The graph below shows the relationship between maternal age and the incidens)gpptq q2ej; u tugv5xmv(gc* / :6r34m tbr8ce of non-disjunction. What:8r uq*g(qm jmrpt3ut xs25g/6;4tpvv eb) cg relationship is suggested by the data in the graph?

  Which stage of meiosis is represented in the diagram beluld dm8e/ij3by2np:h*e/cd 3 ow?

  The diagram below shows chromosomes during meiosis.nzm +6rtowhw( , 1.myy


1.Identify the stage of meiosis from the diagram.It is    I

2.State one process, other than the one shown in the diagram that promotes variation during meiosis.

3.State when the process you named in part (i) occurs in meiosis.It is    I

  Which row correctly states the number orq.z 5; h .gr6yxwc7utf alleles of a single gene which would be present in the nucleu;7hqwycu 6 xg.r. 5rzts of a cell as a result of each process?

  Which keyword is matched to the correctk h6kzur)vr5ca b0y4d+qy 2cgq 1b5p7 definition?

  Which statement(s) about mitosis is/are05a 51ryb )kytk 4z(gfc0kuo g true?
I. Sister chromatids are pulled apart during metaphase.
II. The nuclear envelope reforms during telophase.
III. Chromosomes supercoil and become visible during prophase.

  In the micrograph below, which letter points to a cell in anaphahq/cgp1 n(cmi t( 18).iwiuoise?

  During which stage of mitosis does the *).m uv kw0uwaln x)e(nuclear envelope break down?

  Which one of the followa ljjarlsbwc*8 /c3iw/kh6a b) 2*uf-ing transport proteins only carries out active transport? 6cirb jjslahwwb )3a2 u-f**//lkca8

  Which process does not happen in t )/-djyihe.2vests *uhe shoot apex?

  Which type/s of membrane transport do/does not require energy expenditurb (zi k its*f-ey ttu 7d87botlg*-q17e?
I. Facilitated diffusion
II. Active transport
III. Osmosis

  The diagram below represents a cell with a diploid number of 4. Whie4we 7m (d;su, g;ka 2h(firgxch stage of cell division is the cell curaue7 (e(ksfi x2g d ;,m;rhwg4rently undergoing?

  The photomicrograph below shows a root tip meristem. Which of the follua *w;g *gpw5 xhirv:-owing sentences correctly-grx: u*5wwag*ip vh; defines a meristem?

  When does the random orientation of homologous cwshvb3(skw 9cpg 0*1s+u l, gkhromosome pairs occur?

  Which process does not occur duc7 3bc0qs q5gyring meiosis?

  If a cell with a diploid number of 36 undergoes mitosis, how many chrolkd0o 3u zj6afw)oa u(w3))clmosomes will be present in each daughter cell after cytokinel wo( k3 0uacz)o j6wl)duf)a3sis?

  The image shows a micrograph ohff1x5) 1o ylzf a cell.


What explains the appearance of the cell in the micrograph?

  Which statement(s) about homologous chromosomes is/are not tr7 z2ier:*qh 8vcltm4x ue?
I. Homologous chromosomes have the same centromere position.
II. Homologous chromosomes have genes with the same loci.
III. Homologous chromosomes are identical to each other.

  This karyogram is for* pl 8iw9d8iz0n(nllr(fy*qa an individual with Down syndrome.

Which statement is not correct?

  In the cells of a horse (E. caballus) during b/ mld0tedgk/6;s+fx prophase I of meiosis I there are 64 chromosomes. What is the haploid number of chromosomes//sgmk x0l;+ftebd6 d?

  Which arrow is pointing f/gapj f ros55g.r+ z3to a chiasma?

  The diagram below represents the structure of a shoot apical meristem. Which rowrifh -;yjnpc7xhsvlag; )0,/) h mv 3z 5mjp-q in the table correctly identifi -nji7ph3a,vf5z)lsr- chy/; qmg x)vjhm p 0;es the processes occuring in the structures labeled in the diagram?

  How does meiosis projslh8rrfhqst dv- 6r3732 1;mhkb/h tmote variation?

  Which of the following sta/ j-v+wsgaa+hc8y ,pitements is/are correct for meiosis?
I. It is a reduction division
II. It involves random orientation
III. It produces genetically identical cells

  The diagram shows gametes produced from two homologous chrome;og wwk/ja 35t lja cqam82)1osomes.


What single crossover event could have occurred to produce the gametes?
I. Crossover between Gene A and B
II. Crossover between Gene B and C
III. Crossover between Gene C and D

  Which word describes the fo 5jwxora y+qz3o2;x bsy bz :/d+mb)s7rmation of secondary tumours from primary tumours as a reb3 ozb zjr7yo;/dx:2s+qs)yw b5x ma+sult of the movement of cells?

