The graph below shows mal0; 8lt:8nyhonb 8fthe relationship between maternal age and the incidence of non-disjunction. What relationship is suggested byl8f ynt 8b0lahnm;o8: the data in the graph?

  Which stage of meiosis is represented in the diagramw,+c1z-ach a wa*osr n 377,old(tdwq below?

  The diagram below shows chromosomes during me 6bt1f 8r wz9 ,zabw8qt6ly4hjiosis.


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 numbertl 3tm-70ivu// z ,oirxho us9 of alleles of a single gene which would be present in the nucleus of a cell as a result of each procezo/,xtutoi0-lurmis9/3 h v7 ss?

  Which keyword is matched to the correcmi (4 ynho n1mu8x66 aw4izn;6 x,gelft definition?

  Which statement(s) about mitosis is/a.q ybwg))omqidl *bqv x-309rre 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 cell in anaphase?:d gl/)6: 2k c:webtdmcyyv1 2s)eadz

  During which stage of mitosis does the nuclear env-nc4 ; ryk0sh wts/ots.p 2mi:elope break down?

  Which one of the following transport proteins only w42hq jkyr1+rcarries out active transport?h 1rjyk2rq+4 w

  Which process does not happen in r d/ls4hmz1a1 the shoot apex?

  Which type/s of membrane transport do/does not require en 71upvec jt,efd -*8jpergy expenditure?
I. Facilitated diffusion
II. Active transport
III. Osmosis

  The diagram below represents a cell with a dipd( ,ji.*e8od-qi s ga u9vm(- qgeeov*loid number of 4. Which stage of cell division is the cell currentl-o,s d.ijgo iv*ge e9*( 8qvqmdea-(uy undergoing?

  The photomicrograph below shows a root tip mcxk-3w99m +alyo4u ;mu6q qdvk/ut 2h eristem. Which of the following sentences correctly defines a meristema94uk2 hq t l/ wx9 6umkmo-3;u+cvdqy?

  When does the random orientation of homolog2z, pqk olgq;nhr6+k4vt9iq ;y,ld .bous chromosome pairs occur?

  Which process does not ocu dt k*b3njq3 3(rke0 ljj4e;xcur during meiosis?

  If a cell with a diploid number of 36 undergoe,p;b4: toiq* en9qsl)q a(ynos mitosis, how many chromosomes will be present in each daughter 4l;(9pb ,qaqoe:in otns* yq)cell after cytokinesis?

  The image shows a micrograph of a cell.4.muoc wk29yu


What explains the appearance of the cell in the micrograph?

  Which statement(s) about homoloeytn; 1oy(pw ,gous 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 is s6.x) 3wim lg:ge0icndividual with Down syndrome.

Which statement is not correct?

  In the cells of a horse (E. caballus) during prophase I of meiosis I th7 /n2 vgy6l uijhdggv8:,.qt mere are 64 chromosomes. Whatig:j2gl ,y.qt7uvdv /8 nhm6g is the haploid number of chromosomes?

  Which arrow is pointing to a chiasma? g- )(1h eng+y e- gkz:wab.smi aebn-0

  The diagram below represents the structure of ujfn6;r+rxb6vn8b7v*8 m c wka shoot apical meristem. Which row in the table correctly iden6*7k u8bc+rbmw; vfvj8 x6nnrtifies the processes occuring in the structures labeled in the diagram?

  How does meiosis prom+new *myi 0vs22 -9qdq pdbtc)ote variation?

  Which of the following l0,vyo ev nqdja2 /,5kstatements 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 chromosomes;dkf ;g9ec-;c 2u pmca.


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 oqvi (cp0ixy+5ud k1 /pf secondary tumours from primary tumours as a redp+ y/u p0 i(qxik5c1vsult of the movement of cells?

  How many chiasmata are present in tgk e;c ef6e/r9q 3 t(2thdbhx;he diagram?

  Which statement is a si8qvz3 e iar*.gmilarity between cytokinesis in animal and plant cells?

  Which stage of meiosis i4a.j;t mxo5hm4spa6 oo8 or z3s matched to the correct description?

  Which statement(s) are true of meiosis I but not mel +onddui(,970.qr pa d gyvdv, +n9njiosis 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 resultct++0 w wufap:mtfm+(s in the formation of one large cell and one small cell. What is the fate ofpwfw+a+m:utt m+0(c f the large cell?

  Which row correctly describes diploid and haploid cells in /x +tw*2zj8n9 cognxwhumans?

  The following table shows the diplya9a23 yby/ eyoid chromosome number of a range of species.


Which of these statements is correct?

  What conclusion can be drawn from the karyogram- hvl3su1:zct below?

  Which of the following processes is characteristic of the meiotic and nozausznu z,f +9x+(gh4t the mitotic cell cyclzg ufxsh(+ az 4,9uz+ne?

