The graph below shows the relationship bgygp)hmz xus* ,a2: g:etween maternal age and the incidence of non-disjunction.2 g*u:pxg ayh:sg )z,m What relationship is suggested by the data in the graph?

  Which stage of meiosis is reprepx e5egh 2uq wx/:y/6usented in the diagram below?

  The diagram below shows chromosomes during meio 2s :ejg:chvz+ewq2v)et kegl5+,g, isis.


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 a7)w 3j1k dfrbx single gene which would be present in the nucleus of a cell as a result of each procekf1j) wxd 37brss?

  Which keyword is matched to the corre:t*.x.shod ld p*rn-v ct definition?

  Which statement(s) about mitosis is/are true?vq77yzdr(q8h) w p hz:
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 pointu, n 2ahm4z4 mo,bhrf9gt1 6k92 eyiius to a cell in anaphase?

  During which stage of mitosis does the nuclear envelope break dow6 n( bt9svi;wzn?

  Which one of the following transport proteins only carn1m lty v3psj8f 9)/cyries out active transport?py9s8mjc3 1n/)l y tvf

  Which process does not happen in n 87)i o(fhz i*pdwbvk/ x7/pathe shoot apex?

  Which type/s of memb+laf*0vpp ; xc+su+7 a8hssr urane transport do/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. aia 2wz0q;1a+k0ba um Which stage of cell division is the cell currenub0 wamai 0k+azaq;21 tly undergoing?

  The photomicrograph below shows a root tip meristem. Which of the follob h+tk 3w5jn,wwing sentences correctly defines a men, 3hbtk+5w wjristem?

  When does the random orienta ngiac,n jgb 4nf6,k vt.fc.72tion of homologous chromosome pairs occur?

  Which process does not occur duri h:tqt 6gs5f+bng meiosis?

  If a cell with a diploid number o*xqsb 8-41mmedi ;zs jf 36 undergoes mitosis, how many chromosomes will be present in each daughter cell af4 -qzjmbx med *8i1s;ster cytokinesis?

  The image shows a micrograph of a cell./pkv*u2ftqu v)q+o:jog* a .jfvk- ;n


What explains the appearance of the cell in the micrograph?

  Which statement(s) about homog- (((zs bpuk)hl*jxdp)h fykm0 do29logous 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 an individual with Doa,y:jmb)xat h 7t).i5 8k jgdhwn syndrome.

Which statement is not correct?

  In the cells of a horse (E. caballus) during prophase I of meiosis I there are t c3f)(h;olod 64 chromosomes. What is the haph3oldt( ;fco)loid number of chromosomes?

  Which arrow is pointinnv0uo/is9fiy c so oyg)fr4f 4d1 /2ku4e9l .eg to a chiasma?

  The diagram below represents the stpp7e3.sj p z:5v*qvyiructure of a shoot apical meristem. Which row in the tavpesyi. j 3zv:p7p *5qble correctly identifies the processes occuring in the structures labeled in the diagram?

  How does meiosis promote variat u j9lp q6crasx:yg0-0ion?

  Which of the following statements is/are correct for2qn qk3et.,ji meiosis?
I. It is a reduction division
II. It involves random orientation
III. It produces genetically identical cells

  The diagram shows gametes pr w+a)y m-ne 0ad0qzi:loduced 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 tuilqm)lb,ch6nl6 74,gn dqpxyg 2j9) cmours from primary tumours as a result of the mm 2 gn),dil6qcqb,l)gyhx p ln7c 469jovement of cells?

  How many chiasmata are present in the dgw /h b:hcf98muf2np /.zc7lniagram?

  Which statement is a similarity between cqci 0g l/ix+ khb.rd/t 63bwr:ytokinesis in animal and plant cells?

  Which stage of meiosis is matched to the correct descripugw7gk3f 5-7d eyu)ldtion?

  Which statement(s) are true of me:-hfznz vp ;n i58c)il a)cnw.iosis I 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 firsf0ue 6opr 8)eat meiotic division. This results in the formation of )ar e68fp0 oeuone large cell and one small cell. What is the fate of the large cell?

  Which row correctly w epar.9)r*-fmcap+ 8 z0 mqhedescribes diploid and haploid cells in humans?

  The following table shows the diploid chromoso-0 6 wwey sy x9ab*k-ogi.jhh/me number of a range of species.


Which of these statements is correct?

  What conclusion can be drawn from j.- h,xvh 5cydthe karyogram below?

  Which of the following processes is characterrg-wlslg r*dok u+ td) 1:pi09istic of the meiotic and not the mitd-*l9kds ) u +1il0p:rgrw otgotic cell cycle?

  The diagram represents a bud with aptqiwpc+64 +bbch68 q 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. Whichbw/4+pu hrc w 2r2xa2p row shows the correct chromosome number for different cell a/ h242 pr c2pxurw+bwtypes and cell division stages?.

