1. Proteins

2. Assumed Knowledge Amino acid structures and properties
Secondary structure (α-helix and β-sheet).
Protein synthesis occurs on ribosomes (cytoplasm) – covered in the genetics presentation
Functions of proteins

3. Amino Acids
Amino acids are the building blocks of proteins There are 20 amino acids found in proteins All have a standard structure

4. Properties
Size – small, bulky, affects the folding of a protein
Charge
H – bonding
Disulphide bonding between two cysteine amino acids

5. Protein Structure
Primary structure – the sequence of amino acids (the polypeptide chain)
Secondary structure – folding into an α-helix or a β-sheet
Tertiary structure – further folding of the protein
Quaternary structure – association of multiple proteins to form a multi-subunit protein

6. Peptide bond – bonds between the amino group and the carboxyl groups of amino acids. The bonds form with the loss of water - dehydration reaction

7. α-helix - right handed coil structure with precise spacing throughout β-sheet – a lateral connection of β-strands (stretches of amino acids)

8. Collagen – most abundant protein Made of three left handed helices arranged in a right-handed super helix

9. Protein Function Enzymes - kinase
Transport - haemoglobin and myoglobin (O2)
Storage - haemoglobin
Motility - actin and myosin.
Structure – collagen
Defence - immunoglobulins (antibodies).
Communication - Signals (insulin) and receptors (insulin receptor)
Gene control - transcription factors