Q: Which equation correctly represents the reaction by which creatine phosphate (CP) regenerates ATP in muscle cells?

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

Question 1

Which of the following best describes the phenomenon of fused (complete) tetanus in skeletal muscle contraction?

Accepted Answer

Muscle contractions fuse into a single, sustained plateau of maximum tension with no relaxation between stimuli.

Question 2

A patient is experiencing muscle fatigue after prolonged, intense exercise. Which of the following is LEAST likely to be a direct cause of this fatigue?

Accepted Answer

Depletion of blood glycogen stores in mildly stressed muscles

Question 3

During a laboratory experiment, a muscle is stimulated twice in rapid succession before it has completely relaxed. What is the expected outcome?

Accepted Answer

The muscle will show temporal (wave) summation, increasing force with the second stimulus.

Question 4

Which of the following best explains the 'size principle' in motor unit recruitment during muscle contraction?

Accepted Answer

Motor units with the smallest muscle fibers are activated first, followed by larger fibers as stimulus intensity increases.

Question 5

A muscle is contracting against a load that is greater than the maximum tension it can generate. What type of contraction is occurring?

Accepted Answer

Isometric contraction

Question 6

Which equation correctly represents the reaction by which creatine phosphate (CP) regenerates ATP in muscle cells?

Accepted Answer

$$	ext{Creatine phosphate} + 	ext{ADP} ightarrow 	ext{Creatine} + 	ext{ATP}$$

Question 7

Which muscle fiber type is best suited for maintaining posture and endurance activities such as running a marathon?

Accepted Answer

Slow oxidative fibers

Question 8

A sprinter relies on which primary metabolic pathway for rapid ATP production during a short, intense burst of activity?

Accepted Answer

Glycolysis and lactic acid formation (anaerobic pathway)

Question 9

Which of the following factors does NOT directly increase the force of muscle contraction?

Accepted Answer

Muscle fibers stretched to 150% of their resting length

Question 10

After intense exercise, which process is responsible for restoring muscle cells to their pre-exercise state and is referred to as 'oxygen debt'?

Accepted Answer

All of the above, including reconverting lactic acid to pyruvic acid

Question 11

Which of the following is TRUE regarding isometric contractions?

Accepted Answer

The muscle generates force but does not change length.

Question 12

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

Accepted Answer

ATP is required for detaching cross bridges, pumping Ca\* back into the SR, and restoring Na\* and K\* gradients after excitation-contraction coupling.

Question 13

Which muscle fiber type would be most useful for a student taking a written exam that requires sustained, low-intensity muscle activity?

Accepted Answer

Slow oxidative fibers

Question 14

Which of the following statements about muscle tone is correct?

Accepted Answer

Muscle tone is the constant, slightly contracted state of all muscles due to alternating activation of motor units.

Question 15

Which equation best represents the net ATP yield from glycolysis of one glucose molecule?

Accepted Answer

$$	ext{Glucose} ightarrow 2\ 	ext{Pyruvic acid} + 2\ 	ext{ATP}$$

Question 16

Which of the following is a characteristic of fast glycolytic muscle fibers?

Accepted Answer

Large diameter and rapid fatigue

Question 17

If a muscle fiber is stretched to less than 80% of its resting length before contraction, what is the expected effect on force production?

Accepted Answer

Force production decreases because actin and myosin overlap too much.

Question 18

Which process is more efficient for ATP production in muscle cells: aerobic respiration or glycolysis with lactic acid formation?

Accepted Answer

Aerobic respiration, because it produces more ATP per glucose molecule.

Question 19

During moderate activity, which fuel source becomes the main contributor to ATP production after about 30 minutes of exercise?

Accepted Answer

Fatty acids

Muscle Responses and Contraction Mechanisms in Skeletal Muscle

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