1
Please write clearly in block capitals.
Centre Candidate
number number
Surname
Forename(s)
Candidate re
signatu
A-level
BIOLOGY
Paper 1
Time allowed: 2 hours
Materials For Examiner’s Use
For this paper you must have:
Questio Mark
a ruler with millimetre measurements
n
a scientific calculator.
1
Instructions 2
Use black ink or black ball-point pen. 3
Fill in the boxes at the top of this page. 4
Answer all questions. 5
You must answer the questions in the spaces provided. Do
not write outside the box around each page or on blank 6
pages. 7
If you need extra space for your answer(s), use the lined pages at 8
the end of this book. Write the question number against your
9
answer(s).
Show all your working. 10
Do all rough work in this book. Cross through any work you do TOTAL
not want to be marked.
Information
The marks for the questions are shown in brackets.
The maximum mark for this paper is 91.
*JUN217402101
*
,2
*JUN217402101
*
, 2
Do not write
outside the
Answer all questions in the spaces box
provided.
0 1 .1 Describe the induced-fit model of enzyme action and how an enzyme
acts as a catalyst.
[3 marks]
0 1 .2 Scientists investigated the action of the enzyme ATP synthase. They
made reaction mixtures each containing:
ATP synthase
buffer (to control pH)
substrates.
One of 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
reaction mixtures to produce ATP.
[1 mark]
Adenine
Adenosine
diphosphate
Glucose
Ribose
*02
IB/H/
* Jun21/7402/1
, 3
Do not write
outside the
0 1 .3 The scientists investigated the effect of concentration of inorganic box
phosphate (Pi) on ATP synthase activity.
After 2 minutes, they stopped each reaction and then measured the
concentration of ATP.
Figure 1 shows the scientists’ results.
Figure 1
Suggest and explain a procedure the scientists could have used to stop each
reaction.
[2 marks]
0 1 .4 Explain the change in ATP concentration with increasing inorganic
phosphate concentration.
[2 marks]
8
Turn over ►
*03
IB/H/
* Jun21/7402/1
Please write clearly in block capitals.
Centre Candidate
number number
Surname
Forename(s)
Candidate re
signatu
A-level
BIOLOGY
Paper 1
Time allowed: 2 hours
Materials For Examiner’s Use
For this paper you must have:
Questio Mark
a ruler with millimetre measurements
n
a scientific calculator.
1
Instructions 2
Use black ink or black ball-point pen. 3
Fill in the boxes at the top of this page. 4
Answer all questions. 5
You must answer the questions in the spaces provided. Do
not write outside the box around each page or on blank 6
pages. 7
If you need extra space for your answer(s), use the lined pages at 8
the end of this book. Write the question number against your
9
answer(s).
Show all your working. 10
Do all rough work in this book. Cross through any work you do TOTAL
not want to be marked.
Information
The marks for the questions are shown in brackets.
The maximum mark for this paper is 91.
*JUN217402101
*
,2
*JUN217402101
*
, 2
Do not write
outside the
Answer all questions in the spaces box
provided.
0 1 .1 Describe the induced-fit model of enzyme action and how an enzyme
acts as a catalyst.
[3 marks]
0 1 .2 Scientists investigated the action of the enzyme ATP synthase. They
made reaction mixtures each containing:
ATP synthase
buffer (to control pH)
substrates.
One of 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
reaction mixtures to produce ATP.
[1 mark]
Adenine
Adenosine
diphosphate
Glucose
Ribose
*02
IB/H/
* Jun21/7402/1
, 3
Do not write
outside the
0 1 .3 The scientists investigated the effect of concentration of inorganic box
phosphate (Pi) on ATP synthase activity.
After 2 minutes, they stopped each reaction and then measured the
concentration of ATP.
Figure 1 shows the scientists’ results.
Figure 1
Suggest and explain a procedure the scientists could have used to stop each
reaction.
[2 marks]
0 1 .4 Explain the change in ATP concentration with increasing inorganic
phosphate concentration.
[2 marks]
8
Turn over ►
*03
IB/H/
* Jun21/7402/1
