Question

Assertion: Myofibrils have thick and thin myofilaments.
Reason: Thick myofilament consists of myosin. Thin myofilament constitutes of actin.

• A. Both the assertion and reason are true and the reason is the correct explanation for the assertion
• B. Both the assertion and reason are true but the reason is not the explanation for the assertion
• C. Assertion is true but the reason is false
• D. Reason is true but the assertion is false

Answer 1

The correct option is B Both the assertion and reason are true but the reason is not the explanation for the assertion

Myofilaments are the filaments in myofibrils which play a role in muscle contraction. Myofilaments are of two types
i. Thick myofilament, which contains the protein myosin.
ii. Thin myofilament, which contains the protein actin.
The thick and thin filaments are arranged parallel to each other. The diameter of the thick filament is approximately 15 nm and the thin filament is approximately 7 nm in diameter.