The graph below shows the rz+g wkhp ,ynzi y.3ghr85bd31mc+q/z elationship between maternal age and the incidence of non-disjunction. What relationship is suggested zb5w 8r zg.y+zh3,+mk 1p/d3hnc yi qgby the data in the graph?

  Which stage of meiosis is represented in the diagram below? b:btdonu-wfd5 .g g-; v*kawv8q0v; v

  The diagram below shows chromosome zw;hxsg3,fn,s 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 opof)i awae+r/8jq72 number of alleles of a single gene which would be prep7ei/8afaq2r+ojo )w sent in the nucleus of a cell as a result of each process?

  Which keyword is matched to the correct definition*pmaa(b( 3oo+q + uadx?

  Which statement(s) about mi0+y2jt bjf cka0ksm9 f/rmoo n,-.f/ctosis 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 belogfk2+dvgg y.-3bnw, pw, which letter points to a cell in anaphase?

  During which stage of mitosis does the nuclear envelope break,- i)uf4bcfx*e(zu5h uku0l n down?

  Which one of the following transport proteins onl/ i htf:jdop4w) 2swm 7f1da9ry carries out active transport? r914fo:2h mf 7aitw/wdj)dsp

  Which process does not happen in thwwmcf o/7h;2ze shoot apex?

  Which type/s of membrane trankm0 m 5 4unbnz;/-burxsport do/does not require energy expenditure?
I. Facilitated diffusion
II. Active transport
III. Osmosis

  The diagram below represents a cell wizhi9 q)8jxl*g th a diploid number of 4. Which stage of cell division is the cell currently uzxijh g *q89)lndergoing?

  The photomicrograph below -bf,m 4hscie: shows a root tip meristem. Which of the following sentences correctly defines a me4c:mei-,fb h sristem?

  When does the random orientation ow rjmm+u(620zfimv +z f homologous chromosome pairs occur?

  Which process does not occur during mky6:y8kw l fldvh34 n92x)ucleiosis?

  If a cell with a diploid numu-o1.rpd*r2 ssax m u3, 0h.pd5d lurwber of 36 undergoes mitosis, how many chromosomes will be present in each daughter1p u . ds-*do2urrmxu5ps0hwl,.a 3dr cell after cytokinesis?

  The image shows a mi)vqeslti 4zaq ;i. nt88zvc 40crograph of a cell.


What explains the appearance of the cell in the micrograph?

  Which statement(s) about homologous c,y,pi5zom zy 7hromosomes 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 an individual with Down synd) vphuiqc.ofe+xc 174 rome.

Which statement is not correct?

  In the cells of a horse (E. caballus) during prwqz8)uc)k( h oophase I of meiosis I there are 64 chromosomes. What is the haploid8k)z(c hqwuo ) number of chromosomes?

  Which arrow is pointi2c si3chyd0* gng to a chiasma?

  The diagram below represents the structure of a shoot apical meristem. Whish7i5 )qfw.zv ch row in the table cors7i.qh)v z5f wrectly identifies the processes occuring in the structures labeled in the diagram?

  How does meiosis promojz),bfe rv.hj9s x2 -qte variation?

  Which of the following statements is/are correct for meiosis? /cl3qo9(cji wt*a 7d-jmvzv5
I. It is a reduction division
II. It involves random orientation
III. It produces genetically identical cells

  The diagram shows gametes produced from two homolote- 4jxhek4 t -n)j1exgous 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 pri.zp xaosmhk3vf6g2) 4mary tumours as a result of the movement of cells?hva zm3k)fp4x6.os 2g

  How many chiasmata are present in the diagramus//gnzjx e7ok +in7 o4ov .8q?

  Which statement is a sim) rfo3 x4a//mm2zzxk rilarity between cytokinesis in animal and plant cells?

  Which stage of meiosis is matched to t.f 4 ls j;:p,iwzr+jlphe correct description?

  Which statement(s) are true of meiosis I but not meiosioi1q- 9ibpki o:u)3p ps 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 hj 9l7e g/cg9nan oocyte after the first meiotic division. This results in the formatncgg h 9le9j/7ion of one large cell and one small cell. What is the fate of the large cell?

  Which row correctly describes diploid and haploid cel.n .uqbfdz j0hft: v3/ls in humans?

  The following table shows the diploid chrom*+0o/nfwiu4 ke. s jjoosome number of a range of species.


Which of these statements is correct?

  What conclusion can be drawn from the karyograaevx3bq76k7e0 aapa x *3bj/h m below?

  Which of the following processes is 6m 7au:dfj, vdakif8:y nt4q/characteristic of the meiotic and not the mitotic cell cyclenyva87f:6d4mqj,t a k:/fiud?

  The diagram represents a bud with a shoot apical meristgc7u+v0pwf:flr4 l8mt1.sui em.

