The graph below shows the relationship between maternal age and the incidencep)u(*zkzb)i y of non-disjunction. What relationship is suggested by the data in y(zpukz )*)ibthe graph?

  Which stage of meiosis is represented in the diagram p /m)/xt eq xbni0h,j*below?

  The diagram below sho/dqame +a /w)ows 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 siqyr1-amwv(:sy 3p9mdz6 e: q gngle gene which would be present in th3:z- dvwm qre :9 q(yp16sgymae nucleus of a cell as a result of each process?

  Which keyword is matched to 5z5crj b2; lp()xsyi(w5sq b0maeh6fthe correct definition?

  Which statement(s) about mitpuw7s (w8 prw 50ebr;zosis 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 pointvjl93lk v o cp/,89)wjv)wqi gs to a cell in anaphase?

  During which stage of mitosis does the nucleug;i6dve,j-+c2 2xbqdim ,tjar envelope break down?

  Which one of the following transport proteins only carriahr2+ba*tn. pz c/bt 7es out active transport?ztatn+c* .h rp/2ba7b

  Which process does not happen in the shoot -i2 w* j wh:nw28mbpbsrszd r f:1v+o0apex?

  Which type/s of membrane transport do/dfi*ztihz w f (at :aw.1gf:7j3oes not require energy expenditure?
I. Facilitated diffusion
II. Active transport
III. Osmosis

  The diagram below represents a cell with .h l95-1 ,lxde, 60ljymwl8lo(mfk3us c fxcy a diploid number of 4. Which stage of cell division is the cell cx1h5wld,m.f3y(-y9ec fl8msxu0 lol lj6k ,currently undergoing?

  The photomicrograph below shows a root tip m j/uli 076hy;ai/ak toeristem. Which of the following sentences corruhtlo 7a0;ij/k y6 ia/ectly defines a meristem?

  When does the random orientation of ho0v e od4qv;7sx1 b2szxmologous chromosome pairs occur?

  Which process does not occur dut5z(7/xk qy1aa m. (ttnwrx-cring meiosis?

  If a cell with a diploid number of 36 undergohva-u9(. cwnsyd n9 n;y8hk4des mitosis, how many chromosomes will be present in each daughter cell after cytokinesis (v.nk dh;ydn9uah- sw849cny ?

  The image shows a mi;et9s1 di t1ik9(s cuucrograph of a cell.


What explains the appearance of the cell in the micrograph?

  Which statement(s) about homologous chromosouv3mzrg:9f t1)pcjx o1 warj2) 48qkqmes 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 inty.8 jn :/vftmdividual with Down syndrome.

Which statement is not correct?

  In the cells of a horse (E. caballus) during prophase I of mm3ffvw0xfdad 6.3)y ntdo)w4 eiosis I there are 64 ch o. x n)td)fffy3a4mdvwd 306wromosomes. What is the haploid number of chromosomes?

  Which arrow is pointiq*h h jbazbqvf66v3. +ng to a chiasma?

  The diagram below repres68g gy+oej( x3w/n owi.gcr c:n9e3 cxents the structure of a shoot apical meristem. Which row in the table correctly identifies the processes occuring in the structures l3g/ jr+cxxng 9eoc.y:igc3e(wwo n86abeled in the diagram?

  How does meiosis promote amy1kl(qj. 5nvariation?

  Which of the following statements is/are n(s 8g-ri 8siccb,ct8correct 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 lvvj*lf4f 976 b bt )-rfo4ju*.hpa:qo *akvctwo 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 r;0,urr hyc ;q -cwj2sfrom primary tumours as a result of the moveme 2wqc,rcjy;h s;r0- urnt of cells?

  How many chiasmata are present in they z) jwvq0ij;- diagram?

  Which statement is a similarity between cytok x9)ym+ z3vocl7srs ,rs(nabig.g0) qinesis in animal and plant cells?

  Which stage of meiosis is match04l .n8-rogoajuc4hm ed to the correct description?

  Which statement(s) are trueklr 4jgskn 4(x+ay4b8 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. This retoi(g8k r/ kq/opnz*k(nu27u sults in the formation of one large cell and ont( z * /uok kp(kiu87gon/2qrne small cell. What is the fate of the large cell?

  Which row correctly describes diplzc7/c(gz cch sl6(hhz ; qh5-noid and haploid cells in humans?

  The following table shows the diploid chromosome numberhfd: 3drrq f26 of a range of species.


Which of these statements is correct?

  What conclusion can be drawn from the karyogram below? l* akfffkw if:o 8+tf+5)g1sd

  Which of the following processes is characteristic of wefri.y x;i1/hz4kr2 the meiotic and not the mitot.4iryz xiw/f ;ek1hr2ic cell cycle?

