The graph below shows the relation *c3lsf)pc6 1gw lf7oiship between maternal age and the incidence of non-disjunction. What rel3i l)gf1 oc sw*67fcplationship is suggested by the data in the graph?

  Which stage of meiosis is represe7(cgaq/yrptq u:-onm . cuj,4 nted in the diagram below?

  The diagram below sh g5nkryd7 ;:vpv+uiql(.m ; qpows 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 numbei*m;z v274qdkbhybca * 0i.hwr of alleles of a single gene which would be present in the nucleus of a cellhciq*idkh7 .b v;z *y 40wab2m as a result of each process?

  Which keyword is matched to the correct ;)gvoe p 6tqi yp86m4zdefinition?

  Which statement(s) abouayhoozq yh4y- 6v (5z(t 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 to a cell *7g(0 bj ,rhf8 pzeulnin anaphase?

  During which stage of mitosis does the nucly;mf2f -i ptaen +7,ipear envelope break down?

  Which one of the following transport proteins only carries o- sxj .srxe1kr2: jy 90gqheu qx54p2vut active transport?5xsxj4 9x. q2jh2uk1 repg0 qesr:-vy

  Which process does not happen in the s uj:otb *n. nwsk+2t;qhoot apex?

  Which type/s of membrane transport do/does not require energy expenditure? d2o5px s :zl9xrk y--j
I. Facilitated diffusion
II. Active transport
III. Osmosis

  The diagram below represents a cell with a diploid number of 4. Which stai: r0xlf2g/uzuck( q+:n5 c7sroe ee0 ge of cell division i ofu(0nesx::7 uicr+lrc0q/ ke52gez s the cell currently undergoing?

  The photomicrograph below shows a root tip merisda7 -kl cvhr+9no8 1awu/xl(mtem. Which of the following sentences co8-m7 l hxuo w19(dvaank l/rc+rrectly defines a meristem?

  When does the random orientation of homologous chromosome pawd th90b xm 5jd+z:c)e2mudv -irs occur?

  Which process does not occur during meiosis? ck:e1wb1jk/s

  If a cell with a diploid nx7xj ,2 tkhdk0umber of 36 undergoes mitosis, how many chromosomes will be present in each daughter cell after cytokines,k0k dj2 7xxthis?

  The image shows a micrzu lqd c-1ikq3t :)m*vograph of a cell.


What explains the appearance of the cell in the micrograph?

  Which statement(s) about homologous chromosomes is/are not truxelg f67vns8z)j gb*.e?
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.*h+k;-i (q)act6s ctnum ls.j

Which statement is not correct?

  In the cells of a horsetbj9jswa/ e6+n p*vw 87 *boky (E. caballus) during prophase I of meiosis I there are 64 chromosomes. What is the haploid number of chromosomes?+y*s b 9eaw/kt*jvw8njbp67o

  Which arrow is pointii ;zsv wn wwkwe j t087j4-4t-b0f1wowng to a chiasma?

  The diagram below represents the structure of a shoot apiion06 x+zr+zaj:- taocal meristem. Which row in the table correctly identifies the processes occuring in the structuj zax zn+r-0a:oi6t+ ores labeled in the diagram?

  How does meiosis promote mw ,v.; .-:og8lt)(iiw,mfraf rzxri variation?

  Which of the following g5h*yrc*g9 b5kl n /mkstatements 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 homologous chromosoma)qtmd bept7-f 3d2nr )uv+d;es.


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 secondmfk;l:76a4 m p(/zrni 0be xvwary tumours from primary tumours as a result of the movement of cella0n46l rm ;: kwe7(/bzfmvxpis?

  How many chiasmata are prexvp6+nngmi9i6i owzj*l/1 1 wx( ij .csent in the diagram?

  Which statement is a similarto- ptgj5chjw75et4 *ity between cytokinesis in animal and plant cells?

  Which stage of meiosis is mae p vap;*q8nyp1yb0g+ a 1d4gqtched to the correct description?

  Which statement(s) are true ofb* a9cqy7i7a cezj0 +fkp4xy6 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 the first meie/j0p7o9p e xvotic division. This results in the formation of one large cell and on/xo ev7p9jep 0e small cell. What is the fate of the large cell?

  Which row correctly describes diploid and haplo7(zfs pmysfh) d9.8dxid cells in humans?

  The following table shows the diploid chromosome number of a range of species. v1rpgij:b vx;2:l 8dg a6hlfqwk9.2p


Which of these statements is correct?

  What conclusion can be drawnqw7ve t( t4,wpterh4c :/ee c( from the karyogram below?

  Which of the following processes i1v,/ojwy u )xzl ;)mph;8fjtks characteristic of the meiotic and not the mitotj8) m,lpkx zhvj;uw 1)oty;f/ic cell cycle?

