?
A.They both shuttle back and forth between different membrane-enclosed
compartments.
B.They are both transmembrane proteins.
C.They both release their soluble binding targets at lower pH.
D.They both prevent the escape of proteins to the cell exterior by the “default” pathway.
You are studying the cellular basis of petal coloration in the flowering plant Ipomoea
tricolor. These plants have colorful petals due to the presence of pH-sensitive vacuolar
anthocyanins that change color from red/purple in acidic pH to blue at neutral pH. You
treat petals with either vanadate (a specific inhibitor of P-ATPases) or bafilomycin (a
specific inhibitor of V-ATPases) or both and compare the color with that of control
petals, obtaining the results shown in the table below. Which of the following
conclusions is consistent with these observations?
A.Both P- and V-ATPases are required to sufficiently acidify the vacuoles in petal cells.
B.P-ATPases are sufficient for acidification of the vacuoles in petal cells.
C.V-ATPases are sufficient for acidification of the vacuoles in petal cells.
D.Neither P- nor V-ATPases are necessary for vacuole acidification in petal cells.
Sort the following events to reflect the order in which they occur during engulfment of
an antibody-coated microorganism by a neutrophil in the blood. Your answer would be
a four-letter string composed of letters A to D only, e.g. DACB.
(A)Rho-GEF activation
(B)Activation of Fc receptors
(C)Local PI(4,5)P2 production
(D)Local PI(3,4,5)P3 production
Selectins …
A.mainly mediate cell-matrix attachments.
B.are members of the Ig superfamily of cell adhesion molecules.
C.do NOT require Ca2+ for their adhesive function, unlike integrins.
D.are carbohydrate-binding proteins.
E.All of the above.
Consider an actin subunit that has just been incorporated into an actin filament at the
leading edge of a lamellipodium. Before its ATP is hydrolyzed, how does its distance
from the leading front edge of the plasma membrane change over time? How does its
distance from the F-actin minus end change over time?
A.Decreases; decreases
B.Decreases; remains constant
C.Decreases; increases
D.Increases; decreases
E.Increases; remains constant
Expression of the Even-skipped (Eve) gene in early Drosophila embryos is under the
control of several transcription regulators. In one example, one of the Eve stripes is
positioned near the anterior region of the embryo, and its regulatory module contains
binding sites for Bicoid and Hunchback (activators) as well as Giant and Kr¼ppel
(inhibitors) such that the gene is expressed only in the region where concentrations of
the two activators are high and the concentrations of the two inhibitors are low. A
reporter gene can be placed under the control of this module, and it can be shown to
form a stripe in the same place in the embryo as the corresponding stripe of Eve.
Answer the following question(s) based on these findings.
What would you expect to happen to the pattern of reporter expression in flies that lack
the gene encoding Bicoid?
A.It would be expressed in all seven stripes.
B.It would be expressed in stripe 5 only.
C.It would expand to cover a broad anterior region of the embryo.
D.It would fail to express efficiently in the stripe 2 region.
E.It would be expressed throughout the whole embryo.
Consider the embryonic cerebral cortex of a mammal. Near which side of the cortex are
the cell bodies of radial glial cells located? To which side of the cortex do the first-born
neurons eventually migrate?
A.Inner surface; inner surface
B.Inner surface; outer surface
C.Outer surface; inner surface
D.Outer surface; outer surface
Indicate true (T) and false (F) statements below regarding differentiation of blood cells.
Your answer would be a four-letter string composed of letters T and F only, e.g. TTTT.
( )Most blood cells are derived from the pluripotent stem cells by a few cell divisions.
( )Commitment to a specific differentiation path is a stepwise process.
( )Upon contacting connective-tissue cells of the bone marrow, hematopoietic stem cells
lose their stem-cell character and differentiate.
( )Committed hematopoietic progenitor cells typically divide rapidly.
Indicate true (T) and false (F) statements below regarding glycolysis. Your answer
would be a four-letter string composed of letters T and F only, e.g. TTTT.
( )Molecular oxygen is used in glycolysis to oxidize glucose.
( )Along the glycolytic pathway, ATP is both consumed and generated.
( )In the course of glycolysis, one molecule of NADH is formed per molecule of
glucose.
( )Following the production of one molecule of fructose 1,6-bisphosphate, the rest of
the glycolytic pathway generates four molecules of ATP.
In the following graph, which line (1 to 3) better represents the changes in the level of
EphA receptors on retinal axons along the anterior-posterior axis of the mouse retina?
Which line better represents the changes in the abundance of EphrinA along the
anterior-posterior axis of the mouse optical tectum? Write down your answer as a
two-digit number, e.g. 22.
The membrane potential in a particular hyperpolarized cell is measured to be -70 mV.
For each of the following channels in this cell, the calculated Nernst equilibrium
potential for the corresponding ion is presented. Indicate whether each channel is driven
to pass the ion into (I) or out of (O) the cell. Your answer would be a four-letter string
composed of letters I and O only, e.g. IIII.
( )K+ channel; the K+ equilibrium potential is -60 mV.
( )Na+ channel; the Na+ equilibrium potential is +70 mV.
( )Ca2+ channel; the Ca2+ equilibrium potential is +130 mV.
( )Cl– channel; the Cl– equilibrium potential is -90 mV.
Fill in the blank. These RNA molecules can catalyze a wide variety of biochemical
reactions, including peptide bond formation and RNA splicing. They can be found in
nature or selected in vitro for a desired function. Such a molecule is called a(n) ___
In the following schematic diagram of a meiotic bivalent in diplotene, indicate whether
each of the following chromatid pairs have undergone DNA exchange (E) or not (N).
The different color of the final form of chromatid 3 is for clarity only. Your answer
would be a four-letter string composed of letters E and N only, e.g. NENE.
( )Chromatids 1 and 3
( )Chromatids 1 and 4
( )Chromatids 2 and 3
( )Chromatids 2 and 4
Indicate true (T) and false (F) statements below regarding cytoskeletal motor proteins.
Your answer would be a five-letter string composed of letters T and F only, e.g. TTTFF.
( )All myosin motors move toward the plus end of actin filaments.
( )All myosin motors move toward the minus end of actin filaments.
( )All kinesin motors move toward the plus end of microtubules.
( )All kinesin motors move toward the minus end of microtubules.
( )All dynein motors move toward the minus end of microtubules.
No matter where translation begins, only one polypeptide sequence pattern can be
obtained from the translation of an mRNA chain with the sequence (AC)n; that is, an
mRNA with the sequence 5’___ACACACACAC___3′. In contrast, an mRNA chain
with the sequence (ACG)n can be translated to polypeptide sequences of three distinct
patterns, depending on the choice of the reading frame. Using similar judgment, how
many different polypeptide sequence patterns can be obtained from an mRNA chain
with the sequence (ACGU)n? Write down your answer in digits, e.g. 12
Indicate whether each of the following descriptions matches glycolysis (G) or the Krebs
cycle (K). Your answer would be a four-letter string composed of letters G and K only,
e.g. GGGK.
( )It oxidizes acetyl CoA to CO2.
( )In eukaryotic cells, it is carried out in the cytosol.
( )It produces FADH2.
( )±-Ketoglutarate, one of its intermediates, is used to synthesize the amino acid
glutamic acid.