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A-Level Biology
AQA
Paper 3
Predicted Paper 2023
Name ……………………………………………………………………
Date …………………

2 hours allowed
...

Answer all questions in section A
...


Question
Grade boundaries
These are VERY rough guesses! Getting a
B on this paper does not guarantee you the
same mark in the exam
...


01
The Hawaiian Islands have the most diverse collection of Drosophilid flies
in the world with approximately 800 different species having been
identified
...
It is
hypothesised that this could have been a single fertilised female blown
across in a storm or trapped in a piece of fruit stuck to a bird
...

[6 marks]

c) Drosophila are one group of insects which contain polytene
chromosomes
...
They can be removed and stained so
their banding patterns can be viewed under a light microscope
...

[2 marks]

d) About 100 species of the Hawaiian Drosophila have large, highly
patterned wings and are known as the picture-wing Drosophila
...
g D
...

Suggest how the variety of wing patterns displayed by these flies
helps to maintain them as separate species
...
Nitrogenase enzymes can be inhibited by high
oxygen concentrations
...

a) Explain how each of the following adaptations allow cyanobacteria to
carry out both processes:
i
...


Some colonies of cyanobacteria develop heterocysts;
specialised cells which only contain photosystem I
...

[2 marks]

Some plants make associations with nitrogen fixing bacteria in specialised
structures known as root nodules
...
This is a type of
haemoglobin that is very similar to animal haemoglobin, it also binds to
oxygen
...
They observed
that these plants exhibited less than normal growth
...

Suggest why
...

Suggest why adding leghaemoglobin makes the burgers taste more
like ones containing meat
...
Scientists initially tested this drug on mice
that had visible cancerous tumours in their lungs
...

[2 marks]

b) The scientists concluded that Taxol did not kill cancer cells
...

[2 marks]

c) Taxol works by disrupting spindle activity
...

[3 marks]

d) A more targeted drug needs to be developed
...
TACC3
then binds to microtubules which hold spindle fibres together
...

Suggest how scientists could develop a cancer drug which targets
Aurora A
...
The RT-PCR uses the same reaction mixture as standard
PCR except that reverse transcriptase enzymes and a fluorescent dye
that binds to DNA are included
...

[2 marks]

b) Explain the role of the reverse transcriptase in the RT-PCR
...
A test is
considered positive when the fluorescent signal reaches a certain threshold
...

RT-PCR was used to test if patients were positive for the SARS-CoV-2 virus
...

[2 marks]

d) How many cDNA molecules will have been produced from one
molecule of DNA at the threshold value of this sample?
Your answer should be in standard form
...
In order to confirm if the RTPCR was detecting RNA from the active SARS-CoV-2 virus, the lab would
also carry out a viral culture test on the same sample
...


e) Suggest why penicillin and streptomycin were added to the cell
culture
...

When viewed under the microscope suggest what visible effect viral
infection would have had on the cells
...
The vessels can become
weakened, and they can leak causing bleeding into the space just
under the retina
...


a) Explain why visual acuity is affected if bleeding occurs near the fovea
...
An
area in the centre of the fovea called the foveola has a diameter of
300 µm and contains no rod cells
...
7 million
rod cells in the fovea
...

The area of a circle is πr2
...
14 in your calculation
...

[2 marks]

c) One treatment for retinopathy is to inject medication directly into the
eye
...
The eyedrops contain a synthetic form of atropine
which is a toxin extracted from plants
...

i
...

What branch of the automatic nervous system is inhibited by
the eyedrops?
[1 mark]

ii
...

[2 marks]

Many eye diseases that cause blindness, including diabetic retinopathy, are
due to the over-production of a protein called vascular endothelial growth
factor (VEGF)
...

But overproduction of VEGF can be triggered in tissues that are not
receiving enough oxygen
...


d) One method of treatment is to inject anti-VEGF drugs
...

Use your knowledge of monoclonal antibodies to suggest how these
drugs work
...

Scientists recently conducted a randomised, blind clinical trial of all three
treatments
...


•
•
•
•
•

•

660 patients in total
...

Patients were grouped according to the extent of their vison loss
into high or medium category based on their visual acuity scores
...

Treatment occurred every 4 weeks with injections for a year and
then every 4-16 weeks during the second year depending on
recommended course of treatment for each drug
...


The following graphs show their results
...

[1 mark]

f) A student analysed the graphs and concluded that Eylea was the most
effective and should be used in the majority of retinopathy cases
...

[3 marks]

g) The average dose given in an injection is 2
...
In the UK a 100mg
vial of Avastin costs £242
...
A dose of the newest drug Eylea
costs £816 as it is an artificially made protein
...

[2 marks]

SECTION B
Choose one question to answer in this section
...

The importance of organisms being able to respond to their internal and
external environment
...

The importance of energy transfer within and between organisms
...
Geographic(al) isolation;
2
...
Variation due to mutation;
4
...
Different(ial) reproductive success/
selected organisms (survive and)
reproduce
6
...
Compare banding patterns on chromosomes
from different species of fly
2
...

