Please write clearly in block capitals.
Centre number Candidate number
M
Surname
Forename(s)
ED
Candidate signature
I declare this is my own work.
A-level
C
BIOLOGY
O
Paper 3
N
Wednesday 21 June 2023 Morning Time allowed: 2 hours
N
Materials
For this paper you must have: For Examiner’s Use
O
• a ruler with millimetre measurements
Question Mark
• a scientific calculator.
1
Instructions
IS
2
• Use black ink or black ball-point pen. 3
• Fill in the boxes at the top of this page.
4
• Answer all questions in Section A.
SE
• Answer one question from Section B. 5
• You must answer the questions in the spaces provided. Do not write 6
outside the box around each page or on blank pages.
7
• If you need extra space for your answer(s), use the lined pages at the end of
this book. Write the question number against your answer(s). TOTAL
• Show all your working.
U
• Do all rough work in this book. Cross through any work you do not want
to be marked.
R
Information
• The marks for the questions are shown in brackets.
• The maximum mark for this paper is 78.
*jun237402301*
IB/M/Jun23/E12 7402/3
, 2
Do not write
outside the
Section A box
Answer all questions in this section.
You are advised to spend no more than 1 hour and 15 minutes on this section.
0 1 . 1 Describe how stimulation of a Pacinian corpuscle produces a generator potential.
M
[3 marks]
ED
C
O
N
N
Scientists investigated the stimulation of a Pacinian corpuscle in the skin of a fingertip.
The scientists applied two different pressures to the fingertip and recorded the
O
changes in membrane potential of the Pacinian corpuscle’s sensory neurone.
Figure 1 shows the scientists’ results.
IS
Figure 1
SE
U
R
*02*
IB/M/Jun23/7402/3
, 3
Do not write
outside the
0 1 . 2 Use Figure 1 to describe what is meant by the all-or-nothing principle. box
[2 marks]
M
ED
0 1 . 3 On Figure 1, from 0.6 ms to 4.0 ms, no new generator potential could be produced.
What is this time period called?
C
[1 mark]
6
O
N
Turn over for the next question
N
O
IS
SE
U
R
Turn over ►
*03*
IB/M/Jun23/7402/3
, 4
Do not write
outside the
0 2 A student investigated the effect of different sugars on the rate of respiration in yeast. box
Yeast normally respires glucose.
Figure 2 shows the method she used for her first experiment.
Figure 2
M
ED
C
0 2 . 1 Other than those stated, suggest two variables the student needed to keep constant
in her investigation.
O
[1 mark]
1
N
2
N
O
IS
SE
U
R
*04*
IB/M/Jun23/7402/3
Centre number Candidate number
M
Surname
Forename(s)
ED
Candidate signature
I declare this is my own work.
A-level
C
BIOLOGY
O
Paper 3
N
Wednesday 21 June 2023 Morning Time allowed: 2 hours
N
Materials
For this paper you must have: For Examiner’s Use
O
• a ruler with millimetre measurements
Question Mark
• a scientific calculator.
1
Instructions
IS
2
• Use black ink or black ball-point pen. 3
• Fill in the boxes at the top of this page.
4
• Answer all questions in Section A.
SE
• Answer one question from Section B. 5
• You must answer the questions in the spaces provided. Do not write 6
outside the box around each page or on blank pages.
7
• If you need extra space for your answer(s), use the lined pages at the end of
this book. Write the question number against your answer(s). TOTAL
• Show all your working.
U
• Do all rough work in this book. Cross through any work you do not want
to be marked.
R
Information
• The marks for the questions are shown in brackets.
• The maximum mark for this paper is 78.
*jun237402301*
IB/M/Jun23/E12 7402/3
, 2
Do not write
outside the
Section A box
Answer all questions in this section.
You are advised to spend no more than 1 hour and 15 minutes on this section.
0 1 . 1 Describe how stimulation of a Pacinian corpuscle produces a generator potential.
M
[3 marks]
ED
C
O
N
N
Scientists investigated the stimulation of a Pacinian corpuscle in the skin of a fingertip.
The scientists applied two different pressures to the fingertip and recorded the
O
changes in membrane potential of the Pacinian corpuscle’s sensory neurone.
Figure 1 shows the scientists’ results.
IS
Figure 1
SE
U
R
*02*
IB/M/Jun23/7402/3
, 3
Do not write
outside the
0 1 . 2 Use Figure 1 to describe what is meant by the all-or-nothing principle. box
[2 marks]
M
ED
0 1 . 3 On Figure 1, from 0.6 ms to 4.0 ms, no new generator potential could be produced.
What is this time period called?
C
[1 mark]
6
O
N
Turn over for the next question
N
O
IS
SE
U
R
Turn over ►
*03*
IB/M/Jun23/7402/3
, 4
Do not write
outside the
0 2 A student investigated the effect of different sugars on the rate of respiration in yeast. box
Yeast normally respires glucose.
Figure 2 shows the method she used for her first experiment.
Figure 2
M
ED
C
0 2 . 1 Other than those stated, suggest two variables the student needed to keep constant
in her investigation.
O
[1 mark]
1
N
2
N
O
IS
SE
U
R
*04*
IB/M/Jun23/7402/3
