Problem 113 - Objective Biology for NEET

Question

Action of which enzyme produces glucose? (a) Maltase (b) Lactase (c) Sucrase (d) All of these

Step-by-Step Solution

Answer

All of these (d). Maltase, Lactase, and Sucrase all produce glucose by breaking down their specific substrates.

Step 1: Understand Enzyme-Substrate Interactions

The basic principle behind the action of these enzymes is that they break down their specific substrates into simpler sugars. Maltase breaks down maltose into glucose, lactase breaks down lactose into glucose and galactose, while sucrase breaks down sucrose into glucose and fructose.

Step 2: Identify glucose producing enzyme

Looking at the enzyme-substrate interactions, we can see that all three enzymes produce glucose. Maltase produces glucose from maltose, lactase produces glucose from lactose, and sucrase produces glucose from sucrose.

Key Concepts

Enzyme-Substrate Interactions

Enzymes are biological catalysts that speed up chemical reactions in the body without being consumed in the process. A critical aspect of how enzymes work is the specific interaction between an enzyme and its substrate—the material the enzyme is designed to act upon.

This interaction occurs at the enzyme's active site, which is uniquely suited to bind to a particular substrate due to its highly specific shape. Once bound, the enzyme catalyzes a chemical reaction that convert the substrate into one or more products. This process often compares to a 'lock and key' model, where the enzyme (the lock) has a particular shape that only fits a specific substrate (the key).

Efficient enzyme-substrate interactions are essential for a vast array of physiological processes, including digestion, where enzymes break down complex molecules in food into simpler ones that the body can more easily absorb.

Maltase Function

Maltase is an enzyme that plays a crucial role in the digestive process. Specifically, maltase targets maltose, a disaccharide sugar commonly found in starchy foods like bread, potatoes, and cereals.

The maltase enzyme is located primarily in the small intestine, where maltose is broken down. The enzyme cleaves the maltose molecule into two glucose units, which are simple sugars that the body can readily absorb and utilize for energy. The effectiveness of maltase is evident in how quickly after eating starchy foods blood glucose levels can rise, thanks to the rapid conversion of maltose to glucose.

Lactase Function

Like maltase, lactase is another disaccharidase present in the small intestine, but it targets lactose, the sugar found in milk and dairy products.

Lactase's main function is to facilitate the digestion of lactose by breaking it down into glucose and galactose, both of which are monosaccharides, or simple sugars. The presence of lactase in the small intestine allows individuals to digest dairy without issues. However, in lactose intolerant individuals, lactase activity is insufficient, leading to gastrointestinal discomfort when consuming lactose-containing foods. The activity of lactase and the tolerance for lactose can vary greatly among populations and within individuals over their lifetime.

Sucrase Function

Sucrase's function is similar to that of maltase and lactase, but its substrate is sucrose, the common table sugar composed of one glucose and one fructose molecule.

Found in the lining of the small intestine, sucrase enzymes bind to sucrose and catalyze its hydrolysis into its constituent simple sugars. These sugars are then absorbed into the bloodstream and transported to cells for energy, or stored for later use. The body relies on the function of sucrase for the metabolism of many sweet foods and the regulation of sugar levels in the diet. Without sucrase, sucrose would pass through the digestive system unabsorbed, which is what occurs in rare cases of sucrase deficiency.