Question

The structural protein secreted by the cells of connective tissue:

• A. Keratin
• B. Collagen
• C. Casein
• D. Zein

Answer 1

The correct option is B Collagen

Connective tissues help in linking and supporting other tissues/organs of the body. In all the connective tissues except blood, the cells secrete fibres of structural proteins called collagen. The fibres provide strength, elasticity and flexibility to the tissue. These also secrete modified polysaccharides which accumulate between the cells and fibres act as a matrix which is also called ground substance.

Casein is a milk protein which is commonly found in mammalian milk. Buffalo milk, sheep milk, cow’s milk are also rich in casein. It is a phosphoprotein.

Keratin is one of the structural proteins. It is the major structural component of hair, nail, claws, hooves, and outer layer of skin in the vertebrates. Epithelial cells are also protected from stress or damage by keratin.

Zein is a plant protein which is found in maize.