The graph below shows the rely;bw tehh)g7w pj7wo4.ha5(q ationship between maternal age and the incidence of non-disjunction. What relationship is suggested by the data in tt77j( ho hywwq4 ;5g)wehp.ba he graph?

  Which stage of meiosis is represented in the diagram belo 6bhf5 g*sk8ssw?

  The diagram below shl cj.2siabjiu) )k-+tows 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 sta8g,dzy:aake 3c ),r nates the number of alleles of a single gene which would be present in the nucleus of a cyd3, ka:r)e ,ac gzan8ell as a result of each process?

  Which keyword is matched to the correct definitionw gt/ ;6*8l .ulwu y )d 5;vsqn5atj6eyqvf8ua?

  Which statement(s) about mitosis is/arn :r(ez4 gah sx(7hpf6p :px5we 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 lettkuqhb+c bmn4zkdi*3m + f/9a+ er points to a cell in anaphase?

  During which stage of mitosis does the ;y.jxy 4 *s.xhix )4o,hpmwy tnuclear envelope break down?

  Which one of the following transport proteins only cayaa:efr:-uco-d z 6f3lz,o) l rries out active transport?lu fc::6forl--z3) ayd e,aoz

  Which process does not hap4w qbvpn2v 0e9tcvu7+pen in the shoot apex?

  Which type/s of membr 15yq gd98tjw qiuzxr273 (qdaane transport do/does not require energy expenditure?
I. Facilitated diffusion
II. Active transport
III. Osmosis

  The diagram below represents a ct2j(mz q+j)alsn 8 *qxell with a diploid number of 4. Which stage of cell z* (a+8n2x)q qjjmltsdivision is the cell currently undergoing?

  The photomicrograph below shows a root tip meristem. Which of the following sent0szs 4zw fk/l bubi.*,ences correctly .zf bbw/us 4 z0,lsi*kdefines a meristem?

  When does the random orientation of homologous chromosome pairtpmg q*0 tj7y,w z4jj(-: o-bna;4pusq dm bu9s occur?

  Which process does not oc -y.vj 3;m4kqubk ebi.cur during meiosis?

  If a cell with a diploid nu l- 0(b/jxntt 1,xzdnember of 36 undergoes mitosis, how many chromosomes will be present in each dex1/(bttnj l d- xnz,0aughter cell after cytokinesis?

  The image shows a micrograpwncjwnh.38 7q *e+ loeh of a cell.


What explains the appearance of the cell in the micrograph?

  Which statement(s) about homologous chromosomes is/are not trhq;ud7u2yep l 35 *rklb4 7av xos9l-rue?
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 f*o6pi 7 x7z9 nnrs/(e:chzfk individual with Down syndrome.

Which statement is not correct?

  In the cells of a horse (E. caballus) during prophase I of meiosis I thereoolh;(f n 4,uow o2/fwo r+ip) are 64 chromosomes. What is the hapforo ;)f 2(uhw np4wl,/oio+oloid number of chromosomes?

  Which arrow is pointing to a c 1du(yqu.+asr x0:b oehiasma?

  The diagram below represents txl3c /kgkl0wwln0)(a-inou 2 he structure of a shoot apical meristem. Which row in the table correctly identifies the processes occuring in the str / k0xl(20 no3w wli-lk)ugncauctures labeled in the diagram?

  How does meiosis promotew1 rxt*i f3ru( variation?

  Which of the following statement2cadt7i x:oo(uk bd07s 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 chromo3n*n6duyde c2g ym4182yf dfqsomes.


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 formar q/en18wrm bub 2+6rztion of secondary tumours from primary tumours as a result of the movement rq8r/zmer u 1b+bn 26wof cells?

  How many chiasmata are present in the diapr0 0+s6 :ecrfxow4za gram?

  Which statement is a similarity between cytokinesis in animal and planjyrhm a5: 10get cells?

  Which stage of meiosis is matched to the 4q e(vpdwd *k)e8bqs6. qxd:ycorrect description?

  Which statement(s) are true of meiosis I butkq ojf ,,+p d9ofiw:2l 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 mep.pnr, vod,4yns j-)niotic division. This results in the formation of one large cell ann.vpy ,)4 njno-p, drsd one small cell. What is the fate of the large cell?

  Which row correctly de bq dfx fb-uwzj-98*6x-4it czscribes diploid and haploid cells in humans?

  The following table shows the diploid chromosome number of a range ob (egr e cyg e;y)g7f0)4ah;eqf species.


Which of these statements is correct?

  What conclusion can be drawn from the karyogram below? l efp-/bczn*(ve3g k)c xz/p 9

  Which of the followin+9pk8bcqpx b/ g processes is characteristic of the meiotic and not the mitotic bq/ 8+kb9xpcpcell cycle?

  The diagram represents a bud with a shoot r)n9y 46sljcdapical 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 (Panvk-0l, a1wg qs,eu*.f4;jn m vj5f dro troglodytes) is 48. Which row shows the correct chromosome numbem-vo gnd vw*k; a 51q.ffujrsl ,4e0,jr for different cell types and cell division stages?.

