Enzymes, Metabolism & Nutrients

1. Enzymes, Metabolism & Nutrients

2. 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 Metabolism

3. 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 Enzymes

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

5. 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) Simple Carbohydrates.

6. 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 Amino acids (Protein)

7. 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) Fatty Acids (Lipids)