The graph below shows the relationship between maternal age and the ayhr+9 fe+i k;incidence of non-disjunction. What relations r+hyif; k+ae9hip is suggested by the data in the graph?

  Which stage of meiosis is represented i6fttrkd/ al8 btz+mn33:k t -rn the diagram below?

  The diagram below shows chromosomes during mb9j5 nv8dkr 9eeiosis.


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 single gene whic1-cus-+q):ehrn x( uxa; hzlf6 7bznoh would be present ixfz 6o :- quluae(hn1zb+xsh n-cr;7)n the nucleus of a cell as a result of each process?

  Which keyword is matched to thersccv 52z f/f*qqw)n+ correct definition?

  Which statement(s) about mitosis is/are true? ,+.-pt8 iimgza) ckoi
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 belh8el xk t0h5e/yyt,/g:yei b6ow, which letter points to a cell in anaphase?

  During which stage of mitos/ l;daht95uauis does the nuclear envelope break down?

  Which one of the following transport proteins only b. 3cehymr*gl-id;3jj 57kny carries out active transport?yyl. redhn kmj53ci3b g7 *;-j

  Which process does not happen *ec;k z*g1abaubp5*r in the shoot apex?

  Which type/s of membrane transporh,-7t c+(ivht3sg 5satw yd0 ;w *pyj0kress.t do/does not require energy expenditure?
I. Facilitated diffusion
II. Active transport
III. Osmosis

  The diagram below represents a cell with a dipl3t/c yy1aftr ci,a 1f;oid number of 4. Which stage of cell division iic;t y ,3cfatr 1/yaf1s the cell currently undergoing?

  The photomicrograph below/ e i6(8zww1d zxu;u5w*yg2elx/s sfn shows a root tip meristem. Which of the following sentenclw6/uysf1 i5nx;8*ezzed(s w 2u / wgxes correctly defines a meristem?

  When does the random orientation of homologous chromosome pairsni- . frp ,3ktlpm42mo,j4hcn occur?

  Which process does not occur during meior c7tt .in)zzbl5o6b w6e)ya(sis?

  If a cell with a dipw:( 02c.cwbekr i 0byzloid number of 36 undergoes mitosis, how many chromosomes will be present in: 0wrc(wcky0i.z2 bb e each daughter cell after cytokinesis?

  The image shows a micr16 /gzacj:2k1niv z4pxzq6rm ograph of a cell.


What explains the appearance of the cell in the micrograph?

  Which statement(s) about hvx7t-+y2ka/fcnb5g7eh;6s (kryv w comologous 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 Down nz2fnpvf 1gw j:v vk p37w;/0jsyndrome.

Which statement is not correct?

  In the cells of a horse (E. caballus) during prophase I of meiosis I theb6jd:wmawdoh+j ; r-8re are 64 chromosomes. What is the;j6j8o:ba w wdmd+h r- haploid number of chromosomes?

  Which arrow is pointing / u*q: 6ydlikpto a chiasma?

  The diagram below represents the structure of a shoot apicafzriw:csy6k8- lcc, kp.w-e 7l meristem. Which row in the t:ykwp-i.z ccecf6w8 kls-7, rable correctly identifies the processes occuring in the structures labeled in the diagram?

  How does meiosis promote variationa7neo3g; iip-yxcm v6.9+tehex .u l:?

  Which of the following stalrn.yn l64x8otements 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 c,lq9hbz;p +59z.igqd2wr qhohromosomes.


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 sfpb/xc8z 29:n6u dsuor( kuxn5m q:6of secondary tumours from primary tumours as a result of the mo crsnb5uu do/(8 xn9muf:xsk6p2q :6 zvement of cells?

  How many chiasmata ark0:;rha3 b eocaf0+ eve present in the diagram?

  Which statement is a similarity between cytokinesis y hvpu0x23 0.z*eyt koin animal and plant cells?

  Which stage of meiosis is matched to the correct descri tegl(g+2ro 3wption?

  Which statement(s) are true of meiosis I but not mhmtio x6 lv6m)/cccx/h+4 uo0eiosis 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 afteq51,mdg0 4, 7 nrxgw99;yqveozb mfnlr the first meiotic division. This results in the formation of one large cell and one small cell. What is the fate of the lvf,mwl7;e4n9g 91qo zxmn5 ,yrgb q0darge cell?

  Which row correctly describes diploid and haploid cells in humasl7yt+oztz ,rz/(f *b ns?

  The following table shows the diploid chromosome number of a range of specp yrnh/v30t9qdj d) y)ies.


Which of these statements is correct?

  What conclusion can be drawn(3ljrhcg / okd7a;2s.dldbaeq1 w.) e from the karyogram below?

  Which of the following processes is characteristic of the meiotic an-e1zuaoy 9m7 qd not the mitotic 7-1aq ym9ze oucell cycle?

