Structure of Proteins:
Made of amino acids linked by peptide bonds
Form polypeptides, which fold into 3D structures
Protein structure levels:
1. Primary structure – Amino acid sequence
2. Secondary structure – Helices and sheets
3. Tertiary structure – 3D folding
4. Quaternary structure – Multiple polypeptide chains
Functions of Proteins:
Enzymes (speed up reactions, e.g., amylase)
Hormones (control body functions, e.g., insulin)
Transport (carry oxygen, e.g., hemoglobin)
Immunity (fight infections, e.g., antibodies)