BIO 242 FINAL EXAM 2026 ACTUAL QUESTIONS AND
ANSWERS GRADED A+
✔✔pay attention to where sarcomere is, the h zone (where the thick filament is) and the
a band (the length of the green thing) - ✔✔
✔✔what cytoskeletal element makes up thick filaments - ✔✔myosin
✔✔when calcium ions enter the muscle fiber, what occurs within the tropomyosin-
troponin complex? - ✔✔answer: 2,4,1,3 (1,2,3,4 is the correct answer)
1.Ca2+ binds to troponin
2. tropomyosin-troponin complex changes conformation
3. myosin binding sites are exposed on actin
4. actin binding site on myosin head binds with myosin binding sites on actin, creating a
cross bridge.
✔✔the shortening of a sarcomere due to the sliding filament theory results from what
mechanism - ✔✔thin filaments sliding over thick filaments through multiple power stroke
✔✔the action potential is spread from the plasma membrane of the muscle fiber
(sarcoplasm) directly into the muscle fiber through what cellular component? - ✔✔T-
tubule
✔✔the foot proteins on the lateral sacs of the sarcoplasmic reticulum are activated by
the _____ on the T tubules and release ______ into the muscle fiber cell -
✔✔dihydropyridine receptors; Ca2+ ions
✔✔the spread of an action potential leading to Ca2+ release into the muscle fiber and
finally resulting in the formation of cross-bridges and shortening of the sarcomere is
called - ✔✔Excitation-contraction coupling
✔✔if ATP is unavailable when muscles are in the process of contracting (as is true
when a person dies), what is the result - ✔✔myosin heads detach quickly from actin,
resulting in rigid muscles (rigor mortis)
✔✔motor proteins provide only excitation to muscle cells-resulting in contraction.
Muscle relaxation is achieved by what mechanism? - ✔✔the SERCA pump retrieves
calcium ions and the tropomyosin-troponin complex changes conformation
✔✔rapid stimulation of a muscle fiber before the fiber is fully relaxed leading to a
sustained maximal contraction is called - ✔✔tetanus
, ✔✔all the following statements are true refarding motor units except one. select the
incorrect answer below - ✔✔1. a single motor neuron stimulates multiple muscle fibers
2. muscles with smaller motor units overall create less powerful, but finely controlled
movements
3. recruitment of multiple motor units results in a stronger contraction
4. motor units can work in shifts to prevent fatigue during maximal contractions (THIS
ANSWER IS FALSE)
✔✔what is the source that quickly provides ATP in the first few seconds of a muscle
contraction - ✔✔creatine phosphate
✔✔fast glycolytic muscle fibershave the following characteristics - ✔✔fibers hold an
abundance of glycogen
✔✔skeletal muscle fibers have the following characteristics. they are - ✔✔striated,
unbranched, multinucleate
✔✔what structures connect individual myocardial cells to prevent sharing stress and
conduct action potentials - ✔✔intercalated discs
✔✔the "pacemaker" cells of the heart produce action potentials via - ✔✔a cyclic
depolarization that occurs without stimulation
✔✔identify av bundle (node), - ✔✔
✔✔the bunch of autorhythmic cells that set heart rate is called - ✔✔SA node
✔✔why is it necessary for the bundle of his and purkinje fibers to propagate action
potentials rapidly throughout the ventricles? - ✔✔rapid conduction allows the ventricles
to contract as a unit
✔✔why do myocardial action potentials have a prolonged plateau period? - ✔✔1. the
plateau period allows the heart to fully contract and fully relax
2. the plateau period prevents twitch summation
3. the plateau period creates a long refractory period
4. all of the above (CORRECT ANSWER)
✔✔what is the term for heart relaxation - ✔✔diastole
✔✔Most ventricular filling occurs during what period of the heart cycle? - ✔✔atrial and
ventricular diastole
✔✔the T wave if the ECG represents what portion of the cardiac cycle? - ✔✔ventricular
repolarization
ANSWERS GRADED A+
✔✔pay attention to where sarcomere is, the h zone (where the thick filament is) and the
a band (the length of the green thing) - ✔✔
✔✔what cytoskeletal element makes up thick filaments - ✔✔myosin
✔✔when calcium ions enter the muscle fiber, what occurs within the tropomyosin-
troponin complex? - ✔✔answer: 2,4,1,3 (1,2,3,4 is the correct answer)
1.Ca2+ binds to troponin
2. tropomyosin-troponin complex changes conformation
3. myosin binding sites are exposed on actin
4. actin binding site on myosin head binds with myosin binding sites on actin, creating a
cross bridge.
