The graph below shows thuglrcnd*h x4 (8(( ihmh 3k5nwe relationship between maternal age and the incidence of non-disjunction. What relati5mi (ck(gnd(3h8nxhl 4urhw *onship is suggested by the data in the graph?

  Which stage of meiosis is representemiy 2jd 7 2y8 /ggod*dshij3l*d in the diagram below?

  The diagram below shows chromosomes during meioi73bxtoj7e 5n+ )l vabsis.


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 a e mx m-j, uogoxp2d))qpr;+dg8(b q6vlleles of a single gene which would be present in the nucleus ofgqxqdpo(;m ,-8x)mro vpeg d b2)u6j+ a cell as a result of each process?

  Which keyword is matched t:o9xz9g nd,syetm g8-c ;a;j ro the correct definition?

  Which statement(s) akl;vb-7jl9*s.:r ed ax; 7p/c zgizmvbout 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 letteufprn)y ,/i;d6d.e k nr points to a cell in anaphase?

  During which stage of mitosis does the nuhcyh xir 32;d)clear envelope break down?

  Which one of the following transport proteins only carries out act5omu of(qb4o-ive transport? 5qo ofob4mu-(

  Which process does not happen in the --evr* fy4a6t 1klsecshoot apex?

  Which type/s of membrane transport do/does not require ener3kv0*p r5fxjngy expenditure?
I. Facilitated diffusion
II. Active transport
III. Osmosis

  The diagram below represents a cell with a diploid number of 4. k2s musbr;7q, Which stage of cell division is the cell currentksqr 27msbu;,ly undergoing?

  The photomicrograph below shows a root tip meristem.f04zfa fx l;e6;m(jc i Which of the following sentences correctly delm6fef (z0;x4 ija;cffines a meristem?

  When does the random orientation of homologous chromosome pairs occur?lwkuy 9:l- q e6ojhn57

  Which process does not occur during meizs.+xl4fc/z uosis?

  If a cell with a diploid number of 36 undergoes mitx1 (-n/tissyf7is7 b l,qvdc-osis, how many chromosomes will be present in each daughter cell afnvl 17q- cid(7fs-bsyi, tx/s ter cytokinesis?

  The image shows a microg+1mf vgu)gfg/am g*o 1fs5r+draph of a cell.


What explains the appearance of the cell in the micrograph?

  Which statement(s) about homologous chromosomes is/are not trueg/5j+vr0g gacg +nw -l?
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 individual with Do3ykc0n yzzp0jj2wr 43wn syndrome.

Which statement is not correct?

  In the cells of a horse (E. caballus) durinb +;au1i1.vwu,h swc.3lyx s ig prophase I of meiosis I there are 64 chromosomes. What is the haploid number of chromosome3i l.+via;buw1 cuhyxws.s 1, s?

  Which arrow is pointu834 .s bddtj1z b9j iu kazsimmm954*ing to a chiasma?

  The diagram below represents the structure of a h*jrmxp 88dqs ;t63rpo tt9z4)* mwjyshoot apical meristem. Which row in the table correctly identpwt *dm3r* j96rxst tymqh 8;j z4op)8ifies the processes occuring in the structures labeled in the diagram?

  How does meiosis promote jg xcznvm c.*s 60f,-dvariation?

  Which of the following statements it7- ty5si7n6ejt7 z7k) txhb ks/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 homol 4om,7qzy5if9k w :jarogous 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 tumouf5xk sfvejal8 vj* : 6-3io f(7gb2undrs from primary tumours as a result of th fs(28ffj vvo5:i-a n 37l6dbukxe*jge movement of cells?

  How many chiasmata are pre ze. nt.gokd/1y9vu)esent in the diagram?

  Which statement is a similarity between cy e2df s(69sgldtokinesis in animal and plant cells?

  Which stage of meiosis is matched to the correct description?d, qayvkf 2,94f tachs (zrc8b,znv(oru j-+;

  Which statement(s) are true of meiosis I but nj,lktsq*a q i yzp82 ahh7l3:(ot 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 thn*; cruq c0i/b b/ eur-*7xnllxld 6:he first meiotic division. This results in the formation of one large cell and one s r ibc 6n*xb*u c0/l; /7enh-:rlxuldqmall cell. What is the fate of the large cell?

  Which row correctly describes diploidoq,nb5/yw* o rqj io+- and haploid cells in humans?

  The following table shows the diploihmd):w x okb2)blv2r(d chromosome number of a range of species.


Which of these statements is correct?

  What conclusion can be drawn frhjar5kzw*sd d/6 rl6lzr2:9 kom the karyogram below?

  Which of the following processes is characte)rb1y; b:3 y cavnb)l0e w,ozbristic of the meiotic and not the mitotic celzw o1 ;:nybbv 0yerbc a,)bl3)l cycle?

