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Biology 0610/43 October/November 2023: question paper and mark scheme

Cambridge IGCSE Biology (0610), Paper 4 Theory (Extended), October/November 2023. Read both free below, or download them. Done the paper? Get it marked by AI against this mark scheme.

0610_w23_qp_430610_w23_ms_430610/43/O/N/23

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Paper
Paper 4 Theory (Extended)
Total marks
80
Time
1 hour 15 minutes
Questions
6
Code on the paper
0610/43/O/N/23
0610_w23_ms_43.pdf

0610/43 mark scheme, question by question

Each question as it's printed, and the mark scheme's points for it, as text. Diagrams, tables and graphs are in the PDFs above.

Question 113 marks

Question

(a) Fig. 1.1 is a diagram of an insect‑pollinated flower. A B C G D E F Fig. 1.1 (i) Using the information in Fig. 1.1, complete Table 1.1. Table 1.1 structure in Fig. 1.1 name function A B F [3] (ii) State the names of the two structures that form the stamen in a flowering plant. 1 …… 2 …… [1] (b) (i) Describe the stages in the reproduction of a flowering plant, from self‑pollination to fertilisation. …… [5] (ii) Outline the advantages and disadvantages of self‑pollination compared with cross‑pollination. …… [4] [Total: 13]

Mark scheme

1(a)(i) 3 one mark per correct row structure in name function Fig. 1.1. A stigma trap / stick to / AW, pollen attracts, insects / pollinators OR protects B petal reproductive organs F sepal protect (flower) bud ;;; 1(a)(ii) filament and anther ; 1 either order 1(b)(i) any five from: 5 self-pollination occurs in the same, plant / flower ; pollen (grain) transferred from, anther / C, to, stigma / A (on same plant / flower) ; pollen grain grows into a pollen tube ; pollen / male, nucleus travels down the pollen tube ; (pollen) tube grows / pollen nucleus or male nucleus moves, through the, style / G / ovary ; pollen (tube / grain) releases enzymes ; pollen tube, grows / pollen nucleus or male nucleus moves, through the micropyle / (in)to the, ovule / E ; pollen / male, nucleus fuses with, female / ovule, nucleus ; correct description of haploid to diploid ; zygote is formed ; fertilisation / described, occurs in the, ovary / ovule / E ; AVP ; 1(b)(ii) any four from: 4 Assume answers are about self-pollination unless stated otherwise advantages of self-pollination ora throughout 1 more (chance of successful) pollination / fertilisation ; 2 less pollen wasted ; 3 less / no, need for, (named) pollinators / (named) pollinating agents ; 4 (pollination / fertilisation) can (still) occur in plants that become isolated MP4 A one, plant / parent, only needed (as occurs within same plant) ; 5 advantage to, farmers / plants, in maintaining (named) selected varieties / limiting variation (from one generation to the next) ; disadvantages of self-pollination 6 less, variation / (genetic) diversity ; 7 limited ability to, adapt / evolve, more slowly to (named) change in MP7 A fewer individuals likely to survive environment ; (named) changes in environment 8 more chance of, genetic / inherited, disease ; MP8 A ref. to inbreeding / increased risk of harmful recessive alleles being passed on 9 fewer individuals survive (new infectious) diseases ; 10 more competition between plants (as have similar adaptations) ; 11 AVP ;

Question 211 marks

Question

(a) Fig. 2.1 is a diagram of a cross‑section of part of a leaf. J K Fig. 2.1 Identify and explain how the structures labelled J and K are adapted for photosynthesis. J …… K …… [4] (b) In an experiment, thale cress plants (Arabidopsis thaliana) were grown in normal atmospheric and high carbon dioxide concentrations. The transpiration rate, the mean number of chloroplasts per cell and the concentrations of starch and magnesium ions were measured. The results are shown in Table 2.1. Table 2.1 normal carbon dioxide high carbon dioxide factor measured concentration concentration transpiration rate / AU 8.1 5.6 mean number of chloroplasts 8 11 per cell concentration of starch 38 67 / µg per mg of leaf concentration of magnesium ions 2.7 2.3 / mg per g of leaf Complete the sentences about the data shown in Table 2.1. Table 2.1 shows that increasing the carbon dioxide concentration caused more starch to be produced in the leaves. This shows that, at a normal carbon dioxide concentration, carbon dioxide is a …… for photosynthesis. During photosynthesis, …… molecules of carbon dioxide are required to make one molecule of glucose. The greater quantity of starch stored in the leaves grown in a high carbon dioxide concentration means, when needed, more sucrose can be produced for transport in the phloem, so the leaves act as a …… . The greater number of chloroplasts per cell in the leaves grown in the higher carbon dioxide concentration means that more energy can be absorbed from …… and transferred to …… energy. The transpiration rate is lower when the carbon dioxide concentration is higher. This means reduced loss of …… from the leaves. Magnesium ion concentration is lower in these leaves because they have used the magnesium ions to make …… . [7] [Total: 11]

