The graph below shows the relationship between 5nmlsfidr/5) 4*k 3cxlekh6m maternal age and the incidence of non-disjunction. What relationship is suggestek) 6 c45sfl mn3m/hdr e5*lkixd by the data in the graph?

  Which stage of meiosis is represented wi8l uqacywtg18pk+: 5m 2k dcms:1(din the diagram below?

  The diagram below shows chromosomes during meiosis. xfae5 bbdbh / 3hc./cd*5 xi.v


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 nzx*/q8x c y p,vkto*w)-8wtagene which would be present in the n o8x )w-kcytw,* *n8tzv/pa qxucleus of a cell as a result of each process?

  Which keyword is matched to the cbukohu3kw1-o;9hc+ie b-ru9orrect definition?

  Which statement(s) about mitosis is/are truu7h p4re+vlyfm/ n*;o e?
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 aqm y;0 oy+tbpm l4born7lp p 9,sd1,;j cell in anaphase?

  During which stage of mitosis does the nuclear envelope break d tgyl*f * vw8(l-mi0zzown?

  Which one of the following transport thqz8 ec)n ,/wqyo,9qproteins only carries out active transport?o n,)qy qz w89teqh,/c

  Which process does not happei*bqjbp 6 fwp)i(l2 /tn in the shoot apex?

  Which type/s of membrane transport x m ddy-62irs0do/does not require energy expenditure?
I. Facilitated diffusion
II. Active transport
III. Osmosis

  The diagram below represents a cell with a diploid number of 4. Whwn ./s0p tg jg6n2vnpb:2k;qksf / ;xsich stage of cen gx ;v2t. jsn/bps2wk/f6kg:qn s;0p ll division is the cell currently undergoing?

  The photomicrograph below shows a root tip meristelm ph u3rjyt48;hr 1w9m. Which of the following sentenwu tm3rj1hr p4y;h9l8 ces correctly defines a meristem?

  When does the random orientation of homologous chromosome pairs occu;pannb 2 yi(brx h b4tpa;nf++pc1:ul 8hq(: wr?

  Which process does not occur dur6 o*s -si.ov d0h1(qqnum nsc(ing meiosis?

  If a cell with a diploidnsg/8:6 j::r 5suyib/do nuac number of 36 undergoes mitosis, how many chromosomes will be present in each daughter cell :/u/8 56:no r bsasic:dguyjn after cytokinesis?

  The image shows a micrograph of a celli y mw6 7,w2(y2o*zmi m9siuox.


What explains the appearance of the cell in the micrograph?

  Which statement(s) about homologous chromosomes is/are not tru1,2i77: ir4zwax1 zw drl dtd7t xjzt: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 syndz,/il nlwm48u rome.

Which statement is not correct?

  In the cells of a horse (E. caballussclf, r lzrk* m6r:m5,) during prophase I of meiosis I there are 6,lr lfm ,cr :56kmsrz*4 chromosomes. What is the haploid number of chromosomes?

  Which arrow is pointing to a chih xr e2/k:vl*pasma?

  The diagram below repr,ff/o q sj ,gn7qa9qp); zsku8esents the structure of a shoot apical meristem. Which row in the table correctly identifies the processes occuring ),z ,/uf; sqpajogn8k7qs 9fqin the structures labeled in the diagram?

  How does meiosis promote variation?5+ *z3rssrecde 3u(l+ ka;uqa

  Which of the following statements is/ar;qcg fatyf.,h4 ,oiz;e correct for meiosis?
I. It is a reduction division
II. It involves random orientation
III. It produces genetically identical cells

  The diagram shows gametes prn u9u4 nfvy*rfu(bi,2pjk.lv3 mke92oduced from 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 tumournjm dje; 4a;sc f-me6,hg1z p2s from primary tumours as a result of the moveme,fd m1g; ;-sj enj z2p64emcahnt of cells?

  How many chiasmata ary: d8jr8xs/il:o 1i7f oz0qb ye present in the diagram?

  Which statement is a similarity betwet05ana vvl n.3en cytokinesis in animal and plant cells?

  Which stage of meiosis is matched to the correct descri8+k( e-bgzn uwhylt-8ption?

  Which statement(s) are true of meiosis I but not meiosirdfd 8;f/2fsw s 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 fiazrcic 9 7clwv1a g7i1c6u6(urst meiotic division. This results in the formation of one large cell and one small cell. What is the fate of the large cell? r (vli 6c17 a9gcz7 iuwca6cu1

  Which row correctly describes dic x2czjl 1(7x i yoviabz95is9sd .2;tploid and haploid cells in humans?

  The following table shows the diploid chromosome number of a range of species.: sa8aanzf5(9ow o5n g


Which of these statements is correct?

  What conclusion can be drawn from the kar c4gm gn1k:9lsy q+hc80 bh+cqyogram below?

  Which of the following processes is characteristic of the mn8 ( ;lrb;xq4inbf)qq *o2li neiotic and not the mitotic cell r;nn xfni;8*q ( 4iq2llo qbb)cycle?

