Question

1. what two proteins protect the actin when a muscle is at rest? 1 - 2 - 7) what layer is wrapped around each sarcomere? 8) what mineral ions are necessary for the contraction of muscles?

Explanation:

• Question 6: In muscle physiology, when a muscle is at rest, tropomyosin covers the myosin - binding sites on actin. Troponin is associated with tropomyosin and helps in regulating its position.
• Question 7: The sarcomere is the basic unit of muscle contraction. The endomysium is a layer of connective tissue that wraps around individual muscle fibers (which are made up of many sarcomeres).
• Question 8: Calcium ions (\(Ca^{2 +}\)) play a crucial role in muscle contraction. They bind to troponin, causing a conformational change that moves tropomyosin and exposes the myosin - binding sites on actin.

Answer:

1. 1 - Tropomyosin; 2 - Troponin
2. Endomysium
3. Calcium ions (\(Ca^{2+}\))