Enzyme 1. (a)71(b)Repeat experiment at a range of pH values at closer intervals / atsmaller intervals of pH /eq (on either side of the optimum)1(c)In very /eq acidic conditions / high concentration of H+;Reference to changes in R group ionisation /eqBonding disrupted /eq;Enzyme / active site changes shape / tertiary structure changes denaturation ;Substrate / urea does not bond /eq with active site;3(d)Shape affected more at pH 9 than 8 / more denaturation at pH9 than 8 H converse ;Enzyme-substrate complex formed less efficiently / eq22. (a)(i)The production of juice is increased / more juice is produced ;Four times as much / 15 cm3 more juice was produced ;The rate of production increases / the graph has a steeper line withpectinase ;Production lasts longer ;2(ii)Enzyme digests/breaks down/ hydrolyses pectin ;In cell walls ;Allowing release of juice / reference to permeability ;2(b)(i)Inhibitor has similar shape to, substrate / pectin ;Binds to active site ;Prevents entry of / competition with, substrate ;2(ii)More juice released / juice released faster ;Increased enzyme activity / decreased inhibition ;2(c)1. Use same type / variety of apples ;2. Same / stated mass / volume of pulp ;3. Range of temperatures / at least three stated temperatures ;4. Same / stated volume / concentration of enzyme / pectinase ;5. Same time / stated time period ;6. Measure volume of juice extracted ;7. Plot graph of volume of apple juice vs. temperature ;4[12]

(e)Use (buffer solution) pH7 throughout / optimum pH ;Same / stated concentration / volume of urea / substrateRange of concentrations of urease / enzyme;Use the same / stated volume of urease / enzyme;Named variable (e.g. time / temperature / volume of buffer) keptconstantMax 4[11]3. (a)pH ;enzyme concentration ;enzyme (solution) volume ;substrate (solution) volume ;total volume ;2(b)more collisions / complexes ;with, enzyme / active site (and substrate) ;in unit time / eq ;2(c)enzymes are working as fast as they can / reference to Vmax ;all active sites occupied / eq ;substrate concentration is no longer a limiting factor ;enzyme concentration is limiting ;2(d)line on graph begins at zero and is below original line ; less kinetic energy / molecules moving more slowly ;fewer collisions (between enzyme and substrate) ;less energetic collisions ;in unit time / eq ;3[9]4. Catalysts ;Activation energy ;Substrate ;Active site ;Temperature / non-active site-directed inhibitors ;Change / increase or decrease ;[only accept decrease if referring to inhibitor][6]