Question 1

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

Accepted Answer

ATP hydrolysis provides energy for the myosin head to detach from actin and reset for another contraction cycle.

Question 2

During a 100-meter sprint, which energy source is primarily used by muscle cells to generate ATP?

Accepted Answer

Phosphocreatine (creatine phosphate) system

Question 3

Which of the following is a disadvantage of using the phosphocreatine system for ATP production in muscles?

Accepted Answer

It can only supply energy for a very short duration (6–20 seconds) due to limited phosphocreatine stores.

Question 4

Which equation correctly represents the reaction by which phosphocreatine regenerates ATP in muscle cells?

Accepted Answer

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

Question 5

Why does anaerobic glycolysis lead to muscle fatigue during intense exercise?

Accepted Answer

It generates lactate, which acidifies the muscle environment and inhibits glycolytic enzymes.

Question 6

Which metabolic pathway produces the greatest amount of ATP per glucose molecule?

Accepted Answer

Aerobic metabolism (oxidative phosphorylation)

Question 7

During prolonged, moderate-intensity exercise such as a marathon, which energy source becomes increasingly important for ATP production?

Accepted Answer

Aerobic metabolism of fatty acids

Question 8

Which statement best explains the purpose of carbohydrate loading before endurance events?

Accepted Answer

To maximize muscle glycogen stores, allowing sustained energy production during prolonged exercise.

Question 9

How does adrenaline (epinephrine) help regulate metabolism during exercise?

Accepted Answer

It stimulates breakdown of glycogen and fat, increasing availability of glucose and fatty acids for ATP production.

Question 10

Which cycle is responsible for recycling lactate produced during anaerobic glycolysis back into glucose in the liver?

Accepted Answer

Cori cycle

Question 11

A patient is performing high-intensity exercise and begins to accumulate lactate in their muscles. Which process allows the body to convert this lactate back into glucose?

Accepted Answer

Gluconeogenesis in the liver via the Cori cycle

Question 12

Which of the following best describes the effect of exercise on blood glucose levels?

Accepted Answer

Blood glucose levels remain relatively stable (4–6 mmol/L) due to increased glucose uptake and hepatic glucose production.

Question 13

Which muscle fiber type is best suited for prolonged, low-intensity exercise and why?

Accepted Answer

Slow-twitch fibers, because they have abundant mitochondria and rely on aerobic metabolism.

Question 14

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

Accepted Answer

$\mathrm{Glucose} \rightarrow 2\ \mathrm{Lactate} + 2\ \mathrm{ATP}$

Question 15

During the transition from rest to exercise, what is the primary reason for the rapid increase in oxygen uptake?

Accepted Answer

To support increased aerobic metabolism for sustained ATP production.

Question 16

Which of the following is a key advantage of aerobic metabolism over anaerobic metabolism during exercise?

Accepted Answer

Aerobic metabolism can utilize multiple substrates (glucose, fatty acids, amino acids, ketone bodies) and produces more ATP per glucose molecule.

Question 17

Which process is responsible for removing excess nitrogen generated during amino acid metabolism in exercise?

Accepted Answer

Alanine cycle

Question 18

An athlete consumes a diet high in simple carbohydrates immediately before a short, high-intensity event. What is the primary benefit of this strategy?

Accepted Answer

Rapidly available glucose for anaerobic glycolysis, supporting quick ATP production.

Question 19

Which of the following best explains why muscle glycogen stores are critical for high-intensity exercise?

Accepted Answer

Glycogen provides a rapid source of glucose for anaerobic glycolysis, enabling quick ATP production.

Muscle Metabolism and ATP Production During Exercise

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