BIO 392 | 121 Verified Questions And Answers | Latest
Solutions Rated A+
ATP _______ the myosin head ANS allosterically modulates
During a contraction, which band(s)/zones becomes more narrow? ANS I band and H zone
The A zone contains ANS thick and thin filaments
Detachment of myosin from actin requires ANS the binding of ATP to change the conformation of
myosin's actin-binding site
In order for high-force crossbridges to form in contracting skeletal muscle, calcium must ANS bind to
troponin which moves the tropomyosin
Which of the following occurs when a myofibril contracts? ANS Thin and thick filaments slide past each
other, but do not change in length.
As ATP binds to the myosin head at the beginning of a muscle contraction cycle, the myosin head immediately
ANS detaches from actin.
The binding of calcium to which molecule causes the myosin binding sites to be exposed in skeletal muscle?
ANS troponin
After death, when metabolism stops, in which step of the contractile cycle must skeletal muscles remain? ANS
rigor state
The site of calcium regulation in the skeletal muscle cell is ___ (hint: we're looking for something to which
calcium can bind) ANS troponin and tropomyosin complex
Choose which items that are correctly matched. Note that some textbooks refer to the voltage gate as the
'activation gate'. ANS inactivation gate - closed during repolarization
, When the neuron is at rest, which statement is true? (note that the activation gate is also known as the voltage-
sensitive gate) ANS The activation gate is closed and the inactivation gate is open.
The following opens the voltage-gated sodium channel ANS A local depolarization
What characterizes depolarization, the first phase (also known as the 'rising phase) of the action potential?
ANS The membrane potential changes from a negative value to a positive value.
Which of the following statements best describes the decline in voltage, as shown at point 3? ANS
Voltage-gated potassium channels are open.
The falling phase of the action potential is similar to ANS repolarization
The falling phase of the action potential is due primarily to ANS Voltage-gated Na+ channels inactivated;
Voltage-gated K+ channels open.
What event triggers the generation of an action potential? ANS The membrane potential must depolarize
from the resting voltage of -70 mV to a threshold value of -55 mV.
The rising phase of the action potential is due primarily to ANS Voltage-gated Na+ channels open;
Voltage-gated K+ channels closed.
Which of the following statements best describes the drop in voltage below the resting state, as shown at point
4? ANS Some voltage-gated potassium channels are still open.
Which phase of the action potential is depicted in the image below? The three to the left are voltage-gated
sodium channels, the three to the right are voltage-gated potassium channels. ANS Repolarization
What opens first in response to a threshold stimulus? ANS Voltage-gated Na+ channels
Where do most action potentials originate? ANS Initial segment or axon hillock (a.k.a. the trigger zone)
Identify the states of the voltage-gated Na+ channel. State during repolarization ANS Repolarization
Solutions Rated A+
ATP _______ the myosin head ANS allosterically modulates
During a contraction, which band(s)/zones becomes more narrow? ANS I band and H zone
The A zone contains ANS thick and thin filaments
Detachment of myosin from actin requires ANS the binding of ATP to change the conformation of
myosin's actin-binding site
In order for high-force crossbridges to form in contracting skeletal muscle, calcium must ANS bind to
troponin which moves the tropomyosin
Which of the following occurs when a myofibril contracts? ANS Thin and thick filaments slide past each
other, but do not change in length.
As ATP binds to the myosin head at the beginning of a muscle contraction cycle, the myosin head immediately
ANS detaches from actin.
The binding of calcium to which molecule causes the myosin binding sites to be exposed in skeletal muscle?
ANS troponin
After death, when metabolism stops, in which step of the contractile cycle must skeletal muscles remain? ANS
rigor state
The site of calcium regulation in the skeletal muscle cell is ___ (hint: we're looking for something to which
calcium can bind) ANS troponin and tropomyosin complex
Choose which items that are correctly matched. Note that some textbooks refer to the voltage gate as the
'activation gate'. ANS inactivation gate - closed during repolarization
, When the neuron is at rest, which statement is true? (note that the activation gate is also known as the voltage-
sensitive gate) ANS The activation gate is closed and the inactivation gate is open.
The following opens the voltage-gated sodium channel ANS A local depolarization
What characterizes depolarization, the first phase (also known as the 'rising phase) of the action potential?
ANS The membrane potential changes from a negative value to a positive value.
Which of the following statements best describes the decline in voltage, as shown at point 3? ANS
Voltage-gated potassium channels are open.
The falling phase of the action potential is similar to ANS repolarization
The falling phase of the action potential is due primarily to ANS Voltage-gated Na+ channels inactivated;
Voltage-gated K+ channels open.
What event triggers the generation of an action potential? ANS The membrane potential must depolarize
from the resting voltage of -70 mV to a threshold value of -55 mV.
The rising phase of the action potential is due primarily to ANS Voltage-gated Na+ channels open;
Voltage-gated K+ channels closed.
Which of the following statements best describes the drop in voltage below the resting state, as shown at point
4? ANS Some voltage-gated potassium channels are still open.
Which phase of the action potential is depicted in the image below? The three to the left are voltage-gated
sodium channels, the three to the right are voltage-gated potassium channels. ANS Repolarization
What opens first in response to a threshold stimulus? ANS Voltage-gated Na+ channels
Where do most action potentials originate? ANS Initial segment or axon hillock (a.k.a. the trigger zone)
Identify the states of the voltage-gated Na+ channel. State during repolarization ANS Repolarization
