The graph below shows thew*,x4jp e-eyu tp/zw3 relationship between maternal age and the incidence of non-disjune,u3pt-xzj4 y/pw* ew ction. What relationship is suggested by the data in the graph?

  Which stage of meiosis is represented in the diagram bexyp/q xp9h7b.*3s8qc-tve n jlow?

  The diagram below shows chromosomes duri/eg1nm-8oz) agxkq/.8d j:,r rf mooa ng 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 alleles of a single gmn1 .,im3tw af wj(p8gene which would be present in the nucleus of a . i 3tfmp81j,w(ag mnwcell as a result of each process?

  Which keyword is matched to the ck7i jj a3vh+f8agct1 8k0wir; orrect definition?

  Which statement(s) about mitosis is/arn0yyybtiwn . fs;czv7j,31 x-e 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 l zs5 uuv1 twpchv.)n51ir0 xbx8kf6xq.4b1e cell in anaphase?

  During which stage of mitosis does the4vsq-9lvx 4mep)l rw1 nuclear envelope break down?

  Which one of the following transport proteins only carries ou9x0b2 ,vbtvoua qva *3t active transport?xuabvta2oq9 * 3,vbv0

  Which process does not happp6 u j*e0v01,ywtl wfgen in the shoot apex?

  Which type/s of membrane transpora )i. n +hyjdus)qvx:547z n6n-gdh kvt do/does not require energy expenditure?
I. Facilitated diffusion
II. Active transport
III. Osmosis

  The diagram below represents a cell with a diploid nug drzri,4x5c1 g08vg nmber of 4. Which stage of cell div8 x g4c5g1 rnrd,v0zgiision is the cell currently undergoing?

  The photomicrograph below shows a root tip merist0w5 cgo1lsbw:ti7)agcx,h y gp;k: h/ em. Which of the following sentences correctly definesps/gy,hhxb0:7og )1gww : kica ctl5; a meristem?

  When does the random orientation of homologous chromosome .s z t,w 5qmwv1d,qwsayyv7 qp85*d q)pairs occur?

  Which process does not occur during mpe5 v8tg x q,nlat /+we7cez3/eiosis?

  If a cell with a diploid number of 36 undelbhg:b60 qs8*yvqr-i :g i2mfnc,7k argoes mitosis, how many chromosomes will be prhcril:: qi f aygn026 8v ,*qg7mbskb-esent in each daughter cell after cytokinesis?

  The image shows a micrfyo 9cvc-bl;t8fh 3 4ae hk*p6ograph of a cell.


What explains the appearance of the cell in the micrograph?

  Which statement(s) about homolog7 sa p*d6g+twuous chromosomes 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 an2*ui bqmvq h uqfbn45e h8):*q individual with Down syndrome.

Which statement is not correct?

  In the cells of a horse (E. caballus) during prophase I of meiosis I tv m3yre 4j- (kkbw(j6m/x xgh6here are 64 chromosomes. What is the haploid number of chrmm6-ekg3xh 6wkvb/xyr(j(j 4 omosomes?

  Which arrow is pointing t8-eomd zvmeg7i/ 7vh*o a chiasma?

  The diagram below represents the structure of a shoot apical mey9deezad,9k * ristem. Which row in the table correctly identifies the processes occ ,ky*ede9zd9a uring in the structures labeled in the diagram?

  How does meiosis promote 9ep3g9giym n6variation?

  Which of the following statements is/at61wctaf mfj-s/q47 x re 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 chromosomesz,-e8dlob 6mt1hbk 3x.


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 formatioa: 3r bgm3 zy qf2kqpcid,s;nbhs))--n of secondary tumours from primary tumours as a fhm,q) z pc2a b;i3ys-brsn-kdgq):3 result of the movement of cells?

  How many chiasmata are presnjh jo9 y,,1psbs7be1.wvcjz 038rjh*v ok, eent in the diagram?

  Which statement is a similaritn +8+ ttq8p z0de6aerby between cytokinesis in animal and plant cells?

  Which stage of meiosis is matched to ahffg*wgg-o(,8z 2t zthe correct description?

  Which statement(s) are true of meiosis I but not meiosis II?iyhshx1y b8i:-*s ju +
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 aftoyd8:6 oa ;s3 y1rpzhver the first meiotic division. This results in the formation of one large cell and one small cell. What is the fap 1 ay:63;vrohdyzso8te of the large cell?

  Which row correctly describes diploid and haplaf j0*l j:t grbnz3+*void cells in humans?

  The following table shows the diploid cfn8sqs6k5lo wu5aw9w; w r+t8hromosome number of a range of species.


Which of these statements is correct?

  What conclusion can be drawn from the kavx yjl9365c cp;e yu4uryogram below?

