BIOL 546 FINAL questions well
answered graded A+ passed
2025/2026
1. All of the following are true statements about the action potential EXCEPT:
a) Opening of the voltage-gated Na-channels will move the membrane potential to the
equilibrium potential of Na.
b) Opening of voltage-gated K-channels will move the membrane potential to the equilibrium
potential of K.
c) The Hodgkin cycle causes the fast change in membrane potential during the rising phase of
the action potential.
d) The falling phase of the AP is mainly due to the movement of K+ ions.
e) Voltage-gated Na-channels stay open longer than voltage-gated K-channels. - correct answer
✔✔e) Voltage-gated Na-channels stay open longer than voltage-gated K-channels.
2. Scientists discovered a new animal species with nerve cells physiologically similar to nerve
cells found in other animals. The membrane potential when only sodium ions can move across
the membrane was measured at +116 mV. What is the sodium concentration outside the nerve
cell if the sodium concentration inside the cell is 1 mM?
a) 1 M
b) 0.232 M
c) 0.116 M
d) 0.58 M
e) 0.1 M - correct answer ✔✔e) 0.1 M
3. What is the neurological effect of a drug that prevents priming of vesicles in the presynaptic
terminal of the neuromuscular synapse?
,a) It stops sending impulses to muscles (paralysis).
b) It continues sending impulses to muscles (seizures).
c) It starts glial cells to produce action potentials.
d) None of the above. - correct answer ✔✔a) It stops sending impulses to muscles (paralysis).
4. The safety factor of an action potential is
a) the amount of depolarization above what is needed to reach threshold potential.
b) the amount of depolarization from zero membrane potential to the peak of the action
potential.
c) the change from the membrane hyperpolarization level to the resting membrane potential.
d) the spread of the depolarization along an axon membrane.
e) the protective function of the myelin sheet. - correct answer ✔✔a) the amount of
depolarization above what is needed to reach threshold potential.
5. Excitation of the rod cell by blue light results in the production of an action potential in the
connected bipolar cell.
a) true
b) false - correct answer ✔✔b) false
6. The process that produces the most ATP molecules per molecule of glucose in a cell is
a) substrate-level phosphorylation.
b) oxidative phosphorylation.
c) anaerobic glycolysis.
d) aerobic glycolysis.
e) Krebs (citric acid) cycle. - correct answer ✔✔b) oxidative phosphorylation.
7. Stimulation of a hair cell results in changes in the hair cell membrane such as ....
,a) opening of voltage-gated Na+ channels.
b) opening of voltage-gated K+ channels.
c) opening of voltage-gated Ca2+ channels.
d) none of the above. - correct answer ✔✔c) opening of voltage-gated Ca2+ channels.
8. What is the general purpose of positive feedback mechanisms?
a) To maintain a constant internal environment.
b) To anticipate changes in the environment.
c) To return a variable toward the set point.
d) To bring about a rapid change in the body. - correct answer ✔✔d) To bring about a rapid
change in the body.
9. Water can be transported by the following process(es):
a) by a water pump driven by ATP.
b) by water channels.
c) by solute-coupled transport.
d) b and c.
e) a and b - correct answer ✔✔d) b and c
10. What do you expect when two neurons are connected through presynaptic inhibition?
a) Simultaneous activity in both neurons will reduce the effects of one neuron.
b) Simultaneous activity in both neurons will increase the effects of one neuron.
c) Simultaneous activity in both neurons will not change the effects of the neurons.
d) None of the above. - correct answer ✔✔a) Simultaneous activity in both neurons will reduce
the effects of one neuron.
11. What category do hair cells in the organ of Corti belong to?
, a) Mechanoreceptors.
b) Chemoreceptors.
c) Nociceptors.
d) Photoreceptors. - correct answer ✔✔a) Mechanoreceptors.
12. A complete lesion (destruction) of the left lateral geniculate nucleus produces which one of
the following visual field defects?
a) loss of lateral inhibition.
b) loss of the left visual field.
c) loss of both left and right visual field.
d) loss of color vision.
e) none of the above. - correct answer ✔✔e) none of the above.
