Question

1.contraction of muscle is caused by
a. actin
b. myosin
c. actomyosin
d. ATP
2. H-zone in sarcomere
a. thin filament
b. thick filament
c. both thin and thick
d. only F-actin​

Answer 1

Answer:

first ka a

second Ka d

Muscle contraction occurs when the thin actin and thick myosin filaments slide past each other. ... In this conformation the cross-bridge binds weakly to actin and attaches and detaches so rapidly that it can slip from actin site to actin site, offering very little resistance to stretch.

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Answer 2

Answer:

1. When an Action Potential Travels Along the Nerves to the Muscles.

2. A thin M-line

Explanation:

1. A Muscle Contraction Is Triggered When an Action Potential Travels Along the Nerves to the Muscles. Muscle contraction begins when the nervous system generates a signal. The signal, an impulse called an action potential, travels through a type of nerve cell called a motor neuron.

2. H-band is the zone of the thick filaments that has no actin. Within the H-zone is a thin M-line (from the German "mittel" meaning middle), appears in the middle of the sarcomere formed of cross-connecting elements of the cytoskeleton.