PHYSIOLOGY
SKELETAL MUSCLE
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Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
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According to the sliding filament theory, how does muscle contraction occur? (pg. 192)
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Myosin heads form cross bridges and pull thin filaments, causing them to slide.
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Both thick and thin filaments shorten as the muscle contracts.
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A bands bunch up and shorten as myosin heads attach to thin filaments.
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Myosin heads attach and detach from thin filaments, causing thin filaments to shorten.
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Explanation:
Detailed explanation-1: -According to the sliding filament theory, when a muscle cell contracts, the thin filaments slide past the thick filaments and the sarcomere shortens.-actin monomers can bind with myosin (actin has a myosin-binding site), -they are arranged in an orderly, repeating fashion.
Detailed explanation-2: -In addition to binding actin, the myosin heads bind and hydrolyze ATP, which provides the energy to drive filament sliding. This translation of chemical energy to movement is mediated by changes in the shape of myosin resulting from ATP binding.
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