Name________________________
SID#________________________
MCB 32 Exam #1 9/30/08
Answer questions on the Scantron form using a #2 pencil. All questions 2 pts except where noted.
1. Breathing raises blood O2 concentration, lowers blood CO2 concentration. According to the principles
of negative feedback, sensors that regulate breathing should respond to
I. decrease in blood [O2]
II. increase in blood [O2]
III. decrease in blood [CO2]
IV. increase in blood [CO2]
A. I and III
B. I and IV
C. II and III
D. II and IV
2. _____ in [glucose] in the blood cause release of _____ from the _____ cells in the pancreas.
A. increases, insulin, beta
B. increases, glucagon, alpha
C. decreases, insulin, beta
D. decreases, glucagon, alpha
E. A and D are both correct
3. The skin is an organ that contains
A. neurons
B. connective tissue C. epithelium D. muscle
E. all of these
4. Alpha helices and beta sheets are examples of what level of protein structure?
A. primary
B. secondary
C. tertiary
D. quaternary
5. Which of the following bonds is not important for the structure and function of proteins?
A. hydrogen
B. covalent
C. peptide
D. all are important
6. Hydrogen bonds
A. determine the pH of solutions
B. bind the lipids and proteins of membranes together
C. are important determinants of the double helix structure of DNA
D. A and B are correct, but C is not.
E. A, B and C are all correct.
7. The following characteristics are shared by proteins and fats:
A. contain C, H, O and N in the chemical formula
B. contain the same proportion of O and H molecules
C. both are hydrophilic
D. none of the above is correct
8. Proteins, fats and glycogen are all formed by dehydration synthesis. 1 pt.
A. True
B. False
9. Glycogenolysis occurs prominently in the liver. 1 pt.
A. True
B. False
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Name________________________
SID#________________________
10. A capillary membrane that was permeable to water, Na and Cl but not to proteins separated plasma
containing 150 mM NaCl + 2 mM protein from the interstitial fluid containing 150 mM NaCl and 1
mM protein. Water would flow by osmosis from the interstitial space to the capillaries. 1 pt
A. True
B. False
11. In terms of the number of ATP molecules produced from one glucose molecule during aerobic
metabolism, the energy-yielding processes in cells produce energy in the sequence (highest to
lowest):
Krebs cycle > glycolysis > oxidative phosphorylation. 1 pt.
A. True B. False
12. NADH produced during anaerobic metabolism is maintained at physiological levels by:
A. using NADH to reduce pyruvate to lactate.
B. using NADH to reduce lactate to pyruvate.
C. transferring electrons from NADH to CO2 in the Krebs cycle.
D. transferring electrons from NADH to O2 in the mitochondria
13. Compare the pH and electrical voltage of intermembrane space and matrix in mitochondria during
active oxidative phosphorylation.
A. pH: intermembrane space > matrix; voltage: matrix positive
B. pH: intermembrane space < matrix; voltage: matrix positive
C. pH: intermembrane space > matrix; voltage: matrix negative
D. pH: intermembrane space < matrix; voltage: matrix negative
14. Pyruvic acid formed during glycolysis is converted into ____ and ____ in the Krebs cycle
A. H2O, NADH B. O2, ATP C. CO2, NADH
D. CO2, NAD
E. ATP, NAD
15. The net gain of ATP’s from metabolizing one glucose molecule by anaerobic glycolysis vs aerobic
respiration is roughly in the ratio of
A. 8:1
B. 2:1
C. 1:4
D. 1:16
E. 1:100
16. NADH and FADH both donate electrons to the electron transport chain located in the _____.
A. outer mitochondrial membrane
B. inner mitochondrial membrane
C. mitochondrial matrix
17. Which of the following characteristics is(are) shared by active transport and facilitated diffusion?
A. is saturable
B. occurs down the chemical gradient
C. requires energy in the form of ATP to operate
D. both A and C
E. all of the above
18. Which of the following molecules would normally diffuse from the cytosol to the extracellular
space across the lipid portion of the plasma membrane?
A. glucose
B. Na+
C. ATP
D. O2
E. CO2
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Name________________________
SID#________________________
19. If the Na+/K+ ATPase pump were inhibited, what might occur?
A. decrease intracellular concentrations of Na+
B. increase intracellular concentration of K+
C. change in the resting membrane potential
20. In hyperkalemia (higher than normal extracellular [K+]; normal high cellular [K+]), membrane voltage
will (compared to normal) _____.
A. depolarize
B. hyperpolarize
C. not change
____________________________________________________________________________________
Refer to the schematic drawing of the cell to answer
#21-22
Which of the lettered organelles...
21. may contain digestive enzymes? 1 pt E
22. has DNA, RNA and protein in it? 1 pt C
Refer to the figure to answer #23-24.
23. Letters A – I refer to
A. codons on mRNA
B. anticodons on mRNA
C. codons on rRNA
D. anticodons on rRNA
24. Numbers 1-6 refer to
A. codons on tRNA
B. anti-codons on tRNA
C. amino acids
D. nucleotides
E. nucleic acids
___________________________________________________________________________________
25. At the peak of the action potential, [Na+]cell > [Na+]outside. 1 pt
A. True
B. False
26. The absolute refractory period of an action potential results from the high negativity of the voltage
during repolarization. 1 pt
A. True
B. False
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Name________________________
SID#________________________
27. Depolarization of the nerve membrane voltage can cause
A. activation of Na+ channels.
B. inactivation of Na+ channels.
C. activation of K+ channels.
D. all of the above.
____________________________________________________________________________________
#28 and 29 refer to the action potential shown.
