The graph below shows the relationship between maternal age and the ffq 5ato k n,6v)+:rzxm 1hz5sincidence of t1x )qs,5razf 6fv+on h:zmk5non-disjunction. What relationship is suggested by the data in the graph?

  Which stage of meiosis is repro *0/ rs5zqj*lt2nvxresented in the diagram below?

  The diagram below shows chromosomes during meiolh ) pieluo8+m: i8xz3sis.


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 which woulke 0 ejeg;(x..ng8nyad be present in the nucleus of a cell as a result of each processk(ne. j 0n.;gyege a8x?

  Which keyword is matched to the corr nr7;snr)5.*ajaymo9v mk3k 60wjwto7 h(myoect definition?

  Which statement(s) about mito)xc:7j gktg- 5+uqgb.kr n+azsis 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, whichz 6fmt4a:o -:)tk9y-huhcb al letter points to a cell in anaphase?

  During which stage of mitosis does the nuclear envelope break down xk0slebbg:4. knezd,2ty3 c+*dl/*jtoc 6yy?

  Which one of the following transport pu.): gm,g sgi5 m:xntnroteins only carries out active transport?) mn:ngx .i: ugtg,ms5

  Which process does not happen in thekl 6l+rw k.)la-uqc9ajcshqb q7 8/-g shoot apex?

  Which type/s of membrane transport do/does not a eau 2yb:6+jtm ;y:birequire energy expenditure?
I. Facilitated diffusion
II. Active transport
III. Osmosis

  The diagram below represents a celljk 6dnjrpfbd)k -k- 73 with a diploid number of 4. Which stage of cell dijr d 3 bfj)kk-d7np-k6vision is the cell currently undergoing?

  The photomicrograph below shotbxlxv:85e1y; v( ev rws a root tip meristem. Which of the following sentences correctly defines a meristem?:;vtvb1e yl 5vxx(8re

  When does the random orientation *sidu2lo e5c9of homologous chromosome pairs occur?

  Which process does not occur during meipnxgsgmb)5w +v2+ 8fvcgt .+ yosis?

  If a cell with a diploid number of 36 undergoes mitosi8s6z w wt 5dui (p7vw83dt6o sel0ber1s, how many chromosomes will be present in eac wts5u8est o zevdpd1(r8i 6w6 lbw730h daughter cell after cytokinesis?

  The image shows a micrograph of g +o81c,k,rxfe4puzef(1 lxi a cell.


What explains the appearance of the cell in the micrograph?

  Which statement(s) aboui 848zo;lxt,hz1s2bo an q4tit homologous 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 syndrdkjk - 7h.zg.i -6qx zlin.o7yome.

Which statement is not correct?

  In the cells of a horse (E. caballus) during prophase I of meiosis I there are 6h vjr6yns( *)r4 chromosomes. What is the haploid number of6 h)svy*rjnr( chromosomes?

  Which arrow is pointing to a ( bmwi ;ekbc(,h 1g,tr2ch) ao6q4shh chiasma?

  The diagram below re2jx3ht+65ky kx +ro 7kh 7oid:erp0 fvpresents the structure of a shoot apical meristem. Which row in the table correctly identifies the p7 30+x:2jkyp6hohk7 vxitkfde 5 rro+rocesses occuring in the structures labeled in the diagram?

  How does meiosis promote vb.ab0 q/8(lesk* et nuariation?

  Which of the following statements 5dumxri+36sgpn+4dnyv9nzbfc3 : 4 5k j+gaqis/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 twc 763-n 8m*+zamisdoar*a+7b nqopxpo 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 formation2k2rvq/m c*g.2k0tevmbn ) zn;wr, ak of secondary tumours from primary tumours as a result of the m gez rm 2wmkk,/q*v)c20r a;vkt 2.bnnovement of cells?

  How many chiasmata are present inz m4/sj 6oyh;o9x hn2r the diagram?

  Which statement is a similarity between cflqk7k g1)ypm;e,1ouytokinesis in animal and plant cells?

  Which stage of meiosis is matched to the cmrg 8e+5 rnce2f5bhd 5orrect description?

  Which statement(s) are tr9q hho , c0xxylnm)+w5ue 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 oocyte after the first meiotic division. T.wc5s9sx38qp x w r4nxhis results in the formation of one large s9n s 4xr wc.pxx5w83qcell and one small cell. What is the fate of the large cell?

  Which row correctly describes diploid and haploid cells in 9qiw irj+q(x (lz( (m:2vjtfkhumans?

  The following table shows the yr5l ,; q gkayp c0t.xyk5/ss4diploid chromosome number of a range of species.


Which of these statements is correct?

  What conclusion can be drzmddeb78 up g/qp,(:iawn from the karyogram below?

  Which of the following processes is characteristic of the meiotic and nothi*vmw 3 n4wg) tu9oi+ the mitotic cew v)hnuowi*+m4ig3t 9ll cycle?

