With regard to muscle contraction, which of the following is an INCORRECT statement with regard to the interactions of filaments that occur in the sarcomere? A. When muscles are relaxed tropomyosin blocks binding sites on actin subunits, which keeps cross-bridges from forming. B. The myosin heads conduct a power stroke motion to slide when bound to actin, to move the "thin" filaments towards the center of the sarcomere. C. During contraction, actin subunits are removed from the ends of the "thin" filaments to shorten actin polymers, thus reducing the length of the sarcomere. D. "Thick" filaments are anchored at the M-line, while "thin" filaments are anchored at the Z-line. E. Numerous myosin heads engage with the actin filaments simultaneously, such that there is no back-slipping during the contraction process.
With regard to muscle contraction, which of the following is an INCORRECT statement with regard to the interactions of filaments that occur in the sarcomere?
A. When muscles are relaxed tropomyosin blocks binding sites on actin subunits, which keeps cross-bridges from forming.
B. The myosin heads conduct a power stroke motion to slide when bound to actin, to move the "thin" filaments towards the center of the sarcomere.
C. During contraction, actin subunits are removed from the ends of the "thin" filaments to shorten actin
D. "Thick" filaments are anchored at the M-line, while "thin" filaments are anchored at the Z-line.
E. Numerous myosin heads engage with the actin filaments simultaneously, such that there is no back-slipping during the contraction process.
The muscle cells contain a striped pattern or striations which is formed by a series of basic units called sarcomeres. These are arranged in a stacked pattern throughout muscle tissue. These are highly stereotyped and are repeated throughout muscle cells and the proteins within them can change in length, which causes the overall length of a muscle to change. A single sarcomere contains many parallel thin filaments known as actin and thick filaments known as myosin. The interaction of myosin and actin proteins helps in the shortening of sarcomere during contraction.
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