The graph below shows the relationship between maternal age and the incidence o pb1i /9ljit a;tp 21rq6c*wyaf non-disjunction. Whip c*ajb trw/ ;tlqapyi11692at relationship is suggested by the data in the graph?

  Which stage of meiosis is represented in the diagram belo :mn3uf1ai,b rw?

  The diagram below shows chromosomes dur le:6pt y+9v-ys8qvszing 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 of a sy;hz8bz(uics zo1 -q 9l wrm+;ingle gene which would be present in the nucleus of a cell as a result of each proces+z;8ub 9oc(hys-q;w1 i rmzzls?

  Which keyword is matched to the correct definitxr8 *.e :g:ygqrtfj9lion?

  Which statement(s) about mitosis is/qhm4akp xv :(:( jd;mtare 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 2:v qf; g(rsgoa cell in anaphase?

  During which stage of mitosis does ta2*u7u j)9k 5wr jnuhhsi*x2xhe nuclear envelope break down?

  Which one of the following transport proteins only carries out active transpxp 6fy;tldd6f22 2xw kx 3f)qtort?y)wx qfdx f ;l2t2kp23 dtfx66

  Which process does not happen in the sg3)y5wgjykt )f q3tjxt3 ;i+ ghoot apex?

  Which type/s of membrane tramepqu6q:/ k+kkif e (5nsport do/does not require energy expenditure?
I. Facilitated diffusion
II. Active transport
III. Osmosis

  The diagram below represents a cell with a diploid num6apebju i h..8ber of 4. Which stage of cell6 e.8phubi .aj division is the cell currently undergoing?

  The photomicrograph below shows a mq0kch-; vf g+i;r2f. axjp d-root tip meristem. Which of the following sentences corre;-p20q-dhvfc . a;ifxjgkm + rctly defines a meristem?

  When does the random orientation of homologous chromosome paivtj;.lp4.3m e)u m b8mwbw -xors occur?

  Which process does not ouc 38-o)- vwsm4nli*rmgt c w8ccur during meiosis?

  If a cell with a diploid number of 36 undergoes mitostj f.mp;aum2) is, how many chromosomes will be present in each daughter cellammuf)p.t2;j after cytokinesis?

  The image shows a micrograph of a ccua k t./ql0r+//omfig-pq9m-x h mb5ell.


What explains the appearance of the cell in the micrograph?

  Which statement(s) about hom m- ,8fqofjm9pygvu9 2/o1l egoplt 42ologous 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 qyy :qyg*.iw0individual with Down syndrome.

Which statement is not correct?

  In the cells of a horse (E. caballus) during prophase I of meiosis I there are 6v-x5 nj7 qai 6th;rr*d4 chromosomes. What is the haploid number of chromosomes?rvn6iahxd5;r7 -*tqj

  Which arrow is pointing to a chia plgq8;.-eatlt792e6c ayfzh sma?

  The diagram below represents the structure of a shoot apical meristem. mu2*.y,7fi/igtptki: tf8cy Which row in the table correctly identifies tp/fg*u.:8ii 7 yt icm ,2tfkythe processes occuring in the structures labeled in the diagram?

  How does meiosis promote variation?ta 6y) bncdb-;

  Which of the following stateme*s.g7l(3ew q8utg nmnswg 6;ants 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 chromopy*o5kv w8 p,bsomes.


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 from2ox-; bu: yni,j a6gmqal zr-8 primary tumours as azuobi gy, ;-8:lqa 2a6-mjnrx result of the movement of cells?

  How many chiasmata are presentrs wn1+dz h(;9m2dldp p/op(c in the diagram?

  Which statement is a similarity between cytokinesis in anr7m-c+;phy zy imal and plant cells?

  Which stage of meiosis is matched to the correcaxo8y-ukqz4 fb y-ecs (a)4r9 t description?

  Which statement(s) are true of meiosis I but not ;sam 7rg( g5wvmeiosis 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 oocy3u8loow1oamcn(l l r7mj;27cte after the first meiotic division. This results in the formation of one large cell and one small cell. What is the fate of the co7jcr mol;1awnmo38u(l72 l large cell?

  Which row correctly describes a 4a7rty1wbv 0diploid and haploid cells in humans?

  The following table shows the diploid chromosome number of a range of species. hj /v:8 ihvd1n


Which of these statements is correct?

  What conclusion can be drawn from the karyogram bvn3 4*bfi f z;eo1gb d)gi-(gmelow?

  Which of the following processes bot jnkb+7gz2532xaq (c7 7ve,g *x qe2bcbfw is characteristic of the meiotic and not the mitotic cell b qxtc7kgnob,fexc2*bw +( aqbj2e3g7v2 5z7 cycle?

