Question bank1.2 What happens in cells (and what do cells need)?

1.2 What happens in cells (and what do cells need)?

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Question 23

A student investigates the effect of temperature on the activity of amylase.

She mixes amylase solution and starch solution in a water bath.
Every 30 seconds she tests a drop of the mixture with iodine solution.
She records the first time at which the iodine solution does not turn blue-black.

The Table shows her results.

Table

Temperature in $∘C^\circ\text{C}$	Time until starch is no longer present in $s\text{s}$
20	270
30	120
40	60
50	60
60	still blue-black after 600

The rate of reaction can be calculated using this equation:

$rate=1000time\text{rate} = \dfrac{1000}{\text{time}}$

Calculate the rate of reaction at $∘C30\ ^\circ\text{C}$ .

Give your answer to 2 significant figures.

[1]

The student concludes:

'The optimum temperature for amylase is $∘C40\ ^\circ\text{C}$ .'

Evaluate this conclusion.

[3]

Suggest two changes to the method that would allow the student to find the optimum temperature more precisely.

[2]

Explain why the iodine solution still turned blue-black after 600 seconds at $∘C60\ ^\circ\text{C}$ .

[2]

Question bank1.2 What happens in cells (and what do cells need)?

1.2 What happens in cells (and what do cells need)?

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49

Question 23

A student investigates the effect of temperature on the activity of amylase.

She mixes amylase solution and starch solution in a water bath.
Every 30 seconds she tests a drop of the mixture with iodine solution.
She records the first time at which the iodine solution does not turn blue-black.

The Table shows her results.

Table

Temperature in $∘C^\circ\text{C}$	Time until starch is no longer present in $s\text{s}$
20	270
30	120
40	60
50	60
60	still blue-black after 600

The rate of reaction can be calculated using this equation:

$rate=1000time\text{rate} = \dfrac{1000}{\text{time}}$

Calculate the rate of reaction at $∘C30\ ^\circ\text{C}$ .

Give your answer to 2 significant figures.

[1]

The student concludes:

'The optimum temperature for amylase is $∘C40\ ^\circ\text{C}$ .'

Evaluate this conclusion.

[3]

Suggest two changes to the method that would allow the student to find the optimum temperature more precisely.

[2]

Explain why the iodine solution still turned blue-black after 600 seconds at $∘C60\ ^\circ\text{C}$ .

[2]

1.2 What happens in cells (and what do cells need)?

Question 23

Markscheme

1.2 What happens in cells (and what do cells need)?

Question 23

Markscheme

1.2 What happens in cells (and what do cells need)?

Question 23

1.2 What happens in cells (and what do cells need)? Questions

1.2 What happens in cells (and what do cells need)?

Question 23

1.2 What happens in cells (and what do cells need)? Questions