The graph below shows the relationship between ma:zr40ttv oc/b ternal age and the incidence of non-disjunction. What relv:tb o4tz0cr/ationship is suggested by the data in the graph?

  Which stage of meiosis is represented in the diagram belom hz/c;9deqc(fg 4ay89ghl6n w?

  The diagram below shows chromosomes during m qssozthcdc n7v),9)j382ihaeiosis.


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 /xe 3f,.t: 0qculm s)o:4t1fu axr teistates the number of alleles of a single gene which would be po3 4c,x.ueti)rtf ut/e: m l:sfq0x1 aresent in the nucleus of a cell as a result of each process?

  Which keyword is matched to the correct definition1li921 fkvqum?

  Which statement(s) about mitosis is/axl 6)asdtpc.*qkt h9 9re 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, l- /rqaqmk4j q 65ua6hwhich letter points to a cell in anaphase?

  During which stage of mitosis does the nuclear envelop708 si cpv/h ci,nhgeew/:( qve break down?

  Which one of the following transport.+ws idgp.(o76po )i2wnqkxae m -iv9 proteins only carries out active transport?o) pi-di+iepkw n.2v9 wa q(g.s7m6o x

  Which process does not ha mo00id3+, d;z ;wsh9sbt *a-gjze*csytda)j ppen in the shoot apex?

  Which type/s of membrane transport do/does not require energy expenditurejmllt) crd9p(v2 / -ib?
I. Facilitated diffusion
II. Active transport
III. Osmosis

  The diagram below represents a cell with a diploid number of dr pdj vr6fgf8,5,-d s4. Which stage of cell division is the cell currently unde d-f j,f8,5r grsdpv6drgoing?

  The photomicrograph below shows a root tip meristem. Which of the following sent:ua ) voz.scl .oj,b0cences correctly defines a meristem? avco)oc ,u:ls 0.j.zb

  When does the random orientation of homologous chromosome pairstb w*dtjz*(-*l v4gd w occur?

  Which process does not om 9s(89kykrg6e 7azjj:dns b1ccur during meiosis?

  If a cell with a diploid number of 36 undergoes mitosis, h2 g osale:j kek-9p 6f9d;iw0ixu ji6-ow many chromosomes will be present in each daughter cell after j 0i9okue- ksidl:gjw x;26 f9pi-ae6cytokinesis?

  The image shows a microf/5+3 9u gcr.cirrf ojt)w2 pbgraph of a cell.


What explains the appearance of the cell in the micrograph?

  Which statement(s) about homologous chromosomes is/are b 7cryoib .8v7not 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 dw3.fs6ps bfnz e.lo* j0 q0rorc (*2jDown syndrome.

Which statement is not correct?

  In the cells of a horse (E. caballus) during prophase t/lzvba0qkl,tz)8y8w1(ljys kz:; :nv t /iiI of meiosis I there are 64 chromosomes. What is the haploid n lbizzyi08 kk(lat/t)y z; :lvsn:t/,8j1qvwumber of chromosomes?

  Which arrow is pointing tol2edauo eh-nu++ ehc:( a2j -o a chiasma?

  The diagram below represents the structure of a shoot apical meriimd c069vw7s7f zu)xmstem. Which row in the table correctly identifies the processes occuring in the structure m 9zuf w70dx6vm7csi)s labeled in the diagram?

  How does meiosis promhe;ycd*-z whi3 4oyj 0fm /8tgote variation?

  Which of the following stateme b7kha9pc:cmza 1x-u 3nts 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 priflv: ld(,+b toduced 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 tumours from primary tumours asqaeeti-j/cm5 / )sm g4 a res/t)4 - qi c5gejm/measult of the movement of cells?

  How many chiasmata a5b1 ::*sxb 3qfklt uxy7 kz*ebre present in the diagram?

  Which statement is a similarity 4m4sb xgeg2 o ;jb(u6.i67j.ac rzsqe between cytokinesis in animal and plant cells?

  Which stage of meiosis is matched to the correct des 9yesat4-2vql cription?

  Which statement(s) are true of meiosis f:a+0dc iriaf-.b t mkk ls5)5I 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 meiotic division. This resilbpode20eh( + :ey. vults in the foe+y.e0l di(vp2 ebo:h rmation of one large cell and one small cell. What is the fate of the large cell?

  Which row correctly describess x6z2- r.o 2r;rfx*i-nmjvd m diploid and haploid cells in humans?

  The following table shows the diploid chromosome number of a range of species. c vym5ye6h-v0nf+mlw y-ew :(


Which of these statements is correct?

  What conclusion can beh)pt; owgr5 c2 drawn from the karyogram below?

  Which of the following processe4 )e r07xfbsxi5m0o hds is characteristic of the meiotic and not the mitotic cell c ri 4 mshx0fdo70b)x5eycle?