  At the end of which pha 6qkxysj6bdp i/8,/kl4qq0ihse of meiosis I does crossing over occur, and what is the ou ihs jlqx/64qbk6q8i,d0pk/ytcome of crossing over?

  Which of the following statements doeyv-1 m x 4aqsk)wp8*nms not describe a step in the sodium-potassium pump cycle in the neuronal cells?* v8qkx p awmy1s-nm)4

  Which row in the table below is true ohzj3a/;xr0nmjic* 500 dow a bf meiosis?

Membrane transport is important for allowing particles to move a +bkvf 6 +mzy-gf6trb9r.8q ybcross the cell membrane and respond to changes in the chemical composition of the extracell byf +bt 6rkf9bry6-+m.8gqzvular 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 iyo;y 6o0c+)lo ypzv )d68lvjis 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 shows the conlbwq7b8(3r8;w gq ss ucentrations of different cyclins during the cell cycle. Whic u qwswbq(gl83b;s87rh cyclin is involved in preparing for DNA replication?

The diagram below shows chromosomes 93lk k zha.o/kduring 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 chr z:f cprv+p.;somosomes?

  The mitotic index of throat tissues taken from 4 different patients is shown belkr0p j,ypt1v:ow. Which patient is most likely to have cancerous throat tit01py:,kp vrjssue?

1.Draw a labelled diagram to represent the process of cro7iel6j nflt(oa3y5 3 xssing over.

2.Compare and contrast random orientation and crossing over.

3.Outline the stages of meiosis.

  The image shows an abnormal hu872ll b7mzhfh6f xg e6;dp j6icm 3imh0s4w5iman karyotype.


What is the abnormality in this karyotype and its cause?

The graph below shows the relative amoun5 bk2wqi9nug qb: 71:ny-vyept of DNA in one cell during one completen79 y1nvky iu qqp5 -wbbg:e:2 cell cycle. 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 homozygousv4/fja4ql5sqji t j3 - for brown, long hair a-jvj54stfj 43i/ laqqnd a female cat that has black, short hair.


Which of the offspring has a recombinant genotype?

1.Outline how polygenic traits can show a n,3v egm: khr*rl3e:i oormal distribution.

2.Outline the differences and similarities between homologous chromosomes.

3.Explain why expected and observed Mendelian ratios may differ.

  Which gamete can result frl:w njcwi, 4w3jcltpm -98kf,om the crossing over of non-sister chromatids shown in the diagram beloww:ip8l cnwj9,lcj ,4t m-3kwf?

  The photomicrograph pe :k3bq4t o:u(rbwq. je:naa1j+v*yshows a pollen grain from L. candidum (Lily). Which stage of (eu w .yqje qtpn*4r:bka j3+avb:o:1 meiosis is shown?

1.Outline the events which would lead to an gxx+sto*sy: 4 hqmi.1 individual being born with Down syndrome, which is characoqs:hxgy1* . +4mixstterised 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 od+3.cavx :c.gr w0 ysy+ml7y 1tp 8engrowth. A study was conducted on white onions (Allium cepa), under controlled conditions in a lab, to investigate the effect of soil pH on the mitotic index of the roots.v+xs+y: tce1m nlypocdy.3w 8 ga0 r.7


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 diagm; 9j+jkg hcz0rams below show two cells from an organism wimc h +gjj90kz;th 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 e5c p8 d;nwaxp)yt(o *(ru;a(of4 cqqrxpression 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 ceei:ix43e z7-4rrj lf xll, with a diploid number of 8, in different stages of meiosis. Which row correctly names i3xferji-4 7r 4lz:x eeach stage?

  The micrographs show four phases of meiosis I in a plant. In whax: 6enmj9nk*i tgb;u* t order do these ph uj mb6t*n:x;g*knei9ases occur?

Mitochondria are responsible for supplying metabolic energy in eukaryot.kxday. v1j7 h y ++cordf d),m6hecg8ic 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 ok.jg +)h dmyd1xvo+ 678aer,. yhccdf f 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 differenth5r ez7z(1sa ccu -qsk3g+ i-h stages of the cell cycle in four samples of lung tissue from four patients q hc+czs-s3u71a-izreh5k g (. Which tissue has the lowest mitotic index?

  The diagram shows the dominant cyclin/CDK complexes at differedxo . eta;acj*0c0- eu.ms9j t; .sosynt time points in the cell cycle.auy0a9m dx co0ejot;tsc e.-*s;j ..s Which cyclin/CDK complex activates DNA replication machinery?

  Studies have shown that genes such as Cycli*/p2wzr*qb 8 8pgciv wn Dependent Kinase 3 (CDKN3) are highly overexpressed in c2wbp8zvq* *pgwr/ i8 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 p,ue4z8i9th:zi t gnyngwx5q j+x+:(cyclin E the highest during the cell cycle ?