Zoology-Muscle Contraction

NEET Zoology Muscle Contraction MCQ Question

Type: MCQ-numerical-Medium-Class 11

During muscle contraction, if the concentration of calcium ions in the sarcoplasm is increased by 2.5 mM, what is the immediate effect on the interaction between actin and myosin?

A

Calcium ions bind to troponin, removing the masking of active sites on actin filaments.

B

Calcium ions bind to myosin, initiating ATP hydrolysis.

C

Calcium ions inhibit the release of acetylcholine at the neuromuscular junction.

D

Calcium ions cause the detachment of myosin heads from actin filaments.

Correct Answer

Option A

Detailed Explanation

Increase in Ca++ level leads to the binding of calcium with a subunit of troponin on actin filaments, removing the masking of active sites for myosin, thus facilitating muscle contraction.

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