  The diagram represents a bud with a shoot apical meristemfic 11gynn :3o.

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 chizvme1s0zx.ks 8. +h.s9gdxi umpanzee (Pan troglodytes) is 48. Which row shows the correct chromosome number for different cell types and cell division stages?.e gs.usz8xi9 .+ds zx0m1hv.k

  At the end of which phase of meiosi5*6sc s-1f 5farguiaq s I does crossing over occur, and what is the outco ifq*asf-s6r5g 5 1aucme of crossing over?

  Which of the following statements does not describe helj7zn. , +:ejp:v taik .ki,a step in the sodium-potassium pump pi:kn ,z,le..atvjh 7jk:ie+ cycle in the neuronal cells?

  Which row in the table below is trxalky- f91l;k rbyir9 8nc,)tue of meiosis?

Membrane transport is iybd9 1,n r4nwjmportant for allowing particles to move across the cell m1n ,4jr9wy bndembrane 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 regulated in cells.g v.oqf(1 aa6n

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 ofwi2 bjr jze5aam va/6.(y+ (wf different cyclins during the cell cycle. Which cyclin is involved in preparing for DNA replireym5+i2wb z(jaafw / 6. (ajvcation?

The diagram below shh lbt*vamlby7 fs (/ o chd0i/c :f0tat7/.zm,ows chromosomes 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 3ysho s+l2md -fk+td9 of homologous chromosomes?

  The mitotic index of throat tissues taken from 4 different pat xeb,sh- 9qx2gients is shown below. Which patient is most likely to have cancerous shq-x ,e2bgx9throat tissue?

1.Draw a labelled diagram to represent the process ofl3a6- x(kp+fd lbxx ;n crossing over.

2.Compare and contrast random orientation and crossing over.

3.Outline the stages of meiosis.

  The image shows an abnormal 4tor9 rt(xh*jmu7tk-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 one e ,,kfq ncoled-i 54v7y1f+ee complete cell cycle. Each le+e kf-doence5 le ,v yi47qf1,tter 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 homozygousxs6 jso -s1q)6v4b)anro q9 w )xjze5z for brown, long hair and j)1 nxsxsej)v )-q o 6z564r9bqawzosa female cat that has black, short hair.


Which of the offspring has a recombinant genotype?

1.Outline how polygenic traits *olzb q gn)h 5lyj98-acan 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 from the crossing over of non-si.uscbsf)h( m 3,b;e.:sbq cn vster chromatids shown in the diaembsu:) b cn.; h svb(3scf.,qgram below?

  The photomicrograph shows a pollen grain from L. x11 nfy io087+g beicx 0z*dpjcandidum (Lily). Which stage of meioy8fzxp*1n d0ix og+i j7e1b0csis is shown?

1.Outline the events which would lead to an individ dukkft j,84-t0u(t t 2o5hkbdual being born with Down syndrome, which is characteris2-5t4tu(ju h,k f ktot 80ddbked 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 mesyne(p2,2w(lzwtg ) yasuring plant growth. A study was conducted on white onions (Allium cepa), under controlled condition y)y2p l(w esg2nztw(,s 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 a4*yp,wq/lv9w mdn 2slre two ways in which cells can divide. The diagrams below show two cells from an v ,splq /4y2*d nw9lwmorganism 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 ssk(gfsf7 a( +btem 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 diffee-zz ukj5tj+shpo+ ( 2oi2-fkrent stages of 5ep( -jkt hzzs2jo+uok -fi+2meiosis. Which row correctly names each stage?

  The micrographs show four phases of meiosis I in a pzx8c n;;ogmvok +(:w v ja-(qzlant. In what order do these v v(xka8nzq; oj-g :;w(+czmo phases occur?

Mitochondria are responsible for supply x,cnuc pi3a*gp n4y7+ing metabolic 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 ofpicnpg34 n+a,7y* cxu 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 cellzo;bx ,dic: ; kv/qwor) *a5 k9y5pmmfs in different stages of the cell cycle in four samples of lung tissue from four patients. Which tissue has theofa mop ;;cq,zb9)ky 5kv/d:*i5rwmx lowest mitotic index?

  The diagram shows the dominant cyclin/CDexekuuz w f6n r65kyw+0bb-,9K complexes at different time points in the cell cycle. Which c56+z b 6x,w-eweuy9k0 kunr bfyclin/CDK complex activates DNA replication machinery?

  Studies have shown that wzm3 +0tspe*agenes such as Cyclin Dependent Kinase 3 (CDKN3) are highly overexpressed 0 +pamet w*zs3in 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 cell c x2vxozs a7m46ycle ?