Cell division — Paper 4 · IGCSE Sciences - Co-ordinated (Double) 0654

8 (a) Fig. 8.1 shows a diagram of a grass flower. Grass is an example of a wind-pollinated plant. X Y ovary Fig. 8.1 (i) Name the parts of the flower labelled X and Y. X … Y … [2] (ii) Describe how the following parts of the flower would be different in an insect-pollinated plant. petals … pollen … [2] (b) Pollen is the male sex gamete in plants. Name the process which produces gametes. … [1] (c) In insect-pollinated plants, pollen is transferred by insects to other plants, which may result in fertilisation. This is an example of sexual reproduction. State one advantage and one disadvantage of sexual reproduction. advantage … … disadvantage … … [2] (d) After sexual reproduction, seeds are produced. Seeds are dispersed so that plants can colonise new areas. Describe two ways in which seeds can be dispersed by animals. … … … [2]

9 marks

Mark scheme: 8(a)(i) X anther ; Y stigma ; 2 8(a)(ii) petals larger / brightly coloured ; pollen larger / fewer / rougher surface ; 2 8(b) meiosis ; 1 8(c) advantage genetic variation ; disadvantage two parents needed ; fertilisation is random / mutations can occur ; take more, time / energy ; max 2 8(d) attach to animals, coat / fur / hair ; eaten by animals, dispersed in faeces ; AVP ; max 2

This question in 0654/42 May/June 2017

13 (a) Mitosis and meiosis are two types of cell division. (i) Use words from the list to complete the definition of the term mitosis. Each word may be used once, more than once or not at all. alleles cells chromosomes gamete genes nuclear Mitosis is defined as … division giving rise to genetically identical … in which the chromosome number is maintained by the exact duplication of … . [3] (ii) State two roles of mitosis in the body. 1 … 2 … [2] (b) Table 13.1 shows some statements about sex cells. Place a tick (3) next to all of the statements that describe sperm cells. Table 13.1 tick (3) statement if correct always contain an X chromosome always contain a Y chromosome are diploid cells are gametes are haploid cells contain paired chromosomes contain unpaired chromosomes [2]

7 marks

Mark scheme: 13(a)(i) nuclear ; cells ; chromosomes ; 3 13(a)(ii) growth ; repair (of damaged tissue) ; replacement (of worn out cells) ; asexual reproduction ; max 2 13(b) are gametes ticked are haploid cells ticked contain unpaired chromosomes ticked 1 or 2 correct ; 3 correct ; 2

This question in 0654/42 Oct/Nov 2018

10 (a) A student investigates the effect of temperature on the rate of transpiration. The apparatus in Fig. 10.1 is used to measure the rate of water uptake by a plant shoot. This is approximately equal to the rate of transpiration. plant shoot reservoir capillary tube air bubble ruler beaker of water Fig. 10.1 The rate of water uptake is determined by measuring the distance travelled by the air bubble in a set time. (i) At 30 °C the air bubble travels 8 mm in 2 minutes. Calculate the rate of water uptake. … mm / min [1] (ii) The student repeats the investigation at different temperatures. Sketch a line on Fig 10.2 to show the expected results. rate of water uptake 0 10 20 30 40 50 temperature / °C Fig. 10.2 [2] (iii) Suggest a reason for the shape of your graph in (a)(ii). … … [1] (b) Describe the mechanism that moves water up the xylem. … … … … … [3] (c) Fig. 10.3 shows a photograph of a plant cell undergoing cell division by mitosis. chromosomes cell A Fig. 10.3 (i) State where chromosomes are found in a cell. … [1] (ii) Complete the sentence about the chromosomes in cell A. The chromosomes on the left-hand side of the cell are genetically … to the chromosomes on the right-hand side of the cell. [1] (d) One of the roles of mitosis is growth. State two other roles of mitosis. 1 … … 2 … … [2] (e) State how the number of chromosomes in a cell produced by meiosis is different to the number of chromosomes in a cell produced by mitosis. … … [1] [Total: 12]

12 marks

Mark scheme: 10(a)(i) 4 (mm / min) ; 1 10(a)(ii) rate increasing ; then levelling off / gradient reducing ; 2 10(a)(iii) increasing temperature causes (more) stomata to open (until other factors limit transpiration) ; increasing rate of evaporation ; increasing transpiration (pull) ; max 1 1 10(b) transpiration pull ; difference in water potential / water potential gradient ; draws up a column of water (molecules) ; water (molecules) held together by cohesion ; max 3 3 10(c)(i) in the nucleus ; 1 10(c)(ii) identical ; 1 10(d) any two from replacement of cells ; asexual reproduction ; repair (of damaged tissue) ; max 2 2 10(e) they would contain half the number of chromosomes (in meiosis) ; 1