  The diagram represents a bud with a shoot apice+(lry4dg dc(al 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 the chimpanzee (Pan troglodytes) is9nehay,9xsx (i9vyj;k1 m4h z 48. Which row shows the correct chromosome number for different cell types and cy9e iyakv1 9n( mjzh,x4;x9 shell division stages?.

  At the end of which phase of meiosis I does crosg1xl(h waa9p ;sing over occur, and what is the outcome of crossing (9l ;phxg 1awaover?

  Which of the following statements does not describe a step in the sodium-poteg2l*4 3bd e4ah.8hprkl)geaassium pump cycle in the neuronal cell83* 4 )halrdg42 e.k bgaelephs?

  Which row in the table below is trur u vc27bxd4;3 +0kjfer5iabie of meiosis?

Membrane transport is important g4fw35az8 -i-qvl gftf*-v hl for allowing particles to move across the cell membrane and respond to changes in the chemical composition of the extracellular fluigi ffa4fh3 5lwlg-tv8-v *-q zd.

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 is33mkt)/r,l1az1q7tsc9bjp +qac kme 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 cyclins during hn )u1k za-fh77pa/ss the cell cycle. Which cyclin is involved in kp zn7 1a/-s7)hfuhsapreparing for DNA replication?

The diagram below shows chromosomes during meiwk*e-d 1f5ma)gfu:rz:v/fr :xv b+*b /yxxm xosis.

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 separation of / c+t;wco9swyc7f wcp0ulr mv :r(v3; homologous chromosomes?

  The mitotic index of throat tissues taken from 4 different patients /en1b/ njvm)jpd f.c9 is shown below. Which patient is most likely to have cancerous throat tissue/c/p jbfem9n 1vd. n)j?

1.Draw a labelled diagram to repr xia7zd s59dp4rrc* )jesent 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 humanqlrtsfkveg :i;h(. 6n6ol5g- tp9pb) karyotype.


What is the abnormality in this karyotype and its cause?

The graph below shows the relative amount of DNA in one cell during ongl9 bwkb8f)y q5v6n:ht 5p 2pfg-8tct e complete cell cycle. Each letter represents one stag8qv)tby: lt6htgf2 9b5p5-wn8kfcp ge 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 h.y)e h 0cd-cz4:j ypdlomozygous for brown, long hair and a female cat th4e: d d ylcchyzp.)-0jat has black, short hair.


Which of the offspring has a recombinant genotype?

1.Outline how polygenic traits 4 jd(zgy1b,ilv-c7ryw9tj b ggq ipn4 8( t1)ocan 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 resulth6qc9 w(a2 )k*gjtsgp from the crossing over of non-sister chromatids shown in the di (apqsc* w9kh 6t2j)ggagram below?

  The photomicrograph shows a pollen grain from L. candidum (L9ya wk7:z5lxr06dkx fily). Which stage of meiosxr9 xzk ak6dy:7w5fl 0is is shown?

1.Outline the events which would lead to an indc-lahducv585ov *a.qz h,qj7ividual being born with Down syndrome, which is characterised by the prese-8oaczaulc 5vjqqh v 5, 7*d.hnce 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 grow0d) v 5y/ysukkth. A study was conducted on white onions (Allium cepa), under controlled condvy)sk/y5kd0 u itions 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 can divide. The d dq sweh.*kc c-w,5xvh24mow2iagrams below show two cells from an organism with a diploid number (hhw2- ev s*qckm 2ow4 w5.dx,c2n) 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 expreselldp;7u4 o,qrc1ea uvpc( -2 sion 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 aiy/b rr;uied bfc79;7 cell, with a diploid number of 8, in different stages of meiosis. Which row correctly nabrd7 i;9fb7cri;uy/emes each stage?

  The micrographs show four phases tqjl h7x2pyx9.zoi*)of meiosis I in a plant. In what order do these phases occu )p jto79zi2hq. xlyx*r?

Mitochondria are responsible for supplying metabolic energy in eukaryo cch(tf 5v8gt(q(, 7q3zd19dlyzoz ootic cells. In most eukaryotes, which reproduce by sexual reproduction, mitochondrial DNA (mtDNA) is inherited from only one of the parents: the mo lo(5(ocz z vo8fg1ydhq7tc zq,d9 t(3ther 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 differenr9r/( ed-6 eg3slt68ezmg07 vm lzq gqt stages of the cell cycle in four samples of lung tissue from four patients. Which tissue has the l7ge sl e98zm6gz( -l0 6rg/eq3tv mrdqowest mitotic index?

  The diagram shows the dominac+g c3 pnb/m3b/:y/p hx btc*tnt cyclin/CDK complexes at different time points in the cell cycle. Which cyclin/CDK complex activates DNA replicxn 3pb*y c/+ct /h/m btb3:cpgation machinery?

  Studies have shown that genes such as Cy gnw 3q)48dnpnclin Dependent Kinase 3 (CDKN3) are highly overexpressed in cervical t8)qw 3nngpn 4dumours.


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 Em;l m nf.muzsfk (k:n;/2bfs, the highest during the cell cycle ?