Question

Primary structure of protein involves (a) Vander Waal's interaction (b) Hydrogen bonds (c) Peptide bonds (d) Disulphide bonds

Short answer

(c) Peptide bonds

Step-by-step solution

Understand the Primary Structure of Proteins

The primary structure of a protein refers to the linear sequence of amino acids in a polypeptide chain. It is the most basic level of protein structure.

Identify the Type of Bonds Involved

The primary structure of proteins is defined by peptide bonds. These bonds link individual amino acids together in a chain.

Exclude Other Bond Types

Vander Waal's interactions, hydrogen bonds, and disulphide bonds are not involved in the primary structure. They play roles in the secondary, tertiary, and quaternary structures of proteins.

Conclusion

Based on the definitions, the correct answer is that peptide bonds are involved in the primary structure of proteins.

Key concepts

Peptide Bonds

Peptide bonds are crucial in forming the primary structure of proteins, acting like the glue that holds amino acids together. These bonds are formed through a process known as a condensation reaction. During this reaction, the amino group of one amino acid reacts with the carboxyl group of another, releasing a molecule of water. This results in a covalent bond between the carbon atom of one amino acid and the nitrogen atom of the next, forming a stable link known as the peptide bond.

Peptide bonds are strong and durable, making them essential for maintaining the integrity of the protein chain. Without them, proteins could not maintain their specific shapes or function correctly. As each bond forms between amino acids, a long chain is created, known as a polypeptide chain.

• Peptide bonds form the backbone of protein structures.
• Without peptide bonds, proteins would not have a defined sequence or function.
• The formation of peptide bonds involves the release of a water molecule.

Understanding the significance of peptide bonds helps in appreciating how proteins can maintain their specific structure and functional capabilities in biological systems.

Amino Acids

Amino acids are the building blocks of proteins. Each amino acid has a specific structure composed of an amino group (-NH2), a carboxyl group (-COOH), a hydrogen atom, and a distinctive side chain, all connected to a central carbon atom. It is this side chain, also known as the R group, that gives each amino acid its unique properties and determines how it will interact in a protein.

There are 20 standard amino acids, and they can be categorized based on the characteristics of their side chains. Some are non-polar and hydrophobic, while others are polar or charged, either positively or negatively. This diversity enables proteins to have a wide range of functions, from structural roles to enzymatic activities.

• Amino acids link together through peptide bonds to form proteins.
• The sequence of amino acids determines a protein's primary structure and function.
• The unique side chain of each amino acid affects how it interacts within a protein.

Knowing about amino acids provides insight into why proteins are so versatile and functionally diverse in living organisms.

Protein Structure Levels

Proteins are structured in a very organized manner, and understanding their structure levels helps to comprehend how they function. The primary structure is the first level, defined solely by the sequence of amino acids linked by peptide bonds.

Moving beyond the primary structure, proteins adopt more complex shapes through secondary, tertiary, and quaternary structures. The secondary structure involves the spatial arrangement of the polypeptide chain, typically forming alpha-helices and beta-sheets, stabilized by hydrogen bonds. The tertiary structure is the three-dimensional form of a single polypeptide chain, stabilized by various interactions including hydrogen bonds, disulfide bridges, and van der Waals forces. Finally, the quaternary structure arises when multiple polypeptide chains associate, forming a functional protein complex.

• Primary structure is determined by the order of amino acids.
• Secondary structure introduces patterns like alpha-helices and beta-sheets.
• Tertiary and quaternary structures add complexity and functionality.

Recognizing these levels is essential for understanding how proteins achieve their specific functions in cellular biology.