The graph below shows the relationship between maternal age and the incik3jc;v wy7 xsz2,6hicdence of non-disjunction. What relationship is suggested by the data in the graph ;j, zc2k y7h3s6xwicv?

  Which stage of meiosis is representjyk*qfa+,dmu2:sf zy,8)wjg z zqd: b3u.h e; ed in the diagram below?

  The diagram below shwb,h1v gl27 x ou1 p5u-+uu7b1llnqx cows 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 s 1bxb)3ak1;y gx 7vsxjtates the number of alleles of a single gene which would be present in the nucleus of a cell as a xv;b x1s3g7a)jx1kb yresult of each process?

  Which keyword is matched to ;*, )l(9abqmumwc3z d630lz a6p ycnvw8id s xthe correct definition?

  Which statement(s) about ms n 3vv:2w7 k1zi7iwtmitosis 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 l)qj amba(3hl,gan)/w 7m z i0retter points to a cell in anaphase?

  During which stage of mitosis does u2+ezl8fk: jrzzfrz -2 hnbaa.r:nd k)8a r89the nuclear envelope break down?

  Which one of the following transport proteins only carrit5o;xb/5 yaqd 697d(glbfm8i .xe pudes out active transport?x u l6imd(oby ;dd7 .tax9f8q5/pb e5g

  Which process does not haxve, 2 (+soifcppen in the shoot apex?

  Which type/s of membrane transport do/do zeabasn4co-t4q9 x,,o :ulv8j;/+ :fj ww wmmes 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)3-by lyv4i12 lmhs 3novh6rt of cell division is the cell currently unden 1 y34bh)rvls3 m 62-vyohlitrgoing?

  The photomicrograph below shows a xj76jb ,g8uuf:-ko do root tip meristem. Which of the following sentences correctlykg,fbju786o: o-dx ju defines a meristem?

  When does the random8;qx/ mn7(ltwmht+/;ta sm3 j8oy x do orientation of homologous chromosome pairs occur?

  Which process does not occur during meiosidt a f-nj*i u(z+7ab4ts?

  If a cell with a diploi,n+m;wew5 eleq;n 0mwdrnlu 8lw07y 2d number of 36 undergoes mitosis, how many chromosomes will be present in each daughter cell after cytokil7l lw;,u 0d2wn5+mr8eme wn0n;q ew ynesis?

  The image shows a milnal; nqf7a ,t r,fm -b;fmu:*crograph of a cell.


What explains the appearance of the cell in the micrograph?

  Which statement(s) about homologous ck--czz ejs(f+p5 9cd-p xpyz/hromosomes 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 uq)dqrjq9afvve/rv:s )n 9e 8p+9j 6csyndrome.

Which statement is not correct?

  In the cells of a horse (E. caballus) during prophase I of meiosis I ,f0ugvguek mv+z) 9u ok43nf4there are 64 chromosomes. What is the haploid numbevuog04 vu)e9+ n gkm 4f,fkzu3r of chromosomes?

  Which arrow is pointing to mji9isv;dzit;r)2 : 8ua q2l ka chiasma?

  The diagram below represents the structure( ccec gz*dj,:w-pcjk.dpc 1v4wc(.t of a shoot apical meristem. Which row in the table correctly identifies the processes occuring ccjpj e:d(p,c . z-1 wg(4.ck*cwtcdv in the structures labeled in the diagram?

  How does meiosis promote vawtx; h0qh f v0n o/lb.*4dhm:rw:kk /iriation?

  Which of the following statements is/are correct forab*-q m-: w+p2.qb x ylg,pffk 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 chromosomes. 1;-p x+,rn6pz.v kr gzkmxe*m


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 seconv+ z i37n3kmkudary tumours from primary tumours as a result of the mo73mu3+ nzkv ikvement of cells?

  How many chiasmata are present in /7m .jht9tm ,qudu6fpg0q tbw1h y(i ,the diagram?

  Which statement is a similarity blx.voaclt4; 780bp sn3smv;yetween cytokinesis in animal and plant cells?

  Which stage of meiosis is matched to the correcttkfhm1/pt +,o description?

  Which statement(s) are true of m7g 7j rl e5snt76gz(hxeiosis 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 aft chb-e:t-n- kter the first meiotic division. This results in the formation of one large cel tce-hbn-k-t: l and one small cell. What is the fate of the large cell?

  Which row correctly describes diploid and haploid cells inlaovb ( bv*liu30 a.3-5pvbh q humans?

  The following table shows the diploid chromosome number of a range of specieohdu4k3v 18j7e kpck,s.


Which of these statements is correct?

  What conclusion can be drawn from the karyogram b,h9vaw m-p ,lnelow?

  Which of the following processes is characteristic of the meiotic angt 9 q24va 6ttl).hhbod not the mito htqv.t btah64l29o) gtic cell cycle?

  The diagram represents a bud w3 wxy4v.b.4b -xc gabwith 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 row sh60c 3(eh jrbgv1*dagr ows the correct chromosome gdve1bj arcg r0(3*h6number for different cell types and cell division stages?.

