Multiple Choice
Which of the following is not a structure of the sarcomere?
15. Cytoskeleton and Cell Movement
Muscle Contractions
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When a cross-bridge structure is formed during a muscle contraction, the band lengths shorten and contract.
A
True
B
False
Verified step by step guidance1
Understand the structure of a sarcomere, the basic unit of a muscle fiber, which includes the A band, I band, H zone, and Z lines.
Recognize that during muscle contraction, the sarcomere shortens as the actin and myosin filaments slide past each other.
Identify that the A band remains constant in length during contraction because it is defined by the length of the myosin filaments, which do not change.
Note that the I band and H zone decrease in length as the actin filaments slide over the myosin filaments, bringing the Z lines closer together.
Conclude that while the sarcomere shortens, the A band does not shorten, which is why the statement 'band lengths shorten and contract' is false.
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