This question in 0654/41 Oct/Nov 2019

1 (a) Fig. 1.1 is a photomicrograph of pollen from an insect-pollinated plant. Fig. 1.1 Describe one visible piece of evidence that shows this pollen is from an insect-pollinated plant. … … [1] (b) Fig. 1.2 is a diagram of a flower from a wind-pollinated plant. anther filament ovary stigma Fig. 1.2 Describe two ways the stigma shown in Fig. 1.2 is specialised for wind-pollination. 1 … … 2 … … [2] (c) Pollination is the transfer of pollen. This can lead to fertilisation. Describe the process of fertilisation in plants. … … … … [2] (d) A species of flowering plant has 18 chromosomes in its mesophyll cells. Deduce the number of chromosomes in its: male gametes in its pollen … root hair cells. … [2] (e) Plants can reproduce asexually or sexually. Describe one advantage and one disadvantage of plants reproducing asexually in the wild. advantage … … disadvantage … … [2] [Total: 9]

9 marks

Mark scheme: 1(a) spiky (surface) ; 1 1(b) stigma feathery ; stigma hangs outside flower ; 2 1(c) fusion of nuclei ; ref to pollen and ovule ; 2 1(d) 9 ; 18 ; 2 1(e) advantage fast / colonise areas quickly / only requires one parent ; disadvantage no variety / more prone to extinction / more susceptible to disease ; 2

This question in 0654/42 May/June 2020

4 (a) Fig. 4.1 is a diagram of the blood vessels in the placenta of the mother and her fetus. placenta umbilical cord mother’s fetus’ blood vessels blood vessels Fig. 4.1 (i) Oxygen moves across the placenta from the mother’s blood to the blood of the fetus. Suggest the name of one substance that moves in the opposite direction. … [1] (ii) Oxygen moves across the placenta by diffusion. Define diffusion. … … … … [2] (iii) The placenta is a gas exchange surface. Suggest two features of the placenta that enable efficient gas exchange. 1 … 2 … [2] (iv) Name the part of the female reproductive system where: • the fetus develops … • fertilisation occurs … • the female gametes are released. … [3] (b) The process of mitosis is used for growth. (i) State two other uses of mitosis. 1 … 2 … [2] (ii) The chromosomes inside the nuclei of cells produced by mitosis are different to those produced by meiosis. Describe two of these differences. 1 … … 2 … … [2] [Total: 12]

12 marks

Mark scheme: 4(a)(i) carbon dioxide ; 1 4(a)(ii) (net movement of particles from their) higher concentration to their lower concentration / down a concentration gradient ; ref to random movement of particles ; 2 4(a)(iii) any two from thin membrane ; large surface area ; good blood supply ; (semi) permeable membrane ; 2 4(a)(iv) uterus ; oviduct ; ovary ; 3 4(b)(i) any two from repair (of damaged tissue) ; replacement of cells ; asexual reproduction ; 2 4(b)(ii) chromosomes produced by mitosis have a diploid number / chromosomes produced by meiosis have a haploid number ; cells produced by mitosis, contain two sets of chromosomes / are paired / cells produced by meiosis are unpaired ; cells produced by mitosis are genetically identical (to parent cell / each other) / cells produced by meiosis are genetically different (to parent cell / each other) ; max 2 2

This question in 0654/43 Oct/Nov 2020

7 Different species have different numbers of chromosomes in their cells. (a) State where chromosomes are found in cells. … [1] (b) State the female and male sex chromosomes in humans. female … male … [1] (c) State the number of chromosomes in each human body cell. … [1] (d) Table 7.1 shows the number of chromosomes found in each body cell of four different organisms. Table 7.1 organism number of chromosomes goldfish 94 potato 48 pea 14 fruit fly 8 (i) State the number of chromosomes in each body cell of a goldfish. … [1] (ii) State the number of chromosomes in one gamete of a fruit fly. … [1] (e) A mutation is a change in a chromosome. State one factor that increases the rate of mutation in cells. … [1] (f) State two roles of mitosis in the body. 1 … 2 … [2] (g) The list shows some statements about meiosis. Place ticks (3) in the boxes next to all the correct statements. Meiosis produces genetically identical cells. Meiosis produces sperm in humans. Meiosis is a type of cell division. Meiosis results in the production of diploid cells. Meiosis only occurs when there is a mutation in cells. [2] [Total: 10]

