The graph below shows the relationship between maternal age and the incidence ofp ar9oanr b.nf/v.,6i of 05f5feq2mr non-disjunction. What relationship is suggested by the da b 5nfqfroa6n .m ,ffoae/.29ir0vr 5pta in the graph?

  Which stage of meiosis is represented in the diagram bejcpzmn1ubid0k);tmkqd3 y.z+ qf 148low?

  The diagram below shows c9tb8et 52 ac rssz8i8: s8u1qfz *hponhromosomes 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 th1y-34frjr kywvgr ;x8g8kr 3 de number of alleles of a single gene which would be present inkk ;dvwg83xf rr8yr1-j3gy 4r the nucleus of a cell as a result of each process?

  Which keyword is matched to the correct definition4erlmp:o5p 1r tf( .0 8znuntv?

  Which statement(s) about mitosis i) r2rij7j*kz-y- cbe gs/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 anaphwzpjks5jk9 )c:f y3.ozkw h3: ase?

  During which stage of mitosis does the nuclear envelope break down?o;c l3k4a9 h cj7jflq*

  Which one of the following transport proteins only carries)vpfuk/0 w5fj out active transport?0)kvj5 up/ffw

  Which process does naql4,j .w* //5xdpptzc i go0) sw2muaot happen in the shoot apex?

  Which type/s of membrane transport do/dryv03k: hi xt1oes not require energy expenditure?
I. Facilitated diffusion
II. Active transport
III. Osmosis

  The diagram below represents a cell ; 4je kib,w*hnwith a diploid number of 4. Which stage of cell division ke;,i jh*b4wn is the cell currently undergoing?

  The photomicrograph below shows a root tip mer,+odhd znm,r34y w g2xb :q;mwistem. Which of the following sentences cbd +rzq42hw,,dnom3 :w;myg xorrectly defines a meristem?

  When does the random orientation of homologous chromosome pairs occtd*8j onad1 b(c u;4zj aow16nur?

  Which process does not occu 8j0nm4uphl)i r during meiosis?

  If a cell with a diploid number of 36 undergoes mitosis, how many chromosomes wi, /zhz vl1pi5s -wf7e4t bmh,rll be present in each daughter cell after cyt,4t w/zp ,r57zbh1e h -mlsifvokinesis?

  The image shows a micrograph of a kz -( /lidmirt27i g +f o-xfe,xb7ed*cell.


What explains the appearance of the cell in the micrograph?

  Which statement(s) about homologous chromosomes is/are noaflb:wy +ku3, t 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 ia ,6fkh7if 7nsq ;lu:cndividual with Down syndrome.

Which statement is not correct?

  In the cells of a horse 3 * 6pbktpb hx:cfpdd9ss-qqxc8)2y *(E. caballus) during prophase I of meiosis I there are 64 chromosomes. What q dxx6:sq-s* dycb)*pkhbpf32ct9 p8is the haploid number of chromosomes?

  Which arrow is pointing top-a f-8q6olm/- yfga:v. x yq9z ltfh- a chiasma?

  The diagram below represents the structure of i ls/+a7v7nbo a shoot apical meristem. Which row in the table correctly identi+si/oavl b7n7 fies the processes occuring in the structures labeled in the diagram?

  How does meiosis promote oll 5idr *l3im5qb 5+vvariation?

  Which of the following statemerq -r /6k7k/ejgdw7wdnts 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 ccx9r5el+7vvt m 3j v,hhromosomes.


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 9j-nv2 yapi:t of secondary tumours from primary tumours as a result of t -n2yjtvp9ai:he movement of cells?

  How many chiasmata are presen :r8omefghc:(wg8 4 m(5ypoyit in the diagram?

  Which statement is a similarity between c0hv;x q 7gp:ki 0*8np- lfjodqytokinesis in animal and plant cells?

  Which stage of meiosis is ma-djrbdlu,i*1s )+2q ,nyttc n ; dks;itched to the correct description?

  Which statement(s) are true of meiosis I but not meiosis 2x7t 9mpr qd4wII?
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 t2*z65fxb c 5aktgwx3meiotic division. This results in the formation of one large cell and c65wg2bx3zftkat 5*xone small cell. What is the fate of the large cell?

  Which row correctly describes diploid and haploid cel2au ul7a6uje30 k /3a plgiu(cls in humans?

  The following table shows the diploid chromosomse/ -+ogffr,o d5gf( xe number of a range of species.


Which of these statements is correct?

  What conclusion can be drawf9,g m- guhcklyp z)0;n from the karyogram below?

