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Assertion :As...

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Assertion :Assertion : The portion of the myofibril between two successive 2-lines Is considered as the functional unit of contraction oiled sarcomere Reason: Reason : During contraction, I-bands get reduced whereas A-bands retain the length, thereby causing shroting of the sarcomere

A

If both assertion and reason are true and reason is the correct explanation of assertion.

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B

If both assertion and reason are true but reason is not the correct explanation of assertion

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C

If assertion Is true but reason is false.

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D

If both assertion and reason are false.

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Solution

The correct option is A If both assertion and reason are true and reason is the correct explanation of assertion.
The A band contains about thick myosin filament bands. The I band contains strong thick actin filament. Each I and is divided into two equal halves by a partition which is known as the Z band. Each segment of a fibril between two Z bands is known as a sarcomere. The sarcomere is considered as the ultimate unit for contraction. According to Huxley in his sliding filament theory the I band gets contracted and the A band retains its size thus overall the sarcomere gets contracted.

So, the correct option is 'If both assertion and reason are true and reason is the correct explanation of assertion.'

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