10 marks

Mark scheme: 7(a) nucleus ; 1 7(b) (female) XX (male) XY ; 1 7(c) 46 / 23 pairs ; 1 7(d)(i) 94 ; 1 7(d)(ii) 4 ; 1 7(e) (named) ionising radiation / chemicals ; 1 Question Answer Marks 7(f) any two from: asexual reproduction ; growth ; repair of damaged tissues ; replacement of cells ; 2 7(g) meiosis produces sperm in humans ticked ; meiosis is a type of cell division ; 2

This question in 0654/42 May/June 2021

1 (a) Fig. 1.1 is a photograph of an insect-pollinated flower. A C 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 more energy is usually takes a less genetic no or less used finding a longer length of diversity evolution partner time asexual 3 sexual [2] [Total: 11]

11 marks

Mark scheme: 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

This question in 0654/43 May/June 2021

1 (a) A student monitors his pulse rate at rest and during exercise. Table 1.1 shows the results. Table 1.1 activity pulse rate / beats per minute at rest 64 during exercise 122 (i) Calculate the difference between his pulse rate at rest and during exercise. … beats per minute [1] (ii) Complete the sentences to explain the results in Table 1.1. During exercise, the pulse rate increases because the heart is pumping blood … . The pumping action is caused by contraction of the … wall of the heart. To provide the body with more energy, the process of … increases. This process requires increased blood flow to the cells to deliver more … and … . [4] (b) Genetic predisposition and sex are both risk factors for coronary heart disease. (i) Describe two dietary recommendations to follow to reduce the risk of developing coronary heart disease. 1 … 2 … [2] (ii) Males are more likely to develop coronary heart disease than females. State the sex chromosomes in males. … [1] (c) Male gametes are produced by meiosis. Describe two ways in which the cells produced by meiosis are different from the cells produced by mitosis. 1 … … 2 … … [2] [Total: 10]

10 marks

Mark scheme: 1(a)(i) 58 (beats per minute) ; 1 1(a)(ii) faster ; muscular ; (aerobic) respiration ; glucose and oxygen ; 4 1(b)(i) any two from: don’t consume too much fat ; don’t consume, too much carbohydrate / energy / calories ; don’t consume too much, salt ; don’t consume excessive alcohol ; consume, a balanced diet ; consume plenty of fibre ; 2 1(b)(ii) XY ; 1 1(c) genetically different (to each other) ; contain half the number of chromosomes / are haploid / contains 23 chromosomes / contains unpaired chromosomes ; 2

This question in 0654/42 May/June 2022

7 (a) Albinism is an inherited condition that results in no pigments being made in the skin. The allele for albinism is recessive a. The allele for no albinism is dominant A. Fig. 7.1 is a pedigree chart diagram of albinism in one family. 1 2 3 4 5 6 Key female without albinism female with albinism male without albinism male with albinism Fig. 7.1 (i) Use the information in Fig. 7.1 to state: the genotype of person 4 … the genotype of person 1 … the sex chromosomes of person 5. … [3] (ii) A couple without albinism decides to have a child. Complete the genetic diagram in Fig. 7.2 to calculate the percentage chance of having a child with albinism. parental gametes A a A parental gametes a Fig. 7.2 percentage chance of child having albinism = … % [2] (b) Mitosis and meiosis are two forms of cell division. (i) State two roles of mitosis. 1 … 2 … [2] (ii) State the name of one organ in the human body where meiosis occurs. … [1] (iii) An organism has 32 chromosomes. State the number of chromosomes in a cell formed by meiosis in this organism. … [1] [Total: 9]

9 marks

Mark scheme: 7(a)(i) aa ; Aa ; XX ; 3 7(a)(ii) AA Aa Aa aa ; 25 (%) ; 2 7(b)(i) any two from: growth ; repair (of damaged tissues) ; replacement of cells ; asexual reproduction ; 2 7(b)(ii) testes / ovary ; 1 7(b)(iii) 16 ; 1

This question in 0654/43 May/June 2023

1 (a) Fig. 1.1 is a diagram of the female reproductive system in humans. A B C F E D Fig. 1.1 Identify the letter from Fig. 1.1 that represents the part where: eggs are released … fertilisation occurs … implantation occurs … meiosis occurs … [4] (b) A zygote divides to form an embryo. Describe this type of cell division. … … … … [3] (c) During pregnancy the growing baby is supported by the placenta, umbilical cord, amniotic fluid and amniotic sac. (i) State the function of the amniotic fluid. … … [1] (ii) Describe the function of the placenta and the umbilical cord. … … … … … [3] [Total: 11]

