1. Proteins
Red hunting
B1.3 - Explain how the structure of collagen and haemoglobin are related to their function.

2. Collagen – Structure
Fibrous protein - Cross-linking and staggered covalent bonds.
3 individual polypeptides or strings of amino acids.
The strands wind around one another in an alpha-helix. The helix forms because of the regular amino acid sequence of the strands.

3. Collagen - Function
Connective and supportive structures of the body.
It is found in particularly high amounts in tissues that need to be strong, flexible or both, including cartilage, bones and tendons.
Collagen can allow a tissue to withstand immense pulling pressure without stretching
It can also be elastic, as in skin, and flexible, as in a tendon bending around a joint.

4. Haemoglobin - Structure
Globular protein
 Quaternary structure (multiple protein chai ns linked together to form a greater functional unit which also includes inorganic molecules).
Iron in the centre of heme group
4 subunits
2 alpha, 2 beta chains

5. Haemoglobin - Function
Haemoglobin's function is the transport of oxygen around the body. 
Oxygen binds to Iron in the heme group of each subunit

6. Explain the role of ionic, hydrogen and disulphide bonding in the structure of proteins.