28. Na+ channels are opening at time noted ____. 1 pt A
29. Na+ channels are inactivated and K+ channels are activated at ____.
1 pt B
QuickTime™ and a
TIFF (Uncompressed) decompressor
are needed to see this picture.
___________________________________________________________________________________
30. Which of the following is characteristic of synaptic potentials AND generator potentials (hint:
remember rods and cones)?
A. They are graded in amplitude.
B. They can be either depolarizing or hyperpolarizing.
C. They are propagated from cell bodies to dendrites.
D. Both A and B are true.
E. A, B and C are all true.
31. In neurons Ca2+ channels are located in
A. axons
B. cell bodies
C. dendrites
D. boutons (nerve terminals)
32. Inactivation of the neurotransmitter released into the neuromuscular junction is accomplished by:
A. phosphodiesterase
B. acetylcholine esterase
C. acetylcholine synthetase D. glycolysis
33. A disease that degrades the myelin sheath will
A. decrease magnitude (overshoot) of action potentials.
B. decrease frequency of action potentials that can be transmitted
C. decrease rate of action potential propagation along axons
34. The cortex of the cerebral hemispheres is ______ (gray, white) because it is composed primarily of
______ (cell bodies, myelinated axons)?
A. white, cell bodies
B. white, axons
C. gray, cell bodies
D. gray, axons
35. Sympathetic ganglia are located
A. in the brain
B. in the dorsal roots of spinal nerves
C. in a chain parallel to the spinal cord
D. in or adjacent to the organs innervated
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Name________________________
SID#________________________
36. Compared to a person being chased by a bear, a person resting and digesting would have ___ rate of
action potentials in pre-ganglionic sympathetic nerves to the adrenal gland and _____ concentration of
epinephrine in the blood.
A. decreased, decreased
B. increased, decreased
C. decreased, increased
D. increased, increased
37. Which area of the brain is most directly involved in the control of coordination?
A. cerebellum
B. temporal lobe
C. parietal lobe
D. occipital lobe
____________________________________________________________________________________
#38 refers to the schematic diagrams of sensory and motor pathways shown below.
38. Nerves here terminate in the post-central gyrus A
_____________________________________________________________________________________
#39-40. Match one of the letters pointing to the brain structures to each the functional description:
39. Electrical stimulation here could trigger skeletal muscle
movements ___ 1 pt A
40. Involved in vision sensation ___ 1 pt C
____________________________________________________________________________________
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Name________________________
SID#________________________
41. Acetylcholine receptors of the ______ type are found in glands innervated by the parasympathetic
nervous system and of the ______ type are found in skeletal muscles.
A. nicotinic, muscarinic
B. nicotinic, adrenergic
C. muscarinic, nicotinic
D. adrenergic, nicotinic
42. Rapidly adapting touch receptors exhibit decreasing frequency of action potentials during constant
pressure stimulation of the skin. 1 pt
A. True
B. False
43. Different pressures to the skin elicit different magnitudes of generator potentials, which in turn
stimulate different sizes of action potentials. 1 pt
A. True
B. False
_____________________________________________________________________________________
#44-45 refer to the schematic drawing of the retina.
44. Action potentials are generated in these cells ____ 1 pt A
45. During light exposure these cells depolarize but do not
generate action potentials ____ 1 pt B
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Name________________________
SID#________________________
Short Answer
Answer one of the following questions in the space provided. 5 pts each
1. Explain how cyanide, which blocks cytochrome oxidase C in the electron transport chain, affects
(increase, decrease or no change):
[ATP] in the cytosol decrease
O2 consumption decrease
[NADH] in the cytosol increase
lactic acid production increase
glucose entry into liver cells on facilitated diffusion mechanism increase
2. Explain how the Na/K-ATPase is important for absorption of both glucose and water in the intestine.
Na-glucose cotransport, secondary active transport at apical membrane
Na transported into blood on Na/K pump
glucose leaves cell on facilitated diffusion
increased solutes on basal side drags water by osmosis
3. Explain how light is transduced into a change in electrical voltage inside a rod cell. Mention cis- and
trans-retinene, opsin, phosphodiesterase, cyclic GMP, Na and K channels and membrane voltage.
light --> cis-retinene converted to trans, opsin activates phosphodiesterase (G protein intermediate),
reducing cGMP, closing Na channel and hyperpolarizing cell, turning it off (inhibitory transmitter is
no longer released)
4. Explain how inhibitory neurotransmitters may decrease rates of action potential firing of nerves being
stimulated by excitatory nerves. Mention receptors, excitatory vs. inhibitory effects
excitatory transmitter --> excitatory receptor --> depolarize --> trigger action potentials
inhibitory transmitter --> inhibitory receptor --> hyperpolarize and reduce effect of the excitatory
transmitter, leading to reduction in frequency of action potentials
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