11 marks

Mark scheme: Question Answer Marks 1(a) B ; 4 A ; E ; B ; 1(b) any three from: 3 mitosis ; nuclear division ; production of genetically identical cells ; ref to duplication of chromosomes (before mitosis) ; 1(c)(i) protection (from mechanical damage) ; 1 1(c)(ii) any three from: 3 placenta provides a barrier to toxins ; umbilical cord passes, oxygen / nutrients, to fetus (blood) ; umbilical cord passes, excretory products / carbon dioxide, to mothers (blood) ; ref to exchange of materials by diffusion (across the placenta) ;

This question in 0654/42 Oct/Nov 2023

7 (a) Fig. 7.1 summarises mitosis and meiosis in an organism. mitosis meiosis parentalparental cellcell stage 1 stage 1 stage 2 stage 2 stage 3 cell A cell B Fig. 7.1 (i) The parental cells in Fig. 7.1 have been drawn showing just four chromosomes. The actual number of chromosomes in each parental cell is 24. Identify the actual number of chromosomes in: cell A … cell B … [2] (ii) Identify the name of the type of cells represented by cell B in Fig. 7.1. … [1] (iii) Describe the process occurring at stage 1 in Fig. 7.1. … … [1] (iv) State the name of the type of nucleus in the parental cell in Fig. 7.1. … [1] (v) Describe the arrangement of chromosomes in the parental cell in Fig. 7.1. … [1] (b) State two uses of mitosis. 1 … 2 … [2] [Total: 8]

8 marks

Mark scheme: 7(a)(i) 24 ; 2 12 ; 7(a)(ii) gamete(s) / sex (cell) / haploid (cell) ; 1 7(a)(iii) duplication / replication, of chromosomes ; 1 7(a)(iv) diploid ; 1 7(a)(v) paired ; 1 7(b) any two from: 2 growth ; repair (of damaged tissues / cells) ; replacement (of cells) ; asexual reproduction ;

This question in 0654/42 Oct/Nov 2024

3 (a) (i) Fig. 3.1 shows a violet plant bought from a shop. Fig. 3.1 Many violet plants are produced by asexual reproduction. State two advantages of growing violet plants by asexual reproduction. 1 … … 2 … … [2] (ii) Violet plants also reproduce by sexual reproduction. Complete the sentence about sexual reproduction in plants. Choose words from the list. division fertile fusion seed zygote Sexual reproduction is the process involving the … of nuclei of two gametes to form the … . [2] (b) (i) Fig. 3.2 shows a wind-pollinated flower. A B Fig. 3.2 State the function of structure A and structure B as shown in Fig. 3.2. Structure A … Structure B … [2] (ii) Describe how structure B in Fig. 3.2 would be different in an insect-pollinated flower. … … … [1] (c) (i) The root hair cells of a species of violet plant contain 30 chromosomes. State the number of chromosomes in: a leaf cell of a violet plant … an ovule of a violet plant. … [2] (ii) Flowers produce gametes. Name the process that leads to the formation of gametes. … [1] [Total: 10]

10 marks

Mark scheme: 3(a)(i) any two from: 2 faster less energy required no need to rely on, (named) pollinators / wind / insects no need to produce, flowers / scent only requires one parent more likelihood of success due to lack of random fertilisation genetically identical if has desirable features ; ; 3(a)(ii) fusion ; 2 zygote ; 3(b)(i) A - captures pollen / AW ; 2 B- produces / makes / releases / AW, pollen ; 3(b)(ii) not hanging down / enclosed within the flower or petals ; 1 3(c)(i) leaf cell - 30 ; 2 ovule- 15 ; 3(c)(ii) meiosis ; 1

This question in 0654/42 Feb/March 2025

3 Fig. 3.1 is a magnified image of a plant root tip viewed using a light microscope. X start of zone zone of zone of root cap of cell elongation division specialisation Fig. 3.1 (a) At X in Fig. 3.1, there are 37 cells across the width of the root tip. The actual width of the root tip at X is 1.2 mm. Calculate the average size of the cells in the root tip in μm. … μm [2] (b) Fig. 3.1 shows a zone in the root tip where cells become specialised. Tick (3) one box to identify a type of specialised cell made in the root. ciliated cells guard cells palisade mesophyll cells phloem cells [1] (c) Fig. 3.1 shows a zone in the root tip where cells divide so the root can grow. (i) State the type of cell division needed for growth. … [1] (ii) During this type of cell division, the number of chromosomes is maintained in each daughter cell. Describe two processes in cell division that ensure that the chromosome number is maintained. 1 … … 2 … … [2] (d) A different type of cell division takes place in the ovary and anther of flowers to make gametes. (i) Fig. 3.2 is a diagram of a wind-pollinated flower. Fig. 3.2 On Fig. 3.2, draw a label line and the letter A to identify one anther. [1] (ii) The anthers produce male gametes. Complete the sentences about male gametes in plants. Male gametes in plants are called … grains. During production of male gametes, the chromosome number is halved from … to haploid. Male gametes produced are all genetically … . A nucleus of a male gamete will fuse with the nucleus of an ovule. This process is called … . [4] (iii) Describe one advantage of sexual reproduction to a population of plants in the wild. … … [1] [Total: 12]

