The graph below shows the relationship lbt q.dbp*e34 6fwr3u between maternal age and the incidence of non-disjunction. What relationship is suggested by the datapw ul* .3tr6q4f bdeb3 in the graph?

  Which stage of meiosic8:66)o47qla;s3l,gp dneidbs fdr rs is represented in the diagram below?

  The diagram below shows chromodb2eubo8.+x0 r x* txukh 5+dvsomes 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 alle5m uerl,x0z 8ules of a single gene which would be present in the nucleus of a cell as a result of eachure0z,lux58m process?

  Which keyword is matched to thenh mwz5fo(1n4 correct definition?

  Which statement(s) about sl.1 knel 9ti (rh1ul:h4ap9am pkl*3mitosis 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, which letter po 1kzm)nipcs n q2jn,(27zvg6sints to a cell in anaphase?

  During which stage of mitosis does the nuclear envelope break down*d7ehwibnrl;wu q f :gc43 8/d?

  Which one of the following transport proteins only carries out ac1+xv ,nf2ukul tive transport? l+v2uxn1kuf,

  Which process does not happenbzgo 4 s28mz5j 1uqd n;e4gqp. in the shoot apex?

  Which type/s of membrane tr*vk7icp a :t iv)r13kaansport do/does not require energy expenditure?
I. Facilitated diffusion
II. Active transport
III. Osmosis

  The diagram below represents a cell with a diploid numberu4-nay d9z 9qr of 4. Which stage of cell division i 49za-qndury9 s the cell currently undergoing?

  The photomicrograph below shows a root tip meristem. Which of the followingl/2 dhy bl-az5 sentences correctly defl- ly5hzb2d/a ines a meristem?

  When does the random orientation og9,*q2wjk jy mf homologous chromosome pairs occur?

  Which process does not occur during 9 n )qjh:mo-cimeiosis?

  If a cell with a diploid number of 36 undergoes mitosis, how many chromr(oo :zstr wfm wzn)gz-p i8,,:sw*e-osomes will be present in eazi:owg(8 :*t,z-pm-eorf,wsnrwsz )ch daughter cell after cytokinesis?

  The image shows a micrograph of a*msnmeybk)g- )9,xg o)z3hr j cell.


What explains the appearance of the cell in the micrograph?

  Which statement(s) about homp*ysxmk/8u5 v ologous 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 indicj6yf;oa 0+ (ciik yv5vidual with Down syndrome.

Which statement is not correct?

  In the cells of a horse (E. caballus) during prophase I of meiosis I there-m wuha.ypwu ,37sh7r are 64s,y.mwa w u3-u77hh pr chromosomes. What is the haploid number of chromosomes?

  Which arrow is pointinn xb.tf 4s h.qi ei-mgq)l8zjm cmh4+m8p;/a1g to a chiasma?

  The diagram below represents the structure of a shoot apical meristem0 z ,y exdxtc9,nsmq 5y(7t8rx. Which row in the table correctly identifies thxyqrnxm5zc ,sye(9d7t 0x8t , e processes occuring in the structures labeled in the diagram?

  How does meiosis promote 3lf-vtbnodny. 3t -rt-l/k4 cvariation?

  Which of the following statements is/arewi2qli cg h ,i7yp)q r,9+c5oq 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 homol)u wh4g+i,4+xy+ku*d rm ; cy0 fu(g(uzannf zogous 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 seconlt/1xi qlqzi- (j+)hw.gh6 gndary tumours from primary tumours as a result of the movemen /lqhn t1q(-ixgl) g6 j.hzwi+t of cells?

  How many chiasmata are presenz i a18r 6v0wssz*5cch kzb.4yt in the diagram?

  Which statement is a similar )5tlk*hsfa6 hity between cytokinesis in animal and plant cells?

  Which stage of meiosis is matched to the correct descriss -* vn .mennivtx+*0efo2 :tption?

  Which statement(s) are true of meiosis I -wy9*,6 hksd3yxlxg( mzk,ccdp9c5 kbut 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 hz,0 s( 8iljunsh) cd6meiotic division. This results in the formation of one large cell and one small cell. What is the fate of the large ,c 86izsnldu)0hjh(s cell?

  Which row correctly describes diploid and haploid ce gjr jyb(:53rm)py:f ells in humans?

  The following table sho6cnj:tg(d j65o kf +zgws the diploid chromosome number of a range of species.


Which of these statements is correct?

  What conclusion can be dr.4 r; te:s0q or2vf;cftz5vp*y8plnwawn from the karyogram below?

  Which of the following processes is characterisfzur *))owat;or )t u-tic of the meiotic and not the mitotic cell - toto;)wza)fruur )* cycle?

