Multiple choice

Cross bridges, which connect the molecules of a fibril during muscle contraction, are made of

  1. actin

  2. collagen

  3. myosin

  4. creatine phosphate
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Cross-bridges are formed by myosin heads that bind to actin filaments during muscle contraction. This is the basis of the sliding filament theory. Actin is the thin filament that myosin pulls on, collagen is connective tissue, and creatine phosphate is an energy source.

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