Mark scheme

2(a) J – (upper) epidermis (cell) ; 4 (translucent / transparent / thin / flat / no chloroplasts) to allow passage of light, through / to palisade (cells) / leaf / AW ; K – xylem (vessel) ; continuous tube / no cytoplasm / no (named) cell contents / hollow / no end walls / no cross walls / pits, to allow transport of, water / mineral ions (to leaf) OR lignin, to prevent collapse of water column / support the leaf to maximise light absorption / AW ; 2(b) limiting factor ; 7 A reactant / substrate / raw material 6 / six ; source ; (sun)light ; chemical ; water vapour ; chlorophyll ;

Question 316 marks

Question

(a) (i) Complete Table 3.1 by writing in the percentages of carbon dioxide and oxygen in inspired air and in expired air. Table 3.1 component percentage in inspired air percentage in expired air carbon dioxide oxygen [2] (ii) A scientist measured the number of dust particles in inspired air and in expired air. They found fewer dust particles in expired air. Suggest a reason for their observation. …… [1] (b) Fig. 3.1 is a diagram of alveoli and associated blood vessels. alveoli bronchiole capillary Fig. 3.1 (i) Explain how the structure of a capillary is related to its function. …… [3] (ii) State the name of the component of blood that transports oxygen. …… [1] (iii) State the name of the blood vessel that transports blood from the heart towards the capillaries in the lungs. …… [1] (iv) State the location and function of cartilage in the breathing system. location …… function …… [2] (c) A student measured the rate and depth of breathing of an athlete for 30 seconds at rest. The data are shown in Fig. 3.2. 5 4 3 one volume of air breathed breath in and out / dm3 2 1 0 10 20 30 time / seconds Fig. 3.2 (i) Using the information in Fig. 3.2, calculate the rate of breathing at rest. …… breaths per minute [1] The measurements were repeated while the athlete was running on a treadmill. The data are shown in Fig. 3.3. 5 4 3 volume of air breathed in and out / dm3 2 1 0 10 20 30 time / seconds Fig. 3.3 (ii) Using the information in Fig. 3.3, calculate the volume of air inspired in one breath from 25 seconds. …… dm3 [1] (iii) Explain the effect of exercise on the rate and depth of breathing shown in Fig. 3.2 and Fig. 3.3. …… [4] [Total: 16]

Mark scheme

3(a)(i) 2 MP1 for 2 correct numbers percentage in percentage in MP2 for 4 correct numbers component inspired air expired air carbon 0.04 ; A 0.03–0.08 4 ; A 3–6 dioxide oxygen 21 ; A 19.5–23 16 ; A 13.5–18 3(a)(ii) any one from: 1 trapped in nose hairs ; trapped in mucus ; 3(b)(i) any three from: 3 allows delivery of named useful substances (to tissues) / removal of named waste ; thin (capillary) wall / wall is one cell thick ; small lumen / AW ; short diffusion distance / close contact ; slows down blood flow (to maximise time for diffusion) ; gaps between (capillary) cells ; AVP ; 3(b)(ii) red blood cells ; 1 3(b)(iii) pulmonary artery ; 1 3(b)(iv) 2 function must match location trachea ; A bronchus / bronchi / bronchioles / sternum / ribs / larynx / nose prevents airway collapse / keeps airway open / AW ; A allows, flexibility / movement A protects vocal cords / prevents food from entering the lungs 3(c)(i) 12 / 13 (breaths per minute) ; 1 A 13.3 or 10.9 3(c)(ii) 2.5–2.6 (dm3) ; 1 3(c)(iii) any four from: 4 1 more oxygen needed, for (aerobic) respiration / to release energy ; 2 (exercise uses) muscles (which need more energy) ; 3 ref. to muscle contraction ; 4 (exercise causes an) increased carbon dioxide concentration / lower pH, in the blood ; 5 (change in carbon dioxide / pH) detected by the brain ; 6 brain sends impulses to the, diaphragm / intercostal muscles (to stimulate, faster / larger, contractions) ; 7 to remove more carbon dioxide ; 8 ref. to adrenaline release (during exercise increasing breathing rate) ;

