$$\mathrm{ATP} \rightarrow \mathrm{ADP} + \mathrm{P_i} + \text{energy}$$

$$\text{Force} \propto \text{Number of motor units} \times \text{Frequency of action potentials}$$

Question 1

Which of the following best describes the sliding filament mechanism of muscle contraction?

Accepted Answer

Myosin heads bind to actin, pull the thin filaments toward the center of the sarcomere, then release and reattach further along the filament.

Question 2

What is the primary source of ATP for muscle contraction during prolonged, low-intensity exercise?

Accepted Answer

Cellular respiration

Question 3

Which protein stores oxygen in slow-twitch muscle fibers, allowing them to sustain contraction?

Accepted Answer

Myoglobin

Question 4

A marathon runner is likely to have a higher proportion of which muscle fiber type in their legs?

Accepted Answer

Slow-twitch fibers

Question 5

Which event directly triggers the release of calcium ions from the sarcoplasmic reticulum during muscle contraction?

Accepted Answer

Action potential traveling down T tubules

Question 6

What is the function of tropomyosin in skeletal muscle contraction?

Accepted Answer

It covers myosin binding sites on actin, preventing contraction until moved by troponin.

Question 7

Which equation best represents the breakdown of ATP during muscle contraction?

Accepted Answer

$$\mathrm{ATP} ightarrow \mathrm{ADP} + \mathrm{P_i} + 	ext{energy}$$

Question 8

Which structure connects muscle to bone and transmits the force of contraction?

Accepted Answer

Tendon

Question 9

What is the main function of osteoclasts in bone tissue?

Accepted Answer

Break down bone matrix and dissolve minerals

Question 10

Which type of joint allows movement in multiple directions, such as the hip and shoulder?

Accepted Answer

Ball-and-socket joint

Question 11

During muscle contraction, what role does calcium play after being released from the sarcoplasmic reticulum?

Accepted Answer

It binds to troponin, causing tropomyosin to move and expose actin binding sites.

Question 12

Which of the following is NOT a function of the vertebrate skeleton?

Accepted Answer

Initiating muscle contraction

Question 13

Which connective tissue attaches bone to bone at joints?

Accepted Answer

Ligament

Question 14

What is the primary reason that antagonistic muscle pairs are required for movement?

Accepted Answer

Muscles can only produce force by contracting, not lengthening.

Question 15

Which cell type is responsible for producing new bone during embryonic development?

Accepted Answer

Osteoblasts

Question 16

Which of the following best explains why weightlifting increases bone strength?

Accepted Answer

Exercise increases activity of tendon- and ligament-building cells, producing more collagen and strengthening bones.

Question 17

Which structure is responsible for transmitting action potentials deep into the muscle fiber?

Accepted Answer

T tubules

Question 18

Which equation best represents the relationship between force, number of motor units, and frequency of action potentials in muscle contraction?

Accepted Answer

$$	ext{Force} \propto 	ext{Number of motor units} 	imes 	ext{Frequency of action potentials}$$

Question 19

Which of the following statements about bone remodeling is correct?

Accepted Answer

Osteocytes coordinate the activity of osteoblasts and osteoclasts to adapt bone shape and repair fractures.

Question 20

Which of the following is a real-world consequence of decreased weight-bearing exercise in older adults?

Accepted Answer

Increased activity of osteoclasts, resulting in more fragile bones.

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Study Guide - Practice Questions