Which of the following statement is true?
Answers A – D
A If just one of the essential amino acid is missing from the diet, the body cannot synthesize new protein to replace that lost amino acid.
B The lack of essential amino acids lead to positive nitrogen balance.
C Most animal proteins contain non-essential amino acids.
D. Human body can synthesize essential amino acids.
The Correct Answer and Explanation is :
Correct Answer:
A. If just one of the essential amino acids is missing from the diet, the body cannot synthesize new protein to replace that lost amino acid.
Explanation:
Proteins are made up of amino acids, which serve as building blocks for bodily functions, including muscle repair, enzyme production, and immune system support. The human body requires 20 different amino acids, categorized into essential and non-essential amino acids.
- Essential amino acids cannot be synthesized by the body and must be obtained through dietary sources. These include histidine, isoleucine, leucine, lysine, methionine, phenylalanine, threonine, tryptophan, and valine.
- Non-essential amino acids can be synthesized by the body from other amino acids and compounds.
The reason statement A is correct is because protein synthesis is dependent on all essential amino acids being available in adequate amounts. If even one essential amino acid is missing from the diet, the body cannot complete the protein synthesis process. Instead, the body may break down existing proteins to obtain the missing amino acid or, in extreme cases, halt protein production, leading to muscle wasting and other deficiencies.
Why the Other Options Are Incorrect:
- B (False): A lack of essential amino acids leads to negative nitrogen balance, not positive. A positive nitrogen balance occurs when protein intake exceeds protein breakdown, as seen in growth, pregnancy, or muscle building.
- C (False): Most animal proteins contain both essential and non-essential amino acids, making them complete proteins (e.g., meat, fish, eggs).
- D (False): The human body cannot synthesize essential amino acids and must obtain them from food sources like meat, dairy, eggs, and certain plant proteins.
Thus, A is the correct answer, as a missing essential amino acid prevents new protein synthesis.