Question 413 marks

Question

(a) Complete the sentences about the control of body temperature. The human body maintains a constant internal temperature. This is an example of …… . When the temperature moves away from the set point, the mechanism of …… returns the temperature to the set point. [2] (b) Fig. 4.1 is a diagram of a section of human skin. J K O N L M Fig. 4.1 (i) State the names of the structures labelled L, O and J in Fig. 4.1. L …… O …… J …… [3] (ii) Describe how humans maintain a constant body temperature when the external temperature decreases. Use the structures labelled in Fig. 4.1 in your answer. …… [6] (c) Blood glucose concentration is maintained at a constant set point using the hormones glucagon and insulin. (i) State the organ that secretes glucagon. …… [1] (ii) Describe the effect of glucagon on the body. …… [1] [Total: 13]

Mark scheme

4(a) homeostasis ; 2 negative feedback ; 4(b)(i) L - sweat gland ; 3 O - receptor(s) ; J - (hair) erector muscle ; 4(b)(ii) any six from: 6 1 (temperature / thermo) receptor / sensory neurone / O, detects, stimulus / decrease (in temperature) / external temperature ; 2 (nerve) impulse sent along sensory neurone to, brain / hypothalamus ; 3 impulses from the brain, travel along motor neurone / cause response ; 4 (hair) erector muscles / J, contract OR hairs / K, stand up ; 5 (hairs) trap layer of air as insulation ; 6 fatty tissue / M, acts as insulation ; 7 (skeletal) muscles contract and relax fast / shivering, to release heat / gain warmth / keep warm ; 8 (constriction of) N / arteriole ; 9 ref. to (arterioles / blood vessels / vaso)constriction ; 10 (vasoconstriction) decreases blood flow to the surface ; 11 sweat gland / L, reduces / stops, production of sweat ; 12 (decreased blood flow / less sweat) decreases heat loss (from skin) ; 13 AVP ; e.g. described behavioural change 4(c)(i) pancreas ; 1 4(c)(ii) any one from: 1 (stimulates) the breakdown of glycogen (to glucose) ; increases (blood) glucose (concentration) ;

Question 515 marks

Question

(a) State two cell structures found in both animal and bacterial cells. 1 …… 2 …… [2] (b) State why bacteria are useful in biotechnology. …… [3] (c) Genetically modified bacteria were grown in a fermenter. The number of bacteria was measured, and the data are shown in Fig. 5.1. 11 10 9 8 7 6 number of bacteria / million cells per cm3 5 4 3 2 1 0 0 5 10 15 20 25 30 35 40 45 50 time / hours Fig. 5.1 (i) On Fig. 5.1, draw an X to identify the lag phase. [1] (ii) On Fig. 5.1, draw a Y to show where the birth rate is equal to the death rate. [1] (iii) Calculate how long it takes for the number of bacteria to reduce by half after the bacteria have been in the fermenter for 24 hours. …… hours [1] (iv) Describe and explain the change in bacterial population size from 24 hours to 50 hours shown in Fig. 5.1. …… [3] (v) The fermenter is kept at the optimum temperature for the bacteria. Explain why this is important for enzyme function. …… [3] (vi) State why the bacteria are grown in a liquid that contains amino acids. …… [1] [Total: 15]

