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

Na\textsuperscript{+}/K\textsuperscript{+} ATPase

Question 1

Which ATP-dependent process is directly responsible for detaching myosin from actin during skeletal muscle relaxation?

Accepted Answer

Breaking the cross bridge

Question 2

During a 100-meter sprint lasting about 10 seconds, which ATP source is primarily used by skeletal muscle fibers?

Accepted Answer

Stored ATP and creatine phosphate

Question 3

Which equation correctly represents the reaction catalyzed by creatine kinase in muscle cells?

Accepted Answer

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

Question 4

Which muscle fiber type is most resistant to fatigue and best suited for endurance activities?

Accepted Answer

Slow oxidative fibers

Question 5

A marathon runner relies primarily on which metabolic pathway for ATP production during the race?

Accepted Answer

Aerobic cellular respiration (oxidative phosphorylation)

Question 6

Which of the following is a major contributor to muscle fatigue during intense, short-duration exercise?

Accepted Answer

Lactate buildup and decrease in pH

Question 7

What is the total net ATP yield from the complete aerobic breakdown of one glucose molecule in skeletal muscle?

Accepted Answer

$36$ ATP

Question 8

Which process requires ATP to pump calcium ions back into the sarcoplasmic reticulum after muscle contraction?

Accepted Answer

Ca	extsuperscript{2+}-ATPase

Question 9

If a muscle is subjected to a heavier load, how does this affect the velocity and duration of contraction?

Accepted Answer

Velocity decreases, duration decreases

Question 10

Which of the following best describes the metabolic characteristics of fast glycolytic muscle fibers?

Accepted Answer

Low myoglobin content, few mitochondria, fatigue quickly

Question 11

During anaerobic glycolysis, what is the net ATP gain per glucose molecule, and what is the byproduct that can contribute to muscle fatigue?

Accepted Answer

$2$ ATP; lactic acid (lactate)

Question 12

Which ATP-dependent enzyme is responsible for reestablishing the resting membrane potential of the sarcolemma after an action potential?

Accepted Answer

Na	extsuperscript{+}/K	extsuperscript{+} ATPase

Question 13

A weightlifter performing a single, maximal lift primarily uses which source of ATP?

Accepted Answer

Stored ATP and creatine phosphate

Question 14

Which of the following factors does NOT contribute to muscle fatigue?

Accepted Answer

Excess calcium release from the sarcoplasmic reticulum

Question 15

Which muscle fiber type would predominate in the quadriceps of a sprinter compared to a marathon runner?

Accepted Answer

Fast glycolytic fibers

Question 16

Which of the following is TRUE regarding the duration of muscle contraction when the load is increased?

Accepted Answer

The duration of muscle shortening is briefer

Question 17

Which process is LEAST likely to be a limiting factor in muscle fatigue during prolonged, low-intensity exercise?

Accepted Answer

Lactate buildup

Question 18

Which equation best represents aerobic cellular respiration in muscle cells?

Accepted Answer

$	ext{Glucose} + 	ext{O}_2 ightarrow 	ext{CO}_2 + 	ext{H}_2O + 	ext{ATP}$

Question 19

Which of the following best explains why slow oxidative fibers are more fatigue-resistant than fast glycolytic fibers?

Accepted Answer

They rely primarily on aerobic metabolism and have abundant mitochondria

ATP Utilization and Muscle Fiber Types in Skeletal Muscle

Study Guide - Practice Questions