In human digestion, what is the main function of the enzyme trypsin that is secreted into the small intestine?

Introduction / Context:

The human digestive system uses many different enzymes to break food into absorbable units. Each enzyme is specialised for a particular type of nutrient. Trypsin is one of the major proteolytic enzymes involved in digestion. Understanding exactly what trypsin does helps students connect organ secretions with nutrient breakdown pathways. This question asks for the main function of trypsin once it is released into the small intestine.

Given Data / Assumptions:

• The enzyme under discussion is trypsin.
• Trypsin is secreted as part of pancreatic juice into the small intestine.
• Options suggest different actions such as breaking down carbohydrates, synthesising proteins, digesting fats, breaking down proteins, or neutralising acid.
• We assume a standard human digestive process as taught in school biology.

Concept / Approach:

Trypsin is produced in the pancreas as an inactive precursor called trypsinogen. When trypsinogen reaches the small intestine, it is activated to trypsin by an enzyme present in the intestinal lining. Trypsin is a protease, which means it acts on proteins. It breaks long protein chains into smaller peptides and eventually into amino acids, which can be absorbed by the intestinal wall. Carbohydrates are mainly digested by amylases and disaccharidases, while fats are broken down by lipases with the help of bile. Neutralisation of acid from the stomach is mainly accomplished by bicarbonate in pancreatic juice and by intestinal secretions, not by trypsin itself. Therefore, the core function of trypsin is protein digestion.

Step-by-Step Solution:

Step 1: Recall that trypsin is a digestive enzyme secreted by the pancreas into the small intestine. Step 2: Identify trypsin as a proteolytic enzyme, which means it digests proteins. Step 3: Recognise that its role is to break large protein molecules into smaller peptides and amino acids. Step 4: Compare this role with the digestion of carbohydrates by amylase and fats by lipase. Step 5: Choose the option that states that trypsin breaks down proteins into smaller peptides and amino acids.

Verification / Alternative check:

Digestive system diagrams in textbooks label trypsin under pancreatic enzymes, along with chymotrypsin and carboxypeptidase, and place them under the heading of proteases. Descriptions explain that these enzymes act on partially digested proteins that have come from the stomach. Tables summarising digestion show that carbohydrates are broken down by salivary and pancreatic amylase and by intestinal enzymes, while fats are digested by pancreatic lipase. Neutralisation of acid is credited to bicarbonate ions. These tables consistently assign the role of protein digestion to trypsin, confirming the correct answer.

Why Other Options Are Wrong:

Option A, breaking down complex carbohydrates into simple sugars, is mainly the work of amylases and other carbohydrate digesting enzymes, not trypsin. Option B, synthesising new proteins, refers to protein synthesis which occurs on ribosomes inside cells and not in the digestive tract. Option C, breaking down fats, is primarily the function of lipase, especially pancreatic lipase, in the small intestine. Option E, neutralising hydrochloric acid, is done mainly by bicarbonate in pancreatic juice and mucus secretions, not by trypsin.

Common Pitfalls:

Students may confuse different enzymes because they all act in the small intestine. They might also think that any pancreatic enzyme can digest all types of food. To avoid confusion, learners should group enzymes by substrate: amylase for starch, proteases like pepsin and trypsin for proteins, and lipase for fats. Remembering that trypsin is a protease is a simple way to recall its specific function in protein digestion.

Final Answer:

The main function of trypsin is to break down proteins into smaller peptides and amino acids.