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
The benefits of buying summaries with Stuvia:
Guaranteed quality through customer reviews
Stuvia customers have reviewed more than 700,000 summaries. This how you know that you are buying the best documents.
Quick and easy check-out
You can quickly pay through credit card or Stuvia-credit for the summaries. There is no membership needed.
Focus on what matters
Your fellow students write the study notes themselves, which is why the documents are always reliable and up-to-date. This ensures you quickly get to the core!
Frequently asked questions
What do I get when I buy this document?
You get a PDF, available immediately after your purchase. The purchased document is accessible anytime, anywhere and indefinitely through your profile.
Satisfaction guarantee: how does it work?
Our satisfaction guarantee ensures that you always find a study document that suits you well. You fill out a form, and our customer service team takes care of the rest.
Who am I buying these notes from?
Stuvia is a marketplace, so you are not buying this document from us, but from seller MedConnoisseur. Stuvia facilitates payment to the seller.
Will I be stuck with a subscription?
No, you only buy these notes for $19.99. You're not tied to anything after your purchase.