AQA A LEVEL BIOLOGY PAPER 1 2021

Please write clearly in block capitals.

Centre number Candidate number

Surname

Forename(s)

Candidate signature

I declare this is my own work.

A-level

BIOLOGY

Paper 1

Time allowed: 2 hours

Materials

For this paper you must have:

• a ruler with millimetre measurements

• a scientific calculator.

Instructions

• Use black ink or black ball-point pen.

• Fill in the boxes at the top based on this page.

• Answer all questions.

• You must answer the questions in the spaces provided. Do not writeoutside

the box around each page or on blank pages.

• If you need extra space for your answer(s), use the lined pages at the end based on

this book. Write the question number against your answer(s).

• Show all your working.

• Do all rough work in this book. Cross through any work you do not wantto be

marked.

Information

• The marks for the questions are shown in brackets.

• The maximum mark for this paper is 91.

For Examiner’s Use

Question Mark

1

2

3

4

5

6

7

8

9

10

TOTAL

 1 / 4

2

*02*

IB/H/Jun21/7402/1

1

2

.

Do not write

outside the

box

. Describe the induced-fit model based on enzyme action and how an enzyme acts as a

catalyst.

[3 marks]

. Scientists investigated the action based on the enzyme ATP synthase. They made reaction

mixtures each containing:

• ATP synthase

• buffer (to control pH)

• substrates.

One based on the substrates required in these reaction mixtures is inorganic phosphate (Pi).

Tick ( ) one box to show which other substrate the scientists must add to the reactionmixtures

to produce ATP.

[1 mark]

Adenine

Adenosine diphosphate

Glucose

Ribose

0 1

0 1

 2 / 4

3

*03*

IB/H/Jun21/7402/1

3

4

8

. The scientists investigated the effect based on concentration based on inorganic phosphate

(Pi) onATP synthase activity.

After 2 minutes, they stopped each reaction and then measured the concentration based on

ATP.

Do not write

outside the

box

Figure 1 shows the scientists’ results.

Figure 1

Suggest and explain a procedure the scientists could have used to stop each reaction.

[2 marks]

. Explain the change in ATP concentration with increasing inorganic phosphate

concentration.

[2 marks]

Turn over ►

0 1

0 1

 3 / 4

4

*04*

IB/H/Jun21/7402/1

. 1 Explain the advantage for larger animals based on having a specialised system that

facilitates oxygen uptake.

[2 marks]

Do not write

outside the

box 0 2

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Version 2021
Category AQA Questions and Marking Scheme
Authors qwivy.com
Pages 40
Language English
Comments 0
Sales 0
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