Which of the following amino acids is essential and must be obtained through diet?

Correct option is C

Sol. Lysine is an essential amino acid, meaning it cannot be synthesized by the human body and must be obtained through diet. It plays a crucial role in protein synthesis, calcium absorption, immune function, and collagen formation. It is also important for the production of carnitine, a molecule that helps convert fatty acids into energy. Deficiency of lysine can lead to fatigue, poor concentration, anemia, and delayed growth in children.
Explanation of Each Option:
· Glycine: Incorrect; a non-essential amino acid synthesized in the body, primarily used for collagen production and neurotransmitter function.
· Glutamine: Incorrect; conditionally essential, meaning it is produced by the body but may be required from the diet during stress or illness.
· Lysine: Correct answer; an essential amino acid required from dietary sources like meat, fish, eggs, and dairy.
· Alanine: Incorrect; a non-essential amino acid involved in glucose metabolism and energy production but not required from diet.