  The diagram represents a bud with a shoot api*ftg6w,4d naa* *hz uncal 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. Which r9 or1v;xmj p/jk,w3 mdow shows the correct chromosome number for different cell types and cell divisiono kmjwj;m3xr/d1p,9v stages?.

  At the end of which phase of meiosis I does crossi:sa5q mr29uu 9ktj, bdng over occur, and what is the outcome of crossing,mu52u9t : sqbjrak9d over?

  Which of the following statements does not describe +7 meap-n+y,rd q)trl a step in the sodium-potassium pump cyclleq -ptn7rym rd +)+,ae in the neuronal cells?

  Which row in the table beloie 59jwlz a98nw is true of meiosis?

Membrane transport is important for allowing particles to move across +da cg)-)x+/fyfx hmq 1o5zynthe cell membrane and respond to changes in the chemical composition of the extroy +1) - m+df ca/y5xh)xfgzqnacellular 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 isep i,4e:5:avbt sg9h o regulated 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(jel)29u7w qf, ejfad of different cyclins during the cell cycle. Which cyclin is involvf,duj2ea(l ejq)7f9w ed in preparing for DNA replication?

The diagram below shows chromosomes -zg2c enn3jj*kc2pntg0 /l)i 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 chromofdvx*)n46tzshqtf+/fy z:y, somes?

  The mitotic index of throat tissues taken from 4 different patg :/w;ggx tu94:kakop03abk0 xf/xxxients is shown below. Which patient is most likely to ha0 ;:fxo3tx 0/gkbxaxwkag u/xp49g:kve cancerous throat tissue?

1.Draw a labelled diagram toukn-3tiwau+c -cx- s 0 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 abno+;8*ji2 l6ndk snbmz irmal human 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 c-goxkigieiu3 - -3 )hxomplete cell cycle. Each letter represegx-xk33iiog eu)i --h nts 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 homozygouskn/v7q 2+4gmnisr qyvry0, : a ,ffk9q for brown, long hair and a female ca9y if,k+v: qgy s2qm/kv0qfrr74nn,at that has black, short hair.


Which of the offspring has a recombinant genotype?

1.Outline how polygenic traits can s7 /xhz)o3qe tv auk53yhow 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 chromatidx+1 4dc-zk wp;xpcm r3s shown in the diagram b +r3xdp4c;mk-zx 1cw pelow?

  The photomicrograph shows a pollen grain from L. candidum (Lily). Whicg l9122nk+ pak0ky wkeh stage of meiokwke ln 9g+kyapk2012 sis is shown?

1.Outline the events which would lead to ) r:kyuv 3q6z4 .ux0jt9))yykaijnjvan individual being born with Down syndrome, which is characterised by the prestqyjn v.z: ) 9yiuk63)vyajr)jku0x4ence of three copies of chromosome 21.

2.Explain how meiosis increases variation.

3.Outline the stages of meiosis.

The mitotic index is an indirect waw: iu6jm7s hsm l+j,2by of measuring plant growth. A study was conducted on whit 6ujs2 bjim+ws :l7h,me 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 at7 g*:+xqyi(3 cvbm zbgod*-pkdi*h 7re two ways in which cells can divide. The diagrams below show two cells from an organism with a diploid number: 7-b( *txdobm**yh73ggzkq+vpicid (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 expr: 2;cncm e x)tj,jdfi/;k/oo wession 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 celo/kp1r0sf m8q chp0,hl, with a diploid number of 8, in different stages of meiosis. Wh1qh/,8 cpspfho0km0 rich row correctly names each stage?

  The micrographs show four phases of meiosis I in a plant. In what gzpco4f66 (;8; csm0ao-j khquihs( x order do these phases occur? ;-a ssk f8o6c6 xzgop(m;(h4qhu0 cji

Mitochondria are responsib1tv*bz09nxz s, grvp(le for supplying metabolic energy in eukaryotic cells. In most eukaryotes, which reproduce by sexual reproduction, mitoc,sbz g pv*x09 ntzv1r(hondrial 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 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 dtb6s j:nqcj j* 0+p.azb4-cviifferent stages of the cell cycle in four sampl *0.6 zjjq:bsct4-ijpn cba v+es of lung tissue from four patients. Which tissue has the lowest mitotic index?

  The diagram shows the dominant cyclin/CDK compiaim b.vluk 0-h,f6:rlexes at different time points in the cell cycle. Which cyclin/CDK complex activates DNA replicationl.a m,b-uih0vk f 6r:i machinery?

  Studies have shown that genes such as Cyclin Dependent Kinase 3 (CDKN3) are hhzd iw4v(qo+k:xs z4th;*t x yi op9*2ighlyi2 t:q ws*xo +hzp ztd(xv9h4k*; 4oiy overexpressed 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 thez:fpxi ;so fqnxuqr6hl 6w25 i35/0fq highest during the cell cycle ?