Proteins

• Proteins are polymers composed from amino acid monomers.
• Amino acids contain an amine group (-NH2), a carboxylic acid group (-COOH), and a distinctive ‘R’ side chain.
• Twenty different amino acids exist naturally, but any number of them can be synthesised artificially.
• The ‘R’ group varies from one amino acid to another, affecting characteristics such as solubility and reactivity.
• Peptide bonds are formed when the amine group of one amino acid reacts with the carboxylic acid of another in a condensation reaction, releasing water.
• Proteins’ primary structure refers to the sequence of amino acids.
• Secondary and tertiary structures depend on intramolecular interactions like hydrogen bonds, ionic bonds, and disulfide bridges.
• Quaternary structures are formed when more than one polypeptide chain is involved.
• Different interactions and bonds lead to the folding of proteins into distinctive three-dimensional structures, which determine their biological functions.
• The function of a protein is heavily influenced by its shape and structure. For example, enzymes have precise sites that bind to specific molecules.
• Proteins can denature or lose their structures due to changes in conditions like temperature or pH, leading to a loss of function.
• Enzymes are a particular type of protein that act as biological catalysts, speeding up reactions in living organisms.