Biology 0610/43 May/June 2025: question paper and mark scheme
Cambridge IGCSE Biology (0610), Paper 4 Theory (Extended), May/June 2025. Read both free below, or download them. Done the paper? Get it marked by AI against this mark scheme.
(a) Fig. 1.1 is a diagram of the human digestive system.
A
M
B
L
C
K D
J
H
E
F
G
Fig. 1.1
Table 1.1 shows information about some of the structures shown in Fig. 1.1.
Complete Table 1.1, using Fig. 1.1.
Table 1.1
letter in name of the structure function
Fig. 1.1
G
produces amylase
gall bladder
transports food to the stomach
[4]
(b) (i) Describe the role of chemical digestion.
…… [3]
(ii) Maltose is digested by maltase.
State the name of the product of this reaction.
…… [1]
(iii) Describe where maltose is digested in the small intestine.
…… [1]
(iv) Explain why amylase digests starch in the small intestine but does not digest starch in the stomach.
…… [6]
[Total: 15]
Mark scheme
1(a) 4 one mark per correct row
name of structure function letter in Fig. 1.1
egestion / removal
anus of, undigested G
food / faeces
salivary glands
produce amylase M/D
/ pancreas
gall bladder stores bile L
transports food to
oesophagus B
the stomach
;;;;
1(b)(i) (the breakdown) of large molecules into small molecules ; 3
idea of (only) small molecules can be absorbed ;
idea of insoluble (molecules) to soluble (molecules) ;
1(b)(ii) glucose ; 1
1(b)(iii) (the membranes of the) epithelium lining, epithelial cells (of, small intestine / 1
villi) ;
1(b)(iv) any six from: 6
1 stomach produces, gastric juice / hydrochloric acid / HCl ; MP1 A stomach contains gastric juice / HCl
2 acidic / low pH, in stomach ;
3 (acid) denatures, amylase / enzyme ;
4 changes shape of the active site ;
5 (active site) no longer complementary (shape) to, substrate / starch ;
6 cannot form enzyme-substrate complexes ;
7 bile is released into the, small intestine / duodenum ; MP7 A pancreatic juice instead of bile
8 bile is an alkaline mixture ;
9 neutralises the acidic mixture ;
10 idea of suitable pH for amylase to work in small intestine ;
(a) Alveoli are the gas exchange surface in humans.
State three features of alveoli that make them an effective gas exchange surface.
1 ……
2 ……
3 ……
[3]
(b) Fig. 2.1 is a diagram of the human breathing system.
cartilage
rib
P
Q
S
Fig. 2.1
(i) Three muscles involved in inspiration are labelled P, Q and S in Fig. 2.1.
Identify the letters in Fig. 2.1 that label the muscles which contract during inspiration.
…… [1]
(ii) State the function of cartilage in the breathing system.
…… [1]
(c) (i) State the balanced chemical equation for aerobic respiration.
…… [2]
(ii) During physical activity breathing changes.
Explain the mechanism that links the increase in physical activity to the changes in breathing.
…… [3]
[Total: 10]
Mark scheme
2(a) any three from: 3
large surface area ;
thin, (wall / surface,) / short diffusion distance / one cell thick ;
good blood supply / network of capillaries ;
good ventilation (with air) ;
2(b)(i) P and S ; 1
2(b)(ii) keeps the trachea / bronchi / airway open OR prevents collapse of trachea 1
/ bronchi / airway ;
2(c)(i) C6H12O6 + 6O2 → 6CO2 + 6H2O ;; 2 MP1 correct molecules
MP2 balancing of correct equation
2(c)(ii) any three from: 3
1 increased carbon dioxide in blood ;
2 (high) carbon dioxide (in blood) detected by the brain ;
3 increases impulses to (named) muscles used in breathing / AW ;
4 increases contraction of (named) muscles used in breathing ;
5 adrenaline is released ;
6 to increase rate and depth of breathing ;
(a) Complete the sentences about the control of blood glucose concentration.
Blood glucose concentration increases after a person eats a meal containing carbohydrates.
This causes the …… to release insulin. Insulin causes the
…… to remove glucose from the blood and convert it into
…… .
The control of blood glucose concentration is an example of …… .
[4]
(b) Outline the treatment of type 1 diabetes.
…… [2]
(c) A scientist investigated the effect of an injection of glucose solution on blood glucose concentration in healthy people. The injection was given at 0 minutes.
Fig. 3.1 shows the results.
300
250
200
blood glucose 150 concentration
/ mg per 100 cm3
100
50
0
0 10 20 30 40 50 60 70 time after the injection / minutes
Fig. 3.1
Calculate the percentage change in the blood glucose concentration from 5 minutes after the injection to 30 minutes after the injection.
Give your answer to two significant figures.
Space for working.
…… % [3]
(d) Adrenaline also affects blood glucose concentration.
Suggest how this is an advantage for the “fight or flight” response.
