Enzymes Biology 12

Enzymes Take notes as the video goes Generally what is an enzyme? How does an enzyme react to only one substrate? How do you stop the enzyme when you do not want it working?

Metabolism The sum of all the chemical reactions in a cell Anabolic- build up Catabolic - break apart

Enzyme function Active site - small part of enzyme involved in reaction Lock & Key - substrate fits into active site Induced fit - Active sit undergoes slight shape change in order to fit substrate

Enzyme Reactions Synthesis Reaction (anabolism)

Enzyme Reactions Degradation Reaction (catabolism)

Denatured Enzyme

Enzyme Examples- Specificity Substrate Enzyme Lipid Lipase Maltose Maltase Lactose Lactase Polypeptides pepsin

How do enzymes speed up rxn? Activation energy - amount of energy needed to get rxn to proceed Enzymes lower the activation energy

Factors that affect enzyme activity Substrate & enzyme concentration -more reactants = more rxn can occur Temperature- 35-40C -lower temp, enzyme less flexible… affects induced fit 3. pH- 6-8 (most) -denature protein in pH is too high/ low

Factors that affect enzyme activity 4. Inhibitors Competitive- competes with same active site (substrate can’t bind so enzyme can’t work) Non-competitive- binds to allosteric site (not active site) and causes shape change of active site (substrate wont fit in active site)

Factors that affect enzyme activity Cofactors -fit into allosteric site & assist enzyme activity (change shape of active site to FIT substrate) 1) Organic - Vitamins, haeme, flavin 2) Non-organic - metal ions (Mg 2+,Cu 2+,Mn2+)

Enzymes Song http://www.youtube.com/watch?v=NdMVRL4oaUo