Mark Scheme (Results)

Summer 2023

Pearson Edexcel International GCSE

In Biology (4BI1) Paper 1BR
Edexcel and BTEC Qualifications

Edexcel and BTEC qualifications are awarded by Pearson, the UK’s largest awarding body. We provide
a wide range of qualifications including academic, vocational, occupational and specific programmes
for employers. For further information visit our qualifications websites at www.edexcel.com or
www.btec.co.uk. Alternatively, you can get in touch with us using the details on our contact us page
at www.edexcel.com/contactus.

Pearson: helping people progress, everywhere

Pearson aspires to be the world’s leading learning company. Our aim is to help everyone progress in
their lives through education. We believe in every kind of learning, for all kinds of people, wherever
they are in the world. We’ve been involved in education for over 150 years, and by working across 70
countries, in 100 languages, we have built an international reputation for our commitment to high
standards and raising achievement through innovation in education. Find out more about how we
can help you and your students at: www.pearson.com/uk

Summer 2023
Question Paper Log Number P72582A
Publications Code 4BI1_1BR_2306_MS
All the material in this publication is copyright
© Pearson Education Ltd 2023
General Marking Guidance

• All candidates must receive the same treatment. Examiners must

mark the first candidate in exactly the same way as they mark the
last.
• Mark schemes should be applied positively. Candidates must be
rewarded for what they have shown they can do rather than
penalised for omissions.
• Examiners should mark according to the mark scheme not
according to their perception of where the grade boundaries may
lie.
• There is no ceiling on achievement. All marks on the mark scheme
should be used appropriately.
• All the marks on the mark scheme are designed to be awarded.
Examiners should always award full marks if deserved, i.e. if the
answer matches the mark scheme. Examiners should also be
prepared to award zero marks if the candidate’s response is not
worthy of credit according to the mark scheme.
• Where some judgement is required, mark schemes will provide the
principles by which marks will be awarded and exemplification may
be limited.
• When examiners are in doubt regarding the application of the mark
scheme to a candidate’s response, the team leader must be
consulted.
• Crossed out work should be marked UNLESS the candidate has
replaced it with an alternative response.
Question Answer Mark
Number
1(a)(i) The only correct answer is B (protein synthesis)
1
A is incorrect as chloroplasts perform photosynthesis

C is incorrect as mitochondria perform respiration

D is incorrect as vacuoles store cell sap

Question Answer Mark

Number
1(a)(ii) The only correct answer is B
1
A is incorrect as animal cells do not have cell walls

C is incorrect as eukaryotic cells have cytoplasm

D is incorrect as animal cells do not have cell walls

Question Answer Additional Mark

Number Guidance
1(a)(iii) An explanation that makes reference to
three of the following. 3

• Lactobacillus / they, have cell walls / Ignore refs to

water not entering
red blood cells do not have a cell wall Lactobacillus

/ eq (1)

• water enters (cells) / eq (1)

• by osmosis (1)

• (because) water potential inside the Allow from a high

concentration (of
cells is low(er) / eq (1) water) to a low
concentration (of
water) / from a
dilute to a
concentrated
solution / eq
Question Answer Mark
Number
1(b) A description that makes reference to three of
the following. 3

• respiration / fermentation / ferment (1) Ignore aerobic /

anaerobic
• lactose (1)

• lactic acid / lactate, produced (1) Allow milk

becomes acid(ic)
/ low pH occurs

• (protein) clots / milk thickens / milk Allow protein

coagulates / goes solid / eq (1) denatures

(Total for Question 1 = 8 marks)

Question Answer Mark

Number
2 (a) A description that makes reference to two of the following.
2
• peristalsis (1)

• muscle contraction (1)

• along oesophagus (1)

Question Answer Mark

Number
2 (b)(i) An answer that makes reference to one of
the following. 1

• fibre (1)

• water (1)

• other named vitamin / mineral (1) e.g. vitamin A / iron

Ignore vitamin C
and calcium
Question Answer Mark
Number
2(b)(ii) An answer that makes reference to the
following. 2

• (vitamin C) scurvy / skin does not Allow vitamin C needed

heal / blood vessels are weak / for healthy skin /
cartilage is weak / wounds do not cartilage / connective
heal / eq (1) tissue / eq

• (calcium) rickets / weak bones / Allow calcium needed

osteoporosis / eq (1) for strong teeth / bones
/ eq

Question Answer Mark

Number
2(b)(iii)
2
• RDA = 230 (g) (2) One mark for 227.2727 OR
227 OR 2.3 OR other
answer to correct decimal
places with correct rounding