1
...
Keeps gene pools separate/prevents
interbreeding

Additional Guidance

Marks
1
6

Accept: reproductive isolation

Accept: named abiotic / biotic conditions
Accept: pass on alleles / genes to next generation
as equivalent to reproduce

2

2

11

Question Answer
2ai

2aii

2b

2c
TOTAL

1
...
No oxygen produced to inhibit nitrogenase
enzyme
1
...
nitrogenase enzyme is not inhibited
1
...
nitrogenase inhibited so no nitrogen fixation
occurs
3
...
g chlorophyll for
growth
OR
Plants without external nitrogen source do not
grow as well because they cannot produce
amino acids/DNA/Named protein e
...
g
...
Yes because the mean volume of tumour in
mice treated with Taxol keeps increasing with
time but at a lower rate
2
...
Reference to mitosis
2
...
Cell division/ cell cycle slows down
1
...
Would compete with TACC3 for active site
OR would bind to and block active site of
Aurora A

Additional Guidance

Marks
2

2

Mitosis slows down = 2 marks
Mitosis stopped = 1 mark

3

Allow answer that talks about non-competitive
inhibition of Aurora A

2

9

Question Answer
4a

4b
4c

4d
4e

4f
TOTAL

Any two from:
DNA polymerase,
DNA nucleotides,
Primers,
Sample RNA/Test sample
Produces complementary (c)DNA using
(m)RNA
One suggestion with explanation
from:
1
...
so less / nothing to make
complementary chains;
1
...
so cannot start complementary
chains
1
...
so no polymerisation of
complementary strands;
Ct value = 30 (where line crosses threshold)
1x230 = 1,073,741,824 = 1
...
Higher proportion/Lots more cones in fovea
2
...
Fovea area (3
...
52 mm) - Foveola area
(3
...
15mm) = Area containing rods as
6
...
1,700,000/6
...
32mm-2
OR
2
...
prevents influx of Ca2+ ions (to start
contraction);
2
...
Antibody has specific tertiary structure /
binding site / variable region;
2
...
Prevents VEGF binding (to
receptors)/activating blood vessel growth

Marks
2

2

Allow 242857 if rounded area to 7mm2
1
2

3
Reject same shape as VEGF

5e
5f

5g

Because could affect the growth and
development of the foetus /named organ e
...
Error bars do not overlap at any point for
Eylea for high vision loss group over 2 years
2
...
Not better to be used in majority as
consistently more effective for high vision loss
only
100mg = 40 doses
...
05 per
dose
...
05x200 = 1210
...

((163200-1210)/1210)x100 = 13,388%
TOTAL

16

SECTION B: General Essay Mark Scheme Guide
Marks Description

Assessment Guidance

High
24-25

•

Extended
abstract

•
Generalised
Medium beyond specific
23
•
context
•
Low

•

21-22

•
•
•

High

Relational

•

19-20

Integrated into •
a whole
Medium
•
18

•

Low

•
•

16-17

High
14-15

Multistructural

Several
Medium aspects
13
covered but
they are
Low
unrelated
11-12

•
•
•
•
•

Whole essay flows/is interlinked with points all
contributing to the theme
Clear links between at least four different topics (these can
be different whole specification points, but do not all have
to be from different units)
...

Biology is detailed and comprehensive A-level content (not
GCSE level)
Essay uses appropriate terminology from the specification,
is very well written and always clearly explained
...

For 24+ marks in the band, the answer shows evidence of
wider reading by adding information that is relevant to the
question but not required by the specification
...

Essay links at least four topics to the main theme of the
question
Points are related to each other/linked and clearly
explained
...

Essay contains more than two suitable topics
Topics are not related to each other, and links are not
made to the theme of the question
...

Mostly clearly explained and generally uses appropriate
terminology from the specification
More than one significant error (fundamental incorrect
biological knowledge) and, or more than one irrelevant
topic
...

Biology presented shows some superficial A-level content
that may be poorly explained
Answer lacks detail or shows limited use of appropriate
terminology from the specification
May contain 2-3 significant errors (fundamental incorrect
biological knowledge) and, or irrelevant topics
...

Content and terminology are generally GCSE standard or
below
...


Nothing of relevance or no response
...
1
...


Transport in and out of cells (of specific substances)

I

3
...
6
...
2
...


Haemoglobin

Tr

3
...
7
...
2
...


Behaviour

A

3
...
10
...
4
...


Changes in populations − selection pressures

R

3
...
1
...
5
...


Taxes and kineses

Rc

3
...
1
...
5
...


Control of Heart Rate

Sn

3
...
1 and 2

Simple reflexes and neurones and synapses

Hr

3
...
2 and 5
...
5
...
5
...
5
...
5
...
5
...
5
...
5
...
3
...
2
...
3
...
5
...
1
...
6
...
6
...
6
...
1

Mark

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