……[3]
[Total: 12]
Mark scheme
3(a) pancreas ; 4
liver ;
glycogen ;
negative feedback / homeostasis ;
3(b) any two from: 2
1 monitoring blood glucose ;
2 insulin, injections / pump ;
3 artificial pancreas ;
4 counting carbohydrates (in diet) ;
5 matching, food / carbohydrate, intake to activity ;
6 keeping a healthy weight ;
7 pancreas / islet cell, transplant ;
8 AVP ; e.g. consuming, sugar / glucose, if blood,
glucose is low / AW
3(c) (–)43(%) ;;; 3 MP1 correct readings from graph
210 and 120 mg per 100 cm3
MP2 correct calculation to any number of
significant figures e.g. (–)42.857(%)
MP3 correct rounding to two significant
figures
ecf from previous step
3(d) any three from: 3
1 (adrenaline) causes the, breakdown / conversion, of, glycogen / stored
carbohydrate ;
2 increasing (blood) glucose concentration ;
3 glucose used in respiration releasing energy ;
4 energy used for muscle contraction ;
5 AVP ; e.g. increased glucose uptake by cells
Fig. 4.1 is a photograph of a water lily, Nymphaea alba, in a lake.
Fig. 4.1
Fig. 4.2 is a photomicrograph of a cross-section of part of a water lily leaf.
A
B
D
C
Fig. 4.2
(a) (i) Identify tissue B and tissue C labelled in Fig. 4.2.
B ……
C ……
[2]
(ii) Describe two functions in water lilies of the area labelled D in Fig. 4.2.
1 ……
2 ……
[2]
(iii) A green pigment is found in tissue B in Fig. 4.2.
Describe the function of this pigment.
…… [2]
(iv) Water lilies have a very thin cuticle compared to a plant growing on land.
Explain how this is an adaptation for water lilies.
…… [2]
(b) Table 4.1 shows the stomatal density and habitat of two different hydrophytes.
Table 4.1
stomatal density on stomatal density on type of plant habitat upper leaf surface lower leaf surface
/ stomata per mm2 / stomata per mm2 pondweed under the water 0 0 water lily leaves on the
573 0
surface of the water
(i) Convert the stomatal density of the upper leaf surface of the water lily to stomata per cm2.
…… stomata per cm2 [1]
(ii) Using the data in Table 4.1, explain the stomatal density found in the two different hydrophytes.
…… [4]
(c) Fig. 4.3 is a photograph of rice, Oryza sativa, a monocotyledonous crop plant grown in flooded fields in waterlogged soils.
Fig. 4.3
(i) Identify a characteristic visible in Fig. 4.3 that can be used to classify rice as a monocotyledonous plant.
…… [1]
(ii) Waterlogged soil contains very low concentrations of oxygen.
Suggest how this limits the amount of proteins a plant can make.
…… [3]
[Total: 17]
Mark scheme
4(a)(i) B – palisade mesophyll ; 2
C – (lower) epidermis ;
4(a)(ii) any two from: 2
diffusion of (named) gases for photosynthesis / respiration ;
diffusion of water vapour for transpiration ;
idea of buoyancy / to make the leaf float (to get more light) ;
4(a)(iii) any two from: 2
traps light energy ;
transfers energy from light into energy in chemicals ;
(energy) for the synthesis of (named) carbohydrates ;
4(a)(iv) any two from: 2
1 water lilies do not need to prevent water loss ;
2 carbon dioxide uptake is less restricted / AW ;
3 use less resources to produce a cuticle ;
4 allows more light to penetrate ;
5 to the palisade (mesophyll) layer ;
6 AVP ; e.g. leaf does not need to be rigid / AW
4(b)(i) 57 300 (stomata per cm2) ; 1
4(b)(ii) any four from: 4
1 pondweed is submerged in water so no need for stomata to let air into a
leaf ;
2 oxygen and carbon dioxide can diffuse into, leaf / cells, from water ;
3 water lily has stomata only on upper surface ;
4 because lower surface is, on the surface of the water / under the water ;
5 constant water supply to water lily / no risk of wilting ;
4(c)(i) any one from: 1
1 thin / strap-shaped, leaves ;
2 parallel veins ;
4(c)(ii) any three from: 3
1 reduced aerobic respiration can occur ;
2 less energy released for active transport ;
3 less nitrate ions absorbed ;
4 less amino acids (to make protein) ;
5 less energy released for protein synthesis ;
6 more denitrifying (bacteria) ;
7 less nitrogen fixing (bacteria) ;
8 fewer nitrate ions in the soil ;
Penicillin is an antibiotic.
(a) (i) State the type of organism that antibiotics are used to kill.
…… [1]
(ii) It is important to try and limit the development of antibiotic resistance.
Describe ways of limiting the development of antibiotic resistance.
…… [2]
(b) Penicillin is produced by an organism called Penicillium chrysogenum.
