Protein Functions and Basic Structure
Proteins have four major jobs in your body that you need to know for your exams. Structural proteins literally build you - they're the main components of your muscles, skin, and even your hair. Catalytic proteins (called enzymes) speed up chemical reactions, like breaking down food in your stomach.
Signalling proteins include hormones that carry messages around your body, whilst immunological proteins (antibodies) fight off infections. Think of proteins as your body's ultimate multi-tool.
Every protein starts with amino acids - small molecules with three key parts. There's an amino group, a carboxyl group, and an R group (side chain) that makes each amino acid unique. The R group can be anything from a simple hydrogen atom to a complex ring structure.
When amino acids join together through condensation reactions, they form peptide bonds. Two amino acids make a dipeptide, but when you get more than two, you've got a polypeptide chain. Remember, you can reverse this process through hydrolysis to break the bonds apart.
Quick Tip: A protein is just one or more polypeptide chains folded into a specific 3D shape - that shape determines what job the protein does!