  The diagram representi5w9haqdsw2.; 9nm yu s a bud with a shoot 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 troglodytes) is 48. Which ;h3 n wg qj*lz wj)+*audzo2x6row shows the correct chromosome number for different cell types and cell division sta*; n+ g *a)wuhzzwd2qlo3j6x jges?.

  At the end of which phase of meiosis I does cq:4ba9d:ybyio:: ru..e-psb e9oso crossing over occur, and what is the outcome of cr 9:e:boacb4.so py9y:si duq-e:or.bossing over?

  Which of the following statements does not describe a step in the sodiumc f+pz6a8 /48zurja,nne0 bet-potassium pump cjan /06c b8ez+nu,8tfza4 eprycle in the neuronal cells?

  Which row in the table below is trud9t :e-uudy am4dwc :+e of meiosis?

Membrane transport is important f(vkmccj x 7)a-a-qj)xor allowing particles to move across the cell membrane and respond to changes in the chemical com(q7jvac -a))jxxm c-kposition 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 mitosic z8xw z-hq (uf-9.myfs is regulated 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 differn ilr5q6ev9 +went cyclins during the cell cycle. Which cyclin is involved in preparing for DN+69nqwi5 erlvA replication?

The diagram below shows chromosomes during meioc n)x8ct,bqdc / xy(1csis.

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 chromosd1 cb5pe50 hvu9kp3uromes?

  The mitotic index of throat tissues taken from 4 different patients is shown o1 f *my4h1t1t qpssg:below. Which patient is most likely to have can*oftgq4yt 1h1ss :pm 1cerous throat tissue?

1.Draw a labelled diagram to represent the process ,7cma+ywqkr2 of crossing over.

2.Compare and contrast random orientation and crossing over.

3.Outline the stages of meiosis.

  The image shows an abo3wuay wrqu3(+; :wyhnormal human karyotype.


What is the abnormality in this karyotype and its cause?

The graph below shows the relative amount of DNA in one cell during oxwr u15/ /uqtnne complete cell cycle. Each letter represents one stage of w /ut/5xn q1urthe 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 homoziw +d*4yf*igm+e r (gicj+/nnygous for brown, long hair agngfr*y/iid4i (+++c n m jw*end a female cat that has black, short hair.


Which of the offspring has a recombinant genotype?

1.Outline how polygenic traits can show a normal distribue*py 3s-xhk, snv7jhq4s bm7eu 7p.9ution.

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 chromatids showntw p0zkn+xy2r 7oc a66 in ta7pc no +x0k2zr66wyt he diagram below?

  The photomicrograph shows a pollen grai-g- j 9sttuyxjg)8qh8e 6fl+ glh/+zi n from L. candidum (Lily). Which stage of meiosis is shown? +xguj6llzi g/q9 sgh 8j)hfte 8y-+-t

1.Outline the events w*lcrkqwu jpr2 h4y5df,tm.0,hich would lead to an individual being born with Down syndrome, y rtjdwfql,cp 2,05r4. m*uhkwhich is characterised 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. A study wm1-qnt o x6l5r;qyy13k b 5yymas conducted on white onions (Allium cepa), under controlled conditions in a lab, to investigate the effect of qnyqb 6 l1xro3t y;y-m15mky5soil 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. -a4f- df5jzy y c)bf)bThe diagrams below show two cells from an organ bby 5jaf)4d )cfz--fyism 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 expressiov uhkbupob6hr1m03v/ q324 icn 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 diffeedpgvbt yk (38(.;ma vrent stages of meiosis. Whic;g (m(p8avbvd.eytk3h row correctly names each stage?

  The micrographs show four phases of meiosis I in a plant. In g1 mpdw0wah0kdy.p6- what order do these phasg 16 ah0mkpdyd p0-w.wes occur?

Mitochondria are responsible for supplying metsn.v17gke u y+lf y9.nabolic energy in eukaryotic cells. In most eukaryotes, which reproduce by sexual 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 f ng uvy e.l+.kyn719sfound 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 cells in differe6 hm7 zdge4crepv2a 8eh.p58 lnt stages of the cell cycle in four se.ge4 l7hm58vpa hc zp6 28dreamples of lung tissue from four patients. Which tissue has the lowest mitotic index?

  The diagram shows the dominant cyclin/CDK complexes at differentg ruqjwzer l*kxat:paa. x2pj +9.t-9l o39 k/ time points in the cell cycle. /pej jx lxg.u*k -aka9qr3tw z.to 29+ :lp9raWhich cyclin/CDK complex activates DNA replication machinery?

  Studies have shown that genes such as Cyclin Depen9e1r1um )tb utk7o/ +qujgh ;edent Kinase 3 (CDKN3) are highly overexpresset/)rj1thomg +u9ue;u1b7kqed 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 durinre1 +urkdbcte (9c*j0g the cell cycle ?