$$\text{ATP} \rightarrow \text{ADP} + \text{P}_i + \text{energy}$$

Question 1

Which structure wraps around each myofibril within a muscle fiber and is specialized to store and release calcium ions?

Accepted Answer

Sarcoplasmic reticulum

Question 2

During muscle contraction, which event occurs immediately after calcium ions bind to troponin?

Accepted Answer

Tropomyosin shifts, exposing myosin-binding sites on actin

Question 3

What is the primary function of the sodium-potassium pump ($$	ext{Na}^+/	ext{K}^+) in $$muscle and nerve cells?

Accepted Answer

To move sodium out and potassium in, helping maintain the resting membrane potential

Question 4

Which protein directly blocks the myosin binding site on the actin filament at rest?

Accepted Answer

Tropomyosin

Question 5

What is the correct sequence of events in cross-bridge cycling during muscle contraction?

Accepted Answer

Grab, Pull, Release, Reset

Question 6

Which of the following best describes the role of acetylcholinesterase (AChE) at the neuromuscular junction?

Accepted Answer

It breaks down acetylcholine in the synaptic cleft, allowing muscle relaxation

Question 7

A patient exposed to sarin gas experiences paralysis. Which mechanism explains this effect?

Accepted Answer

Sarin inhibits acetylcholinesterase, causing continuous stimulation of the muscle

Question 8

Which equation represents the hydrolysis of ATP during muscle contraction?

Accepted Answer

$$	ext{ATP} ightarrow 	ext{ADP} + 	ext{P}_i + 	ext{energy}$$

Question 9

What happens to the sarcomere during muscle contraction?

Accepted Answer

The sarcomere shortens as actin and myosin slide past each other

Question 10

Which of the following is required for muscle relaxation?

Accepted Answer

Calcium ions pumped back into the sarcoplasmic reticulum

Question 11

During the latent period of a muscle twitch, which event occurs?

Accepted Answer

Action potential travels through the sarcolemma and T-tubules

Question 12

Which phase of a muscle twitch is characterized by the binding of calcium to troponin and the shifting of tropomyosin?

Accepted Answer

Contraction period

Question 13

What is the effect of repeated action potentials on muscle tension?

Accepted Answer

Tension increases and can lead to tetanus if relaxation is prevented

Question 14

Which of the following best describes the 'Goldilocks' principle in muscle contraction?

Accepted Answer

Muscle fibers must be at an optimal resting length for maximum tension

Question 15

Which of the following is NOT a requirement for continued muscle contraction?

Accepted Answer

Acetylcholinesterase is active in the synaptic cleft

Question 16

What is the main role of the T-tubules in muscle fibers?

Accepted Answer

To transmit action potentials deep into the muscle fiber

Question 17

Which of the following best explains muscle fatigue during intense exercise?

Accepted Answer

Accumulation of lactic acid and depletion of ATP

Question 18

Which equation best represents the movement of sodium and potassium during an action potential?

Accepted Answer

$$	ext{Na}^+$$ moves in, $$	ext{K}^+$$ moves out$

Question 19

Which protein binds calcium during muscle contraction?

Accepted Answer

Troponin

Muscle Contraction: Structure, Neuromuscular Junction, and Excitation-Contraction Coupling L13

스터디 가이드 - 연습 문제