What are the building blocks of proteins?

The building blocks of proteins are amino acids. These are organic molecules that combine in various sequences to form proteins. Here’s an overview:

Structure of Amino Acids

• Central Carbon Atom (C): Forms the core of the molecule.
• Amino Group ($-N{H}_2-NH\_2$​): A functional group containing nitrogen and hydrogen.
• Carboxyl Group ($-COOH-COOH$): A functional group that makes the molecule acidic.
• Hydrogen Atom ($HH$): Attached to the central carbon.
• R Group (Side Chain): A variable group that determines the unique properties of each amino acid.

Types of Amino Acids

1. Essential Amino Acids: Cannot be synthesized by the body and must be obtained from the diet (e.g., leucine, valine, lysine).
2. Non-Essential Amino Acids: Can be produced by the body (e.g., alanine, glutamic acid).
3. Conditionally Essential Amino Acids: Usually non-essential but may become essential in certain conditions (e.g., arginine during illness).

Formation of Proteins

1. Peptide Bonds:
   • Amino acids link together via peptide bonds in a condensation reaction (removing a water molecule).
   • This forms chains of amino acids called polypeptides.
2. Protein Structure:
   • Primary Structure: Sequence of amino acids in a chain.
   • Secondary Structure: Folding into alpha-helices or beta-sheets due to hydrogen bonding.
   • Tertiary Structure: 3D folding of the entire polypeptide chain.
   • Quaternary Structure: Association of multiple polypeptide chains.

Role of Proteins

Proteins are vital for:

• Enzyme activity
• Structural support (e.g., collagen)
• Transport (e.g., hemoglobin)
• Communication (e.g., hormones like insulin)
• Immune response (e.g., antibodies)

Proteins’ function and diversity stem from the sequence and arrangement of these amino acid building blocks.