  The diagram represents a bud with a shoot apiq1m7x/v0p eo zcal 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 th66zhs 7j; ys6akyfn(it8nu/re chimpanzee (Pan troglodytes) is 48. Which row shows the correct chromosome number for different cell types and cell division (6y rj6sa/ uikns;hf8t zn7y6 stages?.

  At the end of which phase of meiosis I does crossing over occur, an+82jizwm ve +ad what is the outcome of crosjwv8ia2+mz +esing over?

  Which of the following statements does not descrl fcmvtlan06; jp6 v9:ibe a step in the sodium-potassium pump cv: vl jp6 ;fntl09a6mcycle in the neuronal cells?

  Which row in the table below isj:1f .xlzwa /*y/hm oloif h6; true of meiosis?

Membrane transport is important for allowppy 58unat+ l.+ tx0zxing particles to move across the cell membrane and respond to pt.n+xa0lt5y 8+ zpuxchanges 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 regulatedscvrp cp f9:q17b 8oe5dhu2)g 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 concentrations of diffvnu shxoqi)/1: m(ly- erent cyclins during the cell cycle. Whic)xuy:/qoi 1v(mnh ls-h cyclin is involved in preparing for DNA replication?

The diagram below shows chromosomes during meiosis.moj8f h1 y+;vos 7.saw

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*9l lj:n3 q+ydcy4hsv chromosomes?

  The mitotic index of throat t2ctpzhyk)g7 u2j71 qfissues taken from 4 different patients is shown below. Which patient is most likely to have cancerous throat qj g7 uhyp1zc2f7t k)2tissue?

1.Draw a labelled diagram to represzf2);4j:sj-rjf ryf bent the process of crossing over.

2.Compare and contrast random orientation and crossing over.

3.Outline the stages of meiosis.

  The image shows an abnormal human karyo- +wlee v,vp9h6+z voutype.


What is the abnormality in this karyotype and its cause?

The graph below shows the relative amount of DNA in one d l(yd:k,+y jecell during one complete cell cycle. Each letter represents one stage of the cell cyc:edd,+y (l jykle.


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 malevl46. sa4 s um9n.ionv cat that is homozygous for brown, long hai.v69ss u4n 4ao vli.nmr and a female cat that has black, short hair.


Which of the offspring has a recombinant genotype?

1.Outline how polygenic traitvg0 -symi+gw ;rx g1(ts 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 chromatidz-czs; bm m)vu2k( mf2s shown in the diag - z2s(z;ucbmkf)2 mvmram below?

  The photomicrograph shows a pollen grain from L. candidum jn;i7c4 .fd wz-ccp0v/vsq pqoqw7.2 (Lily). Which stage of ;co 0.jzw p7snv.7-cd4q2i p w qcvqf/meiosis is shown?

1.Outline the events which would lead to an individual being born with Dowhs* rnely.s r;kzvb /*wgo17 1n syndrome, which is characterised by the presence of three copies of chromosome/bs z rolh;vne g* ry11s.7kw* 21.

2.Explain how meiosis increases variation.

3.Outline the stages of meiosis.

The mitotic index is an indirect way of measuring plant gp 1fn vt+u/)l-xxa 7vdrowth. A study was conducted on white onions (Allium cepa), under controlled conditions in a lab, to investi/alv)+ t1n xpvd fu7x-gate 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 ;iipw1 q8m6h uin which cells can divide. The diagrams below show two cells from an organism with a diploid number (2n)qm;p u6hiwi 81 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 stem gb2b t6 o5te 8vrt5tb0pgsq59yrowth.

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 differents8lo h we)nh 6u9ngt- *z+,afms g:yi g*rg*c8 stages of meiosis. Which row correctly na las)gun6hizo cw -t: 9 *yefm,gg*g8r+n8*sh mes each stage?

  The micrographs show four phases of meiosis I in a plant. In whaj4gbcih1 0.cit order do these c4ih1.jb cg0i phases occur?

Mitochondria are responsible for supplying metabolic energy in eukaryot o .( ooht1;f0nq eesm5jg(*mtic cells. In most eukaryotes, which reproduce by sexual reproduction, mitochondrial DNA (mtDNA) is inherited from only one of the parents: the mothergqmoej0o t*e o 5st(h.n(;mf 1 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 k5sr14v m*pv -unzv(l of the cell cycle in four srsmvvk* u1p4v -nlz(5amples of lung tissue from four patients. Which tissue has the lowest mitotic index?

  The diagram shows the dominant cyc gbub o r1;1j)ifn8ss3lin/CDK complexes at different time points in the cell cycle. Which cyclin/CDK compluobi g;f r3 )bn18ss1jex activates DNA replication machinery?

  Studies have shown that genes such as Cyclin Dependent -r u*(-xphts d (ys(meKinase 3 (CDKN3) are highly ( -(xr*stmy pdesh(- uoverexpressed 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 dz ,hpiktvq u fq4r2;+,0 -hu:*aiwggz uring the cell cycle ?