Problem 41 - A Complete Resource Book in Chemistry for JEE Main

Question

Which of the following is an enzyme? (a) lipids (b) sucrose (c) emulsin (d) maltose

Step-by-Step Solution

Answer

The enzyme is emulsin (c).

Step 1: Understand the Function of an Enzyme

Enzymes are biological molecules (typically proteins) that significantly speed up the rate of virtually all of the chemical reactions that take place within cells. They have unique shapes that determine their specific function and act as catalysts in biological systems.

Step 2: Review Each Option

Examine each option to determine if it can function as an enzyme based on its biological role. - (a) Lipids are fats and do not act as enzymes, but rather are a source of energy. - (b) Sucrose is a type of sugar and is not an enzyme. - (c) Emulsin is a mixture of enzymes that break down glycosides. - (d) Maltose is another type of sugar, not an enzyme.

Step 3: Identify the Correct Answer

Determine which of the options correctly fits the description of an enzyme based on the analysis in the previous step. Among the given options, emulsin is the only one that functions as an enzyme.

Key Concepts

Enzyme Function

Enzymes are fascinating proteins that play a crucial role in biological systems. They function as powerful catalysts, speeding up the rate of chemical reactions without being consumed in the process. This means that they can be used repeatedly to facilitate reactions. Enzymes achieve this by lowering the activation energy required for a reaction to occur, making it easier for the reaction to take place.
Enzymes are highly specific in their action. This specificity is due to their unique 3D structure, which includes an active site. The active site is the part of the enzyme that interacts with the substrate (the molecule upon which the enzyme acts). When the substrate binds to the active site, the enzyme can assist in altering the substrate to form the product of the reaction.

• Enzymes are essential for numerous bodily functions, including digestion, energy production, and DNA replication.
• Their specificity allows them to target particular substrates, ensuring precise control over metabolic processes.

Biological Catalysts

Biological catalysts refer to substances, particularly enzymes, that increase the rate of biochemical reactions in living organisms. Unlike other catalysts, biological catalysts operate in the highly regulated environment of a living cell, requiring an optimal temperature and pH to function effectively.
One of the standout features of enzymes as biological catalysts is their efficiency. They can accelerate reactions by factors of a million or more compared to those without a catalyst. This efficiency is crucial in keeping biological systems functioning smoothly.

• Enzymes as biological catalysts help break down food molecules during digestion, enabling cells to absorb and use nutrients.
• They also play roles in synthesizing essential compounds and detoxifying harmful substances.
• Their ability to operate under mild conditions (such as body temperature and neutral pH) makes them incredibly effective and suitable for biological processes.

Lipids and Sugars in Biology

Lipids and sugars are two major types of biological molecules that serve different, yet vital, roles in the body. While neither of these can function as enzymes, it's important to understand the purpose they serve.
Lipids, such as fats and oils, are primarily used as energy storage molecules. They provide a dense store of energy that can be tapped into when needed. Beyond energy storage, lipids are foundational components of cell membranes and serve as signaling molecules.

• Lipids are hydrophobic, meaning they don't mix well with water, which is why they form structures like cell membranes.
• They play a role in insulating the body and protecting vital organs.

Sugars, on the other hand, are carbohydrates that provide instantaneous energy. They are simple molecules that cells can quickly break down to release energy through cellular respiration. Dietary sugars like sucrose and maltose need enzymes to break them down into simpler sugars like glucose before they can be used for energy.

• Sugars are fundamental to supplying energy for cellular processes.
• They are also important in making up larger carbohydrates, which serve structural roles in cells and energy storage in the form of glycogen or starch.

In summary, while lipids and sugars are critical to biological function and energy management, they do not perform the catalytic roles that enzymes do.