Q: Which equation correctly represents the breakdown of glucose during aerobic respiration in muscle cells?

$ \mathrm{C}_6\mathrm{H}_{12}\mathrm{O}_6 + 6\mathrm{O}_2 \rightarrow 6\mathrm{CO}_2 + 6\mathrm{H}_2\mathrm{O} + 36\text{ ATP} $

Question 1

Which of the following best describes the primary difference between skeletal, cardiac, and smooth muscle tissue?

Accepted Answer

Skeletal muscle is striated and voluntary, cardiac muscle is striated and involuntary, and smooth muscle is non-striated and involuntary.

Question 2

Which component of a muscle fiber stores calcium ions necessary for muscle contraction?

Accepted Answer

Sarcoplasmic reticulum (SR)

Question 3

During muscle contraction, which event occurs immediately after acetylcholine binds to receptors on the motor end plate?

Accepted Answer

An action potential is generated along the sarcolemma.

Question 4

Which equation correctly represents the breakdown of glucose during aerobic respiration in muscle cells?

Accepted Answer

$ \mathrm{C}_6\mathrm{H}_{12}\mathrm{O}_6 + 6\mathrm{O}_2 ightarrow 6\mathrm{CO}_2 + 6\mathrm{H}_2\mathrm{O} + 36	ext{ ATP} $

Question 5

A patient is experiencing muscle weakness and rapid fatigue. Laboratory tests show a deficiency in acetylcholine receptors at the neuromuscular junction. Which condition is most likely?

Accepted Answer

Myasthenia gravis

Question 6

Which of the following best explains the difference between isotonic and isometric contractions?

Accepted Answer

Isotonic contractions change muscle length while maintaining tension; isometric contractions generate tension without changing muscle length.

Question 7

Which of the following is a function of the perimysium in skeletal muscle?

Accepted Answer

Surrounds bundles of muscle fibers (fascicles)

Question 8

During intense exercise, muscle cells rely on anaerobic glycolysis for ATP production. Which byproduct accumulates as a result?

Accepted Answer

Lactic acid

Question 9

Which of the following best describes the role of troponin in muscle contraction?

Accepted Answer

Troponin binds calcium ions, causing tropomyosin to move and expose binding sites on actin.

Question 10

A muscle fiber is stimulated repeatedly at a high frequency, resulting in a sustained contraction without relaxation. What is this phenomenon called?

Accepted Answer

Tetanus

Question 11

Which of the following best explains the difference in ATP yield between aerobic and anaerobic metabolism of glucose in muscle cells?

Accepted Answer

Aerobic metabolism yields more ATP because oxygen allows complete breakdown of glucose to carbon dioxide and water.

Question 12

Which structure transmits the action potential deep into the muscle fiber, ensuring simultaneous contraction?

Accepted Answer

Transverse (T) tubules

Question 13

Which of the following is true regarding the oxygen debt incurred during strenuous exercise?

Accepted Answer

Oxygen debt refers to the amount of oxygen required to restore ATP and clear lactic acid after exercise.

Question 14

Which type of muscle fiber is most resistant to fatigue and is primarily used for endurance activities?

Accepted Answer

Slow oxidative fibers

Question 15

Which of the following best describes the process of muscle relaxation after contraction?

Accepted Answer

Calcium ions are actively pumped back into the sarcoplasmic reticulum.

Question 16

A patient presents with muscle spasms and rigidity following a puncture wound. Which toxin is most likely responsible for these symptoms?

Accepted Answer

Tetanus toxin

Question 17

Which of the following best explains the difference between muscle hypertrophy and atrophy?

Accepted Answer

Hypertrophy is an increase in muscle size due to increased protein synthesis; atrophy is a decrease in muscle size due to lack of use.

Question 18

Which of the following is a symptom commonly associated with poliomyelitis?

Accepted Answer

Progressive muscle weakness and paralysis

Question 19

Which equation represents the calculation of the resting membrane potential ($V_m$) of a muscle cell using the Nernst equation?

Accepted Answer

$ V_m = \frac{RT}{zF} \ln \left( \frac{[	ext{K}^+]_{	ext{out}}}{[	ext{K}^+]_{	ext{in}}} ight) $

Question 20

Which of the following best describes the role of ATP in the cross-bridge cycle during muscle contraction?

Accepted Answer

ATP hydrolysis energizes the myosin head, allowing it to bind to actin and perform a power stroke.

Chapter 9 Study Guide: The Muscular System

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