  The diagram represents a bud with g-sa)qyjlw1, o7 dp 7sa 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 troglzl j2 u -gh.,c4/svluy-pzm7r odytes) is 48. Which row shows the correct chromosome number for different cell types and cell division st47-zm/2j u ,ylgcl-zv hur.psages?.

  At the end of which phase of meiosis I do4dcs)q194qb cfh b)hfes crossing over occur, and what is the ouh q )chb4bq)f1fc9 4dstcome of crossing over?

  Which of the following statements does n2:zsbq4g10vo jh *rd not describe a step in the sodium-potassium pum10 gzh*dvsbj o4n2: qrp cycle in the neuronal cells?

  Which row in the table below +j hzkr4ah4(ee .jav3is true of meiosis?

Membrane transport is important for aubs36j0-krprpnu/ *bo 24d tfqe+0 wellowing particles to move across the cell membranb jw0et6rurbes/+3-0fdon k qpu* 24pe 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 tm dfkdq .fh:oa/7t au:d;: c*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 cycliu,:i rg zvqs*p p//;-glz5s5c j 1 +ikxsg*ifons during the cell cycle. Which cyclin is involved in preparing for DN1 /gp5is-,ok* ilij szvxg f*r pqcgus/+ ;z5:A replication?

The diagram below shows chromosomes during mei 1hry3d o9wskj9z*i3db .c2y gosis.

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 thecg.4vfhy7, ,amzz oi1 kx0j/ w separation of homologous chromosomes?

  The mitotic index of throat tissues taken from 4 different patients is shown belya(l;9 m n 4co;rit2dp *pnu2fow. Which patient is most likely to have cancerous i*f(9u ;pt;npm4or2l c ya2dn throat tissue?

1.Draw a labelled diagram to represent the processq bnjannc8/4 , of crossing over.

2.Compare and contrast random orientation and crossing over.

3.Outline the stages of meiosis.

  The image shows an abnormal human karyo *ov(+ubqiz -xoa .n7qtype.


What is the abnormality in this karyotype and its cause?

The graph below shows the relative amount of DNA in one cell 5j-*la fb-*fa.1ubhodumtghod 8/3r during one complete cell cycle. Each letter represents one stth8o5 fo-d1j r/*abfd3 g*u- .ahubmlage 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 homozr t/o t,aoav,l72ndtmqx ;2x0ygous for brown, long hxat,tm,2 r20v /qx d;la7t oonair and a female cat that has black, short hair.


Which of the offspring has a recombinant genotype?

1.Outline how polygenic traits qw a4bas dr,s;d4xw95can 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-sister c/r whfh6e-ttp h+06amhromatids shown in the diagram bee 6mha/th0- tf6 pwr+hlow?

  The photomicrograph shows a pollenj86lt 610 (yms lcrvwh grain from L. candidum (Lily). Which stage of meiojmy 8t6w vh(rs6l0l c1sis is shown?

1.Outline the events which 9 tao-hvtf6/c would lead to an individual being born with Down syndrome -oath69f/ ctv, which is characterised 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 growth. A study was cotxfv us: opj5. hd8sk0k)-(lfb08 gsenducted on white onions (Allium cepa), undb s8:v kk.h) j pl-xffs 5uetg(ds080oer 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 cells can divide. The diagr l t8)q.:pnqmmwhra3q15arr 4ams below show two cells from an organism with a diploid numwanr )hr5rl43mt1 a.p q:8qqm ber (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 expressioqm) eaub/flo1+q2 q51qdq kt,n 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 b-b6 /bpq 5en(fx di2ea cell, with a diploid number of 8, in different stages of meiosis. 65df nbe-b(i /e pbqx2Which row correctly names each stage?

  The micrographs show four phases of meiosis I in a planpot +( lqshu/7t. In what order do these phasp(su7loh q+/tes occur?

Mitochondria are responsible for sh xsajo3v3egt1* +lztq:b)vzmu9) 9 supplying 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 of humans. This is in contrast to nuclear DNA which is inherited from both parents. It has been suggested that, in some eukaryotietst)uzz hjsq 93g3 al vb9):xov1*m+c 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 c( utfjy0l(d ;eells in different stages of the cell cycle in four samples of lung tissue fromy (e;tjl 0d(fu four patients. Which tissue has the lowest mitotic index?

  The diagram shows the dominant cyclin/CDK co cb nms4u+pl4 i57h(hy-kx,(q 2loyvtmplexes at different time points in the cell cycle. Which cyclin/CDK complex activates D5y 2bcpnht my4i(h (-sq 7kllv4 x,uo+NA replication machinery?

  Studies have shown that genes such as Cyclin Dependent Kinase 3 (CDK4 -vtypk-bnz3k :dv:l N3) are highly overexpressed in certl ykzvb::-v n4k d-p3vical 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 cyclis*gk p5:8 vrbetq4k;02b opc q xn:c0dn E the highest during the cell cycle ?