Zoology-Muscle Contraction

NEET Zoology Muscle Contraction Assertion Reason Question

Type: Assertion Reason-assertion-Medium-Class 11

Assertion (A): Muscle contraction is initiated by the release of calcium ions into the sarcoplasm. | Reason (R): Calcium ions bind to a subunit of troponin on actin filaments, exposing active sites for myosin.

A

Both A and R are true, and R explains A

B

Both A and R are true, but R does not explain A

C

A is true but R is false

D

A is false

Correct Answer

Option A

Detailed Explanation

The release of calcium ions into the sarcoplasm initiates muscle contraction by binding to troponin, which exposes active sites on actin filaments, allowing myosin to bind and contract the muscle. This is directly explained in the NCERT context.

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