13. The optic nerve is composed of axons from which of the following retinal cell types?
a) bipolar
b) ganglion
c) amacrine
d) horizontal - correct answer ✔✔b) ganglion
14. The physiological explanation for our ability to differentiate among sounds of different
pitches (frequencies) is because
a) hair cells respond to high pitch sound by moving cilia into one direction and to low pitch by
moving cilia into the opposite direction.
b) the basilar membrane depolarizes and hyperpolarizes at multiple locations depending on
pitch.
c) hair cells at different locations on the basilar membrane respond to different sound
frequencies.
answered graded A+ passed
2025/2026
1. All of the following are true statements about the action potential EXCEPT:
a) Opening of the voltage-gated Na-channels will move the membrane potential to the
equilibrium potential of Na.
b) Opening of voltage-gated K-channels will move the membrane potential to the equilibrium
potential of K.
c) The Hodgkin cycle causes the fast change in membrane potential during the rising phase of
the action potential.
d) The falling phase of the AP is mainly due to the movement of K+ ions.
e) Voltage-gated Na-channels stay open longer than voltage-gated K-channels. - correct answer
✔✔e) Voltage-gated Na-channels stay open longer than voltage-gated K-channels.
2. Scientists discovered a new animal species with nerve cells physiologically similar to nerve
cells found in other animals. The membrane potential when only sodium ions can move across
the membrane was measured at +116 mV. What is the sodium concentration outside the nerve
cell if the sodium concentration inside the cell is 1 mM?
a) 1 M
b) 0.232 M
c) 0.116 M
d) 0.58 M
e) 0.1 M - correct answer ✔✔e) 0.1 M
3. What is the neurological effect of a drug that prevents priming of vesicles in the presynaptic
terminal of the neuromuscular synapse?
,a) It stops sending impulses to muscles (paralysis).
b) It continues sending impulses to muscles (seizures).
c) It starts glial cells to produce action potentials.
d) None of the above. - correct answer ✔✔a) It stops sending impulses to muscles (paralysis).
4. The safety factor of an action potential is
a) the amount of depolarization above what is needed to reach threshold potential.
b) the amount of depolarization from zero membrane potential to the peak of the action
potential.
c) the change from the membrane hyperpolarization level to the resting membrane potential.
d) the spread of the depolarization along an axon membrane.
e) the protective function of the myelin sheet. - correct answer ✔✔a) the amount of
depolarization above what is needed to reach threshold potential.
5. Excitation of the rod cell by blue light results in the production of an action potential in the
connected bipolar cell.
a) true
b) false - correct answer ✔✔b) false
6. The process that produces the most ATP molecules per molecule of glucose in a cell is
a) substrate-level phosphorylation.
b) oxidative phosphorylation.
c) anaerobic glycolysis.
d) aerobic glycolysis.
e) Krebs (citric acid) cycle. - correct answer ✔✔b) oxidative phosphorylation.
7. Stimulation of a hair cell results in changes in the hair cell membrane such as ....
,a) opening of voltage-gated Na+ channels.
b) opening of voltage-gated K+ channels.
c) opening of voltage-gated Ca2+ channels.
d) none of the above. - correct answer ✔✔c) opening of voltage-gated Ca2+ channels.
8. What is the general purpose of positive feedback mechanisms?
a) To maintain a constant internal environment.
b) To anticipate changes in the environment.
c) To return a variable toward the set point.
d) To bring about a rapid change in the body. - correct answer ✔✔d) To bring about a rapid
change in the body.
9. Water can be transported by the following process(es):
a) by a water pump driven by ATP.
b) by water channels.
c) by solute-coupled transport.
d) b and c.
e) a and b - correct answer ✔✔d) b and c
10. What do you expect when two neurons are connected through presynaptic inhibition?
a) Simultaneous activity in both neurons will reduce the effects of one neuron.
b) Simultaneous activity in both neurons will increase the effects of one neuron.
c) Simultaneous activity in both neurons will not change the effects of the neurons.
d) None of the above. - correct answer ✔✔a) Simultaneous activity in both neurons will reduce
the effects of one neuron.
11. What category do hair cells in the organ of Corti belong to?
, a) Mechanoreceptors.
b) Chemoreceptors.
c) Nociceptors.
d) Photoreceptors. - correct answer ✔✔a) Mechanoreceptors.
12. A complete lesion (destruction) of the left lateral geniculate nucleus produces which one of
the following visual field defects?
a) loss of lateral inhibition.
b) loss of the left visual field.
c) loss of both left and right visual field.
d) loss of color vision.
e) none of the above. - correct answer ✔✔e) none of the above.
13. The optic nerve is composed of axons from which of the following retinal cell types?
a) bipolar
b) ganglion
c) amacrine
d) horizontal - correct answer ✔✔b) ganglion
14. The physiological explanation for our ability to differentiate among sounds of different
pitches (frequencies) is because
a) hair cells respond to high pitch sound by moving cilia into one direction and to low pitch by
moving cilia into the opposite direction.
b) the basilar membrane depolarizes and hyperpolarizes at multiple locations depending on
pitch.
c) hair cells at different locations on the basilar membrane respond to different sound
frequencies.