Question Answer Additional guidance Mark

Number
2(b)(iv) A description that makes reference to three
of the following. 3

• protease / peptidase (1)

• pepsin (in stomach) (1) Allow trypsin (in

duodenum / from
pancreas)

• (digestion) in small intestine / duodenum Ignore absorbed in

/ stomach / (protease) released by small intestine
pancreas / stomach (1)

• (produces) amino acids / (di)peptides (1)

(Total for Question 2 = 10 marks)

Question Answer Mark
Number
3(a)(i) The only correct answer is C (3)
1
A is incorrect as there are more than 1 secondary consumers

B is incorrect as there are more than 2 secondary consumers

D is incorrect as there are fewer than 4 secondary consumers

Question Answer Mark

Number
3 (a)(ii) The only correct answer is B (ecosystem) 1

A is incorrect as the community does not include the

environment

C is incorrect as the habitat does not include the organisms

D is incorrect as population is the number of one species

Question Answer Additional guidance Mark
Number
3 (a)(iii) An explanation that makes reference to
three of the following. 3

• shorter food chain to oak tree / Allow converse for grass

one species between fox and oak Allow fox is a secondary
tree / eq (1) consumer from oak tree /
tertiary consumer from
grass / eq
Allow fewer / 3, levels in
oak tree food chain / eq
Allow only rabbit /
squirrel between tree and
fox / eq

AND two from

(energy lost from)

• excretion / urine / eq (1) Do not award two

marks for excrete faeces
• inedible parts / parts not eaten / eq
(1)

• indigestible parts / faeces /

egestion / eq (1)

• death / decomposition / decay /

some organisms not eaten / eq (1)

• respiration / heat loss / eq (1)

• movement /eq (1)

Question Answer Mark
Number
3 (b)(i) An answer that makes reference to the
following. 1

• avoid bias / make sample Allow fair test /

representative / more accurate valid
(result) / makes (survey) fair / eq (1) Ignore reliable

Question Answer Additional guidance Mark

Number
3 An explanation that makes reference to
(b)(ii) two of the following. 2

• grid area / eq (1)

• repeats / more quadrats / eq (1) Ignore larger quadrat

• identify anomalies / calculate

mean / average / to see if they are

similar / eq (1)

Question Answer Additional guidance Mark

Number
3 (b)(iii) Correct answer
• 2925 (3) gains all three 3
marks

two marks for 4500

If answer incorrect
then up to max 2 of:

one mark for 4000 or

50 x 80

one mark for 500 or

(20 x 50) / 2

one mark for 0.65 x

OR 65/100 x

(Total for Question 3 = 11 marks)

Question Answer Mark
Number
4 (a)(i) The only correct answer is B (chitin)
1
A is incorrect as fungal cell walls do not contain cellulose

C is incorrect as fungal cell walls do not contain glycogen

D is incorrect as fungal cell walls do not contain starch

Question Answer Mark

Number
4 (a)(ii) The only correct answer is A (ethanol and carbon dioxide)
1
B is incorrect as yeast anaerobic respiration also produces
carbon dioxide

C is incorrect as yeast anaerobic respiration does not produce

lactic acid

D is incorrect as yeast anaerobic respiration does not produce

lactic acid

Question Answer Additional guidance Mark

Number
4 (b)(i) An answer that makes reference to the
following. 1

• stops oxygen getting in / prevents Ignore ensures

aerobic respiration / eq (1) anaerobic respiration

Question Answer Mark

Number
4 (b)(ii) A description that makes reference to the following.
2
• water bath (1)

• (monitor with) thermometer / (use of) thermostat

/ eq (1)
Question Answer Additional guidance Mark
Number
4 (b)(iii)
• 4 (2) 2
one mark for 32 OR ÷ 8

Correct answer gains both marks

Question Answer Mark

Number
4 (b)(iv) An explanation that makes reference to
two of the following. 2

• increases up to 16 (min) / 17 Allow times between

16 and 18 for turning
(min) / 18 (min) and then levels point
Allow constant rate (or
off / slows / (bubble production) respiration) until 16 /18
then (respiration) stops
stops / eq / levels off / slows

• (when bubbles increase / initially) Allow glucose is not

limiting when bubbles
glucose is not limiting / eq (1) are increasing

• (levels off because) glucose runs

Allow substrate for
out / is limiting / yeast is poisoned glucose throughout

by ethanol / eq (1)
Question Answer Mark
Number
4 (b)(v) An explanation that makes reference to 3
three of the following.

