The graph below shows the relationship betwey/,nkgx. -.4actn0mdppf s -h,8kt qmen maternal age and the incidence of non-dan ,ps08k qh,xm-p /-. dgyk.4cnt mtfisjunction. What relationship is suggested by the data in the graph?

  Which stage of meiosisoqg e) -iu+r73mi3s gj is represented in the diagram below?

  The diagram below shows chromosomes:pqffz6n.ug+k4m .e o 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 whichf8)z 4uxowshg04 8okw would be present in the nucleus of a cell as a result o 084uxookzf wgw8s4)hf each process?

  Which keyword is matched to the czdpe :0z0 w8ecorrect definition?

  Which statement(s) about mitosis imxp ;u u4*p7yfs/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, whiocgq41-kb 1 zxv9 -bbtch letter points to a cell in anaphase?

  During which stage of mitosis does the nuclear envelope break down?ah6-m utnka+; gzey7 5 +s7xel

  Which one of the following transport proteins only carries out active tran w;hr,es 4vk,i djyj03sport?0 jevkyj;s r,h ,i4wd3

  Which process does not hakeccsf,wo p9qa)81 o 2ppen in the shoot apex?

  Which type/s of membrane transport do/does not require energy expendj.7ujis-1)y.o ae8nkrquky. iture?
I. Facilitated diffusion
II. Active transport
III. Osmosis

  The diagram below represents a cell with a diploid numb )uvd3a* p3zdxer of 4. Which stage of cell division is the cell currently undergod*)u 33vpdzax ing?

  The photomicrograph belovqnas rc:42;l:xk r0zw shows a root tip meristem. Which of the following sentences correctly defines a meri 0zrs cnr;a:l24 :qkvxstem?

  When does the random orientation of homologous chromosome pairs eobyrm.* q,s4ul1pu/ occur?

  Which process does n;jy+xrbddn yl. 5do+ .ot occur during meiosis?

  If a cell with a diploid number of 36 undergoes mitosis 9hbcjj0t/evzc.ex 8 hb/*tv;, how many chromosomes will be present in each daughter ce8/.hj0*zjvxtb h c ;v/t ebc9ell after cytokinesis?

  The image shows a micrograph of 3j 9p1lrjf yn0a cell.


What explains the appearance of the cell in the micrograph?

  Which statement(s) about homologous chromosomes is/az pn yz)cysg+5j)ihj:m7s* 5 dre 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 syndrom be8i vzg.e dq0v.d.(kk9yf l2e.

Which statement is not correct?

  In the cells of a horse (E. caballus) during prophase I of meiosis I there are 5peha6c 4c.zbwr *mj4h6l7 jv64 chromosomes. What is the haploid nmjzej46a rbwp h*4 6ccvh.75lumber of chromosomes?

  Which arrow is pointibs8v ugl6rfwf 41)8n rng to a chiasma?

  The diagram below represents the structure of a shoo.*grrd 7p ub6dt apical meristem. Which row in the table correctly identifies ddrrgu76bp*. the processes occuring in the structures labeled in the diagram?

  How does meiosis promote v pxam yj)3:y8b pz*oq2ariation?

  Which of the following statements i vt penn*mhdor;g26j x:7.. ras/are correct for meiosis?
I. It is a reduction division
II. It involves random orientation
III. It produces genetically identical cells

  The diagram shows gametesjffmv i ,.yj4 *y9uqg olsh3)) produced 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 tumou5q jxl y0x(7yars from primary tumours as a result of the movement o7 5(a xly0xjqyf cells?

  How many chiasmata are present in the diagram?co*wo; psn,7-1 yopc e

  Which statement is a similarity b51mxbnwdw6kh+6 2 6 :ef eeanyetween cytokinesis in animal and plant cells?

  Which stage of meiosis is matched to the correct sqvxjka9fv2.m b7to*o a c0* .description?

  Which statement(s) are true of meioh q(ll 4d e8bl;n6,fnfsis 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 oocyti2 /6x8 le2z 1kujo7tbdde*uz e after the first meiotic division. This results in the formation of one large cell and one small cell. We2 j uklb26 8idu7de*1ztx/zohat is the fate of the large cell?

  Which row correctly describes diploid and haploid cells in humans?zmb9+ l wbk+*y0pgmr0h0uyv .

  The following table shows the diploid chromosome number of a rd ss1.l4zi e7iange of species.


Which of these statements is correct?

  What conclusion can be drawn from the karyogram below?36z0 z1pgdj bcpua h-5

  Which of the following processes is characteristic of the meiotic and n oyreg/;o4:ixmnox n,1 rg0s5 ot the mitotic,0xr/xe roo 51n4gyng;om:si cell cycle?

  The diagram represents a bud with a shoot apical meristemzs d8l -ezc+0q.

