Enzymes

Question 1

What is the independent variable of the enzyme practical?

Answer 1

the pH

Question 2

What is the dependent variable of the enzyme practical?

Answer 2

time to digest starch solution

Question 3

What are the control variables of the enzymes practical?

Answer 3

Volume, concentration and temperature of : Starch solution, amylase solution and pH buffer

Question 4

What is the expected result of the enzyme practical?

Answer 4

extremes of pH (higher or lower than the optimum) will increase the time taken, as the enzyme activity slows as the enzymes become denatured (active site changes shape)

Question 5

What are we investigating in the enzymes practical?

Answer 5

the effect of pH on the rate of reaction of amylase enzyme

Question 6

what is the shape of the graph named?

Answer 6

bell shape

Question 7

What should you do for a more precise result in the enzyme practical?

Answer 7

repeat the investigation using smaller intervals of pH - e.g. 6.2, 6.4, 6.6, 6.8 - near the optimum

Question 8

Where are the errors from and what are the errors in the enzyme practical?

Answer 8

from human judgement of the final colour so a colourimeter to measure the colour and get a quantative result

Question 9

What is an enzyme?

Answer 9

a biological catalyst, speeds up reactions in the body by lowering the activation energy

Question 10

Why might you need a waterbath?

Answer 10

to maintain the correct temperature , because temperature affects reaction rate

Question 11

if you test at pH 3, 4, 5, 6, 7, 8, 9 and 10 why don’t we know the exact optimum pH?

Answer 11

because although two answers may both show quick reactions (e.g. pH7 and pH8), the actual optimum could be between those numbers (e.g. pH7.6) so you need to test diferent pH’s to find out the exact optimum

Question 12

What are some sources of error and weakness?

Answer 12

measuring, starting and stopping timers