Q: Which of the following equations correctly 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 perform a power stroke

Question 4

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

Accepted Answer

Cardiac muscle: involuntary, striated with intercalated discs

Question 5

A patient is unable to perform rapid, powerful movements but can sustain low-intensity exercise for long periods. Which muscle fiber type is most likely predominant in this patient?

Accepted Answer

Slow oxidative fibers

Question 6

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

Accepted Answer

They are connected by gap junctions that allow rapid spread of action potentials

Question 7

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

Accepted Answer

It stores and releases calcium ions to trigger muscle contraction

Question 8

Which of the following equations correctly 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

Which process is responsible for the removal of calcium ions from the cytoplasm to end muscle contraction?

Accepted Answer

Active transport of $$\mathrm{Ca}^{2+}$$ back into the sarcoplasmic reticulum

Question 10

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 11

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

Accepted Answer

Action potential → release of $$\mathrm{Ca}^{2+}$$ from sarcoplasmic reticulum → binding of $$\mathrm{Ca}^{2+} to $$troponin → movement of tropomyosin → cross-bridge formation

Question 12

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

Accepted Answer

Smooth muscle contraction is regulated by calmodulin, while skeletal muscle uses troponin

Question 13

Which of the following best explains why fast glycolytic fibers fatigue more quickly than slow oxidative fibers?

Accepted Answer

Fast glycolytic fibers rely primarily on anaerobic glycolysis, which produces less ATP per glucose molecule

Question 14

During a sustained muscle contraction, which energy system becomes increasingly important after the first minute?

Accepted Answer

Oxidative system (aerobic respiration)

Question 15

Which of the following statements about the structure of skeletal muscle fibers is correct?

Accepted Answer

They are multinucleated and contain myofibrils arranged in parallel

Question 16

A mutation that prevents the release of $$\mathrm{Ca}^{2+}$$ from the sarcoplasmic reticulum would most directly affect which step of muscle contraction?

Accepted Answer

Exposure of myosin-binding sites on actin

Question 17

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

Accepted Answer

Endurance training promotes mitochondrial biogenesis and increased capillary density

Question 18

Which of the following is the correct order of events for the cross-bridge cycle in skeletal muscle contraction?

Accepted Answer

Myosin binds to actin → power stroke → ATP binds to myosin → myosin detaches from actin → ATP hydrolysis cocks myosin head

Question 19

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

Accepted Answer

They connect muscle to bone and transmit the force of muscle contraction to produce movement

The Muscular System: Structure, Function, and Types of Muscle

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