Q: Which equation best represents the hydrolysis of ATP during muscle contraction?

$\mathrm{ATP} + \mathrm{H}_2\mathrm{O} \rightarrow \mathrm{ADP} + \mathrm{P}_i + \text{energy}$

Question 1

Which of the following best describes the primary function of skeletal muscle in animals?

Accepted Answer

To convert chemical energy from ATP into mechanical movement

Question 2

During muscle contraction, which protein directly binds to actin to generate force?

Accepted Answer

Myosin

Question 3

What is the role of ATP in the cross-bridge cycle of skeletal muscle contraction?

Accepted Answer

ATP hydrolysis provides energy for the myosin head to detach from actin and reset

Question 4

Which of the following best explains why cardiac muscle cells can contract nearly simultaneously?

Accepted Answer

They are connected by intercalated discs containing gap junctions

Question 5

A patient is unable to perform rapid, powerful movements but can sustain moderate activity for long periods. Which muscle fiber type is most likely predominant in their muscles?

Accepted Answer

Slow oxidative fibers

Question 6

Which of the following correctly matches the muscle type with its control and location?

Accepted Answer

Cardiac muscle: involuntary, wall of heart

Question 7

What is the function of the sarcoplasmic reticulum in skeletal muscle fibers?

Accepted Answer

It stores and releases calcium ions to trigger contraction

Question 8

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

Accepted Answer

$\mathrm{ATP} + \mathrm{H}_2\mathrm{O} ightarrow \mathrm{ADP} + \mathrm{P}_i + 	ext{energy}$

Question 9

A sprinter relies on which energy system for the first few seconds of a 100-meter dash?

Accepted Answer

Immediate system (preformed ATP and creatine phosphate)

Question 10

Which of the following best describes the sequence of events in excitation-contraction coupling in skeletal muscle?

Accepted Answer

Action potential → release of calcium from sarcoplasmic reticulum → binding of calcium to troponin → movement of tropomyosin → myosin binds actin

Question 11

Which muscle type is characterized by single, centrally located nuclei, involuntary control, and the presence of gap junctions?

Accepted Answer

Cardiac muscle

Question 12

During sustained, moderate-intensity exercise, which energy system is primarily responsible for ATP production?

Accepted Answer

Oxidative system

Question 13

Which of the following is a key difference between skeletal and smooth muscle?

Accepted Answer

Skeletal muscle is striated and voluntary, while smooth muscle is non-striated and involuntary

Question 14

A muscle fiber is observed to have high myosin ATPase activity, few mitochondria, and fatigues quickly. What type of fiber is this?

Accepted Answer

Fast glycolytic fiber

Question 15

Which of the following best explains why endurance training increases the proportion of slow oxidative fibers in skeletal muscle?

Accepted Answer

Endurance training increases mitochondrial density and capillary supply, favoring slow oxidative fibers

Question 16

Which of the following is the correct order of structures from largest to smallest in skeletal muscle organization?

Accepted Answer

Muscle → fascicle → muscle fiber → myofibril → sarcomere

Question 17

Which of the following statements about the role of calcium in muscle contraction is correct?

Accepted Answer

Calcium binds to troponin, causing tropomyosin to move and expose myosin binding sites on actin

Question 18

Which of the following best describes the function of tendons in the muscular system?

Accepted Answer

Tendons connect muscle to bone, transmitting the force generated by muscle contraction to produce movement

Question 19

Which of the following scenarios best illustrates asynchronous muscle contraction?

Accepted Answer

Insect flight muscles contract multiple times per nerve impulse, allowing rapid wing beats

Question 20

A muscle is observed to have many capillaries, high endurance, and slow contraction speed. Which type of exercise would most likely increase the proportion of these fibers?

Accepted Answer

Long-distance running

Muscular System: Structure, Function, and Physiology

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