Question 1

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

Accepted Answer

Titin provides elasticity and stabilizes the position of the thick filament.

Question 2

During skeletal muscle contraction, which event directly triggers the release of calcium from the sarcoplasmic reticulum?

Accepted Answer

Activation of L-type calcium channel (DHP receptor) and ryanodine receptor (RyR).

Question 3

Which statement about the sliding filament theory is correct?

Accepted Answer

Thin filaments slide past thick filaments, but neither changes length.

Question 4

A muscle fiber is in rigor state. What is the primary cause?

Accepted Answer

No ATP is available to release myosin from G-actin.

Question 5

Which equation correctly represents the force generated by a muscle according to Newton's second law?

Accepted Answer

$$F = m 	imes a$$

Question 6

What is the primary metabolic pathway used by slow-twitch (type I) muscle fibers?

Accepted Answer

Aerobic respiration (oxidative phosphorylation)

Question 7

Which structure stores calcium ions in skeletal muscle fibers?

Accepted Answer

Sarcoplasmic reticulum

Question 8

What is the role of troponin in muscle contraction?

Accepted Answer

Troponin binds reversibly to Ca$$^{2+}$$ and controls the position of tropomyosin.

Question 9

Which of the following is true about motor units?

Accepted Answer

A motor unit consists of one motor neuron and all the muscle fibers it innervates.

Question 10

Which statement best explains how whole muscle force is graded?

Accepted Answer

By varying the number of muscle fibers recruited and the frequency of stimulation.

Question 11

Which of the following is a regulatory protein found in the thin filament of skeletal muscle?

Accepted Answer

Tropomyosin

Question 12

What is the function of satellite cells in skeletal muscle?

Accepted Answer

They aid in muscle regeneration and repair.

Question 13

Which band of the sarcomere contains only thin filaments?

Accepted Answer

I band

Question 14

What happens during the power stroke of muscle contraction?

Accepted Answer

Myosin head rotates and binds tightly to actin, pulling the thin filament.

Question 15

Which process provides the fastest supply of ATP for muscle contraction?

Accepted Answer

Phosphocreatine breakdown

Question 16

Which muscle type is under voluntary control and responds to somatic motor neurons?

Accepted Answer

Skeletal muscle

Question 17

Which statement about antagonistic muscle pairs is correct?

Accepted Answer

One muscle contracts while the other relaxes to move bones in opposite directions.

Question 18

Which of the following is NOT a component of the triad in skeletal muscle fibers?

Accepted Answer

Myofibril

Question 19

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

Accepted Answer

Slow-twitch fibers (type I)

Question 20

Which statement about the all-or-none law of muscle contraction is correct?

Accepted Answer

A single muscle fiber contracts fully if threshold is reached, but whole muscle force can be graded.

Skeletal and Smooth Muscle: Structure, Function, and Contraction Mechanisms

Study Guide - Practice Questions