The graph below shows the relationship between maternal age and the incidenc )kzg(r l)6eqge of non-diqekg 6)r) zg(lsjunction. What relationship is suggested by the data in the graph?

  Which stage of meiosis i 22te*kpu8c0hm:qy ed s represented in the diagram below?

  The diagram below shows chz*8tud1 wz :ebtk2)rjromosomes 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 stahj7dyb wt vfa4/,lw+:38 x jm/le1xmr tes the number of alleles of a single gene which would be present in the nucleus of a cell as a result mvf ryatme/h+jd:, 7xlxw1j4/ 8l b3wof each process?

  Which keyword is matched to tn56rmz) (8t,xnd(sk ,hg ngl ohe correct definition?

  Which statement(s) abouq* 6gwxg9f+put 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 l56: u,yjkgc, x4o6wcm 72qoh 3svmyfhetter points to a cell in anaphase?

  During which stage of mitosis does the nuclear envelope dovn9a c.8+i eraa/t 4break down?

  Which one of the following tralp r82lkwci; xpov;) 3nsport proteins only carries out active transport?li 3vwo ;;krx2pc)8l p

  Which process does not happen in the shoot ;iy/ ;oy2wp qtb+uo5(iar2 qg apex?

  Which type/s of membrane transport do/does not require z*o on8;huw(5 qbc/i;m c 4ewgenergy expenditure?
I. Facilitated diffusion
II. Active transport
III. Osmosis

  The diagram below represents a cug6j-tc-q18 pa f3 .dcby ap+xell with a diploid number of 4. Which stage of cell division is the cell currently undergoinggxqcb-- j.1t pau6c3ay dpf+8 ?

  The photomicrograph below shows a root tip meristem. Which ofpso,oeb15il) kk c*;l the following sentences correctly defines a meriss5b 1opk*i,lke cl;)o tem?

  When does the random oriena(hd*4i; ,hxm8eh +ha;kpw 6x*ir pt htation of homologous chromosome pairs occur?

  Which process does not occur durj xoj9(z: 1j3 g(yq zkk/txtp.ing meiosis?

  If a cell with a diploid number of 36 u(f*/, z/lyuah6c(fyqy7d yrzndergoes mitosis, how many chromosomes will be present in each daught//y,ur lqd7 zc*yf((ayfz y6 her cell after cytokinesis?

  The image shows a micrograph of a cewe 1-sjgw0q pn8vq9jub2d p 65ll.


What explains the appearance of the cell in the micrograph?

  Which statement(s) about homologous chromosomn1qobt96;x+1f a,m bwdi(wqa es 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 witnq*k5p pk,t5xh Down syndrome.

Which statement is not correct?

  In the cells of a horse (E. caballus) during p9 i q210ylr+2y fgmtoi*+ aftrrophase I of meiosis I there are 64 chromosomes. What is the haploidifom2+aligf t*2yq1r+t r 0y 9 number of chromosomes?

  Which arrow is pointing to .1bvsbs.j:vm a chiasma?

  The diagram below represents the structure of a shoot ap3bq0*rj(ecr.u5lb ; enm z)q uical meristem. Which row in the table correctly identifies the processes jnz) qube3 c0e *mub.(rqr5 ;loccuring in the structures labeled in the diagram?

  How does meiosis promote varia3dhddix7qb 3th3 n068e7 tzcxw s 7s5otion?

  Which of the following statements is/are(45l vmg xpumzs wy5/.ln12pt correct for meiosis?
I. It is a reduction division
II. It involves random orientation
III. It produces genetically identical cells

  The diagram shows gametes producr(9:qd*+uqef1;6t k4a imal pzlir7 hed 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 primnv,,d vhvj )2lary tumours as a result of th2vhl, jv, nd)ve movement of cells?

  How many chiasmata are present2b-6 u+k sfe + r9hskdno5u ol9f.l4c c.ta6lb in the diagram?

  Which statement is a simi+svu+qxtn; - clarity between cytokinesis in animal and plant cells?

  Which stage of meiosis is r 1rxjize - (phs k.l;v6(v;bmmatched to the correct description?

  Which statement(s) are true of meiosis I but not 4 xbuc.u)l9 rpmeiosis 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 fiw ;.codz p2a9kdh5w1 vrst meiotic division. This results in the formation of one large cell and one small cell. What ishwd5. o2zvpkc1d a9w; the fate of the large cell?

  Which row correctly describes diploid and happk2+g81p 6yoej ku gy;loid cells in humans?

  The following table shows the drm5yl/pqfbe f-h( ( 8piploid chromosome number of a range of species.


Which of these statements is correct?

  What conclusion can be drawn from the karyogrp8e:b2 q3q qazam below?

  Which of the following processes is characteri6 q+ndq.ng iwt9b.ofgyit5. 5stic of the meiotic and not the mitotic ceqfoy.bw.9q6ig nn+ g t d55ti.ll cycle?

