Problem 46 - Objective Biology for NEET

Question

The macromolecular fraction is comprised by which of the following? (a) Polynucleotides (b) Polypeptides (c) Polysaccharides (d) All of these

Step-by-Step Solution

Answer

The correct answer is (d) All of these. The macromolecular fraction is comprised of Polynucleotides, Polypeptides, and Polysaccharides.

Step 1: Understand Macromolecular Composition

Macromolecules are large molecules necessary for life, built from smaller organic molecules. They are typically composed of thousands of atoms or more. The most common macromolecules in biochemistry are biopolymers (nucleic acids, proteins, and carbohydrates) and large non-polymeric molecules (such as lipids and macrocycles).

Step 2: Identify the Components in The Options

Looking at the given options, (a) Polynucleotides are the building blocks of nucleic acids like DNA and RNA, (b) Polypeptides are chains of amino acids that form proteins, and (c) Polysaccharides are carbohydrate polymers that includes sugars and starches. Each of these components are typical constituents of the macromolecular fraction.

Step 3: Match the Components with the Options

After identification, it can be seen that all the given options (a), (b) and (c) are typical constituents of the macromolecular fraction and hence, the correct answer is (d) All of these.

Key Concepts

Biopolymers

Biopolymers are essential components of living organisms. These large molecules are formed from repeating units that link through chemical bonds. They play crucial roles in maintaining the structure and function of cells and tissues.
Biopolymers can be divided into three main categories:

• Nucleic acids (e.g., DNA and RNA) are responsible for storing and transmitting genetic information.
• Proteins, or polypeptides, function as enzymes, hormones, and structural components like collagen.
• Carbohydrates, including polysaccharides, provide energy and structural support.

Understanding biopolymers is key to comprehending biological processes such as metabolism, signal transduction, and gene expression. They also form the basis for biotechnological advances, including genetic engineering and drug development.

Polynucleotides

Polynucleotides are long chains of nucleotides, which serve as the building blocks of nucleic acids. Each nucleotide consists of three components: a sugar molecule, a phosphate group, and a nitrogenous base.
There are two primary types of nucleic acids formed by polynucleotides:

• DNA (Deoxyribonucleic Acid): It holds the genetic blueprint for the development and function of living things.
• RNA (Ribonucleic Acid): It plays a role in protein synthesis and regulates gene expression.

These molecules have a unique ability to self-perpetuate and store vast amounts of information. This enables the transfer of genetic traits from one generation to the next, making them essential for heredity and evolution.

Polypeptides

A polypeptide is a single, continuous chain of amino acids linked by peptide bonds. These chains fold into specific three-dimensional structures to form proteins, which perform a vast array of functions in the body.
Amino acids, the building blocks of polypeptides, are organic compounds composed of carbon, hydrogen, oxygen, and nitrogen. There are 20 standard amino acids, and the sequence in which they are arranged determines the protein’s properties and functions.
Proteins derived from polypeptides have diverse functions including:

• Acting as enzymes to catalyze biochemical reactions.
• Serving as antibodies in the immune response.
• Transporting molecules across cell membranes.

Understanding polypeptides is crucial in biochemistry, medicine, and biotechnology, as modifications or malfunctions in proteins can lead to various diseases.

Polysaccharides

Polysaccharides are complex carbohydrates composed of long chains of monosaccharide units. They are commonly found in nature and serve various functions within organisms.
Polysaccharides can be classified based on their structure and function into:

• Storage polysaccharides: Examples include starch in plants and glycogen in animals, which store energy to be used when needed.
• Structural polysaccharides: Such as cellulose in plants, which provides rigidity and strength to cell walls.

These macromolecules are insoluble in water and often have a branched or linear structure, which contributes to their stability and function. Polysaccharides are not only crucial for biological processes but also have industrial applications, including food products, textiles, and biofuels.