AQA BIOLOGICAL MOLECULES - ENZYMES

Alternative transcript:

and can mould itself around the substrate •The active site forms as the enzyme and substrate interact. • Before the reaction, the active site is not complementary • Shape of the active site changes slightly as substrate binds and the enzyme/substrate complex is formed • As it changes shape, the enzyme puts a strain on the substrate molecule, distorting the bonds and lowering the activation energy. Enzyme Action Reactants: Glucose +0, Enzymes Without enzyme With enzyme Activation energy without enzyme Activation energy with enzyme Overall energy released during reaction Products: CÓ, + HỌ a) Lock and key b) Induced fit c) Conformational selection They allow reactions to happen at a lower temperature than they would without the enzyme being present. This is because they either hold substrates close together reducing repulsion and allowing them to bond more easily or put more strain on the bonds of a substrate allowing them to break apart more easily Denaturing means that the hydrogen bonds begin to break and the tertiary structure begins to unfold meaning the enzyme can no longer function as its active site is no longer complimentary to the substrate Rate of reaction Rate of reaction (H) 1 Temperature Optimum pH pH 3 PHI-logio Lut Rate of reaction Rate of reaction Enzyme concentration limiting factor Enzyme concentration Substrate concentration limiting factor Enzyme concentration limiting factor Substrate concentration Inhibitors Inhibitors reduce enzyme activity. Some bind permanently but many just make temporary attachments to the enzymes active site. There are two types of reversible inhibitors. Competitive • Have a similar shape to the substrate • Can empty active site. • Compete with substrate for the active site so the amount of inhibition depends on the relative concentrations of substrate and inhibitor Non-competitive • Attach themselves to the enzymes away from the active site. • They alter the shape of the active site. • As they are not in competition, adding more substrate will not decrease the effect of the inhibitor • An enzyme is a biological catalyst made of globular proteins with the purpose of lowering activation energy without running out • The enzyme binds with the substrate via its complimentary active site to form a enzyme substrate complex