The graph below shows the relationship between maternal age and thrw0wqw-2dxyo l-( p f:e incidence of non-disjunction. What relationshi2 doq -fr0-ww(ly:x wpp is suggested by the data in the graph?

  Which stage of meiosis x:v.yyj04 .na*9 vl bgqd/ce dis represented in the diagram below?

  The diagram below showsdp 1urrs.m s(6 s2j v5i,aui6d,f1rwc 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 states the number of alleles of a single gene which .9,hkvwy qpv2hi yu 3;would be present in the nucleus of a 9uqhw2v.yp ,yvh;k3icell as a result of each process?

  Which keyword is matched to the co ueyw*n3dg+v r:o)sw6rrect definition?

  Which statement(s) about mitosisj2cc 93 rj kh af7q-.rojkaf,3 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 below;9. ue89 vlyppsum715zukvas d(s i ,x, which letter points to a cell in anaphase?

  During which stage of mitosis does the nuclear envelope break down?vm21x,kn13ifgg 0m c/byg )uc

  Which one of the following transport proteins only carries out active transpor u:gcsj+(ug 3y(,qkf 2tyh-n4h9 ztuu t?u2tq(3gug -(,f4k:hu sy9h y uc+zjnt

  Which process does not happs)4jn6cc8pvx- l (ot uen in the shoot apex?

  Which type/s of membrane transport do/ygr y ut+4*i upibm(fq1k2n57does not require energy expenditure?
I. Facilitated diffusion
II. Active transport
III. Osmosis

  The diagram below represents a cell with a diploid number of 4. (w bw-*te8az 9gz*eqm u8xl9m Which stage of cell div9 ml( z *gtzewa* xu-m8ewqb89ision is the cell currently undergoing?

  The photomicrograph below shows a root tip meristem. Which of the fo7 b c uh;jus)p/swy7p5llowing sentences cop7u5 )cpyuj hsbw; 7s/rrectly defines a meristem?

  When does the random orientation of homologou pxned m1j+) 7:r3zcyls chromosome pairs occur?

  Which process does not ol0e-e)yd uw.; 4cijzvc1iso6y4g a j 6ccur during meiosis?

  If a cell with a diploid number of 36 undergoes mitosis, how many chromosoh(jdpplb 70j 6mes will be present in each daughter cell afte6 jdl(p70hpbjr cytokinesis?

  The image shows a micwmqno eu4(l o; t8 3j.k-wc;xprograph of a cell.


What explains the appearance of the cell in the micrograph?

  Which statement(s) about homologous 0 r gk7vfvm5ywp-g4 e4i*mf+gchromosomes 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 syndromecr-0m f/j nwyx14;u:vqqp:po.

Which statement is not correct?

  In the cells of a horse (E. caballus) during prophase I of meiosh1,sb9lqp1 9 e q,o2pc rk:bcais I there are 64 chromosomes. What is the ha 2:,hlq c q9 sek1ap,brp91ocbploid number of chromosomes?

  Which arrow is pointing to xgcl) vv-;)t4kgd,nv a chiasma?

  The diagram below represents the structure of a (l x hh-ep uhz:a6pe8.shoot apical meristem. Which row in the table czeh h8(xp hple6 u:.a-orrectly identifies the processes occuring in the structures labeled in the diagram?

  How does meiosis promote((gfm c w(bwx7 variation?

  Which of the following statements is/are co1392cepnua g2l alhn ,/uzj s/qm6 7gurrect 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 homol-+ixugya 4u2l ogous 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 8p inihgv;;tzwm kuqf3b m e3:a32/1l primary tumours as a re2lhz/;33piwm:1t bn qgmivafk; ue83sult of the movement of cells?

  How many chiasmata are present in the diagra :f a:uxxcg8p0m?

  Which statement is a similarity bg p) gb/(f)q9v+owjgk etween cytokinesis in animal and plant cells?

  Which stage of meiosis is matched t e juioz2mie t611j35i)uj5tho the correct description?

  Which statement(s) are true of meiosis I but not meiov9-cj f zhww 9l1,7sjzsis 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 ;ty fqj48gairl v(z5 +the first meiotic division. This results in the formation of one large cell and one small cell. What is the fate of the large cel;g5l(aviy8 t+z4 f rjql?

  Which row correctly describes diploid and *fo4m+ymb2eovt tl+hh0-l q )d0c nz ,haploid cells in humans?

  The following table shows the diploid chromosome number of a range of spz0sb. kez/o6 jae +7ltfb(+ k1fbpj -lecies.


Which of these statements is correct?

  What conclusion can be drawt su(6f7ew 18czn4zyj n from the karyogram below?

