Question

Which one is fibrous protein?
A. Collagen
B. Globulin
C. Haemoglobin
D. Hordein

Answer 1

Hint: Fibrous proteins are the major components of the connective tissue and blood vessel walls and these proteins serve as structural proteins. Fibrous proteins contain elongated polypeptide chains that run parallel to one another and are stabilized by cross-linkages.

Complete answer:
Fibrous proteins help to provide support and aid in biomechanics. These proteins are water insoluble and are built upon a single, repetitive structure assembled into cables. The most commonly found fibrous protein is collagen which accounts for more than 30% of the total protein in the body. The basic structure of collagen is triple helix which comes from a high abundance of glycine, hydroxyproline and proline. A fibrous protein is a thread like which may occur singly or in groups. These proteins are tough, structural and non-enzymatic. Keratin is an example of fibrous protein. Some fibrous protein is contractile protein found in myosin of muscles and connective tissue like in tendons, cartilage and bones are collagen.
The collagen protein is present in bones, cartilage, blood vessels, and other body parts. Collagen is also insoluble in an aqueous environment like other fibrous proteins. There are mainly two types of proteins which are fibrous proteins and globular proteins.

Hence, the correct option is A. Collagen.

Note: Fibrous proteins are static molecules which play an important role in providing support, shape and form. The fibrous proteins have polypeptide chains arranged in long strands which are present in the majority of the bones and blood vessels whereas globular proteins have polypeptide chains folded in globular shape.