Question

Write the difference between:

(a) Actin and Myosin

(b) Red and White muscles

(c) Pectoral and Pelvic girdle

Answer 1

(a) Actin

1. Actin is a thin contractile protein.

2. It is present in light bands and is called an isotropic band.

Myosin

1. Myosin is a thick contractile protein.

2. It is present in dark bands and is called an anisotropic band.

(b) Red muscle fibre

1. Red muscle fibres are thin and smaller in size.

2. They are red in colour as they contain large amounts of myoglobin.

3. They contain numerous mitochondria.

4. They carry out slow and sustained contractions for a long period.

5. They provide energy by aerobic respiration.

White muscle fibre

1. White muscle fibres are thick and larger in size.

2. They are white in colour as they contain small amounts of myoglobin.

3. They contain less number of mitochondria.

(c) Pectoral girdle

1. It is a skeletal support from where the forelimbs of vertebrates are attached.

2. It is composed of two bones namely, clavicle or collar bones and scapula or shoulder bone.

Pelvic girdle

1. It is a skeletal support from where the hind limbs of vertebrates are attached.

2. It is composed of three bones, upper ileum, inner pubic, and ischium.

4. They carry out fast work for the short duration.

5. They provide energy by anaerobic respiration