  The diagram represents a bud with a shoot apig x /-gvnzd)df u9jm/b2h-ws 2t 3w*bccal 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 rd ,1kdjm37dq flo0x3the chimpanzee (Pan troglodytes) is 48. Which row shows the cd3,frl13 7kxj m0qddo orrect chromosome number for different cell types and cell division stages?.

  At the end of which phase of meiosis I does crossing over occur, and what is thec 1kthsr)ylg)qg72vb 2j,3oi outc 2gj7vy2srb1, qoht )c) kilg3ome of crossing over?

  Which of the following statements does not describe a step in the sodium-potasshr/:zub7 f1c my8j;3pzhq ;rtium pump cycle in the neuronal hur/zcf 7zt 3;;jpr18h:mq ybcells?

  Which row in the table below xjli ;h i-.u aql.2fc1is true of meiosis?

Membrane transport is important for allowing particles to move aqjh7gkeex myb65c z7m l+ / wt-m+w:s2cross the cell membrane abh mqle++mjt2/6g-s7kx75m ycwwez :nd 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 mitosis is regulated in ced (wql8owlb c5lwnm 2*x i- p0pe/qr5b7y56mclls.

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 cyclins during aq32-8uhcv vgbo: 8h othe cell cycle. Which cyclin is involved23 hb 8ocqvo8 hua-:gv in preparing for DNA replication?

The diagram below shows chromosomes during meios u mvfr7mv16k*is.

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 separationceyax.n5 .uc. of homologous chromosomes?

  The mitotic index of throat tissues tabgx83(om:f;jz 8.w,j prp tm/ zvb eo;ken from 4 different patients is shown below. Which patiejpt; 8g eprv/:fxb;mzw(oojm8,b.z 3nt is most likely to have cancerous throat tissue?

1.Draw a labelled diagram to represent the process of cc guxk bopnq( rlb*9c;6+2 m0xrossing over.

2.Compare and contrast random orientation and crossing over.

3.Outline the stages of meiosis.

  The image shows an abnormal 6x l):bd*mknb s w10xzhuman karyotype.


What is the abnormality in this karyotype and its cause?

The graph below shows the relative amount of DNA in one celrjj) (vlznpcpm mkw1dz) j ),di5, q/5l during one complete cell cycle. Each letter rep1vn/qzj5w l(i)z),pdm) kjj,d p c5rmresents 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+0 cgt3 onu+ aehvu2,s between a male cat that is homozygous for brown, long hair and a female cat that has black, shortvuso3ae 02n+u c,g+ht hair.


Which of the offspring has a recombinant genotype?

1.Outline how polygenic traits can show ao:sy4xlb*y8s gvxl ( 9 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;3b:yxce2wob t+l dj ;ci,di)ssing over of non-sister chromatids shown in the diagram beox yb tld,b3we);2i;c icd:+j low?

  The photomicrograph shows a pollen grain from L./aj)fvk3ef1ea gl84yi;/mo h candidum (Lily). Which stage of meiosis is shownv gji/8)e3h ffl/o;4maae 1ky?

1.Outline the events which would lead to an ind0 7ia1p *xlhunr2+f stividual being born with Down syndrome, which is characterised by the presence of threl a+rs1i7*u0hfxtnp 2e 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 plant7)itd)8lv( y d j+fvcw7lqi z. growth. A study was conducted on white onions (Allium cepa), under controlled conditions in a lab, to investigate the effect of soil pH on the mitoq)8t z y).d7lj(d 7+vcv iiwfltic 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 brx .wpw2z9p-)yq 7iq which cells can divide. The diagrams below show two cells from an orgai7wp w) xr.-b qyz9q2pnism 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 exf(cero g.6mdx 2k7c*xpression 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 amc.z.;ka7ghq z nsc- ; cell, with a diploid number of 8, in different stages of meiosis. qm;.-ck7 ;.s na zzchgWhich row correctly names each stage?

  The micrographs show four phases of meiosis Iziu2t :v7rp31 c)p -o cl;zm6:bly*xqnpqq+g in a plant. In what order do these phasy+l iqct:m6cqnbop-2; 3p:l gzr7pz ) vqux *1es occur?

Mitochondria are responsible for supplying metabolic energy in eukaryotic cells. -y qt6 8-7 kjre.hzzo*53ic lnwjun4w In most eukaryotes, qk8.7nl n *zw6jzy-cu5r 3w4 j-theoi 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 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 in b ) 4.kzdlqk+sz.pdb/ four samples of lung tissue from four patients. Which tissue has the lowest mitotic indedk.d.zl b 4)p/kb+ qzsx?

  The diagram shows the dominantny 2rsp-;p t(s cyclin/CDK complexes at different time points in the cel2(sry ;sp -tpnl cycle. Which cyclin/CDK complex activates DNA replication machinery?

  Studies have shown that genes such as Cyclin Dependent Kinase 3 (CD1g+;iqrapl5 t t/ypq.KN3) are highly overexpressed in cervical tumouqp 5l/1+ ry; .itatqgprs.


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 highes j54q (m /hz2;-llkmskpetgc0t during the cell cycle ?