  How many chiasmata are present in the dia9hrb,zt- ;mul gram?

  Which statement is a similarity 6 itjy2ar hwjf;q5mro,i6+ze** kd6cbetween cytokinesis in animal and plant cells?

  Which stage of meiosis is matchedyd ib0ys ,4brnyw;7:l to the correct description?

  Which statement(s) are true of men ./bw2ykyh6miosis I but not meiosis II?
I. Crossing over occurs during prophase
II. Sister chromatids are pulled apart during anaphase
III. Chromosomes supercoil and become visible during prophase

  The micrograph shows an oocyte afte ciq1nu6zh c*sy10/ntr the first meiotic division. This results in the formation of one large cell and one smaz ntcqyuhni/s 116c 0*ll cell. What is the fate of the large cell?

  Which row correctly describes acb8k(( /intanh 5vp- diploid and haploid cells in humans?

  The following table shows the diploid chrom+kow9c,pzr *f osome number of a range of species.


Which of these statements is correct?

  What conclusion can be drawn from the karyogra 0g yorns3xm3/m below?

  Which of the following processes is characteristic of the me5zv1s k ;exw;x, b sle5lv2 yup3nt8x)iotic and not the mitotic cell cyc v k51yesu 8,wzlp b tsxl;325;xn)evxle?

  The diagram represents a bud with a sh*k)jo4ku x qj9+u19ihsh b. edoot apical meristem.

1.State the type of cell division that occurs in the shoot apical meristem.
   is the type of cell division which occurs in the stem tip.
2.Outline what happens to the cells produced in the shoot apical meristem.

3.State two types of tissue that are produced by the differentiation of cells found at the shoot apical meristem

  The diploid number of the chimpanzee (Pan troglodl5c: qo9xirpu80l: lhytes) is 48. Which row shows the correct chromosoml:q x5oilphu9 l0r:8ce number for different cell types and cell division stages?.

  At the end of which phase of meiosis I does crossing over o1vcvd- 9m;apuv.jl k*ccur, and what is the outcommp9-a vkj.d ;cu*1vvl e of crossing over?

  Which of the following statements does not describe a step in the sodium-pota;d lx4o m5g)isssium pump cycle in the neur d;)ilg5mo4xs onal cells?

  Which row in the table below is true nieu oyqc,wc9 022 4ohkj5k9uoym2t3 of meiosis?

Membrane transport is important for allowing particlexwr89te gt/ tvvb-h .,s to move across the cell membrane and respond to cxte9v,r v/gb t.-h wt8hanges in the chemical composition of the extracellular fluid.

1.Outline the effects of placing a liver cell in a hypotonic solution.

2.Outline how the fluidity of membranes allows materials to be taken into cells or to be released from cells.

3.Compare and contrast four types of membrane transport. Include an example of each.

1.Explain how mitosis is regax6z8kpoh 16mulated in cells.

2.Describe the stages of interphase and their importance to the process of mitosis.

3.Discuss the importance of mitosis to living organisms using named examples.

  The diagram below shows the concentrations 1x5chxu+;w9-ux4k4odv1udgnh 5f li rm ,r )b of different cyclins during the cell cycle. Which xxikru 4 ub1nhw1lg4+r 9f dx,)uhdm5vo;5-c cyclin is involved in preparing for DNA replication?

The diagram below shows chromosomes durink)4f nwq; vozj1olj+( g meiosis.

1.1.On the diagram above, label chiasma with the letter R.

1.2.On the diagram above, label a chromatid with the letter Q.

2.Describe the process of crossing over.

3.Explain how crossing over results in the formation of genetically unique nuclei.

  Which stage of meiosis involves the separation of homologous chromxzuf;e8w 6qvge: q+f 9osomes?

  The mitotic index of throat tissues taken from 4 different patit 2 8* /ggrecsv:neft.u+j 4aaents is shown below. Which patient is most 4:s* etvf gn.aect8gu/a+r j2likely to have cancerous throat tissue?

1.Draw a labelled diagram to represent the process o0y :c1spt*mg aa-:j ppf crossing over.

2.Compare and contrast random orientation and crossing over.

3.Outline the stages of meiosis.

  The image shows an abknc9 sx6vg q3 d hxdwmq/v,*6)normal human karyotype.


What is the abnormality in this karyotype and its cause?

The graph below shows the relative amount of DNA idvlay4zj 3py orw7-,:r2ahe7n one cell during one complete cell cycle. Each letter represents one stage 3:2wapzy 4h ,vo7r -jad7er lyof the cell cycle.


1.1.State which stage of mitosis or interphase is represented by stage B in the graph.

