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If an average globular protein was of the size of a tennis ball, a typical animal cell
would be as large as ___
A.a cubicle.
B.a room.
C.a tennis court.
D.a stadium.
E.a city.
Indicate whether each of the following descriptions matches an ABC transporter (A), a
P-type pump (P), or a V-type pump (V). Your answer would be a five-letter string
composed of letters A, P, and V only, e.g. PPVVV.
( )The pumps in this family are phosphorylated at a key Asp residue in each transport
cycle.
( )This family is the largest among membrane transport proteins and includes some
channels as well as pumps.
( )The pumps in this family are responsible for the acidification of synaptic vesicles.
( )The sodium-potassium pump is a member of this family.
( )The multidrug resistance protein is a member of this family.
Which of the following represents the active form of -catenin in cells stimulated with
Wnt?
A.Phosphorylated by GSK3 and CK1
B.Bound to APC
C.Bound to Groucho
D.Bound to LRP
E.None of the above
Which of the following transcription regulators constitute the master set of transcription
regulatory proteins whose expression is most required for generating induced
pluripotent stem cells and for maintaining pluripotency? Choose three proteins. Your
answer would be a three-letter string composed of letters A to F in alphabetical order,
e.g. CEF.
(A)Myc
(B)Klf4
(C)MyoD
(D)Nanog
(E)Oct4
(F)Sox2
Dopamine is a neurotransmitter involved in the reward pathways in the brain, and its
decreased activity has been associated with diseases such as Parkinson's disease and
attention-deficit/hyperactivity disorder (ADHD). Which of the following drugs is NOT
a likely candidate to treat these diseases?
A.Methylphenidate, a dopamine reuptake inhibitor
B.Amphetamine, a dopamine-releasing agent that triggers the release of dopamine into
the synaptic cleft
C.Carbidopa, which enhances the availability of the dopamine synthesis precursors in
the brain
D.Forskolin, a sensitizer of dopamine receptors
E.Chlorpromazine, a dopamine antagonist that binds to and inhibits dopamine receptors
Which of the following can lead to p53 stabilization and activation?
A.Hypoxia
B.Overexpression of Myc
C.DNA damage
D.Telomere loss
E.All of the above
Consider two cells, A and B. Both are approximately spherical, but cell A is a bacterium
with a diameter of only about 1 , while the diameter of the eukaryotic cell B is about
10 . If the plasma membrane in the eukaryotic cell comprises only about 2% of the
total cell membrane, which cell has a higher ratio of total cell membrane to volume?
Write down A or B as your answer.
According to the cancer stem-cell model for tumor growth and propagation, ...
A.transit amplifying cells are incapable of cell division, which is reserved for the cancer
stem cells.
B.transit amplifying cells constitute the great majority of the cells in the tumor.
C.if each stem cell divides to create one stem cell and one transit amplifying cell, the
abundance of stem cells in the tumor will increase exponentially over time.
D.tumors are genetically heterogeneous, even though they show high phenotypic
homogeneity.
E.the transit amplifying cells, even though each acts transiently, carry the whole
responsibility for maintenance of the tumor in the long term.
A primary mRNA transcript with three exons is depicted below. Which of the following
mature mRNA products of this transcript is a result of exon skipping?
A.
B.
C.
D.
E.
Indicate whether each of the following histone modifications is generally associated
with active genes (A) or silenced genes (S). Your answer would be a four-letter string
composed of letters A and S only, e.g. SSAS.
( )H3 lysine 9 acetylation
( )H3 serine 10 phosphorylation
( )H3 lysine 4 trimethylation
( )H3 lysine 9 trimethylation
For the two following graphs, the same purified protein has been subjected to velocity
sedimentation and gel filtration, as indicated. Two absorption peaks are visible in each
graph, corresponding to the monomeric and dimeric forms of the protein. Which peaks
correspond to the protein dimer?
A.1 and 3
B.1 and 4
C.2 and 3
D.2 and 4
Sort the following molecules based on the amount of energy that is released when their
phosphate bond is hydrolyzed as indicated. Your answer would be a four-letter string
composed of letters A to D only, e.g. ADCB. Put the molecule with the highest amount
of hydrolysis energy on the left.
(A)ATP when hydrolyzed to ADP
(B)Glucose 6-phosphate when hydrolyzed to glucose
(C)1,3-bisphosphoglycerate when hydrolyzed to 3-phosphoglycerate
(D)Phosphoenolpyruvate when hydrolyzed to pyruvate
Which of the following is true regarding genomic imprinting?
A.It is an epigenetic phenomenon.
B.It occurs in most animals.
C.It always involves inactivation of genes through direct DNA methylation.
D.It can "unmask" recessive alleles but cannot "mask" dominant ones.
E.All of the above.
Indicate true (T) and false (F) statements below regarding intracellular vesicle transport.
Your answer would be a four-letter string composed of letters T and F only, e.g. TTTF
( )The plasma membrane is stiffer and flatter than most intracellular membranes, and its
deformation generally requires greater force.
( )Large molecules such as collagen fibers of about 300 µm in length are highly packed
and coiled to fit into normal COPII vesicles of about 80 nm in diameter.
( )Rab proteins are recruited to membranes following activation by Rab-GEFs.
( )A Rab and its effector are always on two different membranes that will then fuse.
Indicate whether each of the following descriptions better applies to class I (1) or class
II (2) MHC proteins of vertebrates. Your answer would be a four-digit number
composed of digits 1 and 2 only, e.g. 2221
( )They mainly present intracellular peptide fragments.
( )They are found on most nucleated cells.
( )They present antigens mainly to helper or regulatory T cells.
( )They are recognized by CD4 co-receptors on helper and regulatory T cells.
A certain region of a mammalian genome is transcribed at low but sustained levels
using two flanking promoters. The RNA products are annealed together, processed, and
used to recruit the RITS complex to this region, as well as chromatin modifying
enzymes, RNA-dependent RNA polymerase, and a Dicer enzyme. Indicate whether this
pathway is more closely related to that seen in miRNA (M), piRNA (P), or siRNA (S)
interference pathways. Write down M, P, or S as your answer.
In the following graphs, the cellular response, as measured in real time by the
concentration of a certain active effector protein, is plotted over time for five cell types
(A to E) that are treated with three different concentrations of a signal molecule. During
the time period indicated by the horizontal gray bar, the signal molecule is present in
the culture media at a concentration of 1 nM (dotted curve), 5 nM (gray curve), or 25
nM (solid curve). Answer the following question(s) based on these graphs.
Which of the cell types A to E shows the lowest sensitivity to the signal?
Indicate true (T) and false (F) statements below regarding the cell cytoskeleton. Your
answer would be a four-letter string composed of letters T and F only; e.g. TTFF.
( )The three major building blocks of cytoskeletal filaments can bind to and hydrolyze
nucleotides.
( )The building blocks of microfilaments and microtubules are globular proteins,
whereas those of intermediate filaments are themselves filamentous proteins.
( )Intermediate filaments are typically thicker than actin filaments but thinner than
microtubules.
( )Plant cells lack microtubules.