  Which of the following processes is characteristic of the meiotic .8mn 6li0rmhj-yddd* and not the mitotic cmdlj 0 8dr6y*.imh- ndell cycle?

  The diagram represents a bud withb:v 62 .72vvpm j (.xarrm4 ltiuf4pnq 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. Whica)sa) )jumlyod/0 t 5uh row shows the correct chromosome number for different cell ta)uj tuymo5as0 )/ld)ypes and cell division stages?.

  At the end of which phase of meiosis I does crossing over occund 9e6tct-eu) r, and what is the outcome o) uecet9n-td6 f crossing over?

  Which of the following statements does not describe a step in y p fdkqjb4m9 e6*2bx1the sodium-potassium pump cycfy6qeb dkb2xm9 pj *14le in the neuronal cells?

  Which row in the table below is tjap pemmp74+)kx*ez xf( .uj,rue of meiosis?

Membrane transport is important for allowing particles to move acrofz8x3o 76to.wbnp . erss the cell membrane and respond to changes in the chemical composition of the extracellulezo3 7fop.w.xntr 6b8ar 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 cells3eby9g 2aufarp)9 hpdr;)hp33 n5xj i.

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 differem ,(uzu*jail3nt cyclins during the cell cycle. Which cyclin is involved (maz ,ulj 3ui*in preparing for DNA replication?

The diagram below shows chromosom * fw3w. tts,fto;/vhqtpsx q9p3q*w/ es 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 homo gq dl(k2by-f4logous chromosomes?

  The mitotic index of throat tissues taken from 4 different patie8ex ,plb7dus+ nts is shown below. Which patient is most likely to have cancerou7 plx+dbseu8,s throat tissue?

1.Draw a labelled diagram to represent twhwsb+8c4z l8hs6ti/ he process of crossing over.

2.Compare and contrast random orientation and crossing over.

3.Outline the stages of meiosis.

  The image shows an abnormal hum1nphoh/ gi5- hl)bc . lbj;5xiuen-(pan 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 comple oea)ur7p+u(a pd2 ev(te cell av(e)apop ( e7u2+drucycle. 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 cat that is hom(cy/5dv:d+ hhj(f0mi5 q ppcfw1xts /ozygous for brown, long hair and a female cat that has blackxh0c/(cs 55hdiw yvt( +dffm/jp1:pq, short hair.


Which of the offspring has a recombinant genotype?

1.Outline how polygenic traits can show a norm6qsm3n5 s1ewut x* pku+5g v1kal 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 okn61ip1b uu. :r-c oygf non-sister chromatids shown in the di1 ub1c.o:ugrp nik6y-agram below?

  The photomicrograph shows a pollen grain from L. candidql)m4 qamnn3g2p3 mgz tv5om,8/ lf5mum (Lily). Which stage of meiosis isn, z4 3q mp525 oggl)afmntm8m3lvmq/ shown?

1.Outline the events which would lead to an individuax cgwc(-)d.8 caaotp )l being born with Down syndrome, which is charactw(c )ctx) o8cgad.p-a erised 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 growh8 ugh0x *6qkith. A study was conducted on white onions (Allium cepa), under controlled conditionsk0 86uix*qhh g 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 cells c;0fynvh xilwyrz0+ hs;-n* ,dan divide. The diagrams below show two cells from an organism with a diploid number (2n) oyn 0h wh,islvr0*y fd+z ;;xn-f 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 growth.;d* c6t4zmi ii

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 numbsy, .rjqxu z7:+ne5nuer of 8, in different stages of meiosis. Which row correctly namqujxu n:y . zs7n5,r+ees each stage?

  The micrographs show four phases of meios,obtfsm 1lik107z.,s7s w zu cis I in a plant. In what order do these phasesb. ,ssoz i1t kz,c1l70f7wu sm occur?

Mitochondria are responsible for supplying meth iyn.+ ds+ 4mzv-h)tnabolic 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 found in hybrid cells, which are the result of sexual reproduction between+h+h-di vz).t4nm ysn 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-w(cg voqa0 h9ap+z, u2y,eue of cells in different stages of the cell cycle in four samples of lung tissue from four patients. Which tissue has the lowest mitotic inuep2wa+oz qh 9 vau,y (gc-0,edex?

  The diagram shows the dominant cyclin/CDK compquq86jyy3u9 ylexes at different time points in 8uu63 yqjy9 qythe cell cycle. Which cyclin/CDK complex activates DNA replication machinery?

  Studies have shown thao m/8.; hucvuxt genes such as Cyclin Dependent Kinase 3 (CDKN3) are highly overexprexum;vuo hc.8/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 cell cycn:lb*j5q5 e ivu3ga 2uz) pxk8le ?