Free Muscle Contraction MCQs with Answers
66 Muscle Contraction MCQs from Biology, each with the correct answer and a written explanation of why it is correct. Free and unlimited, with no account needed.
Muscle contraction is explained by the sliding filament model, in which myosin heads pull actin filaments within sarcomeres using ATP. The topic covers calcium, troponin, tropomyosin, the neuromuscular junction and relaxation, with attention to how filament length stays almost constant while the sarcomere shortens.
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- A. Glucose
- B. Phosphocreatine
- C. Fructose
- D. Lactic acid
Explanation: After glucose, Phosphocreatine serves as a secondary source of energy.
Correct answer: Phosphocreatine- A. Actin slides past myosin
- B. ATP supplies energy
- C. Calcium ions are involved
- D. All of these
Explanation: When muscles need to contract, calcium ions bind with the troponin molecule and cause them to move slightly. ATP is hydrolysed.
Correct answer: All of these- A. Interacting
- B. Separation
- C. Both A an B
- D. None of these
Explanation: Tropomyosin blocks myosin binding sites on actin molecules, preventing cross-bridge formation, which prevents contraction in a muscle…
Correct answer: Interacting- A. Actin
- B. Myosin
- C. Troponin
- D. Sarcomere
Explanation: Calcium binds to troponin C, causing the conformational shift in tropomyosin that reveals myosin-binding sites on actin.
Correct answer: Troponin- A. Troponin
- B. Tropomyosin
- C. Actin
- D. Elastin
- E. Collagen
Explanation: Explanation for this question will be added soon.
Correct answer: Tropomyosin- A. I-band
- B. H-zone
- C. A-band
- D. Sarcomere
- E. Region between two M-lines
Explanation: Explanation for this question will be added soon.
Correct answer: H-zone- A. I-band shorten
- B. A-band shortens
- C. H-zone disappear
- D. Z-lines move closer
Explanation: Among the given options, the event that does not occur during muscle contraction is b) A-band shortens.
Correct answer: A-band shortens- A. Calcium storage
- B. Protein synthesis
- C. Lipid metabolism
- D. Strong cell wastes
Explanation: The sarcoplasmic reticulum of muscle fibers is mainly responsible for "Calcium storage." It plays a crucial role in regulating calcium ion…
Correct answer: Calcium storage- A. Decrease in body temperature after death.
- B. Accumulation of rigid proteins molecules in arcoplasm.
- C. Death of tissue due to unavailability of O2
- D. Unavailability of ATP, which is necessary to break the link between actin and myosin.
Explanation: Rigor mortis is a postmortem process that occurs in the muscles of a deceased individual, and it is caused by a lack of ATP (adenosine…
Correct answer: Unavailability of ATP, which is necessary to break the link between actin and myosin.- A. 2
- B. 4
- C. 6
- D. 8
Explanation: The myosin filament is surrounded by six actin filaments and each actin filament is in turn surrounded by three myosin filaments.
Correct answer: 6- A. Z-line
- B. Actin
- C. Sarcomere
- D. Sarcolemma
Explanation: The basic contractile unit of the myofibril is the sarcomere. It is a portion between two Z-lines and this specific unit undergoes…
Correct answer: Sarcomere- A. Closer together
- B. Farther apart
- C. Towards the Z-line
- D. Both Options B and C are correct
Explanation: When the cross‐bridges bind to actin, they will pivot in such a manner to cause the actin filaments to slide closer together.
Correct answer: Closer together- A. Tetany.
- B. Muscle fatigue.
- C. Cramp.
- D. Sciatica.
Explanation: Tetany is the disease caused by low calcium in the blood
Correct answer: Tetany.- A. I-band shortens
- B. Myosin filaments shorten
- C. Actin filaments shorten
- D. Z-line disappears
Explanation: Option [A] During muscle contraction the following things happen:I band shortensZ lines come closerH zone disappearsHENCE option [A] is…
Correct answer: I-band shortens- A. Sarcolemma
- B. Sarcoplasm
- C. Sarcomere
- D. Muscle fibre
Explanation: The region lying between two Z-bands is called a Sarcomere. Sarcomeres are the functional units of muscle contraction and are composed of…
Correct answer: Sarcomere- A. I-bands shorten
- B. H-zone becomes more visible
- C. Z-lines move further apart
- D. A-bands shorten
Explanation: According to the sliding filament theory, muscle contraction involves the sliding of thin actin filaments over thick myosin filaments…
Correct answer: I-bands shorten- A. I-band shortens only
- B. A-band shortens and Z-lines move apart
- C. I-band shortens and Z-lines come close to each other
- D. Actin filament contracts
Explanation: The I- band is the region near the Z - disc where we only have the actin filament.
Correct answer: I-band shortens and Z-lines come close to each other- A. Cross bridge formation
- B. Cross bridge breaking
- C. Dragging filaments
- D. Shortening of filaments
Explanation: ATP is needed for breaking the bridge between the myosin and the actin.
Correct answer: Cross bridge breaking- A. Extreme fatigue
- B. Muscle contraction
- C. Paralysis
- D. Convulsion
Explanation: Extreme fatigue, or severe tiredness, is an overwhelming sense of exhaustion that isn't relieved by rest.
Correct answer: Extreme fatigue- A. Actin
- B. Myosin
- C. Tropomyosin
- D. Troponin
Explanation: The thick muscle filament is primarily composed of myosin proteins. In muscle fibers, thick filaments work together with thin filaments…
Correct answer: Myosin