The graph below shows the relatiose*o6 ;* :dwsexyh0 ze/t vicblc0+y- nship between maternal age and the incidence of non-disjunction. What relationship is suggested;0/t**s ev h-ieeyodslcx c+ y:b0z6w by the data in the graph?

  Which stage of meiosis+02e fic,lk uvp93bwt is represented in the diagram below?

  The diagram below showsll m3ird* yws.eemrr5 :77 :ck chromosomes 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 a5 9scri67ngaw* dzi5q lleles of a single gene which would be present in th57rns*wdg5qiizc a 9 6e nucleus of a cell as a result of each process?

  Which keyword is matchest,b p:fm 3,bcdsg5oy* l9shl;3 +b9h txjj+md to the correct definition?

  Which statement(s) about mitosis is/are0mq kcew-u;f0 6z;4xi t6a)v iy9ubor 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,y;gal;b/1dvoha8b 8 7gu-g il which letter points to a cell in anaphase?

  During which stage of mimq x/(v4*tjtw qfl5;msx,6rutosis does the nuclear envelope break down?

  Which one of the following transport proteins only carries out active transpo.ja . 5zxa+x dk-x u nq/swikvzh.f)85rt?k5v wkqxz8da/x.)j .aiz.- nx+5fsu h

  Which process does not happen in the sh f ,blnic1+)h/pn;qxl oot apex?

  Which type/s of membrane transport do/does not require energy exev )s1q1s3 v/sawezh9m;pa6m penditure?
I. Facilitated diffusion
II. Active transport
III. Osmosis

  The diagram below represents a cell with a diploid number of 4. Which stuafjmgw;jp 9 f /56y+zage of cell division is the cell currenwmf9jgz5f jyp/u a;+6 tly undergoing?

  The photomicrograph below shows a root tip meristem. Which of the following 4*t xmywtbw: +e hc(v2sentences correctly :t*bye2+(v4cx mwhwtdefines a meristem?

  When does the random orientatio,w.dho:b6m jz epe7- wn of homologous chromosome pairs occur?

  Which process does not occur9sp*oya ud g;. during meiosis?

  If a cell with a dipl/jnsq:4nr * o0jzv ;uloid number of 36 undergoes mitosis, how many chromosomes will be prese 0zsn4 *lu:rqo/vjn;jnt in each daughter cell after cytokinesis?

  The image shows a micrograph of a co jx/4-utb+lfn,dnf;ig f;vqw5a .. mell.


What explains the appearance of the cell in the micrograph?

  Which statement(s) about homologous chro9os7o ;6 pszjz-,q6b8:km+cuaioyj gmosomes 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 individual with Down syndrome.:/ thjckm 4x h980lrcg

Which statement is not correct?

  In the cells of a horse (E. caballus) during prophase I of meiosis I there arb, tq9edl) tw7e 64 chromosomes. What is the haploid t9 e,q)wbl7dt number of chromosomes?

  Which arrow is pointing to a c */d0zv) uykqghiasma?

  The diagram below represey5g7+mzm 4q hxnts the structure of a shoot apical meristem. Which row in the table correctly identifies the processes occuring in the structur7 hmxqg5y m4z+es labeled in the diagram?

  How does meiosis promote variatijj u62), cyjjr69buomp6ll 2qon?

  Which of the following stavthum:: a 9wp,tements 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 frobs n4/i0upnw czm r;5a:l5qj 9m two 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 tum t2wjuxa+s ,0ia 8 8-br0okybwours from primary tumours as a result of the mov0x8-bjtw8 w0aa,2b+yuosrk iement of cells?

  How many chiasmata are present in6 t1 3v;ywg(2jlxoxo 4 wh9zjk the diagram?

  Which statement is a similarity between cytokinesis in ani 8zg- 7tvo6tgbcs -w3fmal and plant cells?

  Which stage of meiosis is matched to the corre6vl qc 5zw2s6n )s55kwvx u9xact description?

  Which statement(s) are true of meioslzq 112mlw*k)hcndpr k; i;2m is 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 the firstamr+sn *0yu9;t.b5px)9 uufj gty +yi meiotic division. This results in the formation of one large cell and one small cell. Whb;+ruyfy5ntutg.amyji0s )u*p9 9 x+ at is the fate of the large cell?

  Which row correctly describes diploid and h5h e4f b uh1ieh2:h(tmaploid cells in humans?

  The following table shows the diploid chromosome number ov 72we 34/taw2t 4ubruhby(tjf a range of species.


Which of these statements is correct?

  What conclusion can be drawn fro mh 3so2qp0tw/p0gb+s,hbs+r m the karyogram below?

  Which of the following processes is ch0eql /fw*rizu /fa*0caracteristic of the meiotic and not the mitotic celli*qlc0/wuafzr0 f e/* cycle?

