Question

1. in one or two sentences of your own words, summarize how muscle cells contract (pull together). what is a claim you can make about how muscles contract?

Explanation:

Muscle cells contract via the sliding filament theory: actin and myosin filaments interact, with myosin heads binding to actin, pulling it in, and using ATP for energy. This shortens sarcomeres, leading to muscle contraction. A claim could be: Muscle contraction relies on the interaction of actin and myosin filaments, powered by ATP, to shorten muscle fibers.

Answer:

Muscle contraction occurs as actin and myosin filaments within muscle cells interact; myosin heads bind to actin, pull it toward the center of sarcomeres (using ATP energy), shortening the muscle fibers. A claim: Muscle cells contract through the sliding of actin and myosin filaments, driven by ATP - dependent myosin - actin interactions, to shorten muscle tissue.