  Which of the followitua-nl99wxt9 jm+uxq +5xy d+njg 94qng processes is characteristic of the meiotic and not the mix9j4j-xuqy 9x++wmnt9 t uqnl5gda 9+totic cell cycle?

  The diagram represents a bud wi c5 pj*-o9 .foghd1m*(b uxnteth a 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 rga5a tuu1up r22.mzkk: 5ao4chimpanzee (Pan troglodytes) is 48. Which row shows the correct chromosome number for different cell types and cell divi4t2a5ak :u2graor1uu 5 zm.kpsion stages?.

  At the end of which phase of meiosis Iiw ezf+1 d++. egnaj;v does crossing over occur, and what is the outcome of cross.gfawi;e + e1zvn++ djing over?

  Which of the following statements does not describe a step in the sodium-pfqdj s/4,ae u5otassif,q 5u/d4jesa um pump cycle in the neuronal cells?

  Which row in the table below is true of m rawm kh82;v.+,i wg;tehmu 0;j -idjneiosis?

Membrane transport is important for allowing particlo8ythue0 jo*e:a*lz 5es to move across the cell membrane and respond to changes in the chemical composition 5t 0 *a:zejyou8lhoe* 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 cel3mn)00f gk ga9 cy+vbq7wp.vuls.

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 showss s ygzwxt60t 2s7r,l+ the concentrations of different cyclins during the cell cycle. Which cyclin is involved in preparing for DNA wtrs sz,+062 7ygxtslreplication?

The diagram below shows chromosomes 9goo*3sxi7gzry q0n/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 homologous chromosr v3 m *(tcfumsku+i:y0z*i/s omes?

  The mitotic index of throat tissues taken yv x0f hmq6v77from 4 different patients is shown below. Which patient is most likely to have cancero7q76hfmx0 v vyus throat tissue?

1.Draw a labelled diagram to represent the process of o+dt)sx :ngh 8crossing over.

2.Compare and contrast random orientation and crossing over.

3.Outline the stages of meiosis.

  The image shows an abnormal hum ;1dpfxsv aj--an 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* gzstwkkgk*54f bd7 - complete cell cycle. Each letter represents one stage of the cell ctb gg wfdk5*-kz*7k s4ycle.


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 fo 32rcub)+kd4ast (wijr brown, long hair a wd+sr(cijk 42 a)b3tund a female cat that has black, short hair.


Which of the offspring has a recombinant genotype?

1.Outline how polygenic tfc ;oeo 1t 58gqfanx20raits 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 chrp9cehjq+ p/ - zg(e5*he..swu c*eyjromatids shown in*he jecyp9ep.ch q* 5gw-.er/ s+(zju the diagram below?

  The photomicrograph shows a pollen grain fvx - ,wdukx3f6rom L. candidum (Lily). Which stage of mkv3xx-,w f 6udeiosis is shown?

1.Outline the events which would lead to an individual being born with Doi*vxxc36rj s-wn syndrome, 6-i*xvrsx3 jc 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 pla.dcg z( oxlt m7/q;s1znt growth. A study was conducted on white onions (Allium cepa), under controlled (7 g.qdlt zx;1ocmz/s 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 diagrams belowoo8 p3bxj q 465yyq pf)u(vw+k show two cells from ay4b8kwoy 35qopf6up vx( )q+j n 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 of gene ex 6u:ztckwht 1+-tax,ipression 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, with a diploid number of 8, in differesw:ach 3j a1/zv sm613;ers-xh, jd font stages of meiosis. Which row correctld3oajjrzf sm w;ve16hch:-sx/ , 1a3 sy names each stage?

  The micrographs show four phases of meiosis I in a plant. In what ordesu0w*z,huy7z 4(gw u *;t.ft r; ogcvwr do these phases o,( wuty ww z*zgfc rt;v.ugs0; ho7*4uccur?

Mitochondria are responsible for supplying metabolic energy inzd *sf9hpv/u x;0.hkq 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, inheritance patterns o /9; *qv dz0hkshpf.xuf 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 the cell cycle in fgi/)e*zjxpia7 1n2 m rour samples of lung tissue from four patients. Whi e/)gpz1*i ijn 7xm2rach tissue has the lowest mitotic index?

  The diagram shows the dominar;j:gqzmf/ yh( h-bz;fof3 a8nt cyclin/CDK complexes at different time points in the cell cycle. Which cyclin/CDK complex activates DNA repli q;;ofahj3zrh(fm8f/- g:z bycation machinery?

  Studies have shown that genes such as Cyclin Dependent Kinase 3 (CDcbgp ucah)w +6h mnz-ac;) p(*KN3) are highly overexpressed in n +cambuacpz*(g )cpwh -;h6) 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 concentrasyb 1h ss0*f mdwi5308sox h9etion of cyclin E the highest during the cell cycle ?