1.2.Explain your answer to part (i).

1.3.Bortezomib is an anticancer medication and arrests cells in the G$_2$ phase. If a cell shown in this graph began the cell cycle at A with 3 relative units of DNA, and Bortezomib was applied to the cell culture at stage A as well, estimate the relative amount of DNA in the cell at the end of C.

2.Explain why the amount of DNA in one cell remains the same in stages C and D.


3.The diagram above shows cells in different stages of mitosis. Label one cell that is in prophase and one cell that is in anaphase.

  The diagram below shows a cross between a male cat that is homozygous 2p eh- 5yakeg/ egqq8zt6 vo*/for brown, long hair and a female cat that 5 a8g -tqo pe6y/evhk2q/*gze has black, short hair.


Which of the offspring has a recombinant genotype?

1.Outline how polygenic traits ca9l(m) do1mecen show a normal distribution.

2.Outline the differences and similarities between homologous chromosomes.

3.Explain why expected and observed Mendelian ratios may differ.

  Which gamete can result from the crossing over of non-sister chroc1e7).vp,eg+gbgz homatids shown in the diagram bgp+e gcb,h )o7.v 1zgeelow?

  The photomicrograph shows a pollen grain from L. candidum (Lilyx(uy-;v kbypi85 z(r l mhw.2v). Which stage of meiosis is ku8vvyry ;zhi5 2.l(bwp -xm(shown?

1.Outline the events which would y wwbyl 3ixq4/w*)lsm;l ,d;zlead to an individual being born with Down syndrome, which is cwsdxmzb* lllw4 y q;w)3/,;iyharacterised by the presence of three copies of chromosome 21.

2.Explain how meiosis increases variation.

3.Outline the stages of meiosis.

The mitotic index is an indirect way of measuring plant growth.k6g s/u e;)/fcj0i mhd A study was conducted on white onions (Allium cepa), under controlled conditions in a lab, to investigate the efegifk/j0s);h/ c6md ufect of soil pH on the mitotic index of the roots.


1.Describe the trends shown in the graph.

2.Outline how the mitotic index is calculated.

3.Discuss whether the data support the hypothesis that onion plants should be grown in soil with a pH of 5.5.

4.Suggest how a pH of 9 affects the process of mitosis.

5.1.Explain why measuring the mitotic index in the root is an indirect way of measuring the overall growth rate of the onion plant.

5.2.Suggest another method, apart from measuring mitotic index, that could be used to measure plant growth.

6.State one of the variables that must be controlled to make this experiment valid.

Mitosis and meiosis are two ways in which cells can divide. The diagrams below4nwf wr s5k 9q+;nfcs bg331zn show two cells from an or4bsqwk nswf35 3zrcg fn1 ;+n9ganism with a diploid number (2n) of 8.


1.Deduce if Cell A is a gamete or a somatic cell. Justify your answer.

2.Identify the stage of meiosis represented in Cell B. Justify your answer.

3.1.Draw a diagram which represents Cell A during metaphase I.

3.2.Draw a diagram which represents Cell A during prophase II.

4.Compare and contrast meiosis and mitosis.

1.Outline the role of gene expression in +xw3 xufaq, v m+-zb/ bhug,0xpfac)4lzle0 9stem growth.

2.Outline how growth is controlled in the shoot apex of plants.

3.Explain the process and applications of micropropagation.

  The diagrams below show a cell, with a diploidd npq(vl )a;rlfl p)*; number of 8, in different stages of meiosis. Which rl;)q v a;l)fpdpl(*nrow correctly names each stage?

  The micrographs show fourng -+8o f.ewhf phases of meiosis I in a plant. In what order do these phases o+go f8h.e-fwnccur?

Mitochondria are responsibleyedd)6a y - siq eg-5iq 1dnh.5*wnhk8 for supplying metabolic energy in eukaryotic cells. In most eukaryotes, which reproduce by sexual repro61ddn8whiyg5 .)* yekh ia-ds -n5q qeduction, mitochondrial DNA (mtDNA) is inherited from only one of the parents: the mother in the case of humans. This is in contrast to nuclear DNA which is inherited from both parents. It has been suggested that, in some eukaryotic organisms, inheritance patterns of mtDNA found in hybrid cells, which are the result of sexual reproduction between two different yeast species, could be influenced by the parent’s genetic background.

In an experiment, scientists investigated if environmental factors could influence the inheritance of mtDNA in hybrid cells resulting from the sexual reproduction between two closely related species S. cerevisiae and S. paradoxus.

The first step in the experiment was to produce hybrid cells, which were then grown on different agar plates, each providing different growing conditions, which simulated different environmental stresses. Cultures were then taken from each agar plate and grown in a liquid medium, with the same respective environmental conditions. The procedure is outlined in the diagram below.


