The graph below shows1u j n),pm/eg , s0h:weulct/k the relationship between maternal age and the incidence of non-disjunction. What relationship is suggested by the data in the graph?:kpj0teh /1nul,) u/,wmcseg

  Which stage of meiosis is represented in the diagram bel5 r d6q/re-hmlow?

  The diagram below shows chromosomes durinu9sk*0-n exa hjc9v4* ,todesg 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;b2t w spubzs3+c.4 :g-mfiud alleles of a single gene which would be present in the nucleus of a cell as a result of each process +.bu cmwg43spfsb; tzd:u 2i-?

  Which keyword is matched w -fj;o3gyij4to the correct definition?

  Which statement(s) arca; 7f.osr6) voqd0obout mitosis 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 to a cellfnhq* lxs l13*e1- m oqmi7q:w in anaphase?

  During which stage of mitosis d q5/-aiwhslb 7rnq8c+ oes the nuclear envelope break down?

  Which one of the following transport proteins only carries out active transport/bub z0as *l- eh3 jwfi00usd-?3u0j-eusi/0h0s- dfa b z bw*l

  Which process does not happzrmyu7.xi0+ dc*xs m+en in the shoot apex?

  Which type/s of membrane transport do/does not require energy expenditure0sybfc0ea 0 cw( 4/etm?
I. Facilitated diffusion
II. Active transport
III. Osmosis

  The diagram below represent2r;6e/je x/ix ...q+ q u e,tryoxwcnns a cell with a diploid number of 4. Which stage of cell .iqujtr;.e2 +,rxen/ 6oxe x .q/c wyndivision is the cell currently undergoing?

  The photomicrograph below shows a root tip meristem. Which of the x7(g0zlinz u2 following sentences correctly defi7l z0( ni2gxuznes a meristem?

  When does the random orientation of homologous 5xf+68ky4j lwwx lat+rh* gp8chromosome pairs occur?

  Which process does not 416tvd gpf-hp occur during meiosis?

  If a cell with a diploid n8-wd dau 27my*vz,vxg umber of 36 undergoes mitosis, how many chromosomes will be present in each daughter cuzd,d yw7-x 2mv*v 8gaell after cytokinesis?

  The image shows a micrograph of a 1cjgm-h3n-2a y jl m1xcell.


What explains the appearance of the cell in the micrograph?

  Which statement(s) abou qx3 d4sg. dy.ugtwxvag*h6 ;-t homologous 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 indivejc7,kwd3 6qg )t i(dq 7,nmobidual with Down syndrome.

Which statement is not correct?

  In the cells of a horse (E. caballus) during prophase I of meiosis I there ld lsd3sf7ytt 3) x:(vare 64 chromosomes. What is the haploid number of chromosomyf vdl s3ls7dt3t(x):es?

  Which arrow is pointin79o;nivth o 19f 3 ,tigpe(xvisd z+a6g to a chiasma?

  The diagram below represents the structure of a shoot apical meristeu32i x(huf b hk(bq+uv-,m*k+7 rdiedm. Which row in the table correctly identifies the processes occuring in ru f*u2+h (,mq-v(kkud3hi+ e7 bxd bithe structures labeled in the diagram?

  How does meiosis promote varia 6 p6dvjuvm-o(,zbz,ation?

  Which of the following statements is/are correct for meiosisn9hs7 5uhv mo8c+ v:by?
I. It is a reduction division
II. It involves random orientation
III. It produces genetically identical cells

  The diagram shows gametezv *.79u nee);uhrabd s 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 tumours from primary tumours7,1c.witx/ebn k- nas as a resu-7 xtewi,nan/bks.c1 lt of the movement of cells?

  How many chiasmata are present in the a, )md)/ )4bd yaihrwidiagram?

  Which statement is a similarity between cytokinesis in animal and plj+(e oipii38lant cells?

  Which stage of meiosis is matched to the correct description veu2-x(om ifq6l1sb-fzpw8gv t7 e44?

  Which statement(s) are true of meiosis I but not meyr.hu8ff lg3oex :+,;,vjg lc iosis 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. This res1 e9-zdz b vejqasu62(ults in the formation of one large cell and one small cell. usz-v6e1eb2z (9 jqdaWhat is the fate of the large cell?

  Which row correctly describes diploid and haploid xf251wpjwnir :dxjp j()8: kccells in humans?

  The following table shows the diploid chromosome.zj4aw4 0dmhn number of a range of species.


Which of these statements is correct?

  What conclusion can be drawn fro*/xs s/kq:opdm the karyogram below?

  Which of the following processes is chaa vd-ik64i/dg ,jty(i:/ir m09gklxpracteristic of the meiotic and not the mitot a/4lkv -jdmr9gy0i /kg6,i:dtx(ii pic cell cycle?