  Which of the following processes is characteristic of the meiotic and notwjv0y rgz*6 6k nl-5rr the mitotic kwj*5 r606r rvng yz-lcell cycle?

  The diagram represents a bud with a shoot apical meriste .hkyy( d1t7( k+lmrxtsdj +w2m.

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 row showsuj dvk+2dhq ;. the correct k; qdh u2d+v.jchromosome number for different cell types and cell division stages?.

  At the end of which phase of meiosis I does crossing over occur, and whaavfhqlz9/, w c :qu mj64qy3;it is the outcome of crossing overq/z,6 v cjf :4qwh;ya3u9iqlm ?

  Which of the following statements does not describe a sa4 ls g4)-dnmkxm (dcx.ck *,btep in the sodium-potassium pump cycxb mc* 4)sac.g l,dxn(4 -mdkkle in the neuronal cells?

  Which row in the tablexwm398ui lu7cv j4dsuih3 q s .zmk.90 below is true of meiosis?

Membrane transport is important for allowing particls wxjndn(p4sq+dxo 0 6nfc ;./es to move across the cell membrane and respond t d(x0pon d;xs/+wn4nsq.c fj 6o 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 mitosis is regulated in nrz6d d*phe ykj*14 o:c+r0pecells.

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 differ7k9d(7xwwad pgcu a*z-0(*o xjm t8 pxent cyclins during the cell cycle. Which cyclin is involved in d9akw *-gd zc(jt*u7m07 xwapxo (px8preparing for DNA replication?

The diagram below shows chromosomes ducw,(u .(ahri kss:8nsring 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 separbj d wx*wwa,ke7;m(po*-99/y.yhiz0kz plf pation of homologous chromosomes?

  The mitotic index of throat tissues taken from 4 different patients ik9fz62ug;.a4ys u ump s shown below. Which patient is most likely to have cancerous throaas.u2mf96 k; 4ugy zput tissue?

1.Draw a labelled diagram to ce9 icj 4qdj375dn qesukv945represent 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 t rl-:3d15jaxvoo r,2vdc(dyrmal 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:mz *p6q6rpk:ae/ay l;u ;cwaomplete cell cycly:ce;/lukp; pwqmz6a *aa6 : re. Each letter 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 ia vrgi( y*immrt/7:,5y7e in(c1p hsup)t s0 homozygous for brown, / hp*(s7ymis,)(a nt0 rieivmc 75ug p i1:yrtlong hair and a female cat that has black, short hair.


Which of the offspring has a recombinant genotype?

1.Outline how polygenic traits can show a normal distribution3/xzfb5 bmu-,,til n(1o jydn.

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 9h9p *po: tktychromatids shown in the diagram bel9*9h p kpty:otow?

  The photomicrograph shows a pollen grain from L7bl ii8bax)0 z. candidum (Lily). Which stage of mei)xl87a0ibbi zosis is shown?

1.Outline the events which would l 4u*ck rg2ytis3l f4k6ead to an individual being born with Down syndrome, wh k rc *3kltgyui2s46f4ich 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 planw ie e5x ser.mcfa/14.t growth. A study was conducted on white onions (Allium cepa), under controlled conditions in a lab, to investigate the ef4sa1cxi mr e5e. e/.wffect 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 divide. The diagrams below +uszqr62-y:j j h/s noshu: o2-6 nz+qyrj jss/how two cells from an organism 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 expression in styv 5 u40nm-wmaem 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, wit wd8(ej+m)wj w)lf .nih a diploid number of 8, in different stages ofe.jfwwd)+li8j wm)n ( meiosis. Which row correctly names each stage?

  The micrographs show four phaseq8ypuegm )7n 5c; ywi3s of meiosis I in a plant. In what order do these phases ocwq);5i nyp873ymg eu ccur?

Mitochondria are responsible for supplying met: /mvfjbzao4m 9dlng0kw,6( nabolic 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 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 yebn,mgvawl(z:/m9no0 j kd 4 6fast 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 differemf b5 /m5wt617i d ,dfymxkdv)oh 8ys8nt stages of the cell cycle in four samples of lung tissue from four patients. Which tissue has the l6 8dty75i8o /dsd k)5m1 vm,w hmbyfxfowest mitotic index?

  The diagram shows the dominant cyl, fz2x7q :yfeclin/CDK complexes at different time points in the cell cycle. Which cyclin/CDK comqx, 27 fzel:fyplex activates DNA replication machinery?

  Studies have shown that gene (hbf +d*x73xtu ma*oas such as Cyclin Dependent Kinase 3 (CDKN3) are highly overexpressed in cera*a bfx*7u(3htmod +xvical 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 o.5w9vwrdy, oduring the cell cycle ?