2.1.4

Question 1

turnover rate definition

Answer 1

number of reactions catalysed in a second

Question 2

how do enzymes lower activation energy

Answer 2

• active site exerts force to destabilise substrate bonds
• push reacting atoms closer together

Question 3

how enzyme structure changes for extreme environments (hot)

Answer 3

more disulfide bonds to hold together

Question 4

describe lock and key (4)

Answer 4

• enzyme’s active site is complementary to a specific substrate
• enzyme and substrate bind successfully (energy and orientation), form ESC
• substrate(s) react
• EPC formed, products released, enzyme can be reused

Question 5

induced fit difference

Answer 5

active site changes structure slightly (as new bonds between substrate and enzyme formed)

Question 6

anabolic reaction

Answer 6

build up

Question 7

catabolic reaction

Answer 7

break down

Question 8

metabolism definition

Answer 8

sum of total reactions in an organism

Question 9

intracellular enzyme

Answer 9

within the cell, e.g. catalase

Question 10

extracellular enzyme

Answer 10

outside the cell, e.g. amylase

Question 11

factors affecting the rate of enzyme reaction

Answer 11

temperature
pH
enzyme conc.
substrate conc.

Question 12

pH on rate + graph

Answer 12

as pH moves away from optimum, active sites denatures if pH changes too much, H+ or OH- ions disrupt with ionic and hydrogen bonds, less ESC

Question 13

temperature on rate + graph

Answer 13

lopsided as even in cold enzymes still work but in hot enzymes denature

Question 14

enzyme/ substrate concentration on rate + graph

Answer 14

rate increases until point of saturation where Vmax and enzyme/ substrate concentration isnt the limiting factor

Question 15

general enzyme rate description

Answer 15

as x increases, rate of reaction increases until optimum.
more frequent, successful collisions, more ESC formed, more products

Question 16

temp coefficient (Q10)

Answer 16

change in rate every 10C

Question 17

cofactor summary

Answer 17

inorganic ions
bind temporarily
help stabilise or help react
(active site cosubstrate)

Question 18

cosubstrate example

Answer 18

chlorine and amylase

Question 19

coenzyme summary

Answer 19

bind temporarily/ permanently
organic
are used up
vitamin derived

Question 20

coenzyme example

Answer 20

nicotonic acid/ B3 in NAD and NADP
pantothenic acid/ B5/ coenzyme A in KREBS

Question 21

inhibitor summary and reasons

Answer 21

reduce/ stop enzyme activity temporarily/ permanently to prevent excess product and regulate rate of reaction

Question 22

competitive inhibitor summary

Answer 22

similar shape to part/ all of the substrate, competes to bind to the active site, lowering rate of ESC formation

Question 23

competitive inhibitor graph, initial rate against sub conc

Answer 23

rate increases with sub conc until Vmax as its almost guaranteed a substrate binds first

Question 24

non-competitive inhibitor summary

Answer 24

binds to allosteric site, alters tertiary and active site (no longer complementary), lowering rate of ESC formation

Question 25

non-competitive inhibitor graph, initial rate against sub conc

Answer 25

fewer active sites available, limit Vmax as sub conc doesnt affect as active site altered at same rate regardless