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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.
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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
- In man and mammals air passes from outside into the lungs through
- The idea of two pigment systems in light reaction of photosynthesis was given
- When a lysosome fuses with a phagosome it results in the formation of
- Vascular tissues in flowering plants develop from:
- Artificial insemination mean :
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
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