Question

Which of the following biomolecule is insoluble in water?

• A. $\alpha$-keratin
• B. Haemoglobin
• C. Ribonuclease
• D. Adenine

Answer 1

Answer: (A)

$\alpha$-keratin

Keratin is a highly durable protein that provides structure to several types of living tissues. It is a major component of mammalian hair and hooves, mammalian and reptilian nails and horns, reptile and fish scales, bird feathers, bird beaks, and the outermost layer of skin in most animals. Keratin is insoluble in hot or cold water and is not attacked by proteolytic enzymes. The disulfide bridges (Covalent bonds) and H bonding in the keratin cause insolubility.

Thus, option A is correct.