  At the end of which phase;7inu r emz11o g;fy.emb.oj ;uy,8jy of meiosis I does crossing over occur, and what is the outcom g7ie;n 1.rz8;1j;yj,yum o.ebo yu fme of crossing over?

  Which of the following statements doesac6a0 t1v x skitt/qxeib6t)e0+u37 r not describe a step in the sodium-potassium pu6/r 0qatveiu)x3 sx t0 7catkti+1eb 6mp cycle in the neuronal cells?

  Which row in the table below is tr e*( zsqxpuzb1p +c ykg9n)p*+ue of meiosis?

Membrane transport is important for allowing parf9t/4rdf/p gcg/ f+rwaz- iw7x m.c (r0 9sqtpticles to move across the cell membrane and respond to changes in the chemical compo9z- w tpr wc/ftfgrd+ .r/x( s/c4gapqfmi 079sition 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 in celg f1/e53l ywwxpuxa td k4-vi:w2 (;lqls.

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 diff4 .(ce8zlhfjzog p z85erent cyclins during the cell cyclfep(4 zc8oz8z5.lgh je. Which cyclin is involved in preparing for DNA replication?

The diagram below shows chromosomes du1uu-yi c0z m:.,ok9 cv z5i1* gqukzvering 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 p xjobd8mj5+yy6,r sd9ir8 r7homologous chromosomes?

  The mitotic index of throat tissues t*k u fk1v0u+h cjvl-e,aken from 4 different patients is shown below. Which patient is most likely to have cancerous throat tissuefku,-uh*10kv +lj ec v?

1.Draw a labelled diagram to represent the process of crossing over. q/dxite j )j7;

2.Compare and contrast random orientation and crossing over.

3.Outline the stages of meiosis.

  The image shows an abnormal huma9n3s9v izmc/tkiqw:(8isx +jn karyotype.


What is the abnormality in this karyotype and its cause?

The graph below shows the relative amount of DNA in one cell duringnyfwc1ivx 8 gg4 g6,i8 one complete cell cycle. Each letter represeicvg 84ifw 8n16,gxygnts 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 croygc uuv+hl1;8,i 1pv b(pd:va ss between a male cat that is homozygous for brown, long hair and a femaleia1ucl p1v y+up;bgv v: hd,8( cat that has black, short hair.


Which of the offspring has a recombinant genotype?

1.Outline how polygenic traiu9g re8ie)cg*- 0 pcepts 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 non-sister c7cfaf:m3n3ux vsl 8q .hromatids shown in the diagram b.s38:vlff u c3nxq 7amelow?

  The photomicrograph shows a pollen grain from L. candidum (Lily). Which stage u ng-lgw d838+w0jwud of meiosis is shown? ggjw wlddu8n +83u-w0

1.Outline the events which would lead to an individual being born wiroj5ezyo(p21- qx 1h.*oz tn pth Down syndrome, which is characterised by the presence of three copies of chromosome *.yr-pn2zjoz(eho1q1 t pox5 21.

2.Explain how meiosis increases variation.

3.Outline the stages of meiosis.

The mitotic index is an indirect way of measuring plant 4t7wk: 6tqm0ao97(nwzzaddfri. b 3fgrowth. A study was conducted on whitdztqaf9z0fw 7:d 7m46 (.3iot br wknae onions (Allium cepa), under 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 wb kg 0du(+i l so5n*q;cxbu:e*ays in which cells can divide. The diagrams below show two cells from an organism with a diploid numbec*;:nqodkl+*bs(i g5ux0 ueb r (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 expression in sga zgg46s r+ +x.fe2rktem growth.

2.Outline how growth is controlled in the shoot apex of plants.

3.Explain the process and applications of micropropagation.

  The diagrams below s8 t xrn-vmw(-bhow a cell, with a diploid number of 8, in different stages of meiosis. Which row correctly names each stage? t--(bw8vrnxm

  The micrographs show four phases of meiosis I in a plant. In wh 4zwsby1tab.) at order do these phasw .z4asb1yb t)es occur?

Mitochondria are responsible for supplying mezmq* fn u 5px6j.ybrcon.y;)(/8p e)t kmrcb(tabolic 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, inherita).r t (xnymn6f()p.rm5zye ujcp8okcb;/b *qnce 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 of ao8t)s irn) *kthe cell cycle in four samples of s ron)8ia* k)tlung tissue from four patients. Which tissue has the lowest mitotic index?

  The diagram shows the dominant cyclin/CDK complexes at different time 7l;iqy r rgfp 89xsb5vuh/)s6points in the cell cycle. Which cyclin/CDK compi ) ;hlf9xv 6ps/r s8ryqg57ublex activates DNA replication machinery?

  Studies have shown that genes such as Cyc+2rl lnp jr-y.lin Dependent Kinase 3 (CDKN3) are highly overexpressed in nj.p+ y- lrr2lcervical 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 cyq*vjge-3 9 go7zb7b cell cycle ?