The graph below shows the relationship between maternal age and the i4ke, 2lo2 i-uebd nr2zncidence of non-disjunct- lebkizo2drun 2,e42ion. What relationship is suggested by the data in the graph?

  Which stage of meiosi+gr;3pz2u *3po fu olxs is represented in the diagram below?

  The diagram below showsq,tvc,f d xy8mt,huu ; (lqh34 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 tkz e8;.7zdata: bi4nof a single gene which would be present in theitt.kaz na:e 4; 78zbd nucleus of a cell as a result of each process?

  Which keyword is matched to the 9n7-9hm u:isi ndg9euq0:7/s qxzyy5 h u6wqe correct definition?

  Which statement(s) about mitotn+ , j* 4z 4r9qyinzg1gmm(fcsis 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 points tod w d08mdkrq(sn) 0o;o a cell in anaphase?

  During which stage of mitosis does the nuclear 2qf2b/jnc58h9c wv xr envelope break down?

  Which one of the following transport proteins only carries out active trm7m-0es w 2tz xncpdmj4+; 4+er8hrrcansport?+ m4 w2rre;cd8xep mnr07h-tm+ zj4cs

  Which process does not happen in the shoot ape ,jt+7p-chrj9xan.hab pu+ cu)nx.9 fx?

  Which type/s of membrane transpzxnq1 ja vu429/a6doi ort do/does not require energy expenditure?
I. Facilitated diffusion
II. Active transport
III. Osmosis

  The diagram below represents a cell with a diploid nuwvql5sw3qva -ko jnw4. q -x7/mber of 4. Which stage of cell division4 v .skqa3x/7-v- wjwqn5lowq is the cell currently undergoing?

  The photomicrograph below shows a d xv,fw2 ;bbv+ )cl +my0n4*lg gb/kujroot tip meristem. Which of the following sente2,v0xggbnd m;cw+ +b4f/ykbul j l )v*nces correctly defines a meristem?

  When does the random o 1:o4gf/ aia (,,un;mgf ersescwn /-mrientation of homologous chromosome pairs occur?

  Which process does not occur during meiosklathe)2i 6 uc. xegeq 5eg(50is?

  If a cell with a diploid num4 gam)oqb 4d9tber of 36 undergoes mitosis, how many chromosomes will be present in ea tog4ba4) mq9dch daughter cell after cytokinesis?

  The image shows a micrograph of a cemze5 :dt* i,oell.


What explains the appearance of the cell in the micrograph?

  Which statement(s) about homologous chromosomes is/are n2m7qhvc7: a nhot 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 indmkekt+w5/ams zm4bl6 z6. j o-ividual with Down syndrome.

Which statement is not correct?

  In the cells of a horse)3q db;w og-ct (E. caballus) during prophase I of meiosis I there are 64 chromosomes. What is the haploid nug3bd w-)oc tq;mber of chromosomes?

  Which arrow is pointing to a chiasma? n.ten,zm7k/;c 1 j f(wl0jdzt

  The diagram below represents tpv5w t3.jxq 2zhe structure of a shoot apical meristem. Which row in the table correctly identifies the pr.32 v5xqtzjpwocesses occuring in the structures labeled in the diagram?

  How does meiosis promote variatioy8--7zy hbl4s qk 5cbsn?

  Which of the following nq 6i5/tbmhj8,hwb5 o9urxl 7 statements is/are 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 homologous chror/9 o.gwfo7r,xsnqw9oh5 4o rmosomes.


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 c fxdfsxf2t87jh.sjnt mx08m/hl65pv) mv *+formation of secondary tumours from primary tumours as a result of the movement on6sh8fm*lt tx /vxj8c5s.+v2j0mdhp mf 7)f xf cells?

  How many chiasmata are prese6 fh m,s)5e;q8wzeed/bpq ,zbnt in the diagram?

  Which statement is a similarity between cytokinesis in animal and plant f;mu4tz-tv ,vf2 g(wkcells?

  Which stage of meiosis is matched to qdk(kuscyfmeo9:-6*ob (a:cg k * 4 olthe correct description?

  Which statement(s) are :z7 zfmpqoiy8 qwl ua s)q4/i6nn)yp) 9-v(ejtrue of meiosis 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 first meiotic division. ne1b4z uom 0cq til;d2nm*4 s0v(n-ar This results in the formation of one l s aq*zc i2rom(4vdbe-0nnlu40m;tn1arge cell and one small cell. What is the fate of the large cell?

  Which row correctly describes diploid and haploid cells ind( k3hmdn3fz4; n*re(7v ryvr humans?

  The following table shows the diploid chromosome nu/;folc v*wht fcb3:x;mber of a range of species.


Which of these statements is correct?

  What conclusion can be drawn from the karyogram beloy/ ,gtf1hi z odi 8mieznl.6 :2gv*7e/h, saynw?

