Problem 104 - Objective Biology for NEET

Question

Which enzyme activates other enzymes in pancreatic juice? (a) Enterokinase (b) Chymotrypsin (c) Trypsin (d) Lipase

Step-by-Step Solution

Answer

The enzyme that activates other enzymes in pancreatic juice is (a) Enterokinase.

Step 1: Identify the question

The question asks which enzyme in pancreatic juice is responsible for activating other enzymes. Given are four options: (a) Enterokinase, (b) Chymotrypsin, (c) Trypsin and (d) Lipase.

Step 2: Evaluate each option

Evaluate each option starting with (a) Enterokinase: This is a key enzyme that activates trypsinogen (an inactive enzyme) to trypsin. (b) Chymotrypsin: This enzyme helps in the breakdown of proteins but is not directly involved in the activation of other enzymes. Similarly, (c) Trypsin assists in digestion of proteins but does not activate other enzymes. (d) Lipase, involved in the breakdown of fats, also does not activate other enzymes.

Step 3: Select the correct answer

Based on the evaluation of each option, it can be concluded that Enterokinase is the enzyme that activates other enzymes in pancreatic juice, thus the correct answer is (a) Enterokinase.

Key Concepts

Enterokinase

Enterokinase, sometimes known as enteropeptidase, holds an important role in the digestive system. It is a specific type of enzyme made by the cells lining the duodenum, which is the first part of the small intestine. One of the primary tasks of enterokinase is to convert trypsinogen, an inactive enzyme precursor present in pancreatic juice, into trypsin, a powerful digestive enzyme. This conversion is critical as trypsin further activates other precursor enzymes into active forms required for digestion.

This activation process performed by enterokinase starts a cascade of enzyme activations. These activated enzymes help break down proteins into simpler forms, which can then be absorbed by intestinal cells. It's interesting to note that without enterokinase, the activation of trypsinogen might be impaired, hampering the overall digestion process. This small yet mighty enzyme ensures that digestion within the small intestine kicks off efficiently.

Pancreatic Juice

Pancreatic juice is a vital component in the digestive process. It is produced by the pancreas and plays a central role in the breakdown of food substances in the small intestine. This juice is a complex mix of water, electrolytes, and enzymes such as amylase, lipase, and proteases.

• Amylase specializes in breaking down carbohydrates.
• Lipase targets fats, transforming them into fatty acids and glycerol.
• Proteases like trypsin and chymotrypsin are crucial for digesting proteins.

To enable these enzymes to function properly, enzyme activation is essential. Pancreatic juice on its own contains inactive forms or precursors of these enzymes. When these precursors reach the small intestine, they require activation, a process swiftly initiated by previously mentioned enzymes like enterokinase.

Enzyme Activation

Enzyme activation is a critical phase in the digestive process where inactive enzymes, known as zymogens or proenzymes, are converted into active enzymes. This process is vital as it prevents these enzymes from digesting proteins within the cells where they are made, which happens before they reach the intestine.

The activation starts when enterokinase converts trypsinogen into trypsin. Trypsin then plays a dual role:

• It helps digest proteins by breaking them into smaller peptides.
• It activates other pancreatic enzymes, thus amplifying the digestive process.

Therefore, enzyme activation is not only about turning on the enzymes but maintaining a balanced and safe internal environment, preventing the corrosion or self-digestion of pancreatic tissues. The sequential activation ensures the digestion process is efficient and sustainable, ultimately aiding in proper nutrient absorption.