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. Wh, qq ,tgo4rmw 4ht/w1aich row shows the w1hw ,oa4 tqt/q4mgr ,correct chromosome number for different cell types and cell division stages?.

  At the end of which phase of meiosis I does cro(xiusck7 s,9epiv/5 u ,zd8bt ssing over occur, and what is the outcome of dvk i e7z9/i5ts 8cuusbp,x(,crossing over?

  Which of the following statements does not descr0a 6t *oir4r;ywhubh uy21l9tibe a step in the sodium-potassium pump cycle in the neur4;by0ta 6i9*ryh 21 uw lrthouonal cells?

  Which row in the table below is true of meiosisd(akw*zc3kt, ?

Membrane transport is important for allowing particles to move acro v /ycge*qj;at+ (cyhvnpiddlg- t, 6-3o:cv)ss the cell membrane and respond t6( a,t-voqt c+ji/d *c-:nl3v;gcpd )ghevy yo changes in the chemical composition 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 i6+o+ujcxg: +pr(ycd e8 hh+nqn 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 concentrations of different cyclins during the (mi);jn/zkap 8tph 0;-y(7l elc ucgy cell cycle. Which cyclin is involved in preparing 8ypht;p -un(zicgely7 / k(ma;j0lc)for DNA replication?

The diagram below shows chromosomes during meio3r8lzp* qa(wm6s9c z)tvv9 o lsis.

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 chromosoy/wa-2j xu3xf g3ldlequ 5*7nmes?

  The mitotic index of throat tissues taken from 4 differeng , rc.qh67thlt patients is shown below. Which patient is most likely to have cancerous throlg6.rchtq,h7 at tissue?

1.Draw a labelled diagram to reghp(+ )hoav zb19lg+ zpresent the process of crossing over.

2.Compare and contrast random orientation and crossing over.

3.Outline the stages of meiosis.

  The image shows an ab71 jj3v vs)mtfnormal human karyotype.


What is the abnormality in this karyotype and its cause?

The graph below shows the relative amount rq89cf9q4g k.c5q gmj of DNA in one cell during one complete cell cycle. Each letter represents one 9qmfkj54.q cc 8rq 9ggstage 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 homozygo cx9 xipt , r0iql /kyndg9y*q8940gqaus for brown, lon9rxid anc/q,*ixkg g0p98lqy 0y9 4qtg hair and a female cat that has black, short hair.


Which of the offspring has a recombinant genotype?

1.Outline how polygenic traits can show a norm,wmax*q 9 4ubeal 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 (h a62hbipua 4non-sister chromatids shown in the diagahph4ui 2a6 b(ram below?

  The photomicrograph shows a pollen grain from L. candidum (Lily). Wh4qwf (i f dme2d(2e5ezich stage of2mew (f4dzdei5 2fqe( meiosis is shown?

1.Outline the events which wouldsdkwe+c r0f /szd *;v2 lead to an individual being born with Down syndrome, which is characterised by the presence of three copies of chromos+0ef*z;sdr/w2dcv ksome 21.

2.Explain how meiosis increases variation.

3.Outline the stages of meiosis.

The mitotic index is an b m0z2(ajlc38 (zj/:*e b8b+jau h mr d2fdptqindirect way of measuring plant growth. A study was conducted on white onions (Allium cepa), under controlled da2(2l z cehu+t3 bbf0p/r8 j(q mjj*:md8zba 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 cell+7ga3 f-kzn9 4o rhhdns can divide. The diagrams below show two cells from an organi-74kdnr 3fhh9+ znoag sm 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 expression w +ltju9zb8l8 xho:b- l 64pjyin 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, withc h;m)ou/s3- a t(7tqrp fvb/e a diploid number of 8, in different stages of meiosis. Which apt(;ch ou/)q-t3m /eb7frs v row correctly names each stage?

  The micrographs show four phases of meiosis I in a plant. In 6;qqsn 8sn j.ygf8zu4 what order do these qs8zsnu. qg8 fj;n46y phases occur?

Mitochondria are responqsf27lwfy 6lw.cn c)udvl-e m 86 m:i7sible for supplying metabolic 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, inheritance patterns 6lf-vc m 7)f d:lcwy sq8l7ei62nmw.uof 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 c(p+ qqcdjbcq 2*diuyc44.d:lycle in four samples of lung tissue from four patients. Which tissue has the lowest p: qc.*4bqcd +ic y24juqld(d mitotic index?

  The diagram shows the dominant cyclin/CDK complex)w5;k+ a lweui2xast2es at different time points in the cell cycle. Which cyclin/CDK co 2axit2su5;lake +ww) mplex activates DNA replication machinery?

  Studies have shown that genes such as hqffw5z12e q m yd*:o6Cyclin Dependent Kinase 3 (CDKN3) are highly overexp1w5fzho2 6*qf:qdm e yressed 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 of cyclin E the highest dui)c d82p cn+ymring the cell cycle ?