The graph below shows the relationship between maternal age and q2mkssyw5b-0b sb l2i5 .myk0 the incidence of non-disjunction.s2ybwi-05mbs.sb2 mk05 l kqy What relationship is suggested by the data in the graph?

  Which stage of meiosis is reg:hjqcru 0*9ypresented in the diagram below?

  The diagram below shows chromosoh(wv,cnn/hk4 *l7g ohmes 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/s ncth1j dn./ of a single gene which would be present in1scn jd /tnh./ the nucleus of a cell as a result of each process?

  Which keyword is matched to the8gzi :wkdkua lu0 xq6:)g9f1s correct definition?

  Which statement(s) about m wudcm (p34dl1itosis 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 cell in anapha/mpuj/t inresl7uql2 -13v88y gkfr3se?

  During which stage o r3+um j*(iowgf mitosis does the nuclear envelope break down?

  Which one of the following transport protei 3 q,vtsu;9fpins only carries out active transport?fsui9p ;3v,tq

  Which process does not happen in the shoot apei/pek40)s0l7al.sd) t h1yg -qstszlx?

  Which type/s of membrane transport do/does not reeddr)2in p*k:mu as oyy0g* +m52j h6nquire energy expenditure?
I. Facilitated diffusion
II. Active transport
III. Osmosis

  The diagram below represents a cell with a diplueqv7kr xdw/,6 bzca, npunk2( 3s)e8oid number of 4. Which stage of cell division is the cell currennk 2,c7 )be,3 rpq/kvuu6d8n(saexwztly undergoing?

  The photomicrograph below shows a root tip meristem. Which of tfg4 c pm./8)krwq/yjthe following sentences correctly defines a merisyjw 4.kg p8/ft/q)cr mtem?

  When does the random orientation nj;/egp++hhr2 :l :y; klazpiof homologous chromosome pairs occur?

  Which process does not occur during 3qmml 1.mfz6yi mq*k8 sl7y3hmeiosis?

  If a cell with a diplotw0i3s 4o)jbv5jm 2v fid number of 36 undergoes mitosis, how many chromosomes will be bv)tjv5fom0j w234ispresent in each daughter cell after cytokinesis?

  The image shows a micrograph of a cellzhn6:.gt ib0mj ph .s d8b62wv.


What explains the appearance of the cell in the micrograph?

  Which statement(s) about homologouspc+*bjhrx6h ,ypy8b . 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 individual with kc5s0gu c18y 5k .teb5rmgsx- Down syndrome.

Which statement is not correct?

  In the cells of a horse (E. caballus) during zm0.h nz*tn9h plc)q7 prophase I of meiosis I there are 64 chromosomeqt0.cl9phn*n)z z7m hs. What is the haploid number of chromosomes?

  Which arrow is pointing to a chiasma?px*+j ou 9g +nuimss20

  The diagram below represents the structure of a shoot apicy ftfi fx53u0ru. e5g2al meristem. Which row in the table correctly identifies the processes occuring in the structures labeled in txgtf5.0yf3 ue25 ifurhe diagram?

  How does meiosis promote variation?h:2du /ufctzd/d botblj4hnvq :) 86/

  Which of the following statements is/are correct for meiob-spvr3lfyt/ +i h:w 7sis?
I. It is a reduction division
II. It involves random orientation
III. It produces genetically identical cells

  The diagram shows gametes produced fro94 nuwhm+sy ix+z69aem 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 f,tcikk) ze e7+/i25kgl h 0nr xjibg/9ormation of secondary tumours from primary tumours as a result of the movement of c/+ 5k en9xi2ggh) zij,0erb i 7lckkt/ells?

  How many chiasmata ar:9z,3hfcj u pue present in the diagram?

  Which statement is a simd-/e1qqe9/1dgyo; i pmrl*e hw: p8gnilarity between cytokinesis in animal and plant cells?

  Which stage of meiosis is matched to thbmb+i+54b kt,k c.cud w1p:3xk9 kbcse correct description?

  Which statement(s) are true33 37 xg bhf,f1dmnk6mkw hov7 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 oocy gem-lvdiw0gwv73bn 5 5 cy.e 9xq:v*mte after the first meiotic division. This results in the formation of one la mg gy9nx*.mv 3e0ib5w:v cw5ev-d7lqrge cell and one small cell. What is the fate of the large cell?

  Which row correctly describ9ub/w:cy zny+1gdx7g es diploid and haploid cells in humans?

  The following table shows the diy zi8nen3; c g)fkw-xpnl:483/ kwzukploid chromosome number of a range of species.


Which of these statements is correct?

  What conclusion can be drawn from the ka 1t4ju+5tfcp:5g tqgog 9.ogk ryogram below?

  Which of the following processes is characteristic of the meiotic and not the p,j ,8drwx:)ef9ibdz mitotic cell wb,:,ep ix)f dz89jdrcycle?