• faster / more, respiration (1) Allow 370C / it, is

(closer to) optimum

• (at 37 oC) more (kinetic) energy /

faster (particle) movement /eq (1)

• more / faster, collisions / more E/S

complexes / eq (1)

• at 37oC glucose runs out (sooner) /

glucose starts to limit / eq (1)

Question Answer Mark

Number
4 (b)(vi) A description that makes reference to the following.
2
• collect volume (of gas) (1)

• using a measuring cylinder / syringe / burette / eq (1)

(Total for Question 4 = 14 marks)

Question Answer Mark

Number
5 (a)(i) The only correct answer is C 1

A is incorrect as W is not the left atrium

B is incorrect as W is not a ventricle

D is incorrect as W is not a ventricle

Question Answer Mark
Number
5 (a)(ii) A description that makes reference to the
following. 2

• X / pulmonary artery, has lower Allow Y / aorta, has

higher oxygen / is
oxygen / is deoxygenated / eq (1) oxygenated

• X / pulmonary artery has higher Allow Y / aorta, has

lower carbon dioxide
carbon dioxide / eq (1)

Question Answer Additional guidance Mark

Number
5(b)(i)
• 89 (2) Allow any number of 2
correct decimal places
e.g. 89.0909, 89.1
Allow 90

One mark for 55

OR
One mark for 75, 75.4,
75.38 etc.

Correct answer gains

both marks
Question Answer Additional guidance Mark
Number
5 (b)(ii) An answer that makes reference to
the following. 5

S – linear scales for both axes and at time must be on x axis

least half grid (1)

L – ruled, straight lines (1)

A – both axes fully labelled (1) Minimum label: heart rate /

bpm and time / min

P – correct plots (1) Allow plots if non-linear

scales
K – key / eq (1) Plots +/- half square

Bar chart: S, A, P, K (max 4)

One data set plotted: S, L, A
Question Answer Mark
Number
5 (b)(iii) An explanation that makes reference to Allow converse for
four of the following. untrained 4

• (trained athlete) has lower heart rate /

heart rate returns to normal quicker /

eq (1)

• (trained athlete) has larger heart / Allow stronger heart

larger stroke volume / pumps more Allow untrained has

to pump faster to
blood / eq (1) move same amount
of blood / eq

• more / faster transport of, oxygen / Allow untrained has

to pump faster to
glucose pumped / more removal of move same amount
of oxygen / eq
carbon dioxide / heat / eq (1)

• (more) (aerobic) respiration / ATP

production / energy / eq (1)

• (more) muscle contraction (1)

• less anaerobic respiration / lactic acid

/ less oxygen debt / eq (1)

(Total for Question 5 = 14 marks)

Question Answer Mark
Number
6 (a) An answer that makes reference to the following.
2
6CO2 + 6H2O → C6H12O6 + 6O2 (2)

one mark if correct equation but incorrectly balanced

Question Answer Mark

Number
6(b)(i) An answer that makes reference to the
following. 1

• destarch the leaves / remove Allow so no starch

starch eq (1) present (in leaves) / so
starch is used up /
starch respired
Question Answer Mark
Number
6 An answer that makes reference to the
(b)(ii) following. 2

• both green areas shaded and area with Allow labelled

areas if not
no green with no shading / eq (1) shaded (black /
orange / starch /
• no shading in strip under paper / eq (1) no starch)

No mp2 if rest of
leaf is blank

2 marks

1 mark

1 mark

1 mark

0 marks
Question Answer Mark
Number
6 (c) An answer that makes reference to six of the
following. 6

• C – (plant ivy in) shaded and unshaded Allow different

light intensities /
area / different exposure to light / eq (1) distances of
lamp
• O – same species / type / age / starting

size of leaf / same plant / eq (1)

• R – repeat with multiple leaves / repeat / Allow groups

eq (1)

• M1 – measure length / width / height / Ignore size of

leaves
surface area / eq (of leaves) (1) Allow measure
size with a ruler
/ in mm / eq
Allow volume

• M2 – grow ivy for same stated time (1) Minimum time

of one day
• S1 - temperature / pests / humidity / plant

density / carbon dioxide / weather / time of

year / wind / eq (1)

• S2 – same water / minerals / soil /

nutrients / fertiliser / pH / eq (1)