  At the end of which phase (wsu t-c*tzh,wj d4 (et sy(x+of meiosis I does crossing over occur, and what is the outcomew-t(+wseu( 4t,dzt(x*y cj hs of crossing over?

  Which of the following statements does not describe a step in the sodx5pbd+dyhww862 p00dy 9q vatium-potassium pump cycle in the neu w+ t0way 0dhyv659xbdp8p2 dqronal cells?

  Which row in the tabelj8: e +s; 4e5kw tdt/auank;le below is true of meiosis?

Membrane transport isj ln9a;j, vxp ptu/(t)dg h26z important for allowing particles to move across the cell membrane and respond to changes in the chemaxltp,pdj g h vt)un2;/( 9z6jical 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 rebdczt+5aj ,.knya;q-zd 3 .g x9i,vffgulated 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 tgm aph.y)qi 5l*x5d7j he concentrations of different cyclins during the cell cycl)j.mhx5q y 5pgi7a l*de. Which cyclin is involved in preparing for DNA replication?

The diagram below shows 2 fp9, bhtq2fqwctyeqs 0n3 .8chromosomes 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 thsk6ead g*yu:*ho6jnf 6n (9cpe separation of homologous chromosomes?

  The mitotic index of throat tissues taken from 4 different patientsz*8q g 8;lemjp is shown below. Which patient is most likely to have calgzqem88* ;pjncerous throat tissue?

1.Draw a labelled dia4ta5* hzldr-2:pftn r gram to represent the process of crossing over.

2.Compare and contrast random orientation and crossing over.

3.Outline the stages of meiosis.

  The image shows an abnow.eqexmi 4p8,w,n zk/rmal human karyotype.


What is the abnormality in this karyotype and its cause?

The graph below show -qss) efm 7a*koe/2cys the relative amount of DNA in one cell during one complete cell cycle. Each letter represents one stage of the cel*k-y/ o scmaf qse)27el 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 croscdrd f 3(0 je8qg8+gfjs between a male cat that is homozygous for brown, long hair and a female cat that has blfg0cjr+qdedj88 fg3( ack, short hair.


Which of the offspring has a recombinant genotype?

1.Outline how polygenic traits can show a *mkd xqxpc(g*/c gheu2o/koui 0:(k8normal 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 chromatx, * 7w ae :cw o7lkeft7khzc+3vzi(f*ids shown in th+fcelz37t ,w7 *chao fkik(xvw :e*7z e diagram below?

  The photomicrograph shows a pnfezx:8yh595 mg*t/ gbcn/ edollen grain from L. candidum (Lily). Which stage of meiosis is shon/89e h/exg zdgfny:5tm 5cb*wn?

1.Outline the events which would lead to an individual being bo:fd9 1 ahtf) p3h;oazdo(d8qbrn with Down syndrome, which is characterised by the presence of three (:h8bd 9 z3ffpdqoa)1;th doacopies 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 was ct6h: zot1 3jx6qend u7dus4g/ onducted on white onions (Allium cepa),:6ho1n3 6ue ttjg dd x7/4zqus under controlled 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 two ways in which u.g m;l2x9hqrk, x b yfc:r2l:cells can divide. The diagrams below show two cer2:kb9 : r.u2hf,cgxll;x qmylls 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 expression4h f-r*w:ybruo3 arm/n3. dnf 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 cwa9, e 5ga82iw yhrt 848b nmq(qv3jyqell, with a diploid number of 8, in different stages of meiosis. Which row corre,a2wgwrqy 5yeaq hji 3984t b8q(mvn8ctly names each stage?

  The micrographs show foo18 9zxja6hpi q +pb3lur phases of meiosis I in a plant. In what order do these phasesqbz6ol3j hxp+8 9pai1 occur?

Mitochondria are responsible for supplyingfnh1i8jgm8ek/p5(spu3ye 5ibn7 0 jovhq 2v, metabolic energy in eukaryotic cells. In most eukaryotes, which reproduce by sexual rep1 o5h8kpb(jg2/5fsiq0,my i v v87heup 3 jnneroduction, 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 cells in different stages of the cell cspvsyt 3*7o.i ycle in four samples of lung tissue from four patients. Which iy*pt .osv37 stissue has the lowest mitotic index?

  The diagram shows the dominant c*4gawdpr-. m i)e3qdy3hfnc .yclin/CDK complexes at different time points in the cell cycle. Which cyclin/CDK complex activat.hprydn3da cifw q -*m.e) g43es DNA replication machinery?

  Studies have shown thal m xiau* (8ln9 tdjvy.i*o/5):itcmjt genes such as Cyclin Dependent Kinase 3 (CDKN3) are highly overexpressiv i9m 8aydjx /)o5l*:*jtm iu.nc(lt ed 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 theon7osuq jsuqcrp rf n)16:+++x 7*vjj highest during the cell cycle ?