Problem 46 - A Complete Resource Book in Chemistry for JEE Main

Question

Primary structure of protein contains which type of bond? (a) only hydrogen (b) only covalent (c) only van der Waals (d) all of these

Step-by-Step Solution

Answer

The primary structure of protein contains only covalent bonds (b).

Step 1: Understand the Basics

The primary structure of a protein refers to the specific sequence of amino acids. The link between consecutive amino acids is a peptide bond, which is a type of covalent bond.

Step 2: Identify the Bond Type

Peptide bonds are formed during a reaction known as a condensation reaction, where the amino group of one amino acid bonds to the carboxyl group of another. This bond formation results in the release of a water molecule.

Step 3: Evaluate Each Option

Let's consider each option: (a) Hydrogen bonds involve attractions between molecules, not the formation of peptide bonds. (b) Covalent bonds include peptide bonds, which are found in the primary structure. (c) Van der Waals forces are weak attractions between molecules, and do not define the primary structure of proteins. (d) Not all bond types listed are involved in forming the primary structure of proteins.

Step 4: Make a Decision

Based on the understanding that the primary structure consists of covalent bonds known as peptide bonds, the correct answer is option (b), only covalent bonds.

Key Concepts

Peptide Bonds

Proteins are essential molecules in biological systems, and their structure plays a crucial role in their function. The primary structure of a protein is its unique sequence of amino acids, and the peptide bond is the key link that holds this sequence together. A peptide bond is a special type of covalent bond that forms between two amino acids during a condensation reaction. During this process, the amino group of one amino acid bonds with the carboxyl group of another, releasing a molecule of water. This water-releasing reaction is what forms the peptide bond.

• Peptide bonds are strong and stable, providing durability to protein structures.
• They are formed in a specific order, determined by the sequence of nucleotides in DNA.

Peptide bonds are essential for the linear chain configuration of amino acids, which eventually folds into the functional three-dimensional shapes critical for protein activity.

Covalent Bonds

Covalent bonds are chemical bonds formed by the sharing of electrons between atoms. In proteins, the covalent bonds play a vital role in maintaining the integrity of the primary structure. When two atoms share electrons, they create a strong and stable connection, which is crucial for building larger and more complex molecules like proteins.

• The primary structure of proteins relies heavily on covalent bonds, specifically peptide bonds.
• Covalent bonds are stronger than other types of chemical bonds, such as hydrogen bonds or ionic bonds.

This strength and stability are why covalent bonds, particularly peptide bonds, form the backbone of the protein's primary structure, allowing it to perform its biological functions effectively.

Amino Acids Sequence

The amino acids sequence in a protein is like a language, where each amino acid is a letter that combines to form a meaningful sentence. This sequence dictates the protein's properties and function, so any change can significantly impact the protein's biological role. The sequence of amino acids is coded by the DNA and ultimately determines the protein's three-dimensional structure.

• A change in even a single amino acid can alter the protein's function or make it nonfunctional.
• The sequence also affects how the protein folds, which is essential for its biological activity.

Understanding the sequence of amino acids helps in studying genetic information, predicting protein structure, and designing new drugs. This makes the amino acid sequence a fundamental concept in biochemistry and molecular biology.