Question 1

Which of the following best describes an isometric muscle contraction?

Accepted Answer

Muscle tension increases, but the muscle does not change length.

Question 2

During a biceps curl, as you lift the weight, which type of contraction is primarily occurring in the biceps muscle?

Accepted Answer

Concentric isotonic contraction

Question 3

Which process is responsible for the fastest regeneration of ATP in muscle fibers during short, intense activity?

Accepted Answer

Direct phosphorylation of ADP by creatine phosphate

Question 4

A muscle fiber is stimulated repeatedly at a high frequency, and the contractions begin to fuse into a sustained contraction. What is this phenomenon called?

Accepted Answer

Fused (complete) tetanus

Question 5

Which of the following equations correctly represents the direct phosphorylation of ADP by creatine phosphate?

Accepted Answer

$\mathrm{Creatine\ phosphate} + \mathrm{ADP} \rightarrow \mathrm{Creatine} + \mathrm{ATP}$

Question 6

Which factor does NOT contribute to muscle fatigue during prolonged exercise?

Accepted Answer

Increased glycogen stores

Question 7

If a muscle fiber has a sarcomere length greater than 120% of its resting length, what happens to the force of contraction?

Accepted Answer

Force of contraction decreases

Question 8

Which of the following is the correct sequence of events for muscle contraction and relaxation?

Accepted Answer

Excitation-contraction coupling, cross bridge formation, calcium pumped back into SR

Question 9

A muscle fiber can use anaerobic glycolysis to generate ATP. How many ATP molecules are produced per glucose molecule in this pathway?

Accepted Answer

$2$

Question 10

Which of the following best explains why muscle tone is important?

Accepted Answer

It keeps muscles firm, healthy, and ready to respond to stimulation.

Question 11

During aerobic respiration, how many ATP molecules can be produced from one glucose molecule?

Accepted Answer

$32$

Question 12

Which of the following is a correct description of a motor unit?

Accepted Answer

A motor neuron and all the muscle fibers it innervates

Question 13

Which of the following is a major cause of muscle fatigue during intense exercise?

Accepted Answer

Ionic imbalances disrupting membrane potential

Question 14

What is the primary role of creatine kinase in muscle contraction?

Accepted Answer

It transfers a phosphate group from creatine phosphate to ADP to form ATP.

Question 15

Which of the following best describes the relationship between the number of motor units recruited and the force of muscle contraction?

Accepted Answer

Increasing the number of motor units recruited increases the force of contraction.

Question 16

Which of the following is true regarding the duration of ATP supply from creatine phosphate in muscle fibers?

Accepted Answer

It lasts for about $15$ seconds.

Question 17

Which of the following is a result of excess postexercise oxygen consumption (EPOC)?

Accepted Answer

Oxygen reserves are replenished and lactic acid is converted to pyruvic acid.

Question 18

Which of the following best describes the effect of increased frequency of stimulation on muscle tension?

Accepted Answer

Muscle tension increases and can reach fused (complete) tetanus.

Question 19

Which of the following is the correct formula for the aerobic breakdown of glucose in muscle cells?

Accepted Answer

$\mathrm{C}_6\mathrm{H}_{12}\mathrm{O}_6 + 6\mathrm{O}_2 \rightarrow 6\mathrm{CO}_2 + 6\mathrm{H}_2O + 32\ \mathrm{ATP}$

Question 20

Which of the following is a direct effect of muscle fatigue?

Accepted Answer

Physiological inability to contract despite continued stimulation

Muscle Contraction: Mechanisms, Responses, and Energy Systems

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