What are the protein filaments in striated muscle fibers?

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Multiple Choice

What are the protein filaments in striated muscle fibers?

Actin and myosin are the contractile protein filaments in striated muscle. They form the sarcomeres, the repeating units that create the striated appearance. When a muscle contracts, myosin heads pull on actin filaments, causing them to slide past one another and shorten the sarcomere. This process is driven by ATP and is regulated by calcium through the proteins troponin and tropomyosin, which control access to actin’s binding sites. Troponin and tropomyosin are regulatory components, not the filaments themselves. The other options are structural or regulatory proteins that do not form the actual contractile filaments in muscle.

Actin and myosin are the contractile protein filaments in striated muscle. They form the sarcomeres, the repeating units that create the striated appearance. When a muscle contracts, myosin heads pull on actin filaments, causing them to slide past one another and shorten the sarcomere. This process is driven by ATP and is regulated by calcium through the proteins troponin and tropomyosin, which control access to actin’s binding sites. Troponin and tropomyosin are regulatory components, not the filaments themselves. The other options are structural or regulatory proteins that do not form the actual contractile filaments in muscle.

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