The graph below shows the relationship betweei.pfw ny5zfr 32 r8-exn maternal age and the incidence of non-disjunction. What relation2ir .w8yxzrpff- e3n5ship is suggested by the data in the graph?

  Which stage of meiosis is represe3m boo2(gxcn3c4q u b5nted in the diagram below?

  The diagram below shows chromosomes duringe m x9y(l-xoiz-3 (yja7h,vii 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 of4q /l jlp,u)ns alleles of a single gene which would be present in the nucleunslq)j 4/pl ,us of a cell as a result of each process?

  Which keyword is matched to the coro ok4ju(- 7-j)9y qwktro*tgsrect definition?

  Which statement(s) ab-( z;ewnus4 e(gap)nxout 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 lejstj 1*/axyp5 a dj74ttter points to a cell in anaphase?

  During which stage of mitosis does the nuclear envelope break down?v5ceqta , z**b6h 4 cyuvqlrrno,5.t9

  Which one of the following transport proteins only carries ou-;z6vah .h9r nuqq-y8dp hk/ut active transport?hpra8;uhz6 uqy9n -vd k/.qh-

  Which process does not happen in the shoot apex1n:pb1zzz )ng?

  Which type/s of membrane transport do/does not requirec8q3ho9p 1f 6wz*jwrkd mri;* energy expenditure?
I. Facilitated diffusion
II. Active transport
III. Osmosis

  The diagram below represents a cell with a diploid numbm(q86-: zeys2luzxpgm7t b./)z yssi er of 4. Which stage of cell division is the cell currentlz-(2si 867/glyx mmbzteu :y.sp zsq)y undergoing?

  The photomicrograph below shows a root tip meristem. Which of the fol)dyfi1lj la,:5 hrf0:t 1d yqylowing sentences correctly defines yhjd,d1lr: 1y:fqiafl)y5 t0a meristem?

  When does the random ori 87c8;l - x6e6rzv)kkd.go iip5osswcentation of homologous chromosome pairs occur?

  Which process does not occur during me4 d9 wepmj+,mna.soph ii d1qso5e7;( iosis?

  If a cell with a dipzk o pqmu 060zy/nz+c7loid number of 36 undergoes mitosis, how many chromosomes will be present in each daugyn z0oc/0zqzp7+u6 k mhter cell after cytokinesis?

  The image shows a micrograwy:j* sc o+f9dph of a cell.


What explains the appearance of the cell in the micrograph?

  Which statement(s) about homologous chrs/lw6 1ql5z6 igw41p stm )kzoomosomes 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 individul:rt( vi,r).hr. nsolt w8)n yal with Down syndrome.

Which statement is not correct?

  In the cells of a horse (E. ca)nmr8 m/s6mvcn;l /t dballus) during prophase I of meiosis I there are 64 chromosomes. What is the haploid ndmm vm8 /str;lnc/)n 6umber of chromosomes?

  Which arrow is pointing to a chiasma? /v4t+ qtb l9m b2-d0mwjbhg*j

  The diagram below rep :xdw cm( f79h6pn5(rzzs/rcvresents the structure of a shoot apical meristem. Which row in the table correctly identifies the processes occuring in the structures labeled irnvc:pwz(fxchz 9( 5/rs7d 6 mn the diagram?

  How does meiosis promote variati2:h lpio-qoh-dgg0v 1on?

  Which of the followi bvhbhty6gm4-7n5sgf/z: i :nng statements 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 oz 4uzt25,*gef:sm jyhomologous 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 formam2l.he+vtrwf ( u 2l;oo5sf4 ntion of secondary tumours from primary tumours as a n2l ;sm ouo2ev(l54rhf+f .t wresult of the movement of cells?

  How many chiasmata are present in the dib:1cxhgqf qcq(o+:2kz vw -s rip :+;yagram?

  Which statement is a similarity between cytokinesis in animal and plant cellsjw()f b.,x ekl?

  Which stage of meiosu:pq. ;(2ui.y alrp yxis is matched to the correct description?

  Which statement(s) are true of meiosis I but nj*pho1f+nd t z(fop dd113k+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 f 5h8w3 (x- qapvcu9lxv3e9qbwirst meiotic division. This results in the formation of one large cell and one small cell. What is the3lbvw9h ex 5pq 3vc89uwqa(-x fate of the large cell?

  Which row correctly describes diploid an -d h ;w5rm9nbfszgmu6 s75c3zd haploid cells in humans?

  The following table shows the diploid chromosome number of a range6ps y+ r6weolmew-dt)* ei soc57t2f1 of species.


Which of these statements is correct?

  What conclusion can be drawnp276g 1voz1y1ub9:mxlse jo-vx+ gr t from the karyogram below?

  Which of the following processes is charactlk* i1bvrv i5rfmd4g3tt7 9 )leristic of the meiotic and not the mitotic cellid1 f5g9*rb4trl7 i v3)lmvtk cycle?

