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

Question

Which is not a macromolecule? (a) DNA (b) Starch (c) Palmitate (d) Insulin

Step-by-Step Solution

Answer

Palmitate is not a macromolecule.

Step 1: Define Macromolecules

Macromolecules are large, complex molecules with a high molecular weight. They are typically composed of thousands of atoms. Common types of macromolecules include proteins, nucleic acids, carbohydrates, and some lipids.

Step 2: Analyze Each Option

Evaluate each option to determine if it's a macromolecule: (a) DNA is a nucleic acid, a type of macromolecule. (b) Starch is a carbohydrate, another form of macromolecule. (c) Palmitate is a fatty acid, which is generally not considered a macromolecule. (d) Insulin is a protein, making it a macromolecule.

Step 3: Identify Non-Macromolecule

From the analysis, palmitate is a fatty acid composed of a relatively small number of molecules and is not a macromolecule compared to the others, which are large and complex structures.

Key Concepts

DNA

DNA, or deoxyribonucleic acid, is a fundamental macromolecule essential for all known living organisms. It carries the genetic instructions used in growth, development, and reproduction. Structurally, DNA is composed of nucleotides, which include a sugar, a phosphate group, and a nitrogenous base.
This double-helical structure allows DNA to hold extensive information required for the synthesis of proteins and the proper functioning of cells. DNA is often referred to as the "blueprint of life" because it encodes the information necessary to construct an entire organism, guiding cellular activities and inheritance.

• DNA replication is a crucial process that ensures genetic information is consistently passed from one generation to the next.
• Mutations in DNA can lead to variations within a species and are a driving force in evolution.

Understanding DNA and its role is vital to fields such as genetics, molecular biology, and forensic science.

Starch

Starch is a polysaccharide and an important carbohydrate macromolecule found in plants, where it serves as a way to store energy. It is made up of many glucose units joined together by glycosidic bonds.
Starch consists of two types of molecules: amylose, which is linear, and amylopectin, which is branched, making it an excellent energy reserve. In human diets, starch is a major source of energy and is present in foods like potatoes, rice, and bread.

• During digestion, enzymes break starch down into glucose molecules, which are then used by our bodies to produce energy.
• Starch's ability to store energy makes it crucial for plant structure and function.

The understanding of starch and its breakdown plays a significant role in nutrition and food science.

Insulin

Insulin is a vital protein macromolecule that plays a key role in regulating glucose levels in the blood. Produced by the pancreas, insulin helps cells absorb glucose, which is used for energy.
This hormone facilitates the storage of glucose as glycogen in the liver and muscle, and as fat in adipose tissues. Insulin's main function is to lower blood glucose levels, keeping them steady and reducing the risk of diabetes.

• Insulin resistance or lack of insulin production leads to conditions like type 1 and type 2 diabetes.
• Insulin therapy is often a critical component of diabetes management.

Understanding insulin's function is crucial for comprehending metabolic processes and managing glucose-related disorders.

Fatty Acids

Fatty acids are the building blocks of lipids but are generally not considered macromolecules due to their smaller and simpler structure. They consist of long hydrocarbon chains with a carboxylic acid group at one end.
Fatty acids can be saturated or unsaturated based on their chemical bonds, affecting their properties and roles in the body. They are crucial for various bodily functions, including energy provision and forming cell membranes.

• Essential fatty acids, like omega-3 and omega-6, must be obtained through the diet as they are critical for health yet cannot be synthesized by the body.
• Fatty acids contribute to the production of signaling molecules that regulate inflammation and other physiological processes.

Understanding the role of fatty acids is significant for nutrition and maintaining a healthy balance of lipids in the body.