## **Core Concept**
Glutathione is a crucial antioxidant molecule found in cells, composed of three specific amino acids. It plays a significant role in maintaining cellular health by neutralizing free radicals and detoxifying harmful substances.

## **Why the Correct Answer is Right**
Glutathione is a tripeptide, meaning it is made up of three amino acids: glutamic acid, cysteine, and glycine. The correct sequence of these amino acids in glutathione is γ-glutamylcysteinylglycine. This unique composition allows glutathione to perform its antioxidant functions through the sulfhydryl group of cysteine.

## **Why Each Wrong Option is Incorrect**
- **Option A:** This option suggests glutathione is composed of a single amino acid, which is incorrect because glutathione is a tripeptide.
- **Option B:** This option suggests glutathione is composed of two amino acids, which is incorrect because it specifically consists of three amino acids.
- **Option D:** This option suggests glutathione is composed of four amino acids, which is incorrect because it is a tripeptide, not a tetrapeptide.

## **Clinical Pearl / High-Yield Fact**
A key point to remember is that glutathione's antioxidant properties are crucial in protecting cells from oxidative stress, which can lead to cell damage and death. Its levels can decrease with age and in certain diseases, making supplementation or dietary support (e.g., with N-acetylcysteine) a consideration in some clinical contexts.

## **Correct Answer:** . Glutathione contains 3 amino acids.