Fig. 5.1 is a diagram of Penicillium chrysogenum.
spore
cell wall made of chitin
hypha
Fig. 5.1
(i) State what Penicillium in the scientific name of Penicillium chrysogenum represents in the binomial system.
…… [1]
(ii) Using the information in Fig. 5.1, identify the kingdom that contains
Penicillium chrysogenum.
…… [1]
(c) Penicillin can be made in a fermenter.
(i) State the name of one other product made in a fermenter.
…… [1]
Fig. 5.2 shows a fermenter.
Penicillium, amino acids and carbohydrates
water
thermometer
gas X
water stirrer
Fig. 5.2
(ii) Gas X in Fig. 5.2 is needed for the production of penicillin.
State the name of gas X.
…… [1]
(iii) The concentration of gas X is one of the conditions that must be controlled to ensure that penicillin is produced.
State the other conditions required to produce penicillin and describe how they are controlled in the fermenter.
…… [5]
(d) State the name of the organism that is used in bread-making and in biofuel production.
…… [1]
[Total: 13]
Mark scheme
5(a)(i) bacteria / prokaryote(s) ; 1
5(a)(ii) any two from: 2
only use for bacterial infections / when essential / when necessary ;
use appropriate antibiotic ;
AVP ; e.g. complete the course / shorter course /
reduce use in livestock / take the full dose /
do not share antibiotic
5(b)(i) genus ; 1
5(b)(ii) fungus / fungi ; 1
5(c)(i) insulin / mycoprotein / ethanol / (named) alcohol / carbon dioxide / amino acids / 1
hormones / proteins / factor VIII / AVP ;
5(c)(ii) oxygen ; 1
5(c)(iii) any five from: 5
1 monitoring ;
2 temperature ;
3 water jacket / described / water bath ;
4 pH ;
5 carbon dioxide might reduce pH ;
6 buffer / described ;
7 keep, pH / temperature, at suitable value for enzyme activity ;
8 (named) nutrient supply ;
9 carbon dioxide / waste products, removal ;
10 stirrer to equally (distributed), temperature / pH / nutrient concentration /
oxygen concentration / microorganisms ;
11 idea of regulating (gas) pressure ;
12 vent or exhaust ;
13 sealed to prevent contamination / AW ;
5(d) yeast ; 1
In Fig. 6.1, the diagrams of an island show the land covered by forest in 1982 and 2013.
Key land covered by forest
1982
2013
Fig. 6.1
(a) (i) Describe the change in land covered by forest between 1982 and 2013 in Fig. 6.1.
…… [2]
(ii) State two possible causes for the change in land covered by forest in Fig. 6.1.
1 ……
2 ……
[2]
(b) Fig. 6.2 is a diagram of the carbon cycle.
carbon dioxide in the atmosphere
T U
V
plants animals decomposers
fossil fuels
Fig. 6.2
State the names of the processes labelled T, U and V in Fig. 6.2.
T ……
U ……
V ……
[3]
(c) Deforestation is linked to an increase in global temperatures.
(i) Explain how deforestation can contribute to an increase in global temperatures.
…… [3]
(ii) Describe other undesirable effects of deforestation.
…… [3]
[Total: 13]
Mark scheme
6(a)(i) any two from: 2
less (land) covered by forest ;
more fragmented forest ;
less forest around the coast / AW ;
6(a)(ii) any two from: 2
1 housing / AW ; MP1 A urbanisation / industrialisation
2 agriculture / AW ;
3 (logging), for timber / fuel / paper ;
4 extraction of natural resources ;
5 wildfires ;
6 climate change ; MP6 A global warming A drought
7 disease / invasive species ;
6(b) T photosynthesis ; 3
U (aerobic) respiration ;
V combustion ;
6(c)(i) any three from: 3
1 decrease in photosynthesis leads to less carbon dioxide removed from
atmosphere ;
2 increase in decomposition of felled trees leads to more carbon dioxide
added to the atmosphere ;
3 increase in combustion of felled trees leads to more carbon dioxide
added to the atmosphere ;
4 carbon dioxide traps, infrared / long wavelength, radiation (from the
ground) ;
5 increase / enhanced, greenhouse effect ;
6(c)(ii) any three from: 3
1 loss of habitat ;
2 extinction of species ;
3 reducing biodiversity ;
4 disrupt cycling of nutrients ;
5 disrupt, energy flow / food web / food chain ;
6 loss of possible, fuels / crop plants / drugs / genes ;
7 soil erosion / infertile land ;
8 (more run off) flooding ;
9 (fewer trees means) less transpiration / less water vapour in the
atmosphere ;
10 so less rainfall / droughts / desertification ;
11 AVP ; e.g. loss of, tourism / areas of natural
beauty
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Biology 0610/43 for May/June 2025 is out of 80 marks, with 1 hour 15 minutes to answer it, across 6 questions.
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