  The diagram represents a bud with a shoot apical meb;9bc n*ohlk. ristem.

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. Whvt6qzz5f a( m*ich row shows the correct chromqv(z 6 tza*f5mosome number for different cell types and cell division stages?.

  At the end of which phase of meiosis I does crossing over occur, and whapw7o mv.x22rqzf e.;at is thefpax;ew .2 .vqmoz 7r2 outcome of crossing over?

  Which of the following statements does not describe a stgw7y +as lo7w/ep in the sodium-potassium pump cycle in the neuronal cellg7+swaol7/w ys?

  Which row in the table below is true of meiosis?1)kerd8; r fzt

Membrane transport is important for allowing particles to move across thge5v; lklxmj;wi 9hj+x48 ,eaasy4u 9 e cell membrane and respond to changes in the chemical composition of the extracellular fluidl;,8sxuekj4y9hwla+x avg 9e;jmi 45 .

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 re1;t3xn1b pytrgulated 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 tnfxl6isdhr-,j+1s/dj20nhu he concentrations of different cyclins during the cell cycle. Which cyclin is involved in preparing for DNA replic06d nx j2niushd,+ fl- hjs/1ration?

The diagram below shows chromosomes during meio 8p8n03lb phjvsis.

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 chrp7 mv3u,u s62l bw9msqomosomes?

  The mitotic index of throat tissues taken frol1)4ecy2u yu5b h2hsrm 4 different patients is shown below. Which patient is most likely to have canc hh2cubeyl15)ru42 syerous throat tissue?

1.Draw a labelled diagram to represent the process of a0o*yeoaepc;ul p*) eg(fo*5rv* e 3/;bhsb e crossing over.

2.Compare and contrast random orientation and crossing over.

3.Outline the stages of meiosis.

  The image shows an abnormtx*,-ae+d8oco g;- em wq 9qojal 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 compl* eld9htim(c yl*;ise i))jg,ete cell cycle. Each letter; siteeh)gjli*i 9 ,(yd*)lcm 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 homozygous fox*8l *4l;zl+zljsohrq+ 9yf xr brown, long hair and a female c+;j* z*49rl +xq xoszlf8 llyhat that has black, short hair.


Which of the offspring has a recombinant genotype?

1.Outline how polygenic trait*c oabv+7 y .7ievd)kws 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 from the crossing over of npo+ / ;.)bog2hpnvha2 .qi gndon-sister chromatids shown in the n/p 2n 2+hg..hb ;idagopv)oq diagram below?

  The photomicrograph shows a pollen grain fro6 6bmxp;crwg ;m L. candidum (Lily). Which stage of;m xprgw cb6;6 meiosis is shown?

1.Outline the events which wouvnxo 7sp07pum3m j8: nld lead to an individual being born with Down syndrome, which is chn3m npx8:juv7 smp7 0oaracterised 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 h+ft8i mjbd:n*3qq ,xindirect way of measuring plant growth. A study was conducted on white onions (Allium cepa), under controlled conditions in a lab, to investigate the effect of soiqx*jd b 3ftq8+,:imhnl 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 wzrsu64-/zpm ocv):a in which cells can divide. The diagrams below show two cells svwz r)/: z4aopmuc-6from 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 ofb .up )4t*qo+gmjz gj7 gene expression 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 cell, withv6fi9p ji1g (h a diploid number of 8, in different stages of meiosis. Which row correctly h1ig(vf6p9ij names each stage?

  The micrographs show four phases of meiosis I in a plant. In what order8vsd4 k;rmc th5tm5w( do these phases occuct vwmrmd5;h(t8k54s r?

Mitochondria are responsible for supplying metabolic energy iadio d ,qaxi 1j7t/u*1n eukaryotic cells. In most eukaryotes, which reproduce by sexual/ oi*dda,t1aui 7j qx1 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 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 differidu r-z9gpvd9 pl ,r/t;0t 1i9.tfqcyent stages of the cell cycle in four samples of lung tissue from four patients. Which tissue has the lowest mitotic ing9., ;1uldprv0c9yf9ztirt/q d pti-dex?

  The diagram shows the dominant cyclin/CDK complexes at different time pointexdp co14 gaa cd53 +56sab.xss in tgabx e d+s4docs 5.pcaa5x613he cell cycle. Which cyclin/CDK complex activates DNA replication machinery?

  Studies have shown that genes such as Cyclin Dependuxwjsg.4a)w 6/nm2g rofz7 vxke 86o3ent Kinase 3 (CDKN3) are highly overexpressed in cervic 2/fz.ws6kxe7 )noxw 83 ujmvg6arg4 oal 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 vswnax-d f6b 66iye2fm.2o 4h highest during the cell cycle ?