1. Enzymes, Metabolism & Nutrients

2. Metabolism Metabolism: all of the chemical reactions which occur in a cell Catabolism: large molecules are broken down into smaller ones + release energy Anabolism: small molecules are built up into larger ones + require energy complex carbohydrates  glucose proteins  amino acids lipids  fatty aids + glycerol

3. Enzymes Activation Energy: Energy required for a reaction to occur Catalyst: Substance that speeds up a reaction without being permanently changed by decreasing the amount of energy required to start the reaction. (activation energy) Enzyme: specific proteins which are biological catalysts (lock & key) Substrates: molecules involved in reaction

4. Enzymes Factors affecting Enzyme Activity: Concentration Temperature pH Co-Factors (many are vitamins)

5. Simple Carbohydrates. Major source of energy Carbs are mainly sugars, starch & cellulose Sugar: sweets Starch: cereals, potatoes, peas & dried beans Cellulose: all plant foods (in cell walls). Monosaccharide: smallest unit of a Carb (eg glucose, fructose, galactose) Disaccharide: two monosaccharide molecules joined (eg sucrose, maltose, lactose) Polysaccharide: large numbers of monosaccharides (eg glycogen, starch, cellulose )

6. Amino acids (Protein) Used to build into proteins (synthesis) Structural material of cells and enzymes are proteins Essential amino acids: 9 amino acids that cannot be made by the body Amino acids: smallest unit of a protein (20 diff amino acids) Dipeptide: two amino acids Polypeptide: ten or more amino acids

7. Fatty Acids (Lipids) Essential fatty acids: fats which must be consumed in small quantities Monoglyceride: one glycerol molecule & a fatty acid. Diglyceride: one glycerol molecule & two fatty acids. Triglyceride: one glycerol molecule & three fatty acids. (98% of fats in body)