5. factors affecting enzyme acitivity

Question 1

how does temperature thats too high affect enzyme

Answer 1

1. rise in temperature = enzyme molecules vibrate more.
2. temperature goes ablove a certain level this vibration breaks bonds that holds enzyme in shape
3. active site and enzyme no longer fit together
4. enzyme is denatured

Question 2

how does temperature affect enzymes

Answer 2

more heat = more kinetic energy = molecules move faster = enzymes more likely to collide with substrate molecules
energy of collision increases = collision is more likely to result in a reaction

Question 3

how can PH denature enzymes

Answer 3

above and below optimum PH the H+ and OH- ions found in acids and alkalis can disrupt ionic and hydrogen bonds that hold enzymes tertiary structure in place
active sight changes shape = enzyme denatured

Question 4

optimum temp for most human enzymes

Answer 4

37 C

Question 5

optimum ph for most human enzymes

Answer 5

7

Question 6

increasing concentration of enzymes

Answer 6

more likely it will collide with a substrate and form an enzyme-substrate complex
increased rate of reaction

Question 7

increasing concentration of enzyme if substrate is limited

Answer 7

reaches point where all the substrate reacted

adding more enzyme has no effect

Question 8

increasing substrate concentration

Answer 8

collision between substrate and enzyme more likely so more active sites used = increased rate of reaction
this is only up to ‘saturation point’ (all active sites full) adding more substrate = no difference

Question 9

substrate concentration decreases with time =

Answer 9

rate of reaction decreases with time (initial rate the highest rate)

Question 10

competitive inhibition

how does it work?

Answer 10

similar shape to substrate
compete with substrate to bind to AS
block AS so no substrate molecules can fit

Question 11

competitive inhibition

high concentration of inhibitor?

Answer 11

takes up nearly all AS

hardly any substrate can get to enzyme = rate decrease

Question 12

competitive inhibition

higher concentration of substrate?

Answer 12

substrates chance getting to AS before a inhibitor increased
increases rate of reaction (up to a point! saturation point)

Question 13

non competitive inhibition

how does it work?

Answer 13

binds to enzyme away from active site (allosteric site)
= AS changes shape so substrate molecule can no longer bind
rate of reaction decreased

Question 14

non competitive inhibition

increase conc of substrate?

Answer 14

doesn’t make any difference to reaction rate

enzyme activity still inhibited