AIIMS CRE, SNO-2024: Glutathionate is classified as which type of molecule?

AIIMS CRE, SNO-2024

Biochemistry & Nutrition

Medium

Appeared in: AIIMS CRE, SNO-2024

Explanation

Glutathione is a tripeptide, a molecule composed of three amino acids: γ-glutamic acid, cysteine, and glycine.
Peptides are short chains of amino acids linked by peptide bonds.
Proteins are large, complex molecules also made of amino acid chains (polypeptides).
Because glutathione is made of amino acids, it falls under the broad biochemical category of proteins, especially when compared to lipids, carbohydrates, or nucleic acids.

Option A: Lipids are fats and oils, composed primarily of fatty acids and glycerol, not amino acids.
Option C: Carbohydrates are sugars and starches, composed of monosaccharide units. Glutathione is not a sugar.
Option D: Nucleic acids, like DNA and RNA, are made of nucleotides and store genetic information. Glutathione does not have this structure or function.

Visual 1: Diagram - The chemical structure of Glutathione, highlighting the three amino acid components (Glutamic Acid, Cysteine, Glycine) and the peptide bonds linking them. This helps visualize why it's a tripeptide.
Visual 2: Chart - A comparison table of the four major classes of biomolecules (Proteins, Carbohydrates, Lipids, Nucleic Acids), showing their monomers and primary functions, to reinforce the classification.

Clinical Relevance

Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain Biochemical classification of molecules as background academic context rather than a clinical decision trigger.
Glutathione is the body's master antioxidant, protecting cells from damage caused by free radicals and reactive oxygen species.
It plays a crucial role in detoxification by binding to toxins in the liver, making them water-soluble and easier to excrete.
Nurses may administer N-acetylcysteine (a precursor to glutathione) as an antidote for acetaminophen (paracetamol) overdose to replenish glutathione stores and prevent severe liver damage.

How to Approach the Question

First, identify the key term in the question: 'Glutathionate,' which is the ionized form of glutathione.
Recall or determine the basic chemical composition of glutathione. The name itself (ending in '-thione') and its biological context suggest it's not a simple sugar, fat, or genetic material.
Recognize that glutathione is a well-known tripeptide (a molecule made of three amino acids).
Compare this composition to the four options provided, which represent the major classes of biomolecules.
Since peptides are made of amino acids, the same building blocks as proteins, select 'Protein' as the best and most fitting category.
Eliminate the other options by recalling the basic definitions of lipids (fats), carbohydrates (sugars), and nucleic acids (genetic material).

Concept Tested & Keywords

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E6 Textbook of Biochemistry for medical Students 11th Edition DM Vasudevan Part 2 — Subpart A (pp 1-239 of 478) p. 239-478