  The diagram represents a bud with a shoot apicalp+ 9e g,nxup3l 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. Whiqr 2*yn fdml:ni9w v)6(w ka9gch row shows the correct chromosome number for i:nw rg *l yna2mw6df()kq v99different cell types and cell division stages?.

  At the end of which u*kv4(f gm-m46zch 2z1 ffew ophase of meiosis I does crossing over occur, and what is the outcfem(*m2c-z 4k hfvog6 w14uzf ome of crossing over?

  Which of the following state6 0g(k7tcg b f.psj bw+0ao.idments does not describe a step in the sodium-potassium 0.sgwbct.ao fdb 7j6i+gp 0k( pump cycle in the neuronal cells?

  Which row in the table b* 8aak3a 6igri5)vlnc out21nelow is true of meiosis?

Membrane transport is important for allowing particles to movej7e 3 w 9x s)0afnipab::-yptd across the cell membrane and respond to changes in the chemipib73-fpe:9a nw:0d)t xas yjcal 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 reg1.p f+e1okbryt,v8 htulated 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 e3gpczq:( zp,fm.t -cdifferent cyclins during the cell cycle. Which cyclin,t3z.e g:-(q cpfc zmp is involved in preparing for DNA replication?

The diagram below shows chromosoms,bbj wgz.4tbz+ya* .es 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 involveclx 2ny .+s)p2wr8thec(s lv; s the separation of homologous chromosomes?

  The mitotic index of throat tissues taken from 4 different eix o3qf p0/7s:iallz4n *tax3 j)-gqpatients is shown below. Which patient is mostz4x qxli0 i 7npj-oe3fql:3g*sa/a)t likely to have cancerous throat tissue?

1.Draw a labelled diagram to5e6.4bqc gbln 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 abnormal human k/nettz)+yxure / c ,l8aryotype.


What is the abnormality in this karyotype and its cause?

The graph below shows th7icm 2esc0zzl4 i+;c be relative amount of DNA in one cell during one complete cell cycle. Each letter r imlz;7cz2e0cbc i +s4epresents 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 ca+xy;i6 vpp -ub.q hgt6t that is homozygous for brown, long hair and a fem it-+pu6hp ygx ;b.qv6ale cat that has black, short hair.


Which of the offspring has a recombinant genotype?

1.Outline how polygenic traits can show 4h*q 61ozlr zys p).a+rfqujoev457ga 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 chromatids shown i5vj ((r*unrjfokbz 47n the drofvz(7 ku j(b jnr*45iagram below?

  The photomicrograph shows a pollen grain from L. cand;oz yygwfk4ygw:m6 9m(1 fobuv p9fw7:yd*-cidum (Lily). Which stage of meiosis is om: y6y :-dv ;1(gwf b * ygmfouwckpzfw49y97shown?

1.Outline the events which would lead to an individu z) /yokszldfk-:kpp0*, b2pjal being born with Down syndrome, whpk,*- k)k:/zyoz sj0b 2dplpfich 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 plant gr62s61qlkyjm les) zj,rkvga: y*eyd l/)i4 2bowth. A study was conducted o yseqjb /vy 1y)r6l2dl2k6:lk,4izjsa*gm) en white 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 ways in which cells can dividep(,m 7*crlws x3rykxvv.lw;4. The diagrams below show two cells from an organism with 7 v;y ws3mkc4rrvxl (l.x*p,wa 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 in stem sk .nq .vj;j-jgrowth.

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 diplspq9- ryba+ 6eoid number of 8, in different stages of meiosis. Which row correctly names eac6 eyb+as9-qpr h stage?

  The micrographs show four phases of meiosis I in a plant. Isnnj u2f,p ra8,2p yy,n what order do these phases oc u pjannf2y8spr,y2,,cur?

Mitochondria are responsible for supplying metabolic ea- 6p*p1nli) 3z pbyjbnergy 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 of mtDNA found in hybrid cells, which are the result of sexual reproduction between two different yeast species, could be influenced by the p*pyajb1i3l-p pn )6zb arent’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 stages8d/ )jpcbb .h/(:r7e6aavh w1mkv mhl l2/pa l of the cell cycle in four samples of lung tissue from four patientwh1acapda8 r2/jl vvh(67b /p /b:le m)kml.hs. Which tissue has the lowest mitotic index?

  The diagram shows the dominant cyclin/CDK complexes at diff3)s(nzk1peya g : s(hjerent time points in the cell cycle. Which cyclin/CDK complex acti1a (3ez(gypn:sk h) jsvates DNA replication machinery?

  Studies have shown that genes such as Cydkc2g 8 hnt 9;i*w.ctigb2:f uclin Dependent Kinase 3 (CDKN3) are highly overe89c*hnb; ttiig :2kdc2.u fwg xpressed 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 cycle ob+m-z,rf 9cujz3h7j ?