The digestion of protein is facilitated by:

RRB Staff Nurse Ahmedabad-2015

Biochemistry & Nutrition

Easy

Appeared in: RRB Staff Nurse Ahmedabad-2015

Explanation

Trypsin is a key proteolytic enzyme, meaning its primary role is to break down proteins.
It is produced by the pancreas as an inactive precursor (trypsinogen) and becomes active in the small intestine.
Once activated, trypsin continues the digestion of proteins that began in the stomach, breaking them down into smaller peptides and amino acids for absorption.
This process is essential for the body to utilize dietary protein for various functions like muscle repair, enzyme synthesis, and immune response.

Option B: Amylase is a carbohydrase, not a protease. Its function is to break down carbohydrates (starches) into simpler sugars like maltose and glucose.
Option C: Secretin is a hormone, not a digestive enzyme. It regulates the pH of the duodenum and stimulates the pancreas to release bicarbonate-rich fluid, but it does not directly break down food molecules.
Option D: Lipase is an enzyme that specifically digests fats (lipids or triglycerides), breaking them down into fatty acids and glycerol.

Visual 1: Diagram - An illustration of the human digestive system highlighting the stomach, pancreas, and small intestine, showing where each major enzyme (pepsin, trypsin, amylase, lipase) is produced and where it acts.
Visual 2: Flowchart - A flowchart depicting the process of protein digestion, starting from the mouth, moving to the stomach (pepsin action), and finishing in the small intestine (trypsin and other proteases action), ending with amino acid absorption.

Clinical Relevance

Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain Biochemistry of Digestion as background academic context rather than a clinical decision trigger.
In conditions like pancreatitis (inflammation of the pancreas), the premature activation of trypsinogen to trypsin within the pancreas can lead to autodigestion of the organ, a painful and life-threatening condition.
Nurses monitor serum amylase and lipase levels as key diagnostic markers for acute pancreatitis. Elevated levels indicate pancreatic injury.
For patients with cystic fibrosis or pancreatic insufficiency, pancreatic enzyme replacement therapy (PERT), which includes trypsin, amylase, and lipase, is prescribed to aid digestion and prevent malnutrition.

How to Approach the Question

First, identify the core subject of the question, which is the digestion of a specific macronutrient: protein.
Recall the three main classes of digestive enzymes and the macronutrient each one targets: Proteases (for proteins), Amylases/Carbohydrases (for carbohydrates), and Lipases (for fats).
Evaluate each option based on this classification. Trypsin is a well-known protease.
Eliminate Amylase and Lipase as they act on carbohydrates and fats, respectively.
Recognize that Secretin is a hormone that regulates digestion, rather than an enzyme that directly participates in it. This makes it an incorrect choice.
Conclude that Trypsin is the only enzyme listed that facilitates protein digestion.

Concept Tested & Keywords

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