7 (a) A student has two peas. Pea A is green. Pea B is yellow. The colour of peas is controlled by a single gene. • The allele for green-coloured peas is g. • The allele for yellow-coloured peas is G. (i) Circle two words that can be used to describe the genotype of pea A. allele dominant heterozygous homozygous phenotype recessive [2] (ii) State the two possible genotypes of pea B. … and … [1] (b) Two pea plants are crossed. Fig. 7.1 is an incomplete genetic diagram showing a genetic cross of two pea plants. (i) Complete the genetic diagram in Fig. 7.1 to show the expected genotypes of the offspring. parental gametes G g parental gametes G … … g … … [1] Fig. 7.1 (ii) State the percentage chance of the parent plants in Fig. 7.1 producing offspring that have the genotype gg. … [1] (c) Chromosomes, DNA and genes are involved in inheritance. (i) List these structures in order of size from smallest to largest. … … … [1] smallest largest (ii) State the phenotype of a person with the sex chromosomes XX. … [1] [Total: 7]

7(a)(i) homozygous ; recessive ; 2 7(a)(ii) GG and Gg ; 1 7(b)(i) GG Gg Gg gg ; 1 7(b)(ii) 25(%) ; 1 7(c)(i) DNA, genes, chromosomes ; 1 7(c)(ii) female ; 1

10 (a) A farmer keeps ponies. The ponies show variation in height. The farmer sells the smaller ponies for more money than the larger ponies. (i) Name the type of variation shown by differences in height of the ponies. … [1] (ii) Complete the sentences to describe the method the farmer uses to increase the number of smaller ponies on the farm. The farmer selects the ponies with the desirable feature. These ponies are then … . The … offspring are then selected and used for … . This process is then … over many generations. [4] (iii) State the name of the process the farmer uses. … [1] (b) The inheritance of sex in ponies is the same as in humans. (i) Complete Table 10.1 to show the inheritance of sex. Table 10.1 male sex chromosomes X … female sex chromosomes X XX XY … XX XY [1] (ii) State the ratio of male to female offspring shown in Table 10.1. … [1] (c) Chromosomes contain genes. Define the term gene. … … [2] [Total: 10]

10(a)(i) continuous ; 1 10(a)(ii) crossed / bred / AW ; smallest ; breeding ; repeated ; 4 10(a)(iii) selective breeding ; 1 10(b)(i) X Y X XX XY X XX XY ; 1 10(b)(ii) 1:1 ; 1 10(c) length of DNA ; that codes for a protein ; 2

1 (a) Fig. 1.1 is a photograph of an insect-pollinated flower. C A B Fig. 1.1 (i) Identify the parts labelled A, B and C in Fig. 1.1. A … B … C … [3] (ii) Describe two visible pieces of evidence from Fig. 1.1 that suggest this is an insect- pollinated flower. 1 … … 2 … … [2] (iii) Describe two ways the pollen from the flower in Fig. 1.1 would be different from pollen in a wind-pollinated flower. 1 … 2 … [2] (b) Pollen contains the male gametes. State one way the chromosome number in the nuclei of a gamete is different from that of a zygote. … [1] (c) A zygote is produced after fertilisation. State where fertilisation occurs in a plant. … [1] (d) Many plants are capable of both asexual and sexual reproduction. Complete Table 1.1 to show the disadvantages of asexual and sexual reproduction in plants by placing ticks (3) in the correct boxes. One has been done for you. Table 1.1 less genetic diversity more energy is used finding a partner no or less evolution usually takes a longer length of time asexual 3 sexual [2] [Total: 11]

1(a)(i) A stigma ; B petal ; C anther ; 3 1(a)(ii) (large) petal ; stigma inside of flower ; anther inside of flower ; avp ; max 2 2 1(a)(iii) larger ; heavier ; spiky / sticky ; fewer in number produced ; max 2 2 1(b) haploid / has half the number (of chromosomes) ; 1 1(c) ovary ; 1 1(d) less genetic diversity more energy is used finding a partner no or less evolution usually takes a longer length of time asexual   sexual   ;; 2

4 (a) Antibiotics are drugs that are used to kill bacteria. A scientist investigates antibiotic resistance in bacteria. The scientist uses four different antibiotics discs A, B, C and D. The results are shown in Fig. 4.1. The white areas show where no bacteria have grown. The dark areas show where bacteria have grown. A B C D no bacterial growth bacterial growth Fig. 4.1 (i) Identify the antibiotic that is most effective against the bacteria. … [1] (ii) Identify the antibiotic that the bacteria are most resistant to. … [1] (b) The development of antibiotic resistance is an example of evolution by natural selection. (i) Complete the sentences to describe how strains of bacteria with antibiotic resistance develop. A mutation occurs which causes a change in the … . This mutation causes some bacteria to be resistant to antibiotics. Antibiotics kill non-resistant bacteria. Resistant bacteria survive and … . The … for resistance is passed on to their offspring. Eventually all the population of bacteria will be resistant to antibiotics. [3] (ii) Describe one way natural selection is different from artificial selection. … … [1] (c) Bacteria reproduce by a type of asexual reproduction. State one advantage and one disadvantage of asexual reproduction. advantage … … disadvantage … … [2] [Total: 8]

4(a)(i) D ; 1 4(a)(ii) C ; 1 4(b)(i) chromosome / gene ; reproduce / AW ; allele ; 3 4(b)(ii) traits / characteristics, are selected by humans (in artificial selection) / traits are selected by the environment in natural selection ; traits / characteristics, are usually chosen for economic reasons (in artificial selection) / traits are beneficial for survival in natural selection ; faster results (from artificial selection) / ORA ; (artificial selection only) takes place in selected individuals / natural selection takes place in whole populations ; (artificial selection) does not lead to evolution / ORA ; (artificial selection) results in decreased (genetic) variation / diversity / ORA ; (artificial selection) leads to increased likelihood of inherited / genetic disease ; AVP ; max1 4(c) advantages: no mates required / rapid / AVP ; disadvantages no (genetic) diversity / no evolution / extinction more likely ; 2

Cambridge IGCSE Co-ordinated Sciences · 0654

IGCSE Co-ordinated Sciences (0654) Inheritance past paper questions

Revise IGCSE Co-ordinated Sciences (0654) — Inheritance with real Cambridge past-paper questions grouped by topic, each shown with its marking scheme. Working one topic at a time targets exactly the skill each question tests.

84 free questions from 2016–2021, each with its marking scheme. Open the full topical bank to filter by subtopic, paper, and year.

Inheritance in IGCSE Co-ordinated Sciences 0654 exams, 2020–2025

Across 2020–2025, Inheritance accounted for 112 questions worth 537 marks in Cambridge IGCSE Co-ordinated Sciences (0654) papers.

By year
Year	Questions	Marks
2020	18	91
2021	19	68
2022	18	87
2023	13	73
2024	23	104
2025	21	114

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2021 Oct/Nov · Paper 3 · Q7 · 7 marks
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2021 Feb/Mar · Paper 3 · Q10 · 10 marks
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2021 May/Jun · Paper 4 · Q1 · 11 marks
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2021 Oct/Nov · Paper 4 · Q4 · 8 marks
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2021 Feb/Mar · Paper 1 · Q11 · 1 mark
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Answer: A
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