PHYSIOLOGY
MUSCLE CONTRACTION
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Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
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as long as ADP is available
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as long as the muscle fiber is stimulated to expand
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both are true
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both are false
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Detailed explanation-1: -Myosin filament is 1.6 m in length, approximately 300 Å in diameter and has an axial repeat of 429 Å along its length (Figure 3b, c). Actin filament is 1.0 m in length, approximately 100 Å in diameter and has an axial repeat of 370 Å (Figure 3c, d).
Detailed explanation-2: -The movements of myosin appear to be a kind of molecular dance. The myosin reaches forward, binds to actin, contracts, releases actin, and then reaches forward again to bind actin in a new cycle. This process is known as myosin-actin cycling.
Detailed explanation-3: -Sliding-filament model of muscle contraction. The actin filaments slide past the myosin filaments toward the middle of the sarcomere. The result is shortening of the sarcomere without any change in filament length.
Detailed explanation-4: -Myofibrils, which are made up of bundles of strong myosin filaments and thin actin filaments, are long, thread-like structures found in the cytoplasm of muscle fibres. Sarcoplasmic reticulum (SR) is a tubular network that accumulates calcium ions and surrounds actin and myosin filaments.