1. Which molecular event at the neuromuscular junction contributes to activation of a muscle contraction
a. voltage-gated k+ propagation of an action potential along presynaptic axon
b. glycine inhibition of voltage gated K+ hyperpolarization on postsynaptic membranes
c. acetylcholine gated Ca2+ channel activation on postsynaptic membrane
d. acetylcholine mediated closure of postsynaptic cation channel
2. which is not true of cancer-critical genes
a. gain of function genes are genetically dominant
b. oncogenes activate programmed cell death
c. loss of function mutation of tumor suppressor genes abolish the inhibitory controls that normally hold cell numbers in check
d. specific cancer critical are mutated in the majority of all cancers
3. which of the following is false
a. cancer progression relies on accumulating mutations in multiple cancer critical genes
b. tumor initiators are environmental effectors that change gene expression patterns
c. tumor promoters do not alter DNA sequence
d. epigenetic events that promote tumor growth are not passed along to offspring
e. involves turning off proapoptotic signaling pathways
4. in some lung cancers the x-linked inhibitor of apoptosis protein (XIAP) binds to capase-9, resulting in the suppression of the activity of apoptotic activator cytochrome c. the fate of these cells is to
a. undergo necrotic cell death
b. undergo programmed cell death
c. form a tumor
d. enter M phase
e. form germ cells
5. the cell death cascade initiates with
a. the cell cycle S phase
b. binding of external death signals, FAS ligand
c. release of mitochondrial Ca2+ and cytochrome c
d. mitogenic factors
e. 2 and 3
f. none of the above
6. a 45 year old male diagnosed with metastatic adenocarcinoma was determined to have a subset of genes whose over expression was characteristic of a metastatic signature. Up regulated genes in the signature include: SNRPF, HNRPAB, DHPS and securin. Mutations in which additional genes are found in almost all aggressive metastatic human tumors?
a.Ras
b.Myc
c.P53
d.Rb
e.Tor
f. 1 and 3
g. All of the above
7. to support proper function of the visual pigments (rhodopsin) domains in rod and cone cells have a composition that makes them very fluid. Which of the following would support a high degree of membrane fluidity?
a. A high proportion of sugars
b. Saturated fatty acids
c. High cholesterol concentration unsaturated trans fatty acids
d. Small polar head groups
8. replication of the chromosomes in S phase includes
a. accurate copying of the entire DNA molecule in each chromosome
b. expressions of the DNA binding proteins that package the DNA
c. S-Cdk activation of proteins that unwind the DNA and intiate its replication at specific DNA locations (ori, origins of replication)
d. S-Cdk activation enabling only one round of DNA replication
e. All of the above
9. intestinal mucosal cells in the duodenum and upper jejunum absorb the bulk of the dietary sugars following metabolism of polysaccharides to monomeric sugar subunits. The driving force for sugars to be transported into cells which already contain high concentrations of intracellular sugars is.
a. antiport using the concentration gradient of K+
b. K+ sugar=dependent ATPase, sugar pumps
c. Extracellular break down of sugars to pyruvate by glycolysis. Pyruvate then passively diffuses into cells
d. Passive diffusion by sugar uniport transporters
e. Na+ driven symport
10. the transmembrane helical domain of membrane proteins typically ______.
a. is exposed
b. forms beta barrels
c. contains amino acids such as serine, asparagine and lysine
d. interacts with lipids via side chains of valine, alanine and leucine
e. interacts with lipids via peptide bond carbonyl oxygen and amide nitrogen via Hydrogen bonding
11.which is a property of the FAS domain of lymphocytes?
a. the are antiapoptotic
b. they are mitogens
c. the are mitochondrial membrane associated proteins
d.they bind to the death receptor
e. they are part of the intrinsic pathway of apoptosis
12. which proteins are not involved in programmed cell death
a. IAP
b. apoptosome
c. cytochrome c
d. BH domain proteins
e.caspase
f. phospholipase
13. a patient with heart disease presents with arrhythmic, ventricular fibrillation. Following a biopsy of the diseased ventricles, antibody-directed analysis (WESTERN) reveals quantitative reduction in the gap junction protein connexin43. Transport of which solute could be disrupted between the affected cardiomyocytes?
a. sodium
b. potassium
c. Ca2+
d.cholesterol
e. hemoglobin
14. the resting potential of a nerve cell is not due to:
a. Na+ K+ pump
b. K+ leak current
c. K+ electrochemical gradient
d. Na+ electrochemical gradient
e. The insulating properties of the phospholipids bilayer
f. 1 2 3 and 5
15. Cancer is an accumulation of abnormal cell traits that can originate from
a. activation of oncogenes
b. inactivation of tumor suppressor genes
c. DNA damage
d. Epigenic gene expression changes
e. exposure to carcinogens
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