  The diagram represents a bud with a shoot apical meristq;8emi)gv* ylxv2o /f9 jegq 9em.

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. Wh lrl+e/c/b0aupw :0 di lz+4bjich row shows the correct chromosome number for diip+0/c z+:du lel jwabb4lr0/ fferent cell types and cell division stages?.

  At the end of which phase of meiosis I does crossing over occuon6zws t*d;eby 2c*l xkm,:f8r, and what is the outefow,k *zm xcn; bl8tys2*6:dcome of crossing over?

  Which of the following statements does not describe a 4md*;tog d w5qdmp2 n5step in the sodium-potassium pump cyclpmm2gndo 4 tdw5;5q d*e in the neuronal cells?

  Which row in the table below is true of meiosici n04qg b9ji;s?

Membrane transport is important for allowing particles to move across the cel1 j/o+rjy ,.d vzt; ip6lf4gtxl membr+o. t typ/6 d1f gzr;4v,jxljiane and respond to changes 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 mitosij xy7he/ , s ubrudlg,,5,kz(ys is 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 concentray)e. q04ne :kbw2z inntions of different cyclins during the cell cycle. Which cyclin is involved in preparing for DNA reeqn:.by04 kn )z2niwe plication?

The diagram below shows chromosomes durin hf+j -fkd(,qad6z5d ag 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 separ k6nf7dgp zhy706 2ymoation of homologous chromosomes?

  The mitotic index of throat tissues takenyty p*rl7)men;4a1 sn from 4 different patients is shown below. Which patient is most likely to have cancerous thas7*rmnnp yt e);4l1yroat tissue?

1.Draw a labelled diagr9 :da4 g di mwzbgi/-2dhv;ms0am 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 abnormnwyp:mib *+4 wp7 eco6 +aa9mwezd)u;al human karyotype.


What is the abnormality in this karyotype and its cause?

The graph below shows the relative amotrrtq , 2wi*3hunt of DNA in one cell during one complete cell cycle. Each letter represents one stage of the cell cycle3 r*2twqi tr,h.


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 showftnqq:y s/8gg,..cm 1w bu /tls a cross between a male cat that is homozygous for brown, long hair and a female cat that has black, short hair. lw,t/ fqqgs/unyg.m c1b8.t:


Which of the offspring has a recombinant genotype?

1.Outline how polygenic traits can show a normal di8a1fmi le6zd9stribution.

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 i ;zba t b)r5zaqqu:887 rvti.wn the dia bqq):t5;u.v air rz8wabzt78gram below?

  The photomicrograph shows a pollen grain from L. candidum (Lil*h2bfmk * u40gswwt+qy). Which stage of mew4f*gsw*0 bkuhmqt 2+ iosis is shown?

1.Outline the events which would lead to an individual being bxpocu u+3gh9f/b. px +orn with Down syndrome, which is characterised by the preseb +xo3cuup9px f+.gh /nce 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 meaa2n;x tx 6o3kwg.r qjymv)c9z-6q+f osuring plant growth. A study was conducted on white onions (Allium cepa), under controlled conditioy6;m tw6x+oqxvz.29 - nk oj3a)gcfr qns 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 canepu:8*u z9h; i 3htavy divide. The diagrams below show two cells from an organism with a diploidvu *8p:tue;ihaz h93y 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 gef.i pzfhp5 j-+ ko(4t,+ +xb lnjz:brane expression 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 num mu yr0+on5ytf(8i+rkber of 8, in different stages of meiosis. Which row c m+f5no0iuyr (8t+rkyorrectly names each stage?

  The micrographs show four phases of meiosis I in a plant. In what order do thesq . 76dhostty*e phases occur?7y*ho tsdtq.6

Mitochondria are responsible for suo3ggldw94s+ ld0c t*nqti ymy.xv 9:6 pplying metabolic energy 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 s09mli43 ow.nd d+x9vg*y cgy6:lt q tfrom 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 of the cell cycle iip g,0qr 2apvt,wgwa -3 50irin four samples of lung tissue from four patients. Which tissue has the loi5,ar0 pw g3 irvqp,ai0-tw 2gwest mitotic index?

  The diagram shows the domi gb+a7rx0bn4o2 tus/b,fnu deoed+-1 nant cyclin/CDK complexes at different time points in t-0+ 7e,o/ubra2 don snugf+b te41xbdhe cell cycle. Which cyclin/CDK complex activates DNA replication machinery?

  Studies have shown that genes such as Cyclin Dependend7wbbm/0eooj wvusxx:4m k25j6u g-3t Kinase 3 (CDKN3) are highly overexpressed in cervical tumourseb6w7o:mu xk - wj3mbds54gvu/0oj2x .


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 highevjrtqe./6nz+ m q36yi st during the cell cycle ?