NEET Biology: Skeletal muscle-contractile proteins and muscle contraction Practice Questions
15 free multiple-choice questions on Skeletal muscle-contractile proteins and muscle contraction (Locomotion and Movement) for NEET Biology, each with the correct answer and a step-by-step explanation. Attempt a question, then reveal the solution to check your reasoning.
Practice thousands more NEET questions in the app →Q1. The thin filaments in a muscle fiber are primarily composed of which protein?
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Correct answer: A — Actin
The thin filaments are composed of the protein Actin, which interacts with myosin to form the functional contractile unit.
Q2. Which structure spans the entire length of the sarcomere and anchors the thin filaments?
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Correct answer: B — Z-disc
The Z-disc (Z-line) anchors the thin filaments (Actin) and helps define the boundaries of a single sarcomere.
Q3. The process by which the muscle fiber shortens during contraction is primarily due to the interaction between which two filament proteins?
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Correct answer: B — Actin and Myosin
The shortening occurs due to the relative sliding of the thin (Actin) and thick (Myosin) filaments past each other, known as the sliding filament mechanism.
Q4. The regulatory protein in muscle contraction that binds to calcium ions to initiate the sliding filament mechanism is:
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Correct answer: A — Troponin
Troponin is the key regulatory protein that undergoes a conformational change upon binding Ca²⁺, thereby moving tropomyosin and allowing myosin binding.
Q5. The fundamental principle by which skeletal muscle generates force is the interaction between which two types of filaments within the sarcomere?
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Correct answer: A — Actin and Myosin
Muscle contraction occurs due to the interaction and sliding motion between the thin filaments (actin) and the thick filaments (myosin).
Q6. Which of the following proteins is primarily responsible for generating the force during muscle contraction?
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Correct answer: D — Myosin
Myosin filaments contain the myosin heads, which bind to actin filaments and execute the power stroke, thus generating the contractile force in the muscle.
Q7. Which molecule acts as the direct energy source required for the cyclical attachment and detachment of myosin heads during muscle contraction?
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Correct answer: A — Adenosine Triphosphate (ATP)
ATP hydrolysis provides the energy necessary for the myosin heads to bind to actin and subsequently detach, driving the cross-bridge cycling process.
Q8. Which of the following proteins forms the thick filament of the sarcomere?
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Correct answer: D — Myosin
Myosin forms the thick filaments, which are responsible for generating the force during muscle contraction.
Q9. Muscle contraction is fundamentally caused by the interaction between which two types of myofilaments?
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Correct answer: B — Myosin and Actin
The force generation in muscle relies on the interaction and sliding motion between the thick filaments (myosin) and the thin filaments (actin).
Q10. Which protein forms the thick filament of the sarcomere in striated muscle?
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Correct answer: C — Myosin
Myosin forms the thick filaments, which are responsible for generating the force during muscle contraction in striated muscle.
Q11. What is the primary role of ATP in the muscle contraction cycle?
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Correct answer: C — To cause the detachment of the myosin head from actin
ATP hydrolysis is essential for the detachment of the myosin head from the actin filament, which is a key step in the cross-bridge cycle.
Q12. What is the crucial ion that initiates the process of muscle contraction by binding to regulatory proteins in muscle tissue?
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Correct answer: B — Calcium ions (Ca²⁺)
The release of calcium ions (Ca²⁺) into the sarcoplasm triggers the interaction between actin and myosin, leading to muscle contraction.
Q13. Which of the following proteins constitutes the thick filament of the sarcomere structure in striated muscle?
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Correct answer: D — Myosin
The thick filaments in a sarcomere are primarily composed of myosin, which contains the myosin heads responsible for interacting with the thin filaments (actin) to generate force.
Q14. The sliding filament theory describes the mechanism of muscle contraction. This theory states that muscle shortening occurs due to the interaction between which two filaments?
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Correct answer: C — Actin and Myosin
Muscle shortening occurs when the thin filaments (Actin) slide past the thick filaments (Myosin) in a process called the sliding filament theory.
Q15. Which of the following proteins forms the thick filament of the sarcomere during muscle contraction?
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Correct answer: A — Myosin
The thick filaments of the sarcomere are primarily composed of myosin molecules, which possess the myosin heads responsible for interacting with actin filaments and generating force during muscle contraction.
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