BIOMOLECULES AND ENZYMES

Detailed explanation-1: -Actin filaments, usually in association with myosin, are responsible for many types of cell movements. Myosin is the prototype of a molecular motor-a protein that converts chemical energy in the form of ATP to mechanical energy, thus generating force and movement.

Detailed explanation-2: -Myosin is a type of molecular motor and converts chemical energy released from ATP into mechanical energy. This mechanical energy is then used to pull the actin filaments along, causing muscle fibers to contract and, thus, generating movement.

Detailed explanation-3: -Sarcomeres. A sarcomere is the functional unit (contractile unit) of a muscle fiber. As illustrated in Figure 2-5, each sarcomere contains two types of myofilaments: thick filaments, composed primarily of the contractile protein myosin, and thin filaments, composed primarily of the contractile protein actin.

Detailed explanation-4: -Myosin II is the form responsible for generating muscle contraction. It is an elongated protein formed from two heavy chains with motor heads and two light chains. Each myosin motor head binds actin and has an ATP binding site.

Detailed explanation-5: -1 Contractile Proteins. The contractile proteins are myosin, the principal component of thick myofilaments, and actin, which is the principal component of thin myofilaments.