The effect of changing enzyme concentration on rate of reaction.

Question 1

Independent variable

Answer 1

concentration of enzyme

Question 2

Dependant variable

Answer 2

time taken for enzyme to break down substrate

Question 3

Other variables to control (5)

Answer 3

• Temperature
• Volume of enzyme
• Volume of substrate
• Concentration of substrate
• pH

Question 4

Equipment (8)

Answer 4

• Protease
• casein solution
• small beakers
• thermometer
• distilled water
• syringes
• stop-clock
• large beaker

Question 5

Outline the method

Answer 5

make up different concentrations of enzyme using distilled water. Ensure different syringes for different chemicals to prevent cross contamination. Set up water bath for temperature to keep constant. Place 1 test tube of 5cm3 casein solution into water bath alongside second tube containing 2cm3 of 0.2% trypsin. Allow to acclimatise for 3 mins so that at same temperature then add trypsin to casein, start stop clock. Time how long it takes for casein solution to turn transparent. (mark a ‘X’ on the other side of tube, as soon as seen through solution stop clock). Repeat a further 2 times then repeat for next concentration.

Question 6

Possible evaluation issues (4)

Answer 6

• Maintaining constant temperature
• Accurately making up the different concentrations
• Identifying end point consistently
• Difficult to see the cross through the solution