(Total for Question 6 = 11 marks)

Question Answer Mark

Number
7 (a) (i) The only correct answer is A
1
B is incorrect as fertilisation does not occur in the ovary

C is incorrect as fertilisation does not occur in the uterus

D is incorrect as fertilisation does not occur in the vagina

Question Answer Mark
Number
7(a)(ii) A description that makes reference to the
following. 2

• (oestrogen) repairs / thickens lining / Allow builds up

thickens wall / eq (1) lining

• (progesterone) retains / maintains

Allow fall in
lining / vascularises endometrium / progesterone causes
prevents menstruation / eq (1) lining to shed /
causes menstruation
Allow increase
blood flow in lining

Question Answer Additional Mark

Number guidance
7(b)(i) A description that makes reference to the
following. 2

• fusion of nuclei / fusion of egg and

sperm / zygote (forms) / eq (1)

• mitosis / cell division / (to form an Reject meiosis

embryo) / eq (1)
 Answer Additional guidance Mark
Question
Number
7 (b) (ii) An answer that makes reference to five of the
following. Allow age 5
references for any
• number of (multiple births) has decreased / eq (1) ages of >=37 for
older women
• constant / steady /eq, decrease, (in multiple births)

until 2007 / 2008 / 2009 / before

recommendations / eq (1)

• (steep) decrease / since 2007 / 2008 / 2009 / since MP3 also gets MP1

recommendations / eq (1)

• (so) less risk to health / multiple births increase Allow

recommendations
health risks / eq (1) have made it safer
/ multiple births are
• (repeated IVF) is expensive / stressful / eq (1) dangerous

• IVF success rate / fertility decreases with age / eq Allow older women
have low(er)
(1) success rate /
young(er) women
have high success
rate

• (older women have lower success rate) so better to Allow restricting

number of embryos
use more than one embryo / eq (1) for younger women
has less effect on
success / eq

• no information on sample sizes / only one country / Allow cannot be

generalised / needs
only UK data / eq (1) to be researched in
other countries / eq
• reliable as data is for a long period of time / eq (1)

• (could be affected by) other health issues / diet / Allow no

information about
genetics / sperm / eq (1) health issues / eq

(Total for Question 7 = 10 marks)

Question Answer Mark
Number
8(a)(i) The only correct answer is C (Y)
1
A is incorrect as T is combustion

B is incorrect as X is consumption

D is incorrect as Z is death

Question Answer Mark

Number
8 (a)(ii) • photosynthesis (1) 1

Question Answer Additional guidance Mark

Number
8 (b) (i) • CFCs / water (vapour) / eq (1) Allow fluorinated gases 1
e.g. hydrofluorocarbons (HFC),
perfluorocarbons (PFC), sulphur
hexafluoride
Question Answer Additional Mark
Number guidance
8 (b)(ii) An answer that makes reference to five of the Allow traps / 5
following. absorbs heat
for GWP

• carbon dioxide (poses the greatest risk) (1) If just quoting

numbers, they
• carbon dioxide is released in high(est) amounts need to be
qualified e.g.
/ eq (1) ONLY 1 (GWP)

• carbon dioxide is produced by many human Allow cement /

vehicles /
activities / fossil fuel use / eq (1) deforestation / eq

• carbon dioxide stays for long(est) time / eq (1)

• carbon dioxide has low(est) global warming

potential / GWP / eq (1)

• methane has a high(er) GWP than carbon

dioxide / has middle GWP BUT low(er) amount /

second highest amount, released / more

released than nitrous oxide / eq (1)

• methane has a high(er) GWP than carbon

dioxide / has middle GWP BUT methane does

not last long / stays least time / eq (1)

• nitrous oxide has high(est) GWP BUT has

low(est) percentage released / eq (1)

• nitrous oxide has high(est) GWP BUT stays less Allow highest
GWP BUT stays
time than carbon dioxide / stays for a medium longer than
methane
amount of time / eq (1)

(Total for Question 8 = 8 marks)

Question Answer Mark
Number
9(a)(i) An answer that makes reference to the
following. 1

• (transfer of) genes / alleles / DNA Allow (organism) with

between different species (1) gene / allele / DNA from
different species

Ignore genetic
modification alone

Ignore organism

Question Answer Additional Mark

Number guidance
9 (a)(ii) An answer that makes reference to two of the
following. 2

• (herbicides) kills / removes, weeds but not crops Allow

(herbicide)
/ eq (1) only affects /
kills, weeds /
unwanted
plants
• less competition / eq (1)