Mark scheme

5(a) any two from: 2 cell membrane ; cytoplasm ; ribosomes ; DNA ; 5(b) any three from: 3 1 rapid reproduction rate / AW ; 2 reproduce asexually / offspring are genetically identical ; 3 small / do not need much space ; 4 simple requirements to, grow / keep / AW ; 5 ability to make complex molecules ; 6 few / no, ethical concerns ; 7 presence of plasmids ; 8 same, genetic code / type of DNA / AW, as other organisms ; 9 AVP ; e.g. great, variety / diversity, of bacteria that are (or could be) useful in biotechnology / haploid 5(c)(i) X placed in lag phase ; 1 between 0–8 hours 5(c)(ii) Y placed in stationary phase ; 1 between 18–24 hours 5(c)(iii) 12 (hours) ; 1 5(c)(iv) any three from: 3 1 death phase OR death rate above birth rate OR (bacterial population) is decreasing ; 2 limited / lack, of (named) resources / nutrients / space ; 3 increased competition (for resources / nutrients / space) ; 4 build-up / high concentration, of (named) waste / toxins ; 5 build-up of pressure / increase in temperature (above optimum) ; 6 appropriate use / description, of data ; 5(c)(v) any three from: 3 1 sufficient kinetic energy (at optimum temperature) ; 2 for many collisions between enzyme and substrate / many enzyme- substrate complexes form ; 3 to maximise, rate of reaction / enzyme activity (at optimum temperature) ; 4 to prevent, enzymes / active site, from denaturing (at higher temperatures) ; 5 so that the active site does not change shape (at optimum temperature) ; 6 active site fits / is complementary to, substrate / reactants (at optimum temperature) ; 5(c)(vi) any one from: 1 (amino acids are used) to make, proteins / enzymes / nucleic acids / AW ; quicker / efficient, absorption ; amino acids are, soluble / dissolved ;

Question 612 marks

Question

(a) Xerophytes are plants that are adapted for an environment which has very little available water. Describe the meaning of adaptation. …… [3] (b) Fig. 6.1 is a photograph of a saguaro cactus, Carnegiea gigantea, which lives in a desert. The climate in a desert has very low rainfall and very high daytime temperatures. Fig. 6.1 Describe two visible adaptive features shown in Fig. 6.1 and explain how each feature is beneficial for living in a desert. feature 1 …… explanation …… feature 2 …… explanation …… [4] (c) Table 6.1 shows some data about stomatal density in the leaves of one plant that is not a xerophyte and three xerophyte plants. Table 6.1 number of stomata per mm2 species plant type upper leaf surface lower leaf surface oak tree not a xerophyte 94 503 tongue leaf plant xerophyte 0 18 lace aloe xerophyte 2 15 ice plant xerophyte 0 42 (i) Using the information in Table 6.1, estimate the total number of stomata in an ice plant leaf with a lower leaf surface area of 8 cm2. …… stomata [1] (ii) Explain the data shown in Table 6.1. …… [2] (d) There are xerophytic forests which are threatened by human overexploitation. Suggest reasons why it is important to conserve xerophytic ecosystems. …… [2] [Total: 12]

Mark scheme

6(a) (process) resulting from natural selection ; 3 (populations) becoming better suited to their environment ; over many generations ; 6(b) total of four from: 4 two correct features with two matching explanations feature: spines / needles / thorns / spikes / AW ; explanation: reduced surface area for, transpiration / water loss or defence against, herbivores / animals killing plant / AW ; feature: fleshy / thick / wide / swollen / AW, stem / stalk / trunk ; explanation: store water ; feature: corrugated / AW, stem / stalk / trunk ; explanation: increased shading / increased surface area for photosynthesis (of stem) / reduces, evaporation / transpiration ; 6(c)(i) 33 600 (stomata) ; 1 (8 cm2 = 800 mm2, 800 × 42) 6(c)(ii) any two from: 2 ora throughout 1 lower (leaf) surfaces are, cooler / in the shade / more sheltered from wind / AW ; 2 lower (leaf) surfaces have (more) stomata to reduce, transpiration / water loss ; 3 few(er) stomata in xerophytes to reduce, transpiration / water loss ; 4 xerophytes, exchange gases / photosynthesise / respire, more slowly / less (because of a lack of water / they are slow growing / in an extreme environment / exposed to high light intensities) ; 6(d) any two from: 2 to maintain / increase, biodiversity / genetic diversity ; reduce extinction ; to ensure stability of, food chains / food webs / interdependence of organisms ; to protect vulnerable, ecosystems ; to maintain, nutrient cycling / soil structure / climate stability ; to provide (named) resources ;; AVP ; e.g. economics reasons such as ecotourism / aesthetic reasons / ethical duty or moral responsibility / future research / carbon sinks

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Where can I find the 0610/43 October/November 2023 mark scheme?

On this page, free: the mark scheme for IGCSE Biology 0610/43, October/November 2023 (0610_w23_ms_43), and the question paper (0610_w23_qp_43), to read or download, with each question's marking points written out underneath.

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Biology 0610/43 for October/November 2023 is out of 80 marks, with 1 hour 15 minutes to answer it, across 6 questions.

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