  Which of the following processes is charmp1hwao- gs8qy4w s(z2 a)k .zacteristic of the meiotic and not the mitotic cell cycle?(wzs8 4 wyq kpg-a)ohs1m.z2a

  The diagram represents a bud with a shoot api+lpctux ud2rt(t+m r+g-v3a o+g; 2omcal 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)pkokb oy(q v(c*v1 dym3.v63c is 48. Which row shows the correct chromosome number for d1vmd(6 q. (vcbo opck33kvyy*ifferent cell types and cell division stages?.

  At the end of which phase of meioyjge+w0mtln*j7fs * v 3, jg;csis I does crossing over occur, and what is the outcom v7sj cw lgget*3, 0+yfnm;jj*e of crossing over?

  Which of the following statements does not describe a step in the sodium-po,sy4slwqfp1d +v9kki2d+hc :f 8u* jntassium pump cycle in the neuronfnl1q, i kjcp8 2 4ks9y*h:++udf wdvsal cells?

  Which row in the table below i8 khd8huqf1+87mrmx1 csn ar4s true of meiosis?

Membrane transport is important for allowing particles to mhdhfmz)7w8 54 xmpxp7i/gn k .ove across the cell membrane and respond to changes in the chemical composition of the extracellular khi485.xz7fhm) 7gwn pp/x dmfluid.

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 d0l1r6i; rkz u ;yk1 qt.wx0 koc.v7eain 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 shogry.m-q, rq /mfj k ,u:v,rux+ws the concentrations of different cyclins during the cell cycle. Which cyclf:/.kgu,- jr mq rymr,,vxq+u in is involved in preparing for DNA replication?

The diagram below shows chromosomes dex,:98aa*u*8u q+f saaogwc ve 3kal-uring 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 invol1,4wiecbk+d eqxg52 oves the separation of homologous chromosomes?

  The mitotic index of throat tissues taken from 4 different patients is shown be 9meh2oa / glcb;q(7fflow. Which patient is most likel;c/ef2m fhbg(7oq l9a y to have cancerous throat tissue?

1.Draw a labelled diaiu9ry j(.1wjjgram 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 able y(; wj /frtv0kz: zy bgncw2(x,(5pnormal human karyotype.


What is the abnormality in this karyotype and its cause?

The graph below shows the relative amount of DNA los.bfm 6dr-xk:+ sa 4 r34jwfin one cell during one complete cell cycle. Each lett+r3k r mfs:xso bf64wd -4a.ljer represents 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 cross between a male cat that is homozygous for p-.fv)f iyf8 ibrown, long hair and a female cat that has f8p vfy.if i-)black, short hair.


Which of the offspring has a recombinant genotype?

1.Outline how polygenic traits can show a nordqg +(vcwmgx8. k q(v1mal 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 chromatidstk ho,v5/w:f-qge;a w5m u r9i shown in the diagram w,q9athgvirf /k5moue;w-5 : below?

  The photomicrograph shows a pollen grain from L. candidum (Lily). Which stage oq+my7v4y1.2g.zvi gn ltxhpfx+ ;:i k f meiosis is shx pii:km.;y+ gql.2g+ 7nt 1vzxf vy4hown?

1.Outline the events which would lead to vp n2n9zjn3 cel gmcy5*3pq/*an individual being born with Down syndrome, which is characterised by the presence of th*2pn/c qy339 vng*clzjpmn 5e ree copies of chromosome 21.

2.Explain how meiosis increases variation.

3.Outline the stages of meiosis.

The mitotic index is an indirect way of measuke2*j-h/le w6 k5eh vtring plant growth. A study was conducted on white onions (Allium cepa), under controlled conditions in a lab, to investigate the effect of soil pH on the mitotic index of the j5/ee-w6lvkk2h eth*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 arf/u e/ q1shwr :/ybr6me two ways in which cells can divide. The diagrams below show two cells from an orb /uey rw :s/h/6mrfq1ganism 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 1r*og u b/ .dwmes 3smid04nh5hh)2u eexpression 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 different )7kpfo. edt)3:afx krstages of meiosis. W7o.t3e:kx a rpfk)df) hich row correctly names each stage?

  The micrographs show four phases of meiosis I in a plant. In wh2qugn) ;n2ryev trg11at order do thesey neu)rqrn1tg;g 21v 2 phases occur?

Mitochondria are responsible for supplying metabolic energc rik7-cg1 .lgy 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 nu kir-.glgc1c7clear 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 b6+zdpf0i/h a in different stages of the cell cycle in four samples of lung tissue from four patiez0h6bip a+d/fnts. Which tissue has the lowest mitotic index?

  The diagram shows the dominant cyclin/CDK compllj1 s x9a.stn)exes at different time points in the cell cycle. Which cyclin/CDK complex activates DNA rtj1 nl.sx)s 9aeplication machinery?

  Studies have shown that genes such as Cyclin Depel7/;6iqnk0oi qi 9gnpndent Kinase 3 (CDKN3) are highly o 9l iig;nkp/7qnq6 0oiverexpressed 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 during the cell cy6 ;ks n6joidg27t67 tpxzh m*acle ?