What happens during muscle contraction to the length of each myosin and actin filament?
Correct answer: D. Z- lines get close
- A. A band becomes short
- B. | band elongates
- C. There is no change in sarcomere
- D. Z- lines get close
Explanation
Option D is correct since the sarcomere shortens during muscle contraction. A sarcomere is a structure bound by two consecutive Z lines. So when the sarcomere shortens, the Z-lines come closer. Option A is incorrect since, during muscle contraction, the width of the A-band does not change. Option B is incorrect since the I-band shortens and does not elongate during muscle contraction. Option C is incorrect since the width of the sarcomere reduces during muscle contraction. The changes observed during muscle contraction are as follows :
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