[A] : Upon stimulation of a muscle cell, cal- cium ions `(Ca^(++))` are released from the sar- coplasmic reticulum.
[R]: In reacting with a protein complex, `Ca^(++)` unmasks myosin binding sites on the ac-tin filaments.

Which muscle protein binds with calcium ions that are released from the sarcoplasmic reticulum?

Assertion: on stimulation, a muscle cell releases calcium ions (Ca^(2+)) from sarcoplasmic reticulum. Reason: By reacting with a protien complex, Ca^(2+) uncover active sites on the actin filaments.

Assertion: on stimulation, a muscle cell releases calcium ions (Ca^(2+)) from sarcoplasmic reticulum. Reason: By reacting with a protien complex, Ca^(2+) uncover active sites on the actin filaments.

Assertion: on stimulation, a muscle cell releases calcium ions (Ca^(2+)) from sarcoplasmic reticulum. Reason: By reacting with a protien complex, Ca^(2+) uncover active sites on the actin filaments.

Assertion: on stimulation, a muscle cell releases calcium ions (Ca^(2+)) from sarcoplasmic reticulum. Reason: By reacting with a protien complex, Ca^(2+) uncover active sites on the actin filaments.

Muscle protein __binds Ca^(2+) that is released from the sarcoptasmic reticulum.

Which of the following statements given below are true with reference to muscle contraction. I. Neurotransmitter acetycholine is released as nerve impulse reaches the end of axon and binds to receptor sites of motor end plate. II. Action potential passes from motor end plate over sarcoplasmic and then into the T-tubules and sarcoplasmic reticulum. III. Calcium ion are released into the sarcoplasm bind to troponin, causing a change in its shape and position. IV. Myosin cross bridges are able to bind to exposed active sites of actin. Choose the correct option.

The steps involved in the mechanism of muscle contraction are given below. Arrange the steps in proper sequential order and select the correct option. I. Release of calcium ions in the sarcoplasm. II. Signal sent by the CNS via a motor neuron. III. Binding of calcium with a subunit of troponin on actin filaments. IV. Generation of the action potential in the sarcolemma. V. Binding of myosin head to the exposed active sites on actin to form a cross-bridge. VI. Inward pulling of ‘Z’ line attached to actin causing shortening of the sarcomere. VII. Pulling of the attached actin filaments towards the centre of 'A' band. VIII. Release of neurotransmitter acetylcholine and generation of the action potential in the sarcolemma.

The steps involved in the mechanism of muscle contraction are given below. Arrange the steps in proper sequential order and select the correct option. I. Release of calcium ions in the sarcoplasm. II. Signal sent by the CNS via a motor neuron. III. Binding of calcium with a subunit of troponin on actin filaments. IV. Generation of the action potential in the sarcolemma. V. Binding of myosin head to the exposed active sites on actin to form a cross-bridge. VI. Inward pulling of ‘Z’ line attached to actin causing shortening of the sarcomere. VII. Pulling of the attached actin filaments towards the centre of 'A' band. VIII. Release of neurotransmitter acetylcholine and generation of the action potential in the sarcolemma.

Go through the following statements During muscle contraction, the width of A-band remains constant while I-band shortens. During muscle contraction, the Ca^(2+) released from the SR bind to the troponin component of thin filament The process of muscle contraction is faster in smooth muscle as they have a well developed sarcoplasmic reticulum. The red muscle fibres have abundant mitochondria, low glycogen and poorly formed sarcoplasmic reticulum.