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. Which row showx ,l.k+rxq3y,l w* vcas the correct chromosome numbrlx3ay+,k., l w*cvx qer for different cell types and cell division stages?.

  At the end of which phase of meiosis I does crossing over occur, and wj56jmqxc+ q2d kl+(a 1gwm3pe hat is the outcome of crossingqxj(+3makgpldm15c+wqe2j6 over?

  Which of the following statements does not describe a ste-u eo ,/ 7gsvfgps14cdr0eu8 qp in the sodium-potassiumge74 ur 1c8pefgqu,ss-/ d0 ov pump cycle in the neuronal cells?

  Which row in the table below is true bbxmh wl-t7r2 sfq/y ;:r.i c,of meiosis?

Membrane transport is important for allowing particles to movsu25 o)*t4saym tqm( yh)s rwqfz+a:l7n4y y5 e across the cell membrane and respond to changes in the chemical composition mwss 2yhrlay5us+n:t7f) moa 5z(y*y4 )q4tq 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 isqxep r.n4xb xu+a/ (y- 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 concezpi1kc5+q pl z6q:;bnc q ej/8ntrations of different cyclins during the cell cycle. Which cyclin is involved in pri85:pzc;q/ l1 6 p+kjzqn eqcbeparing for DNA replication?

The diagram below shows ch uudg ky fph6+rw0/z+7bw;ro7romosomes 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 homolock jl69e2u bt 01t0jqagous chromosomes?

  The mitotic index of throat tissues taken from 4 different pa5x ebj+mbe -,opc6h-/atz1dwtients is shown below. Which patient is most likely to ha6de b5-z- p,1wh tcjaxob/e m+ve cancerous throat tissue?

1.Draw a labelled diagrazi qrcpt pd(c 737ua/0m to represent the process of crossing over.

2.Compare and contrast random orientation and crossing over.

3.Outline the stages of meiosis.

  The image shows an abngsyr2 p e,rk:ap0+x 9eormal human karyotype.


What is the abnormality in this karyotype and its cause?

The graph below shows 7w0u4h5u8 /rbwm kduq the relative amount of DNA in one cell during one complete cell cycle. Each letter represents one stage of the cell cyck87uu/d qrubw mh054 wle.


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 bezm7 , ( s00nveqygdx9jtween a male cat that is homozygous for brown, long hair and a fe,ym 0sqgxvz0 d ej(9n7male cat that has black, short hair.


Which of the offspring has a recombinant genotype?

1.Outline how polygenic traits can show a normal dis7t 6v)i 29zehn zmz6is,rq,lv7z3 elotribution.

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 chromat,mgrc l dk8 j/7+0wzbwv 7iy8ekv30fzids shown in the diagram belowfz/dkj0 +,y0imgvw87lzce rv 7k83 b w?

  The photomicrograph shows a pollen gra(k4ks tslz :e-in from L. candidum (Lily). Which stage of meios:s( ezkstl4 -kis is shown?

1.Outline the events which would lead to an individual being b7ts4aq1r 2ue eorn with Down syndrome, which is characterised by the presenrq47t2s eeu a1ce 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 measu6;( fisdcdd6t ring plant growth. A study was conducted on white onions (Allium cepa), under controlled conditions in a lab, to investigate the effect of soil pH onfid6td ;cs6( d 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 bszsr xo29tyn9d;,j 8 cells can divide. The diagrams below show two cells from an organism with a diploid number b;xrtjz9 sy9n82o d,s(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 en2w wu( u,r.h-uz o/vn x:tkt;xpression 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,; 7c)dj ,pgza:b7 vstl with a diploid number of 8, in different stages of meiosis. Which row correctly names each7,bts:7zjvgp)c ; l da stage?

  The micrographs show four phases of meiosis I ins 5+ivtel+ 3fg12d zor a plant. In what order do these 12 53 +d tlzgs+ovriefphases occur?

Mitochondria are responsible nr)hsxt0-wxt 6oz9i+ for supplying metabolic energy in eukaryotic cells. In most +w zr6no-) st 90txhixeukaryotes, 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 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 different stages ox6zb 5(gd5gyl f the cell cycle in four samples of xlyd5ggb56z(lung tissue from four patients. Which tissue has the lowest mitotic index?

  The diagram shows the dominant cyclin/CDK complexes a mps4xnd b*j .fl-6a)jt different time points in the cell a6m .4 plj *bd-fsjn)xcycle. Which cyclin/CDK complex activates DNA replication machinery?

  Studies have shown that t22p4qe qr e5h 23vosotq)1nwgenes such as Cyclin Dependent Kinase 3 (CDKN3) are highly overexpress5tp2hwet2nsqoq ve1 42 )ro3qed 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 ud f pqhd6+8y6of cyclin E the highest during the cell cycle ?