During muscle contraction in humans the

⇦

⇨

During muscle contraction in humans the

Options

(a) Actin filaments shorten
(b) Sarcomere does not shorten
(c) A band remain same
(d) A, H and I bands shorten

Correct Answer:

A band remain same

Explanation:

Increase in Ca⁺⁺ level into the sarcoplasm leads to the binding of calcium with a subunit of troponin on actin filaments and there by remove the masking of active sites for myosin. Utilising the energy from ATP hydrolysis, the myosin head now binds to the exposed active sites on actin to form a cross bridge. This pulls the attached actin filaments towards the centre of ‘A’ band. The ‘Z”‘ line attached to these actins are also pulled inwards thereby causing a shortening of the sarcomere, i.e., contraction. It is clear from the above steps, that during shortening  of the muscle, i.e., contraction, the ‘I’ bands get reduced, whereas the ‘A’ bands retain the length.

Related Questions:

1. Heart to pump blood evolved for the first time in
2. Megaspores are produced from the megaspore mother cells after
3. The structures that help some bacteria to attach to rocks and / or host tissues are:
4. Bone marrow is absent in
5. The figure depicts a diagrammatic view of the female reproductive system of humans

Question Type: Memory (964)
Difficulty Level: Easy (1008)
Topics: Locomotion and Neural Control (33)
Subject: Biology (4253)

---

Important MCQs Based on Medical Entrance Examinations To Improve Your NEET Score

18000+ students are using NEETLab to improve their score. What about you?

Solve Previous Year MCQs, Mock Tests, Topicwise Practice Tests, Identify Weak Topics, Formula Flash cards and much more is available in NEETLab Android App to improve your NEET score.

---

Share this page with your friends