Assertion: On stimulation, a muscle cell releases calcium ions (Ca2+) from sarcoplasmic reticulum. Reason: By reacting with a protein complex, Ca2+ uncover active sites on the actin filaments.

Question

Assertion: On stimulation, a muscle cell releases calcium ions (Ca2+) from sarcoplasmic reticulum. Reason: By reacting with a protein complex, Ca2+ uncover active sites on the actin filaments. (A) If both assertion and reason are true and reason is the correct explanation of assertion (B) If both assertion and reason are true but reason is not the correct explanation of assertion (C) If assertion is true but reason is false (D) If both assertion and reason are false

Tardigrade Admin · Accepted Answer

A neural signal on reaching the neuromuscular junction releases a neurotransmitter (acetylcholine) which generates an action potential in the sarcolemma.This spreads through the muscle fibre and causes the release of calcium ions from sarcoplasmic reticulum into the sarcoplasm. Increase in Ca2+ level leads to the binding of calcium with a subunit of troponin on actin filaments and thereby removing the mask of active sites for myosin.

Q. Assertion : On stimulation, a muscle cell releases calcium ions (Ca2+) from sarcoplasmic reticulum. Reason : By reacting with a protein complex, Ca2+ uncover active sites on the actin filaments.

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

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

If assertion is true but reason is false

If both assertion and reason are false

Q. Assertion : On stimulation, a muscle cell releases calcium ions $(C a^{2 +})$ from sarcoplasmic reticulum.
Reason : By reacting with a protein complex, $C a^{2 +}$ uncover active sites on the actin filaments.