The mtDNA genotypes of the resulting hybrid cells were then identified and compared to that of the original parents.


1.Describe how the pattern of inheritance of mtDNA in the hybrid cells is affected by the different conditions.

2.Identify the liquid medium which resulted in the greatest AND smallest difference in number between hybrid cells with mtDNA from S.cerevisiae W303 and S paradoxus YDG197.

3.Calculate, for the 2% glucose condition, the percentage of hybrid cells which contained mtDNA genotypes of both S. cerevisiae and S. paradoxus.

4.Compare and contrast the results from the first and second experiments for the 2% glucose condition.

5.Identify the liquid medium condition which resulted in the greatest difference in the number of hybrid cells with mtDNA genotype from both parents between experiments 1 and 2.

In a final experiment, the team of scientists wanted to examine the activity of mitochondria, as indicated by respiratory competency, in the hybrid cells grown under each of the aforementioned growing conditions.
Respiratory competence was measured by using a stain, which stains respiratory competent cells red. The absorbance of cells was then measured, with higher absorbances indicating higher levels of respiratory competency.
Note that hybrid cells which contained both parents' mtDNA were excluded from this experiment.


6.State the growing condition and strain which resulted in the highest levels of mitochondrial activity.

7.Discuss the hypothesis that hybrid cells inherit the mtDNA from parents who are best adapted to their environment.

8.Evaluate the use of S. cerevisiae and related strains in the study of mtDNA inheritance in humans.

  The table shows the numbe,,wgippup8 w;:j4f;ra0 wxder of cells in different stages of the cell cycle in four samples of lung tissue from four patients. Which tissue has the lowes8p:wi;dw 0pa,r egwux 4p,; jft mitotic index?

  The diagram shows the dominant cyclin/CDK coe8 f vm.pgc)d8y(cv:emplexes at different time points in th)88p.fcd vgcvey(e: me cell cycle. Which cyclin/CDK complex activates DNA replication machinery?

  Studies have shown that genes such as Cyclin Dependent Kinase 3 (CDKN3)a3)a7qm ie k39 ak7hmw are highly overexpressed ia7mkim)h q3kaew79a3 n cervical tumours.


1.Calculate the percentage increase of CDKN3 gene expression in cancerous cervical tissue compared to healthy cervical tissue. Make sure you show your working.The number is   %.

Overexpression of CDKN3 in cervical tumours has been associated with decreased survival rates in cervical cancer patients and has been shown to trigger cells to exit mitosis and begin cytokinesis.


2.A hypothesis has been proposed that overexpression of CDKN3 in cervical tumours results in an increased chance of patient death. Evaluate the evidence for this using the data given.

3.Overexpression of CDKN3 results in increased levels of cell division. Describe how CDKs and cyclins are involved in the cell cycle.

4.CDKN3 has been identified as an oncogene. State the definition of an oncogene.

c-REL is another gene that has been linked to cervical cancer and its expression is correlated with the expression of CDKN3. Using CRISPR technology, cervical cancer cells have been created that do not express c-REL (c-REL -/-). Expression levels of c-REL were checked using protein analysis.


When c-REL is overexpressed in cervical epithelial cells it results in greater proliferation of cells and the cells spend less time in prometaphase (the phase between prophase and metaphase) compared to healthy cervical cells.


5.1.Looking at the photomicrograph above, identify the stage of mitosis that most of the cells are in.

5.2.Based on the evidence provided, suggest, with a reason, which of the labelled cells would be present in the highest numbers in c-REL -/- cervical cancer cells.

cREL-/- cervical cancer cells and cervical cancer cells with high expression levels of c-REL were treated with the chemotherapeutic drug, cisplatin. Both types of cells were exposed to different concentrations of cisplatin over a 21-hour period, and the effects on cell number were analysed.


6.Using the graph above, compare the response of cervical cancer cells that express c-REL and the cells that do not express c-REL (c-REL -/-) in response to exposure to different concentrations of cisplatin.

7.Suggest a reason for the different effects that cisplatin has on cervical cancer cells expressing c-REL and those that do not express c-REL (c-REL -/- ).

8.Suggest why some c-REL -/- cervical cancer cells have a similar level of cell death to those cervical cancer cells expressing c-REL.

9.Deduce whether cervical cancer cells expressing high levels of c-REL and CDKN3 will have a higher mitotic index than those with lower levels of c-REL and CDKN3..
Cervical cancer cells with a high expression of both genes will have a  ----待选择----higherlower  mitotic index, as they are dividing more rapidly.

  When is the concentration of cyclin E the highest during the cell cy0noz0o1m)hvn 7x,mwg cle ?