  The diagram represents a bud with a shoot apical meristq+eifzokg2gzc;6 3 3 yp/)rxlem.

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)xn,, vldz9yd5 is 48. Which row shows the correct chromosome number for differ,5,9vddx lznyent cell types and cell division stages?.

  At the end of which phase of meiosis I does crossing over occur, and what is te;)t 8n9bvua(gil za1 he outcome of crossina;ln uav ) 8(g9zb1teig over?

  Which of the following statements does not describe a step in the soddr1 3xb yxfz;k8lgncf)1(yy+ ium-potassium pump cycle in thefb g( x lyrzx3k)18yny+1df;c neuronal cells?

  Which row in the table below is true of meioh,u;7un/f a,wnc-v lt sis?

Membrane transport is important for allowing particles to move across the ceo(*mazdv n:6l ll membrane and respond to changes in the chemical composition of the extramv(lo: 6dzn*acellular 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 amjjetzi/jxkt786:h* iz9/ a 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 concentrats6 won3ykb d* 5 kuipeal01/y(ions of different cyclins during the cell cycle. Which cyclin is involved in prepari(k uys/ie n5pl0o*63kaybw d 1ng for DNA replication?

The diagram below shows c5e. o*r mcln:khromosomes 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 involves4 yh qayp8gyp.r*4fg+ the separation of homologous chromosomes?

  The mitotic index of throat tissues taken fro d(: f 4dw7lgg ex:ewc16zxtb(m 4 different patients is shown below. Which patient is most likely to have cancerous d6wb eedt: (ggz4w(c:lx7x1fthroat tissue?

1.Draw a labelled diagra tnm.d*iv(p- rm 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 abnormal huvahm ,2vl0c i0man karyotype.


What is the abnormality in this karyotype and its cause?

The graph below shows themk hz3g4fhy w/+*tbzue8*x3 e relative amount of DNA in one cell during one complete ce3*4b8mxwf/ze+*3 tekg huzyh ll cycle. 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 thaa1+ ts:nbfqb0ehi4 .hzit6y,z5.u a0dc:oaut is homozygous for brown, long hair and a female0n .zit5ua,oyh+6: 1:hbc. fi 4destq0auzba cat that has black, short hair.


Which of the offspring has a recombinant genotype?

1.Outline how polygenicafn* )ki jdl* + d2gnedg1s2q* traits can show 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 cro g8-2bb4*zsmxz8bi mwt z zch9-2pcl7ssing over of non-sister chromatids shown in i pl 7bgm*zwtc28b 2 zx8bmz4h-9zc s-the diagram below?

  The photomicrograph shows a pollen gr gl2sy3vf7+;e 1 uv :da5tgxryain from L. candidum (Lily). Which stage of meiosis is x: 2f35y+adg7 g lurtye sv;1vshown?

1.Outline the events which would lead to an individual being born with Dtxg2z 4tv(.hs own syndrome, 4 tgz(t.v 2hxswhich 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 a +a9r q6nlgri cf.;ofsetk*:3n indirect way of measuring plant growth. A study was conducted on white onions (Allium cepa), under controlled conditions in a lab, to investigate the effeck 3 t6 .gfr9csf *a;i:+enloqrt 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 xrsc6q t2f6 *clt) bj100wo.yjfsr : wdy3d f6can divide. The diagrams below show two cells from aw.*fs61wjxy6rqtff 0 db lj0dcot3y 2s ):c6rn 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 stem growt.6:ubcww3qzf-hfi g 3 h.

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 m j l850:tlxrsdiploid number of 8, in different stages of meiosis. Which row correctly names each j5 t:l8xl r0smstage?

  The micrographs show four phases of meiosis I in a plant. In wfhuzs0co +;1w hat order do these phases occu; hwocs f+zu10r?

Mitochondria are responsible for supplying metabolic energy in eukarcdz j:2tr /qs*yotic 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 org:c /r qdjts*z2anisms, 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 cyclj7fn9j ibwp-q1uif*g+: pp bf0 r1um,e in four samples of lung tissue frp,1mrpj- jqui7: ff iub* 9pb10g+ wfnom four patients. Which tissue has the lowest mitotic index?

  The diagram shows the dominant cyclin/CDK complexes at diffejla/f(e z+ uye4 nf4;sx+shnr+ p4 2jfrent time points in the cey +un4ze p4j+srfs( xlj; faf4eh+n2/ll cycle. Which cyclin/CDK complex activates DNA replication machinery?

  Studies have shown that genes such as Cyclin Dependent Kinase 3 (CDKsqj )sw /si *aj8xzuwk- ;w22wN3) are highly overexpressed in cew-)2ww8sz*ja;u2kx/ iss jwq rvical 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 celli;/,yi ,6pasj.aojs l cycle ?