The graph below shows the rexxyo -h:b+ lzftf( d45lationship between maternal age and the incidence of non-disjulxz yf+5 -to(:f xhd4bnction. What relationship is suggested by the data in the graph?

  Which stage of meiosis is represented in tte oe0, l/zh0mhe diagram below?

  The diagram below shows chromo-(v:g*q mbhsk somes during meiosis.


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 of alleles of a single gene whk8ed,3e c2rkr;kb rml9 2p8hs ich would be present in the nucleus of a cell as arbd,9pe2ck;2k8 hr3mrke l s8 result of each process?

  Which keyword is matched to the correct definitixhbinf39 q8q) on?

  Which statement(s) abol4 72 ;;hib :fwiwgxnqhmc,3wut mitosis is/are 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 tog w -1z.j(abj r(yh4xr76 yovl a cell in anaphase?

  During which stage of mitosis does the nuclear enw:3 tnl/j r0vfvelope break down?

  Which one of the following transport proteins only carries out active transport?nj6 ;l+w3 ibon oed gv.c9 i:bynm7v+8 iwv:d n o7e9+in+m g38.ovjbbn6ycl;

  Which process does not happen in the shoot iyd zqz(37oo lf.,epy+(fw 5lapex?

  Which type/s of membraneb-rtp lwyq ;:,x6ihj wr6;v2dc/ mwg+ transport do/does not require energy expenditure?
I. Facilitated diffusion
II. Active transport
III. Osmosis

  The diagram below represents a cell with a diploid number of 4. Which stage o6 6-4 zxp3jyotbe typ+,;eartf cell division is the cell cub3prx;4a 6ze t6y y,-t +tpoejrrently undergoing?

  The photomicrograph below shows a ro 3hxdj)5axe8 m;n9odtot tip meristem. Which of the following sentences correctly defines a me; xmtd5o93nhx d)8ja eristem?

  When does the random orientation of homologous chromosome pairs oc;9i6pp;9 vnoit5tvx ij gbt,b8eai98 cur?

  Which process does not occur 35o5nlz m q(shduring meiosis?

  If a cell with a diploigl: kwa6 pde8ux.h 8 n/gq:w9xd number of 36 undergoes mitosis, how many chromosomes will be present in each daugh. nhweq8ug adx69::x8k/l pwg ter cell after cytokinesis?

  The image shows a micrograph of a cell.kk/ bepa5e thx +l3ugz5z8 5s2


What explains the appearance of the cell in the micrograph?

  Which statement(s) about homologousj 29lhnhm+of yrbir)r12, v 5o chromosomes is/are not true?
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 an indz5/ ug,fk0pi+ 6bwc5ooq/z ifividual with Down syndrome.

Which statement is not correct?

  In the cells of a horse (E. caballus) during prophase I of meiosis I there3wik (8awd4gb/ ,yqf 7hgv -mx are 64( yfxgg/ 8w bh4m7q3,-daiwk v chromosomes. What is the haploid number of chromosomes?

  Which arrow is pointing t3ernlz7y5p 6v6m v 2j0ofk sy1i n3ns-o a chiasma?

  The diagram below represents the structured5y fhva66i x7 of a shoot apical meristem. Which row in the ta5i yh7 dv6x6fable correctly identifies the processes occuring in the structures labeled in the diagram?

  How does meiosis promote variahekn mm -x7oc: wp6j+3+z+fu vtion?

  Which of the following statemejb.aa/;x/,nkg p ;ikvnts 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 tw ty8 3wapss:d2o homologous chromosomes.


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 formation of secondary tu *yr h;ri5na pf*js+q;mours from primary tumours as a result of the movement of 5 +*;aj;snyhf*qrrpi cells?

  How many chiasmata are pre ras*jp 1ykfqc*ug 4e 73zfm2:sent in the diagram?

  Which statement is a similarity between cytokinesis in animal /4mwu ,tx0x :4wqhew9u)uszland plant cells?

  Which stage of meiosw0dxx /:wv .y3i8lu g/rcd ca0is is matched to the correct description?

  Which statement(s) are true oshmp dzbv0:go4t 50 :kf meiosis 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 after th9-twa4g y;fzn.1 lz.ocb jz 2n+2g1dnim qqb:e first meiotic division. This results in the formation of one large cell and one small cell. What is thla jwoy:m b1;+2f qz gbt .91dn-nz.inc24qzg e fate of the large cell?

  Which row correctly describes diploid and haploid k+9it ::5aoni njc(cl.bss b0cells in humans?

  The following table shows the diploidi , 6mskod*(gnqq a.zv 8d/st1 chromosome number of a range of species.


Which of these statements is correct?

  What conclusion can be drawn from the kau;q6. m:ppxdvw9c7v nryogram below?

  Which of the following processes is cw*n udp:39sz zharacteristic of the meiotic and not the miz zu*:pn 9sw3dtotic cell cycle?

