Question

What Is The Light Band In The Myofibril?

Answer 1

Myofibril:

1. A muscle cell is made up of a number of fibres known as muscle fibres. These muscle fibres have rod-like structures made up of a protein called the myofibrils.
2. These protein structures are arranged in thin and thick rods called myofilaments, and the repeating units in myofibrils are called sarcomeres.

The filaments are of two types, actin and myosin.

1. The myosins are the thick filaments made up of 300-500 myosin molecules.
2. Each myosin molecule has two strands and can be differentiated into the head, neck and tail. The head has binding sites for the actin and ATP molecules.
3. The thin filaments are the actin filaments that are made up of smaller actin proteins. 300-400 such proteins come together to form an actin filament.
4. Light bands comprise actin and are referred to as I-band or isotropic band.

The actin and myosin filaments work in conjunction for the contraction and relaxation of muscles.