• so increased yield / more (crop) growth / eq (1)

• no need to remove weeds by hand / eq (1)

Question Answer Additional guidance Mark
Number
9 (b) (i) 1
• RR, Rr, (rR) (1) Reject if rr included
Allow other letters but not two
different letters
Allow ‘homozygous dominant and
heterozygous’

Question Answer Mark

Number
9 (b)(ii) An answer that makes reference to the
following. 3

• parents as Rr and rr (1) Allow other letters

but not two different
• gametes as R or r and r (or r) (1) letters

• genotypes and stated phenotypes of Rr

and rr AND non-resistant and resistant (1)

ECF for one mark
only for gametes

Allow all marks from

Punnett square

Question Answer Additional guidance Mark

Number
9 (b)(iii) • 0.5 / ½ / 50 % (1) Allow 2/4
1
Question Answer Mark
Number
9 (b)(iv) An explanation that makes reference to four of
the following. 4

• mutation (produces resistance) / eq (1)

• (produces) variation (1)

• (weeds with gene) survive / eq (1) Allow converse

Allow correct
ref to selection
pressure /
selective
advantage

• reproduce / pollinate / eq (1)

• pass on the allele / gene / mutation / eq (1) Allow pass on

allele to next
generation for
mp4 and mp5
Question Answer Additional guidance Mark
Number
9 (b)(v) An explanation that makes reference to two
of the following. 2

• dominant alleles always expressed / Allow recessive

alleles are not
expressed in heterozygotes OR always shown (in
phenotype)
recessive alleles only expressed when

homozygous / not expressed in

heterozygotes / eq (1)

• if resistance is recessive, only Allow no plants

with dominant
homozygous (recessive) plants alleles survive

survive / no heterozygous plants

survive / eq (1)

• if resistance is dominant, Allow some plants

carrying recessive
heterozygous plants survive / eq (1) alleles will survive /
carriers survive

• (when resistance is dominant) if two Allow carriers for

heterozygotes
heterozygotes breed, non-resistant
Allow both parents
weeds produced / some homozygous can pass on a
recessive allele
recessive plants produced / eq (1)

(Total for Question 9 = 14 marks)

Question Answer Mark
Number
10 (a)(i) • iris (1)
1

Question Answer Mark

Number
10 (a)(ii) A description that makes reference to three
of the following. 3

• X / ciliary muscle, contracts (1)

• Y / suspensory ligaments go slack / Ignore relax

Ignore suspensory
loosen / eq (1) muscle

• lens becomes thicker / more spherical Allow fatter /

more rounded /
/ more convex / eq (1) bulges

• so (lens) refracts light more / bends

light more / eq (1)

Question Answer Mark

Number
10 (b)(i) A description that makes reference to two of
the following. 2

• less light can pass through / refraction Allow cannot

focus well / bend
affected / eq (1) light
Allow stops light
getting into eye

• to retina / fovea / rods / cones /

photoreceptors (1)

• so fewer impulses (to brain) (1)

Question Answer Mark
Number
10 (b)(ii) An answer that makes reference to four of the
following. 4

• numbers increase as exposure to sunlight Allow more sunlight

increases / eq (1) increases chance of
cataracts
Allow percentage of
cases increases

• groups sizes are different / eq (1) Allow number of

people vary / increase

• credit calculation of proportions / Sunlight Percentage

percentages (1) 7 2.0
8 1.9
9 2.0
10 1.6
11 3.2
12 6.5

• the proportion / percentage of cases Allow no / little effect

fluctuates / does not change (much) between 7 – 10 (hrs) /
between 7 and 10 (hrs) / eq (1) 10 (hrs) is lower than 7
/ 8 / 9 (hrs)

• proportion / percentage, rises after 10 Allow (proportion of)

(hrs) / 11 (hrs) / 12 (hrs) (1) cases only increases
after 10 / 11 (hrs)

• the large number of people makes it Allow reliable / valid as

reliable OR (less reliable as) only one it is a long survey /
country / no information on location / lasts 25 years
Allow other countries /
climate / eq (1)
regions should be
investigated

• age / sex / health status / genetics / diet / Allow other correct,

clothing / sunglasses / could affect the relevant factors
results / eq (1)

(Total for Question 10 = 10 marks)

Pearson Education Limited. Registered company number 872828
with its registered office at 80 Strand, London, WC2R 0RL, United Kingdom