12 marks

Mark scheme: 3(a) 1.2 / 37 or 0.0324 ; 2 32.4 (μm) ; 3(b) phloem cells ; 1 3(c)(i) mitosis ; 1 3(c)(ii) any two from: 2 replication (of, DNA / chromosomes) ; separation of chromosomes (into two identical sets) ; cells only divide once / splits into two daughter cells; 3(d)(i) 1 A correct labelling of any one anther = 1 mark ; 3(d)(ii) pollen ; 4 diploid ; different ; fertilisation ; 3(d)(iii) any one from: 1 produces (genetic) variation ; able to adapt to change in environment ; spreads offspring through dispersal of pollen / seeds ;

This question in 0654/41 May/June 2025

4 (a) (i) Mitosis is a type of cell division. State two roles of mitosis in the human body. 1 … 2 … [2] (ii) Describe what happens to the chromosomes before mitosis occurs. … … [1] (b) Meiosis is another type of cell division. Place one tick (✓) in each row to show if the process occurs in mitosis, meiosis or both. process mitosis meiosis both produces diploid cells produces genetically different cells separates chromosomes produces pollen [2] (c) Pathogens infect human cells. Describe how active immunity is gained after an infection by a pathogen. … … … … … [2] [Total: 7]

7 marks

Mark scheme: 4(a)(i) any two from: 2 • growth ; • repair of damaged tissues / repair of damaged organs ; • replacement of cells ; 4(a)(ii) replication (of chromosomes) / replication (of DNA) / AW ; 1 4(b) 2 process mitosis meiosis both produces diploid cells ✓ produces genetically ✓ different cells separates chromosomes ✓ produces pollen ✓ 4 rows correct = 2 marks 2 or 3 rows correct = 1 mark 1 row correct = 0 marks 4(c) any one from: 2 • (antigens on the pathogen) stimulate lymphocytes to produce antibodies ; • antibodies bind to antigens leading to direct destruction of pathogens ; • antibodies marking of pathogens for destruction by phagocytes ; AND memory cells produced (that give long term / active immunity) ;

This question in 0654/41 Oct/Nov 2025

1 (a) Plants and bacteria are made of cells. State two ways the plant cells and bacterial cells are similar and two ways that they are different. similar 1 … 2 … different 1 … 2 … [4] (b) (i) Plant cells can divide by mitosis. Complete the sentence about mitosis. The exact replication of … occurs before mitosis. [1] (ii) Plants can reproduce by sexual reproduction. State one advantage and one disadvantage of sexual reproduction. advantage … disadvantage … [2] (c) (i) In plants, the flower contains both the male and female gametes. Fig. 1.1 is a diagram of an insect-pollinated flower. D A C B Fig. 1.1 Identify the parts labelled A and B in Fig. 1.1. A … B … [2] (ii) The parts labelled C and D in Fig. 1.1 would be different in a wind-pollinated flower. Describe these differences. C … … D … … [2] (d) State the type of cell division that produces gametes. … [1] [Total: 12]

12 marks

Mark scheme: Question Answer Marks 1(a) similar, any two from: 4 • cell wall ; • cell membrane ; • ribosomes ; • DNA/genetic material ; • cytoplasm ; different, any two from: • plant has cellulose cell wall / bacterial has cell wall not made from cellulose OR bacteria has cell wall made of sugars and amino acids / peptidoglycan ; • plant cells have chloroplasts / bacterial cells do not have chloroplasts ; • plant cells have vacuole / bacterial cells do not have vacuole ; • plant cells have a nucleus / bacterial cells do not have a nucleus ; • plant cells have chromosomes / bacterial cells have circular DNA / bacterial cells have plasmids ; 1(b)(i) chromosomes ; 1 1(b)(ii) (advantage) (more) genetic variation ; 2 (disadvantage) process of development takes longer / idea of offspring having to develop from fertilised egg taking longer ; 1(c)(i) A – stigma ; 2 B – style ; 1(c)(ii) C – would not be colourful / dull (colour) / absent / small / have no smell / have no scent ; 2 D – would be hanging outside the flower ; 1(d) meiosis ; 1

This question in 0654/43 Oct/Nov 2025