Page 1 of 24
Exam 3 Anatomy and Physiology Practice test 2025- 2026 Review GRADED A+
QUESTIONS WIT H CORRECT ANSWERS GRADED A+
When calcium is released inside a muscle cell, what does it bind to?
-myosin
-tropomyosin
-troponin
-actin
troponin
-Troponin has a binding site for calcium, which initiates the exposure of the active
sites on actin.
Myosin molecules form cross-bridges when they attach to __________.
-troponin
-tropomyosin
-calcium
-actin
actin
-The attachment of a myosin head is a linkage between the thick and thin filaments--
a cross-bridge. These molecules remain attached through the force-generating
power stroke of the cross-bridge cycle.
What happens immediately after the myosin head binds to the active site on
actin?
-The myosin head detaches from the active site on actin.
-ATP binds to the myosin head.
-The myosin head pivots, moving the actin strand.
-Tropomyosin moves away from the active site on actin.
The myosin head pivots, moving the actin strand.
-When the myosin head binds to actin, the head pivots towards the center of the
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sarcomere. This action moves the actin strand, pulling the Z-lines inward. This is the
basis of sarcomere shortening during muscle contraction.
ATP binding leads to which of the following actions?
-pivoting of the myosin head
-cross-bridge formation
-detaching and resetting cross-bridges
-exposure of active sites on actin
detaching and resetting cross-bridges
-ATP binding causes the myosin head to detach from actin. The energy from ATP
hydrolysis is then used to reactivate the myosin head. This energy use is similar to
setting a mouse trap, where the energy is used to set the trap, not to release the
trap.
During neuromuscular transmission, the axon terminals release
-acetylcholine
-sodium ions
-acetylcholinesterase
-calcium ions
acetylcholine
The muscle action potential penetrates into a fiber along the
-sarcoplasmic reticulum
-neuromuscular junction
-Z discs
-transverse tubules
transverse tubules
In response to an action potential along the transverse tubules, the
__________ release(s) calcium ions into the sarcoplasm.
-calcitonin
-thin filaments
-troponin molecules
-sarcoplasmic reticulum
sarcoplasmic reticulum
The narrow space between the synaptic terminal and the muscle fiber is the
-synaptic knob.
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-synaptic cleft.
-motor end plate.
-M line.
-motor unit
synaptic cleft.
Each skeletal muscle fiber is controlled
by a motor neuron at a single
-neuromuscular junction.
-synaptic cleft.
-synaptic knob.
-transverse tubule.
-sarcomere.
neuromuscular junction.
Active sites on the actin become
available for binding after
-calcium binds to tropomyosin.
-actin binds to troponin.
-troponin binds to tropomyosin.
-calcium binds to troponin.
-myosin binds to troponin.
calcium binds to troponin.
Receptors for acetylcholine are located on the
-transverse tubule.
-synaptic cleft.
-synaptic knob.
-sarcomere.
-motor end plate.
motor end plate.
The action potential is conducted into a skeletal muscle fiber by
-triads.
-neuromuscular junctions.
-motor end plates.
-sarcoplasmic reticulum.
-transverse tubules.
Exam 3 Anatomy and Physiology Practice test 2025- 2026 Review GRADED A+
QUESTIONS WIT H CORRECT ANSWERS GRADED A+
When calcium is released inside a muscle cell, what does it bind to?
-myosin
-tropomyosin
-troponin
-actin
troponin
-Troponin has a binding site for calcium, which initiates the exposure of the active
sites on actin.
Myosin molecules form cross-bridges when they attach to __________.
-troponin
-tropomyosin
-calcium
-actin
actin
-The attachment of a myosin head is a linkage between the thick and thin filaments--
a cross-bridge. These molecules remain attached through the force-generating
power stroke of the cross-bridge cycle.
What happens immediately after the myosin head binds to the active site on
actin?
-The myosin head detaches from the active site on actin.
-ATP binds to the myosin head.
-The myosin head pivots, moving the actin strand.
-Tropomyosin moves away from the active site on actin.
The myosin head pivots, moving the actin strand.
-When the myosin head binds to actin, the head pivots towards the center of the
, Page 2 of 24
sarcomere. This action moves the actin strand, pulling the Z-lines inward. This is the
basis of sarcomere shortening during muscle contraction.
ATP binding leads to which of the following actions?
-pivoting of the myosin head
-cross-bridge formation
-detaching and resetting cross-bridges
-exposure of active sites on actin
detaching and resetting cross-bridges
-ATP binding causes the myosin head to detach from actin. The energy from ATP
hydrolysis is then used to reactivate the myosin head. This energy use is similar to
setting a mouse trap, where the energy is used to set the trap, not to release the
trap.
During neuromuscular transmission, the axon terminals release
-acetylcholine
-sodium ions
-acetylcholinesterase
-calcium ions
acetylcholine
The muscle action potential penetrates into a fiber along the
-sarcoplasmic reticulum
-neuromuscular junction
-Z discs
-transverse tubules
transverse tubules
In response to an action potential along the transverse tubules, the
__________ release(s) calcium ions into the sarcoplasm.
-calcitonin
-thin filaments
-troponin molecules
-sarcoplasmic reticulum
sarcoplasmic reticulum
The narrow space between the synaptic terminal and the muscle fiber is the
-synaptic knob.
, Page 3 of 24
-synaptic cleft.
-motor end plate.
-M line.
-motor unit
synaptic cleft.
Each skeletal muscle fiber is controlled
by a motor neuron at a single
-neuromuscular junction.
-synaptic cleft.
-synaptic knob.
-transverse tubule.
-sarcomere.
neuromuscular junction.
Active sites on the actin become
available for binding after
-calcium binds to tropomyosin.
-actin binds to troponin.
-troponin binds to tropomyosin.
-calcium binds to troponin.
-myosin binds to troponin.
calcium binds to troponin.
Receptors for acetylcholine are located on the
-transverse tubule.
-synaptic cleft.
-synaptic knob.
-sarcomere.
-motor end plate.
motor end plate.
The action potential is conducted into a skeletal muscle fiber by
-triads.
-neuromuscular junctions.
-motor end plates.
-sarcoplasmic reticulum.
-transverse tubules.
