PHYSIOLOGY
MUSCLE STRUCTURE FUNCTION
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Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
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actin
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myosin
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Either A or B
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None of the above
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Detailed explanation-1: -The major protein components of smooth muscle thin filaments are actin, tropomyosin and caldesmon, present in molar ratios of 28:4:1 respectively. Other smooth muscle proteins which may be associated with the thin filaments in the cell are filamin, vinculin, alpha-actinin, myosin light chain kinase and calmodulin.
Detailed explanation-2: -The major cytoskeletal protein of most cells is actin, which polymerizes to form actin filaments-thin, flexible fibers approximately 7 nm in diameter and up to several micrometers in length (Figure 11.1).
Detailed explanation-3: -In the sarcomere, myosin II is assembled into thick filaments, which cyclically bind to the actin-containing thin filaments in the presence of adenosine triphosphate (ATP) to generate force. However, access to actin is modulated by the control proteins troponin (Tn) and tropomyosin (Tm).