Rice is deficient in which amino acid ?
**Core Concept**
Rice, a staple cereal, is a good source of carbohydrates but lacks essential amino acids, making it a poor protein source. This deficiency is due to its low content of a specific amino acid, which is crucial for human health.
**Why the Correct Answer is Right**
Rice is particularly deficient in **lysine**, an essential amino acid that plays a vital role in various bodily functions, including the production of proteins, hormones, and enzymes. Lysine is also essential for growth and development, particularly in children and adolescents. The deficiency of lysine in rice is due to the low activity of the enzyme **aspartate kinase**, which is involved in the biosynthesis of lysine.
**Why Each Wrong Option is Incorrect**
* **Option A:** Methionine is an essential amino acid, but rice is not particularly deficient in it. Methionine is important for the synthesis of taurine, carnitine, and other sulfur-containing compounds.
* **Option B:** Threonine is another essential amino acid, but rice is not notably deficient in it. Threonine is involved in the synthesis of proteins, collagen, and other biomolecules.
* **Option C:** Tryptophan is an essential amino acid that is important for the synthesis of serotonin and other neurotransmitters. However, rice is not particularly deficient in tryptophan.
**Clinical Pearl / High-Yield Fact**
It's essential to note that consuming rice alone as a protein source can lead to lysine deficiency, which can cause growth retardation, fatigue, and other health issues. A balanced diet that includes a variety of protein sources, such as legumes, nuts, and whole grains, can help mitigate this risk.
**Correct Answer:** Lysine.