✔✔the shortening of a sarcomere due to the sliding filament theory results from what
mechanism - ✔✔thin filaments sliding over thick filaments through multiple power stroke
✔✔the action potential is spread from the plasma membrane of the muscle fiber
(sarcoplasm) directly into the muscle fiber through what cellular component? - ✔✔T-
tubule
✔✔the foot proteins on the lateral sacs of the sarcoplasmic reticulum are activated by
the _____ on the T tubules and release ______ into the muscle fiber cell -
✔✔dihydropyridine receptors; Ca2+ ions
✔✔the spread of an action potential leading to Ca2+ release into the muscle fiber and
finally resulting in the formation of cross-bridges and shortening of the sarcomere is
called - ✔✔Excitation-contraction coupling
✔✔if ATP is unavailable when muscles are in the process of contracting (as is true
when a person dies), what is the result - ✔✔myosin heads detach quickly from actin,
resulting in rigid muscles (rigor mortis)
✔✔motor proteins provide only excitation to muscle cells-resulting in contraction.
Muscle relaxation is achieved by what mechanism? - ✔✔the SERCA pump retrieves
calcium ions and the tropomyosin-troponin complex changes conformation
✔✔rapid stimulation of a muscle fiber before the fiber is fully relaxed leading to a
sustained maximal contraction is called - ✔✔tetanus
, ✔✔all the following statements are true refarding motor units except one. select the
incorrect answer below - ✔✔1. a single motor neuron stimulates multiple muscle fibers
2. muscles with smaller motor units overall create less powerful, but finely controlled
movements
3. recruitment of multiple motor units results in a stronger contraction
4. motor units can work in shifts to prevent fatigue during maximal contractions (THIS
ANSWER IS FALSE)
✔✔what is the source that quickly provides ATP in the first few seconds of a muscle
contraction - ✔✔creatine phosphate
✔✔fast glycolytic muscle fibershave the following characteristics - ✔✔fibers hold an
abundance of glycogen
✔✔skeletal muscle fibers have the following characteristics. they are - ✔✔striated,
unbranched, multinucleate
✔✔what structures connect individual myocardial cells to prevent sharing stress and
conduct action potentials - ✔✔intercalated discs
✔✔the "pacemaker" cells of the heart produce action potentials via - ✔✔a cyclic
depolarization that occurs without stimulation
✔✔identify av bundle (node), - ✔✔
✔✔the bunch of autorhythmic cells that set heart rate is called - ✔✔SA node
✔✔why is it necessary for the bundle of his and purkinje fibers to propagate action
potentials rapidly throughout the ventricles? - ✔✔rapid conduction allows the ventricles
to contract as a unit
✔✔why do myocardial action potentials have a prolonged plateau period? - ✔✔1. the
plateau period allows the heart to fully contract and fully relax
2. the plateau period prevents twitch summation
3. the plateau period creates a long refractory period
4. all of the above (CORRECT ANSWER)
✔✔what is the term for heart relaxation - ✔✔diastole
✔✔Most ventricular filling occurs during what period of the heart cycle? - ✔✔atrial and
ventricular diastole
✔✔the T wave if the ECG represents what portion of the cardiac cycle? - ✔✔ventricular
repolarization