  The diagram represents a sr, gys) :xkq8n,jh8k bud with a shoot apical 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 1po+hcrz / u4cbd1w-s the chimpanzee (Pan troglodytes) is 48. Which row shows the corrpd4rwc1 /z+husb- co1ect chromosome number for different cell types and cell division stages?.

  At the end of which phase of megsd 57p+v*oi tiosis I does crossing over occur, and what is the outcome of +5ip7g* osvt dcrossing over?

  Which of the following statements does not descri *24v. a6deigomxn unugi:7 *l7ebx1f be a step in the sodium-potassium pump cycle in the neuronal cells?leb*:xvdi26xf*o47m n1e7n ua. guig

  Which row in the table below is true oa+* skqrsi5:re 6vpa7f meiosis?

Membrane transport is important for allowing particles to move a )6gnx--jdshokbq 5 s(cross the cell membrane and respond to d6bn( --h kxj 5gsoq)schanges 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 regulatedvv11 wz j/eazfk, c*n5 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 cycqk+3t59fw7tkq fcni ;l-+ mjllins during the cell cycle. Which cyclin is involved in preparing for DNA r3-fq +;f7l tin5l qk 9wcj+tmkeplication?

The diagram below shows chromosomes during meiosis.h 8xkgf qbxy-s6a6**b

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 seebck/,eu;7 xz paration of homologous chromosomes?

  The mitotic index of throat tissues taken from 4 dicx7 c y g+gy8zl *ntd1;.cs/xqfferent patients is shown below. Which patient is most likely to have cance/1n yc7tdx x yq*c+gczl.s8 ;grous throat tissue?

1.Draw a labelled diagram to represeumtd7v c 4h)tt moa .r(/l.d q))qrzn7nt 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 human k-u7zoc- z3f8n)w8a jv,/l)iwm mvrozaryotype.


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(ezc*p hrx0t- omplete cell cycle. Each letter represents one stagc* 0(xp-ehr zte 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 dm*bh27y p-/qjk+e rxomozygous for brown, lonx kdp7rq -+be/*2 hmjyg hair and a female cat that has black, short hair.


Which of the offspring has a recombinant genotype?

1.Outline how polygenic traits can scnkph x70077x ypse*c viq3a- how 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 crossing over of non-s dlwl/yw ,q*.pister chromatids shown in the diagram below?wq/yl dw,. l*p

  The photomicrograph shows a pollen grain from L. c mx*8m/sq6s*3ksud xr andidum (Lily). Which stage of m/*s*k s3sd uxq6m8rmxeiosis is shown?

1.Outline the eventsmd ((prmfo1d/ccs (zf :yi0 b/ which would lead to an individual being born with Down syndroo:/(c/0 p1bf zd mdyf(irc(sm me, which 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 aneyr8d 7kc) tt1r7m 9gtutni6: indirect way of measuring plant 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 mitotic index of the roots. :1tti9k877r)td tmge uryc 6n


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 qreg0kht3le57u.1.hav4 q q f. The diagrams below show two cells from anuh ahf.7t .q qe3e5vl14kq0rg 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 expressioo0sd)lcs k26d n 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 c b7h5cot,m y8jbzi9;jgty47q ell, with a diploid number of 8, in different stages of meiosis. Which row correctly names each5bjgzj8 q; bo9ct7i 7y,yh mt4 stage?

  The micrographs show four phases of meiosis I in a pl0 atfi)g * nmxx1dzr:/usn 21mant. In what order do these phases otmnurs2a / z01xx*) :gm dfi1nccur?

Mitochondria are responsible for supplyniopxid5jp,/+7bb sco9 0yqy +)y 4iping metabolic energy in eukaryotic cells. In most eukaryotes, which reproduce by sexual reproduction, mitochondrial DNA (is, 5iop+d9+ p)bj/74q x iyyy0n cobpmtDNA) 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 foub le)q/*be(/- e puytor samples of lung tissue from four patients. Whichuyp b )*e/ b(eet-/qlo tissue has the lowest mitotic index?

  The diagram shows the dominankorv dpd3mwn t:j2/a ,t/sh34t cyclin/CDK complexes at different time points in the jhma23w rpt4t dnvd/3:oks,/cell cycle. Which cyclin/CDK complex activates DNA replication machinery?

  Studies have shown that dyyt 2)1q)i+bl8 hmcb genes such as Cyclin Dependent Kinase 3 (CDKN3) are highly overexpressed in cb 1dq)tbi yhl my28+)cervical 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 )n)k08zu ,cbsp-lsti the cell cycle ?