Q: Which equation correctly represents the net ATP yield from anaerobic glycolysis of one glucose molecule in skeletal muscle?

$$\text{C}_6\text{H}_{12}\text{O}_6 \rightarrow 2 \text{C}_3\text{H}_6\text{O}_3 + 2 \text{ATP}$$

Q: A sprinter relies on the phosphagen system for immediate energy. Which equation best represents the reaction catalyzed by creatine kinase?

$$\text{ADP} + \text{CP} \xrightarrow{\text{creatine kinase}} \text{ATP} + \text{creatine}$$

Question 1

Which of the following best describes the role of dystrophin in skeletal muscle fibers?

Accepted Answer

It anchors myofibrils to the sarcolemma and transfers force to extracellular tissue.

Question 2

A patient is exposed to a toxin that inhibits acetylcholinesterase (AChE) at the neuromuscular junction. What is the most likely physiological effect?

Accepted Answer

Muscle fibers will undergo continual contraction, leading to spastic paralysis.

Question 3

During muscle contraction, which event directly follows the binding of calcium to troponin?

Accepted Answer

Tropomyosin shifts to expose active sites on actin.

Question 4

Which equation correctly represents the net ATP yield from anaerobic glycolysis of one glucose molecule in skeletal muscle?

Accepted Answer

$$	ext{C}_6	ext{H}_{12}	ext{O}_6 ightarrow 2 	ext{C}_3	ext{H}_6	ext{O}_3 + 2 	ext{ATP}$$

Question 5

Which property of muscle tissue allows it to return to its original length after being stretched?

Accepted Answer

Elasticity

Question 6

A muscle fiber is stimulated and sodium ions rush into the cell, making the inside of the membrane briefly positive. What is this process called?

Accepted Answer

Depolarization

Question 7

Which connective tissue layer surrounds individual muscle fibers?

Accepted Answer

Endomysium

Question 8

A sprinter relies on the phosphagen system for immediate energy. Which equation best represents the reaction catalyzed by creatine kinase?

Accepted Answer

$$	ext{ADP} + 	ext{CP} \xrightarrow{	ext{creatine kinase}} 	ext{ATP} + 	ext{creatine}$$

Question 9

Which of the following is TRUE regarding the length of thick and thin filaments during sarcomere shortening?

Accepted Answer

Neither thick nor thin filaments change length; only the amount of overlap changes.

Question 10

A patient with Duchenne muscular dystrophy has a genetic defect in which protein, and what is the consequence?

Accepted Answer

Dystrophin; muscle cell membranes are damaged during contraction

Question 11

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

Accepted Answer

ATP is no longer produced, so myosin cannot detach from actin.

Question 12

Which muscle fiber type is best adapted for endurance activities such as marathon running?

Accepted Answer

Slow oxidative (SO), type I fibers

Question 13

During excitation-contraction coupling, what is the role of the T tubules?

Accepted Answer

They conduct action potentials deep into the muscle fiber.

Question 14

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

Accepted Answer

Isometric contractions maintain tension without changing length; isotonic contractions change length while maintaining tension.

Question 15

Which of the following is a correct sequence of events in skeletal muscle contraction?

Accepted Answer

Myosin hydrolyzes ATP, cocks its head, and forms a cross-bridge with actin.

Question 16

Which of the following best explains the concept of recruitment in muscle physiology?

Accepted Answer

Bringing more motor units into play as stimulus intensity increases.

Question 17

Which equation best represents the sodium-potassium pump responsible for maintaining the resting membrane potential?

Accepted Answer

$$3 	ext{Na}^+_{	ext{in}} + 2 	ext{K}^+_{	ext{out}} + 	ext{ATP} ightarrow 3 	ext{Na}^+_{	ext{out}} + 2 	ext{K}^+_{	ext{in}} + 	ext{ADP} + 	ext{Pi}$$

Question 18

Which of the following is a function of the sarcoplasmic reticulum in skeletal muscle fibers?

Accepted Answer

It stores and releases calcium ions to trigger contraction.

Question 19

A patient is suffering from flaccid paralysis after exposure to curare. What is the mechanism of action?

Accepted Answer

Curare blocks acetylcholine receptors, preventing muscle stimulation.

Chapter 11: Muscular Tissue – Structure, Function, and Physiology

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