  The diagram represents a bud with a shoot apical meri fa20.ohfbbkbh6r 4o- stem.

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 c549kmyhr b(ekhimpanzee (Pan troglodytes) is 48. Which row shows the correct chromosome number for different cell types eb( kyk9r m45hand cell division stages?.

  At the end of which phase of meiosis I does crogx +;ot, cc*fsssing over occur, and what is the outx,*+s gtco fc;come of crossing over?

  Which of the following statementd;ddzzvzp(hb 8y .y7 ,s does not describe a step in the sodium-potassium puvy.p; dz8y b dd(7z,zhmp cycle in the neuronal cells?

  Which row in the table below is true ofep* hn7x8h;g;v +npip meiosis?

Membrane transport is important for allowi . (oib/igtow 35uo9ptng particles to move across the cell membrane and respond to changes in the chemical compoio5u( bt9 .pwtg/o io3sition 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 ip9iszyg4b,tn6jq ki9dujsjudti 3t) ( :, +:h s 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 shor/a +0ggt4/o1 9ygxiuzlkj, sy r0.a tws the concentrations of different cyclins during the cell cycle. Which cyclin is involved in preparing for DNA replicalxg 4y 90za1aty i/g ,t+r/rs0o.ugj ktion?

The diagram below shows chogx5h :f :b8jfs9oc( xromosomes 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 separation of homologous chro42 cvnfn b*p4nmosomes?

  The mitotic index of throat tissues eqgno.4(-g0abaj6xox )(q :cs v8 c zstaken from 4 different patients is shown below. Which patient is most likely to have cancerous throat tissqj (4.a)b qnes :vg8o6-za0cxog sc (xue?

1.Draw a labelled diagram to represent the prorpu;ai+s:mv6s fw d7ay13k - jcess of crossing over.

2.Compare and contrast random orientation and crossing over.

3.Outline the stages of meiosis.

  The image shows an abnormal human kj*1.v mu.e crqxh;z0daryotype.


What is the abnormality in this karyotype and its cause?

The graph below shows the relative amount of DNA in one cell dur(w ;1cxvje xoii62iw:;j(to(qy bs,x ing one complete cell cycle.oy(1sbii: (c ;o2( ;xe6qw xxjwtvij, Each 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 ca:x+,i; m3dgln,eb2 goh:mh ao t that is homozygous for brown, long hair and a female cat that has black, shem+,2g m::o,ond;axigbhh l 3ort hair.


Which of the offspring has a recombinant genotype?

1.Outline how polygenic traitv x8we6 q3njg.s can 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 fm (vbwxm4n.n:rom the crossing over of non-sister chromatids shown in the diagram below?v (wn.nm4xm:b

  The photomicrograph shows a pollen graig58 u4l6sd x66mcekjun from L. candidum (Lily). Which stage of meiosis is shown?lkm8665 cgs e xud64uj

1.Outline the events which would lead to an individual bei+/w9-xsz ln t gi)+wopng born with Down syndrome, which is chazt+nx igw)s/ w l9-po+racterised 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 )f/ /:w c;pnfaxhs)y2 (;ixww axnhz9of measuring plant growth. A study was conducted on white onions (Allium cepa), under controlled conditions in a la;zaxfn 9//;) ixwahp(w:n f2 yw)hsxcb, 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 r2wgbe )cp jv9:t, ml w47yj,dwhich cells can divide. The diagrams below show two cells from an organism with a diploid number wg,ebw m4ptjc :,lr2)jvd 9y7(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 owmd/kr4,a *fhjw.y 2growth.

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 diploir mdd6 /2-ywmcd number of 8, in different stages of meiosis. Which row correc m /2cm-y6rwddtly names each stage?

  The micrographs show four phases of meiosi4x ;o)vi afp)ts I in a plant. In what order do these phases occap;tvxfo 4 ))iur?

Mitochondria are responsible for supplying metabol v2*jzos fz.kydv :*l9ic 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 jvvfs.k9:o 2zyl*d*z 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 cellsty f+cs57*hkzo:m 8ztf jkh)vxj. ;9f in different stages of the cell cycle in four samples of lung tissue from four patients. 9 ctoktfxhmz+ 5v )j;8 :jkfsf *h7.yzWhich tissue has the lowest mitotic index?

  The diagram shows the dominant cyclin/CDK complexes at different time points in v0wr(u ; hs (/sv(7qndbn:vf bthe cell7 rq(dvfv (nsbhw/(s;bv 0 nu: cycle. Which cyclin/CDK complex activates DNA replication machinery?

  Studies have shown that genes such as Cyclin Dependent 3r,9 epsnr xb6Kinase 3 (CDKN3) are highly overexprex6 3bnrrsep9 ,ssed 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 ce41vhple61um u ll cycle ?