  The diagram represents a bud with a shootj2 opz2i3sw+:3cx t nj 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 chimpty.2(.ktin8h he l)z panzee (Pan troglodytes) is 48. Which row shows the correct chromosome number for different cell types and cell division stages?.p.(e2.tlzytn 8 ki)h h

  At the end of which phase of meiosis I does crossing over occur, and what dknm8 ak4b -,ic;p l8cis the outcome of crossing over?k,ak 8i8dnm;-bcp c4l

  Which of the following statements does not describe a step in the so76qyg3 wumbo-2j .hzi dium-potassium pump cycle in -6yguw 73hibm .zoqj2 the neuronal cells?

  Which row in the table/socq+hp:9p3exjga a wi56 (l below is true of meiosis?

Membrane transport is important for allowing particles to m(+fgsl earm;h r 3d 2snrf(0b/ove across the cell membrane and respond to change be/f +s0s(mgd;larf3 h(r r2ns 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 r3vm1 8k:psbft4j e; ruegulated 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 of differezh26 m zmy 8(ltgoc2:fnt cyclins during the cell cycle. Which cyclin is involved in pre mmo2 g82y: flzt(ch6zparing for DNA replication?

The diagram below shows chrompl.w pehju91f)e7.fltbf c 96s2y 3s nosomes during 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 smsd . falzq-r j1e(.(1)d:wx:jckq zbeparation of homologous chromosomes?

  The mitotic index of throat tissues taken) zbx:w i(zh7s from 4 different patients is shown below. Which patient is most likely to have cancerous thro:(7izxwbz h) sat tissue?

1.Draw a labelled diagram to repres pmcrb:k;muzg7i;tsv; +7z -gent the process of crossing over.

2.Compare and contrast random orientation and crossing over.

3.Outline the stages of meiosis.

  The image shows an abnormal human karyotyp4w v6zi8.qwau e.


What is the abnormality in this karyotype and its cause?

The graph below shows the relative amount of DNA in one cellu ge rscw7)hz 1h0-gi* during one complete cell cycle. Eachis- weruz*cg gh1 )70h letter represents one stage of 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 homozwsx ug)/ushs7 ra(:v,ygous for brown, long hair and a female cat that has blaaw g,uus7vsxs (/rh :)ck, short hair.


Which of the offspring has a recombinant genotype?

1.Outline how polygenic traits can show a normajvp.jl n6to9l7md93 y l 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-s/fomm/4lclbm:rz9xdgbg 7 +5. ix *t/u8kyyoister chromatids shown in the5bglxk myb.9:4o ry d* i7 /mcm/zxf/gul8t+o diagram below?

  The photomicrograph shows a pollen grain from L. ca52r75mqx brcw h aepv +ev26-zndidum (Lily). Which stage of meiosv5c6 2za 5mrev+ ew7-pxbhrq 2is is shown?

1.Outline the events which would lead to an individual bei 1(lna7oc -ya3hgoeu4ng born with Down syndrome, which is characterised by the presence of tlg4ea 31oahnyc- o(7uhree copies of chromosome 21.

2.Explain how meiosis increases variation.

3.Outline the stages of meiosis.

The mitotic index is an indirect way of measurin )if6x. fa .caxck- lh31+)ctqqrs6zf g plant growth. A study was conducted on white onions (Allium cepa), under controlled conditions in a lab, to investigate the effect of soil pH on the mitotic index of the roots. .3 qlsc)6qf+atf- akixzhr)c1 xf 6 c.


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 ch2 8+b2 rm/jum0a bk 0h5gfyklells can divide. The diagrams below show two cells from an organism with a diploid nubb m+g h h0uy05k/kml2 jr28famber (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 expressio,6z ik;uu e *zp73fs;7f xfjofn in stem 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 diploid number of 8, in differr2l ukunjy6 r-.egs*8 ent stages of meiosis. Which r ur.jsr ngu l6y2k*e8-ow correctly names each stage?

  The micrographs show four phases of meiosis I inqs /ot3 k(: +lylxy0ye a plant. In what order do these phases occl: 3lse yy+x0t(koqy /ur?

Mitochondria are responsih7y5 p+u e+ une0i; p vt(2vj(bj3bkheble for supplying metabolic energy in eukaryotic cells. In most eukaryotes, which reproduce by sexvju;e25pty 3+pu+ihn ( eh0 b vje(kb7ual reproduction, 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 number of c mrtst ixz; h)p+qrvi 6td28.,ells in different stages of the cell cycle in four samples of lung tissue from four pati, r2i )x8 vqsi .p;m6dzrt+tthents. Which tissue has the lowest mitotic index?

  The diagram shows the dominant cyclin/CDK complexes at diffd m9todzuhnqg/ moek;0xfn-/d5h :*4erent time points in the cell cycle. Which cyclin/CDK complex activates DNA replication ma0 9 hk end: duox-;ngmqzo/d4*f ht/5mchinery?

  Studies have shown that genes such as Cyclin Dependent Kinaiq+p6 ;jk4v 0rbep2*yay se q(se 3 (CDKN3) are highlp;j2veb0* qai(qysp4 erk +y 6y overexpressed in 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 cel k4 xqkxmrk97a1dvq r7nvs(:/l cycle ?