1. Metabolism
U4 AOS 2 Chemistry

2. Healthy diet
The food we eat provides the raw materials that our bodies require to function properly.
Nutrients are large biomolecules required for a variety of functions. Where large amounts are needed they are referred to as macronutrients and micronutrients are essential for normal functioning and are required in smaller amounts

3. The digestive system
Metabolism refers to the chemical processes occurring in cells or organisms that are necessary for the maintenance of life.
Digestion is the process whereby large molecules are broken down into smaller molecules to enable them to be absorbed. This process involves both mechanical digestion and the use of enzymes that break specific molecules down.

4. Digestion of Carbohydrates
Chewing food increases the surface area (mechanical digestion) and mixes the enzyme amylase from the saliva to start the chemical digestion.
Poly saccharides are broken into disaccharides which are then broken down to monosaccharides.

5. Digestion of Proteins
The digestion of proteins involves the enzyme pepsin which starts the breakdown process in the stomach. The length of the peptide chain gets progressively shorter as digestion continues through the digestive system.

6. Digestion of triglycerides
Triglycerides are fats and oils. Digestion is catalysed by the enzyme lipase in the duodenum and hydrolyses the peptide bond to form glycerol and three fatty acid chains

7. Hydrolysis and condensation reactions
Condensation produces larger molecules with smaller molecules being made as well (eg water).
Hydrolysis breaks down larger molecules into smaller ones by putting the smaller molecule back in.

8. Digestion Many Chemical concepts are observed in the digestion process
Reaction rates - ↑ SA of food speeds up digestion and absorption
Solubility – polar substances are absorbed in the aqueous acidic environment of the stomach while non-polar substances are absorbed in the non-polar environment of the intestines
Enzyme action – body cells have approx enzymes acting as catalysts speeding up chemical reactions
Polymerisation – polymers of proteins and polysaccharides are produces in condensation reactions and hydrolysis reactions break them up!