PHYSIOLOGY
MUSCLE CONTRACTION
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Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
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energy is gained
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a phosphate group is lost
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ATP becomes ADP
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None are true
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Detailed explanation-1: -ATP is critical for muscle contractions because it breaks the myosin-actin cross-bridge, freeing the myosin for the next contraction.
Detailed explanation-2: -The myosin head releases from the actin; Hydrolysis of ATP to ADP causes the myosin to straighten out. The split of ATP (into ADP + phosphate) stores energy in the myosin head and releases some heat.
Detailed explanation-3: -ATP is required for the process of cross-bridge cycling which enables the sarcomere to shorten. The steps of cross-bridge cycling are as follows: When ADP** is bound to myosin heads, they are able to bind to actin filaments of the adjacent myofibril to form a cross-bridge.
Detailed explanation-4: -(Ch. 12.1; Skeletal Muscle) Which of the following is TRUE of the crossbridge cycle? ATP binding triggers the power stroke. In the cocked state the myosin head group is bound to ADP.