Final Exam BIOL 546/ 312 Qs & Ans/ 2024-
2025.
What best describes homeostasis - Answer: organisms maintain a narrow range of
internal conditions
the diffusion rate of chemical X across a cell membrane can be increased by -
Answer: decreases the concentration gradient for X across the membrane
placing red blood cells in a hypotonic solution would cause them to - Answer: first
swell, then shrink
graded potential - Answer: are local changes in membrane potential that occurs in
varying degrees of magnitude and can be depolarization or hyperpolarizations
what can stop the Hodgkin cycle - Answer: inactivation of Na channels and
activation of K channels
Page 1 of 100
,conduction of AP along a nerve axon requires - Answer: a depolarization large
enough to excess the threshold potential leading to the AP
If an AP was initiated at the axon hillock by a grade potential coming from the cell
body, what direction would the AP travel - Answer: away from the cell body
if an AP was initiated at the center of the axon, what direction would it travel -
Answer: both direction
If a neuron were experimentally stimulated at both ends simultaneously - Answer:
the Ads would stop as they meet in the middle
what is the neurological effect of a chemical such as sarin, the inhibits AChE in the
neuromuscular synapse - Answer: nerve continues to send impulse to the muscles
(seizures)
what determines if a synapse is excitatory or inhibitory - Answer: type of NT and
type of ion channel opened by the postsynaptic receptor activated by NT
the vertebrate neural system conducts signals in only one direction. This one way
signaling occurs - Answer: as a result of voltage gated Na Channels, bc the
postsynaptic ending cannot release NT, bv only the postsynaptic membrane can
bind NT
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.
Page 2 of 100
,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. -
Answer: e) Voltage-gated Na-channels stay open longer than voltage-gated K-
channels.
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 - Answer: e) 0.1 M
3. Which neurotransmitter binds to the nicotinic ACh receptor?
a) muscarine
b) atopine
c) norepinephrine
d) glutamate
e) None of the above - Answer: e) None of the above ***
4. The period of excitability of neuron during which both Na+ and K+ activation
can occur is called the
a) interphase period.
Page 3 of 100
, b) relative refractory period.
c) absolute refractory period.
d) hyperexcitable period.
e) latent period - Answer: b) relative refractory period. ***
Excitation of the cone cell by blue light results in the production of an action
potential in the connected bipolar cell.
a) true
b) false - Answer: F
6. Which concept is the defining feature of the discipline of physiology?
a) Descent with modification
b) Homeostasis
c) Evolution
d) Equilibrium
e) Differentiation - Answer: homeostasis
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) answers a and b.
d) none of the above. - Answer: d) none of the above. ***
8. What is the general purpose of positive feedback mechanisms?
a) To maintain a constant internal environment
b) To anticipate changes in the environment
Page 4 of 100
2025.
What best describes homeostasis - Answer: organisms maintain a narrow range of
internal conditions
the diffusion rate of chemical X across a cell membrane can be increased by -
Answer: decreases the concentration gradient for X across the membrane
placing red blood cells in a hypotonic solution would cause them to - Answer: first
swell, then shrink
graded potential - Answer: are local changes in membrane potential that occurs in
varying degrees of magnitude and can be depolarization or hyperpolarizations
what can stop the Hodgkin cycle - Answer: inactivation of Na channels and
activation of K channels
Page 1 of 100
,conduction of AP along a nerve axon requires - Answer: a depolarization large
enough to excess the threshold potential leading to the AP
If an AP was initiated at the axon hillock by a grade potential coming from the cell
body, what direction would the AP travel - Answer: away from the cell body
if an AP was initiated at the center of the axon, what direction would it travel -
Answer: both direction
If a neuron were experimentally stimulated at both ends simultaneously - Answer:
the Ads would stop as they meet in the middle
what is the neurological effect of a chemical such as sarin, the inhibits AChE in the
neuromuscular synapse - Answer: nerve continues to send impulse to the muscles
(seizures)
what determines if a synapse is excitatory or inhibitory - Answer: type of NT and
type of ion channel opened by the postsynaptic receptor activated by NT
the vertebrate neural system conducts signals in only one direction. This one way
signaling occurs - Answer: as a result of voltage gated Na Channels, bc the
postsynaptic ending cannot release NT, bv only the postsynaptic membrane can
bind NT
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.
Page 2 of 100
,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. -
Answer: e) Voltage-gated Na-channels stay open longer than voltage-gated K-
channels.
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 - Answer: e) 0.1 M
3. Which neurotransmitter binds to the nicotinic ACh receptor?
a) muscarine
b) atopine
c) norepinephrine
d) glutamate
e) None of the above - Answer: e) None of the above ***
4. The period of excitability of neuron during which both Na+ and K+ activation
can occur is called the
a) interphase period.
Page 3 of 100
, b) relative refractory period.
c) absolute refractory period.
d) hyperexcitable period.
e) latent period - Answer: b) relative refractory period. ***
Excitation of the cone cell by blue light results in the production of an action
potential in the connected bipolar cell.
a) true
b) false - Answer: F
6. Which concept is the defining feature of the discipline of physiology?
a) Descent with modification
b) Homeostasis
c) Evolution
d) Equilibrium
e) Differentiation - Answer: homeostasis
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) answers a and b.
d) none of the above. - Answer: d) none of the above. ***
8. What is the general purpose of positive feedback mechanisms?
a) To maintain a constant internal environment
b) To anticipate changes in the environment
Page 4 of 100