  The diagram represents a bud with a shoo; vg ;mo8 c uby(puq3(,lelto ai(2ux3t 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 troglodyt.(;-;cg 7 d,lakzp oij tlkb-/i,lnemes) is 48. Which row shows the correct chromosome ,lki-gt- ijpl ,l;ek7 omc n.;ba(/dznumber for different cell types and cell division stages?.

  At the end of which phase of meiosis I q; 3) ;g+yps r3;slmdu,mvs vvdoes crossing over occur, and what is the outcome of crossp; lv mq3musr+s; y3vdv);s,ging over?

  Which of the followika:67 fi**)pehmgs f rng statements does not describe a step in the sodium-potassium pump cycle in tef* ipk)*gsamrh76:f he neuronal cells?

  Which row in the table below fs ydba4d wl:q+y71q5(n p- lfis true of meiosis?

Membrane transport is important for allowing particles to move acro inwpy2bdh59o8 f++y c5kc; sfss the cell mem5 h+p+5 ; cb9osf y8cinkfwd2ybrane and respond to changes 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 regul4o zpd*qscw/ /ated 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 different cycli5mh9sqy. g yt(ns during the cell cycle. Which cyclin is involvey g( 9h.mtsyq5d in preparing for DNA replication?

The diagram below shows chromosomes during oucy) 9;w snqq 5+sn5lmeiosis.

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 meiosi+5rx t(hyal;rs involves the separation of homologous chromosomes?

  The mitotic index of throat tissues taken from 4 different patients is a rb j0dy-r:z-shown below. Which patient is most likely to have cancer-r0 dab:rz-j yous throat tissue?

1.Draw a labelled diagram to represent the process of crossing hu:0r 4v *:hprp,mqtxover.

2.Compare and contrast random orientation and crossing over.

3.Outline the stages of meiosis.

  The image shows an abnormal human st1c-t3irww9.*0nfx kdzw e/ karyotype.


What is the abnormality in this karyotype and its cause?

The graph below shows the *ky7gieb6 phw6 bru) +relative amount of DNA in one cell during one complete cell cycle. Each letter represents one stage of the cell cycle.+by 6giehk r) u6*wbp7


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 +qf vt435 q;cey tpq3r*s*bskdx:-wi is homozygous for brown, long hair and a female cat that has 4qeyc: -xd *qwp+ bif3s*k5vqtt s;r3black, short hair.


Which of the offspring has a recombinant genotype?

1.Outline how polygenic traits can show a normal distr.b2rb q.ja3e3g3;h p dw mcto/ibution.

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 ov:z1gtnmz w4c)5 cfz mauq3b36 a8xx(z er of non-sister chromatids shown in the di413nqb(mgcut5zzx a6 ca8xwzfm3 ) z: agram below?

  The photomicrograph shows a pollen grain from L. canddun3 e2*q ) n:oyt.be./punzr idum (Lily). Which stage of meiosp /3n)e*2qu odte.u rybn :n.zis is shown?

1.Outline the events which would lead to an individual being born with2( jlr3nsi xe/ Down syndrome, which is characterised by the presence of three copies of chromoers3 ni xj(l2/some 21.

2.Explain how meiosis increases variation.

3.Outline the stages of meiosis.

The mitotic index is an indirect way of measuring,vk/g:v+ uwki plant growth. A study was conducted on white onions (Allium cepa), under cog w,v/i:k+kvu ntrolled conditions in a lab, to investigate the effect 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 twopz.t. -1oq6qm93 wnfiu q5irut/,ion ways in which cells can divide. The diagrams below show 6omi-5urf/9p.wu,ti q nqzt 3 qn1. oitwo cells from an organism 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 stem gro :8 6-lukjssnom3 j*lmwth.

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 ceh0ap2qv 8a.optfm2;y ll, with a diploid number of 8, in different stages of meiosis. Which row corra20 vf. qpao8t2hm ;ypectly names each stage?

  The micrographs show four phases ug8*c/7pbawb):y)e*hbnr yd of meiosis I in a plant. In what order do these phases g **n c8:yby7 b rwe))du/apbhoccur?

Mitochondria are responsible for supplying metabolic energy in eukaryat-rgnbj87 o:otic 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 found in hybrid cells, which are the result of sexual reproduction between two different yeast species, could be influenced by t 8 ron:-tjgba7he 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 different stages of the cell cycle in mal4oy(xs l,) four samples of sxol4(m y, )allung tissue from four patients. Which tissue has the lowest mitotic index?

  The diagram shows the dominant cyc.d9 hsib 9 *su8mun)anlin/CDK complexes at different time points in the cell cycle. Which cyclin/CDK complex activates DNn9 ai.n8hus*u m) bd9sA replication machinery?

  Studies have shown that genes such as Cyclin Depenbn2v2gx7-mw r 6otqy0 dent Kinase 3 (CDKN3) are highly o-y6 o2 xnvqgmw r02tb7verexpressed 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 t4yfcl+4rkv +p mw3 wa.he highest during the cell cycle ?