AP Biology : Understanding Muscle Cells

Study concepts, example questions & explanations for AP Biology

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Example Questions

Example Question #495 : Cellular Biology

Which of the following best represent characteristics of type IIa skeletal muscle tissues?

Possible Answers:

They don't have many mitochondria and are anaerobic

They contain many mitochondria

They feature aerobic activity

They are both aerobic and contain many mitochondria

Correct answer:

They are both aerobic and contain many mitochondria

Explanation:

Type IIa skeletal muscle tissue is a subtype of skeletal muscle tissue that is related to fast twitch muscles. Type IIa tissues are aerobic and have many mitochondria.

Example Question #31 : Understanding Muscle Cells

Which of the following best describes how type IIb skeletal muscle tissue differs from type IIa skeletal muscle tissue?

Possible Answers:

Type IIb tissue has many mitochondria while type IIa tissue has fewer mitochondria

Type IIb tissue has no mitochondria while type IIa tissue has many mitochondria

Type IIb tissue is anaerobic while type IIa tissue is aerobic

Type IIb tissue is aerobic while type IIa tissue is anaerobic

Correct answer:

Type IIb tissue is anaerobic while type IIa tissue is aerobic

Explanation:

Type IIb skeletal muscle tissue is a subtype of skeletal muscle tissue that is anaerobic and has fewer mitochondria than type IIa.

Example Question #32 : Understanding Muscle Cells

Which of the following best describes type IIx skeletal muscle contraction?

Possible Answers:

It is the fastest muscle type in humans

All of these

It contracts more quickly than aerobic muscles 

Sustains short bursts of anaerobic contraction

Correct answer:

All of these

Explanation:

Type IIx skeletal muscle tissue is the fastest muscle type in humans. This subtype of skeletal muscle tissue is characterized by short bursts of anaerobic contraction. It is also able to contract more quickly than aerobic muscles.

Example Question #33 : Understanding Muscle Cells

In regard to muscles, which of the following statements best defines a sarcomere?

Possible Answers:

Sarcomeres are the areas between two I bands

Sarcomeres are Z lines

Sarcomeres include A bands and I bands

Sarcomeres are the areas between Z lines

Correct answer:

Sarcomeres are the areas between Z lines

Explanation:

Sarcomeres are considered to be the functional units of muscles and are defined as the areas between two Z lines. Sarcomeres are the units that are responsible for the striated appearance of certain muscle types (skeletal and cardiac). 

Example Question #35 : Understanding Muscle Cells

Which of the following best represents the generic term for a muscle cell?

Possible Answers:

Myoblast

Sarcomere

Myofibril

Myocyte

Correct answer:

Myocyte

Explanation:

Muscle cells are often referred to as “myocytes.” Myocytes are tubular cells that develop during a process called myogenesis and specialize based on their association with specific muscle types.

Example Question #504 : Cellular Biology

Which of the following pairs of two motor proteins are critical in human muscle contraction?

Possible Answers:

Actin and kinesin

Myosin and kinesin

Kinesin and dynein

Actin and myosin

Correct answer:

Actin and myosin

Explanation:

Human muscle contraction relies on the action of the motor proteins actin and myosin. Muscles contract through the sliding of myosin and actin filaments along one another.

Example Question #34 : Understanding Muscle Cells

Which of the following best describes the difference between the sarcoplasmic reticulum (SR) in myocytes and the smooth endoplasmic reticulum (smooth ER) in other cells?

Possible Answers:

The SR is significantly larger than the smooth ER

The SR synthesizes molecules and the smooth ER is involved in calcium storage

The SR is involved in calcium storage and the smooth ER synthesizes molecules

There are no differences between the SR and the smooth ER

Correct answer:

The SR is involved in calcium storage and the smooth ER synthesizes molecules

Explanation:

The sarcoplasmic reticulum (SR) is a specialized type of smooth endoplasmic reticulum in striated muscle tissue. The SR has a different function than the smooth ER. The SR is involved in calcium ion storage that is critical in contraction while the smooth ER synthesizes new molecules.

Example Question #31 : Understanding Muscle Cells

Myocytes and muscle tissue are formed during which of the following stages of embryogenesis?

Possible Answers:

Myogenesis

Organogenesis

Gastrulation

Neurulation

Correct answer:

Myogenesis

Explanation:

During embryogenesis, the process of myogenesis forms myocytes and muscle tissue.

Example Question #39 : Understanding Muscle Cells

Which of the following cellular structures in muscle tissue is comparable to cytoplasm?

Possible Answers:

Sarcoplasm

Sarcomere

Sarcoplasmic reticulum

Myofibrils

Correct answer:

Sarcoplasm

Explanation:

The sarcoplasm in muscle cells is comparable to the cytoplasm in other types of cells. The sarcoplasm is specialized in the high amount of myoglobin present. Its specialized regulation of calcium ion concentrations controls muscle contractions.

Example Question #35 : Understanding Muscle Cells

Which of the following best describes “intercalated disks”?

Possible Answers:

Portions of the cell that contain high quantities of myoglobin

They form the boundaries of actin filaments

Structures that connect cardiac muscle cells

They are observable characteristics of striated muscle tissue

Correct answer:

Structures that connect cardiac muscle cells

Explanation:

Intercalated disks are structures that connect cardiac muscle cells, allowing them to work together and communicate within the heart. Intercalated disks are made up of different types of cell junctions and are observable under the microscope. This makes cardiac muscle tissue distinguishable.

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