  The diagram represents a bud with a shoot apical meristr r/se,s++hld gc 1lw8em.

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 chimpanzerolg zbj,tio 3):344 lm:cqfv e (Pan troglodytes) is 48. Which row shows the correct chromosome number for different cell tyfl) zrjl4gv:34,ot: ocbimq3 pes and cell division stages?.

  At the end of which phase of meiosis I does crossing over ocg q/y. 88qe0l chixdpggkv5zo **8i f3cur, and what is the outcome of crosk i p5ie /z*3xy8*go8l cg 8qgdfqh.v0sing over?

  Which of the following statements does not describe a step in the sod39kcq bo/z zi/cyr0v .ium-potassium pump cycle in th zzrq9/o3kci cv/b0.y e neuronal cells?

  Which row in the table below .68efpn(6v v7 .wiqnm d un)sym38nsnis true of meiosis?

Membrane transport is important for +a7jkwr(6xcg,2q ehyallowing particles to move across the cell membrane and respond to changes in the chemical composition of the extracellulaa ,2wq(re6xghyjk7c+ r 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 isow7t vo;vtbl1 6yjxi y7e-05f 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 of different cyc 58-npp4s idx d.;k;w gfyrmg(v 3;yxqlins during the cell cycle. Which cyclin is involved in prep.gnp3( 5;xxpv;k8 dsy4irqf;- gy wdm aring for DNA replication?

The diagram below shows chromosomes du*+,c xoc8hne pring 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 separatio;zfxd x0fln6me+mr; m9x ./p pn of homologous chromosomes?

  The mitotic index of throat g;/ ,ioydlc1mu(m ,p ctissues taken from 4 different patients is shown below. Which pati ply,1;d / c,miomcug(ent is most likely to have cancerous throat tissue?

1.Draw a labelled diagram to represent th n5oots:94qqq e process of crossing over.

2.Compare and contrast random orientation and crossing over.

3.Outline the stages of meiosis.

  The image shows an abnormkvj)6usw zcxso7hl/.e x:(r.(ory 3s al human karyotype.


What is the abnormality in this karyotype and its cause?

The graph below shows the relative amount of DNA io xxyym-ib 3h 1btk215n one cell during one complete cell cycle. Each letter represents one stage of the cel1hx x o25y bmkiby1t3-l 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 shiuc 6yls;e ,4bows a cross between a male cat that is homozygous for brown, long hair and a female cat that 6uibc ys;,4 elhas black, short hair.


Which of the offspring has a recombinant genotype?

1.Outline how polygenic traits can show a normal distributispmkjd).: ,ykd f.a h+on.

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 croy/ vtkz4u wgtv( 0v,3nssing over of non-sister chromatids shown in the diagr v0zyg vvt uw4t(,nk3/am below?

  The photomicrograph shows a pollen grain from L. candidum (Lily). Whojg*jmad 0s5 +5ca 2ipich stage of meiosis i0j+digj*5 a p25sm ocas shown?

1.Outline the events which would ;qdvsds:4g2p lead to an individual being born with Down syndromep;vd 2:qsds 4g, which 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 growth. A e5ke z f v)avmh-3tkrgb:i,;:study was conducted on white onions (Allium cepa), under controlled conditions in a lab, to investigate the effect of soil pH okegv r m3:zb,ehf:v)a5i - kt;n 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 twmk tbo vjq-4rdf3wb-0 9 7t8lko ways in which cells can divide. The diagrams below show two cells from an organism with a diploid numbvl4b-k798jf3bw km rd tq0 to-er (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 expt 7+ v,qrn0)ze4ig, ttddy z8vression 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 ohx9dugv6 7db ,f 8, in different stages of meiosis. Which row corre697g,xbud v hdctly names each stage?

  The micrographs show four phases of meiosis I in a plant. In w6pe qmr)6tu,trb34q m y(r-h uhat order do these phases occur)rp6 ,m4by( em3ru6ur- tq htq?

Mitochondria are responsible for supplying metabolic energy i u:nc,fyyxu+)x2njv1m8bba ) n 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 th2yvm1fy8 anbn ))c,uxu+j: bx e 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 differ:foulv* bqgk-0 s(c n0) bfk-gent stages of the cell cycle in four samples of lsn00 bk ( c-vf-gog) fl*kqb:uung tissue from four patients. Which tissue has the lowest mitotic index?

  The diagram shows the dominant cyclin/CDK complexes at different 5e +bsboq av kq719nw0time points in the cell ck7vb 0owb15 sqeaq+n 9ycle. Which cyclin/CDK complex activates DNA replication machinery?

  Studies have shown that genes such as Cyclin Depend/z re.:u yt1ejent Kinase 3 (CDKN3) are highly overexprtz.e/j r1:yeu essed 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 tb x(tl7 gv(u5whe cell cycle ?