the effect of enzyme concentration on the rate of reaction

Question 1

the effect of enzyme concentration on the rate of reaction

Question 2

what is the reaction being investigated?

Answer 2

Hydrogen peroxide —> water + oxygen

2H2O2 –> 2H2O + O2

Question 3

what enzyme catalyses this reaction?

Answer 3

the enzyme catalyse (also known as peroxidase)

Question 4

where is this enzyme found?

Answer 4

naturally occurring in a range of tissues such as liver and potato. it is also found in yeast cells

Question 5

How will we be varying the amount of enzyme?

Answer 5

by diluting the yeast suspension by varying amounts

Question 6

Describe the method used to investigate the effect of enzyme concentration on the rate of reaction?

Answer 6

1. prepare 5 yeast concentrations of different concentrations by diluting with varying amounts of distilled water (100, 80, 60, 40, 20 , 0%)
2. set up apparatus, using a bung with a syringe nozzle and a delivery tube fitting
3. For each enzyme concentration to be used, use a syringe to add 2cm^3 of enzyme suspension to the conical flask and replace the bung
4. then use a second syringe to inject 10cm^3 of hydrogen peroxide into the conical flask, without removing the syringe
5. immediate start timing
6. record the volume of oxygen collected in the gas syringe at set time intervals
7. Record values down in a results table
8. repeat the experiment again to find average values
9. Draw a graph to show results

Question 7

What could affects this investigation and reliability of the results?

Answer 7

• Water may get inside of bug and gas syringe
• Water will make the bung move slower
• Therefore may not have accurately measured the volume of gas produced

Question 8

How is the rate of reaction in this experiment measured?

Answer 8

Capture the amount of gas produced in the gas syringe

Question 9

describe how you could keep the temperature constant?

Answer 9

• use a thermometer/ water bath
• regularly check the temperature, add hot or cold water to stop temperature from fluctuating

Question 10

describe how you could keep pH constant?

Answer 10

add a buffer solution

Question 11

using your knowledge of kinetic energy explain why changing the temperature of this reaction from 30 to 15 would affect the results?

Answer 11

• molecules have a lower speed, so fewer collisions, rate of reaction decreases

Question 12

explain the advantage of giving the results in the investigation a ratio?

Answer 12

• allows comparison as fungus is a different size at the start
• makes it easier to analyse, identify the difference

Question 13

suggest why intracellular enzymes are more expensive to purify?

Answer 13

intracellular enzymes stay inside cells, so in order to open them and purify them, needs to go through a longer process which requires more energy

Question 14

FINISH