Which biomolecule is an example of fibrous protein?

Myosin

The correct answer is Option (4) → Myosin

Proteins are broadly classified into fibrous proteins and globular proteins based on their structure and function. Fibrous proteins have long, thread-like structures and mainly perform structural or mechanical functions in the body. They are generally insoluble in water.

Examples include: • Keratin • Collagen • Myosin

Myosin is a fibrous protein found in muscle fibers and plays an important role in muscle contraction.

Option A: Epinephrine

Epinephrine is a hormone (adrenaline), not a protein. This is not a protein at all; it is a hormone and neurotransmitter derived from the amino acid tyrosine, often referred to as an amine hormone. Incorrect.

Option B: Insulin

Insulin is a globular protein hormone, not a fibrous protein. This is a globular protein. Globular proteins have polypeptide chains that coil around to form a spherical or compact shape and are typically soluble in water. Incorrect.

Option C: Albumin

Albumin is a globular protein found in blood plasma. Like insulin, albumin is a globular protein. It is found in blood plasma and egg whites and is known for its high solubility in water and role in transport functions. Incorrect.

Option D: Myosin

Myosin is a fibrous protein involved in muscle contraction. This is a classic example of a fibrous protein. These proteins are characterized by long, thread like polypeptide chains that run parallel and are held together by hydrogen and disulfide bonds. Myosin is found in muscles and is essential for muscle contraction.

Correct.