What is the sliding filament model of muscle contraction?

• A. It details the process of ATP synthesis in muscle cells.
• B. It outlines the role of troponin in muscle relaxation.
• C. It describes how actin and myosin filaments slide past each other to shorten the sarcomere.
• D. It explains how calcium ions are stored in the sarcoplasmic reticulum.

Answer: (C)

Verified step by step guidance

1. Begin by understanding the structure of a sarcomere, the basic unit of a muscle fiber, which is composed of actin (thin filaments) and myosin (thick filaments).
2. Learn about the role of myosin heads, which bind to specific sites on the actin filaments, forming cross-bridges necessary for muscle contraction.
3. Explore how ATP is crucial for muscle contraction, as it provides the energy for myosin heads to pivot and pull actin filaments towards the center of the sarcomere, shortening the muscle.
4. Understand the role of calcium ions, which are released from the sarcoplasmic reticulum and bind to troponin, causing a conformational change that moves tropomyosin away from actin's binding sites, allowing myosin to attach.
5. Recognize that the sliding filament model describes the process where actin and myosin filaments slide past each other, resulting in the shortening of the sarcomere and muscle contraction.