Q: Which of the following equations correctly represents the ATP yield from glycolysis of one glucose molecule in skeletal muscle?

$2 \text{ ADP} + 2 \text{P}_i + \text{Glucose} \rightarrow 2 \text{ATP} + 2 \text{Pyruvate} + 2 \text{H}_2\text{O}$

Question 1

Which of the following best describes the function of the Na+/K+ ATPase pump in skeletal muscle fibers?

Accepted Answer

It moves three sodium ions out of the cell and two potassium ions into the cell using ATP.

Question 2

A muscle fiber is stretched to twice its resting length. Which property allows it to return to its original shape after being stretched?

Accepted Answer

Elasticity

Question 3

During the depolarization stage of a muscle action potential, which ion movement occurs across the sarcolemma?

Accepted Answer

Sodium ions enter the cell

Question 4

Which protein is a major component of the thick filament in skeletal muscle fibers?

Accepted Answer

Myosin

Question 5

A patient is given a drug that blocks acetylcholine (ACh) receptors at the neuromuscular junction. What is the most likely immediate effect on skeletal muscle contraction?

Accepted Answer

Decreased or absent muscle contraction due to failure to generate an end-plate potential

Question 6

Which of the following best explains why Type I muscle fibers are more resistant to fatigue than Type II fibers?

Accepted Answer

They have more myoglobin and mitochondria, supporting oxidative catabolism

Question 7

A muscle contraction that results in the muscle lengthening while producing tension is called:

Accepted Answer

Isotonic eccentric contraction

Question 8

Which of the following equations correctly represents the ATP yield from glycolysis of one glucose molecule in skeletal muscle?

Accepted Answer

$2 	ext{ ADP} + 2 	ext{P}_i + 	ext{Glucose} ightarrow 2 	ext{ATP} + 2 	ext{Pyruvate} + 2 	ext{H}_2	ext{O}$

Question 9

A person is experiencing muscle fatigue after intense exercise. Which of the following is NOT a likely contributing factor?

Accepted Answer

Increased oxygen availability to muscle fibers

Question 10

Which of the following best describes the role of titin in the sarcomere?

Accepted Answer

It anchors thick filaments and provides elasticity to the muscle fiber

Question 11

A patient with Duchenne Muscular Dystrophy lacks functional dystrophin. What is the primary consequence at the cellular level?

Accepted Answer

Disrupted structural integrity of the muscle fiber membrane

Question 12

Which of the following statements about cardiac muscle is correct?

Accepted Answer

Cardiac muscle cells are connected by intercalated discs and are autorhythmic

Question 13

Which of the following best explains why rigor mortis occurs after death?

Accepted Answer

ATP is no longer available to detach myosin heads from actin

Question 14

Which of the following is a direct result of acetylcholine binding to its receptor on the motor end plate?

Accepted Answer

Opening of ligand-gated cation channels

Question 15

A muscle fiber is unable to generate tension after repeated stimulation. Which of the following best explains this phenomenon?

Accepted Answer

The sarcomere is either overly stretched or overly shortened, preventing effective crossbridge formation

Question 16

Which of the following best describes the difference between smooth and skeletal muscle contraction?

Accepted Answer

Smooth muscle contraction involves myosin light-chain kinase, while skeletal muscle does not

Question 17

Which of the following is a function of muscle tone?

Accepted Answer

Maintaining posture and stabilizing joints

Question 18

Which of the following best describes the relationship between the concentration and electrical gradients for potassium ions in a resting muscle fiber?

Accepted Answer

The concentration gradient favors movement out, while the electrical gradient favors movement in

Question 19

Which of the following is a correct statement about the energy sources for muscle contraction?

Accepted Answer

Creatine phosphate provides a rapid but short-lived source of ATP

Question 20

A person is performing repeated 20-second sprints. Which muscle fiber type is most likely to be recruited for this activity?

Accepted Answer

Type IIx (fast glycolytic)

Skeletal, Cardiac, and Smooth Muscle: Structure, Function, and Physiology

Study Guide - Practice Questions

Study Guide - Flashcards