Question

The protein that is a structural material is:
A. Albumin
B. Oxytocin
C. Haemoglobin
D. Keratin

Answer 1

Hint: Proteins being a complex compound composed of amino acid building blocks can be classified on the basis of chemical composition, shape, and function. Proteins based on chemical composition are simple proteins and conjugated proteins. Classification of proteins on the basis of shape are fibrous, globular, and intermediate proteins. Three of all four options are classified on the basis of biological functions.

Complete Step by Step Solution:
Albumin is a member of the globular protein, which is itself a category of simple proteins. Protein can be classified on the basis of chemical composition or structure, such as simple, complex, and derived proteins. Alumina is used to transport a good number of amino acids through binding with proteins and responsible for osmotic pursuit in plasma.
Oxytocin is a hormone protein (a natural hormone) and a peptide consists of nine amino acids. Oxytocin is released by the pituitary gland in blood, spine, and other parts of the brain during kissing, hugging and sexual touching. Its main function is to regulate emotions, effective social interaction, birth of children, and contraction stimuli of the beast to help locomotion.

Haemoglobin is classified as a protein based on functioning. Haemoglobin is an oxygen carrier which carries oxygen from lungs to muscle tissue passing through blood. Keratin or scleroproteins are a group of fibrous structural proteins. Alpha keratin, which is a type of keratin, is present in vertebrates that help to make nails, hairs, claws, feathers, horns of animals and outside the skin of vertebrates (having back).
Thus, the correct option is D. Keratin.

Note: Albumin and Keratin are both the family of structural globular and fibrous proteins, which both are part of simple proteins, classified on the basis of chemical composition. But keratin is used to form hair, outer layer of skin, horns, claws, and many others.