Which of the following enzymes converts fats into fatty acids and glycerol?

Appeared in: AIIMS Patna NO - 2020

Explanation

Lipase is the specific enzyme responsible for the hydrolysis (breakdown) of dietary fats, which are primarily triglycerides.
It catalyzes the conversion of triglycerides into absorbable molecules, namely free fatty acids and glycerol.
The most significant site of lipase activity is the small intestine, where pancreatic lipase acts on emulsified fats.
While small amounts of lingual and gastric lipase exist, pancreatic lipase is the most important enzyme for fat digestion.

Option A: Bile is a digestive fluid, not an enzyme. It aids fat digestion by emulsifying large fat globules into smaller droplets, but it does not chemically break them down into fatty acids and glycerol.
Option B: Trypsinogen is the inactive form of trypsin, a protease. Its function is to digest proteins into smaller peptides and amino acids, not fats.
Option C: Salivary amylase is an enzyme that begins the digestion of carbohydrates (starches) in the mouth. It has no role in fat digestion.

Clinical Relevance

Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain Enzymatic digestion of macronutrients as background academic context rather than a clinical decision trigger.
Understanding the role of lipase is critical for nurses managing patients with pancreatic insufficiency (e.g., from pancreatitis or cystic fibrosis), where fat malabsorption is a major issue.
Elevated serum lipase levels are a key laboratory marker used to diagnose acute pancreatitis, as damage to pancreatic cells causes the enzyme to leak into the bloodstream.
Some weight-loss medications, like orlistat, work by inhibiting pancreatic lipase, thereby reducing the absorption of dietary fats and, consequently, caloric intake.

How to Approach the Question

Identify the key terms in the question: 'enzyme', 'converts fats', 'fatty acids', and 'glycerol'. This points to the chemical breakdown of lipids.
Recall the major classes of digestive enzymes and the macronutrients they act upon: proteases for proteins, amylases for carbohydrates, and lipases for lipids (fats).
Evaluate each option based on this knowledge.
Eliminate 'Bile' because it is an emulsifier, not an enzyme.
Eliminate 'Trypsinogen' as it is a protease precursor involved in protein digestion.
Eliminate 'Salivary amylase' as it is involved in carbohydrate digestion.

Concept Tested & Keywords

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E6 Physiology Guyton 4SAE Part 2A p. 202-204

E6 Physiology Ganong 27e Vol 2 Part 1 p. 30-32

E6 Textbook of Biochemistry for medical StudentsDM Vasudevan Part 1 (pp 26-370 of 370) p. 208-210

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Attempt every question from this paper in a timed mock, then review the full solution for each one.