The graph below shows thib bzy-q:8ze tt/yp++8x6 i+r ku 10mij+kxt be relationship between maternal age and the incidence of non-disjunction. What relationship is suggested by the -yuj88xk mb:it bxz+qp+ybe +kr/1it60 z +itdata in the graph?

  Which stage of meiosis is represenvcwd dr(6,o /kbwx9+rqes99ited in the diagram below?

  The diagram below shows chromosomes during meiosi:yw *k5yu kqded;)h*hs.


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 od0d) mblqw)h4s0++h wdl(ugu9; u,)od ulo e kf a single gene which would be present in the nucleus o);+owo wh)ddldb usu0 +m0 e l(g9kl4q,hd uu)f a cell as a result of each process?

  Which keyword is matched to the correct definitjt0/ ,-vvdcmi ion?

  Which statement(s) about jj m;;cxs6xm3d,s i7lmitosis 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 letter points to a cell in anaphb:xpw j2j 1l fnd7h9j)ase?

  During which stage of mitosis does zu7hl mu..lfk s.dufyc(*2 e1l)p um.the nuclear envelope break down?

  Which one of the following transport proteins only carries out actib.ktpj mlv.)(-ox zj:*t g +fkve transport?t klz.)xkmptf+o. v-: * g(jbj

  Which process does notuii; iq5r*n )o happen in the shoot apex?

  Which type/s of membrane transport do/does not require s8cw1c,8vxgt1tjr( lu7bbo(energy expenditure?
I. Facilitated diffusion
II. Active transport
III. Osmosis

  The diagram below represents a cell with a diploid number of 4. Which sta hlzb wvh ,rb(i*o;78lfhjh;3ge of cell dh;o3hb;lh jzlh78*i( w brv,fivision is the cell currently undergoing?

  The photomicrograph below shows a root tip meristem. Which of the following sent9rsly4 z ,ts/v+w og8hences correct8 9,/+4hw zrls ysogtvly defines a meristem?

  When does the random orientation of homoloaz/::qwszir( gous chromosome pairs occur?

  Which process does not occur during meioswmuabw o t6ozo5a3-l x /jw36*is?

  If a cell with a diploid number of 36 undergoes mitos q jv3xa9b.q+fis, how many chromosomes will be present in each daughter cell after cytokinesis fq.vqjb9 +x3a?

  The image shows a micronjs v8 m:te:ri )5tos6graph of a cell.


What explains the appearance of the cell in the micrograph?

  Which statement(s) about homologous chromosomes is/are not ty92opthz:q j 0dg(3kvrue?
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 indf7zf3 dh, xbfi2 tm+w(9h lm/bividual with Down syndrome.

Which statement is not correct?

  In the cells of a ho4s*fj2zjrc6vq+mk 5 n rse (E. caballus) during prophase I of meiosis I there are 64 chromosomes. What is the haploid nuz5jkv*f4 2r sjqm6 nc+mber of chromosomes?

  Which arrow is pointing to a chiasma? 9wca* / walosh e (1n82yt5voq

  The diagram below represenn /zx6* 581 lfpeemb.tuf6bf 5)hwhfr ts the structure of a shoot apical meristem. Which row in the table corr*.6w lbtfef xhn86uf reb5)51z/fphmectly identifies the processes occuring in the structures labeled in the diagram?

  How does meiosis promoj+s8 ybyn k;tegis01rue (f:8te variation?

  Which of the following statements hza55: 0jfeb*xhmfb.v m:0q y blv.w0 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 chrogs*3x0:zz*gksl q, db mosomes.


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 secondarxn +fxr /n8sxt(7z e1xy tumours from primary tumours as a reefrn7t8n x x/s+1(xxz sult of the movement of cells?

  How many chiasmata are present ljb,n66cl ywij3-8s u in the diagram?

  Which statement is a similarity between lo6fvo 3ye 2c:0dtjr9cytokinesis in animal and plant cells?

  Which stage of meios7kwtamxj*:6l;exha 4*v*g y d/ stptr) *-rvsis is matched to the correct description?

  Which statement(s) are true of meiosis I but nogjqki6n8 n+ 0vt 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 divish/y2; qmnbj8aq66v suion. This results in the fo6juvs86 qahb;mqn /2yrmation of one large cell and one small cell. What is the fate of the large cell?

  Which row correctly describes diploid and haploid cebqa,x5p)b 1jnnc*g b 9lls in humans?

  The following table shows the d k+vpdq6f.*d ; mr(mkniploid chromosome number of a range of species.


Which of these statements is correct?

  What conclusion can be drawn from then(ktgz5 9y gdl-th .8r karyogram below?

  Which of the following processes is charaj,rr bjf a(8y3+ nz7hvku y.y-cteristic of the meiotic and not the mitotic c+a.,jv(y3zyhr7r-ky8j n fb uell cycle?

  The diagram represents a bud with a shoot apical meristem.z 9q:/t8c:qy nmt wt2z

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 trogloe:s5 * o5;jdi cei:ggddytes) is 48. Which row shows the correct chromoei* s ;i55:gdjegodc: some number for different cell types and cell division stages?.

  At the end of which phase of meiozv nzn6s:30qnj+ cq x( /dezb8sis I does crossing over occur, and what is the outcnd:sv 6+e8nz ncqx 0 jz3q(bz/ome of crossing over?

  Which of the following statements does not describewooa/lvlg.q1 v.f g g. y,0t+h a step in the sodium-potassium pump cycle in the neu0q.,g+val1o v.to flh/g. wygronal cells?

  Which row in the table below is true of meiosis?5r2qkwy04 oo:a fc/u h7zo; ss7oj4vv

Membrane transport is important for allowinn5 / qibc6t0 svy4dh,og particles to move across the cell membrane and respond to chad/oh,6ni tcy qv4sb05nges 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 rd4dwhzf1 .ov95ap .wwr31 yfw egulated 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 the )kmka 2y p85tycell cycle. Which cyclin is ink t85k y)a2pmyvolved in preparing for DNA replication?

The diagram below shows chromosomes during meiosis. (q u1xv,aqa c+

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 icra0 2z iw+ mophk3;1ynvolves the separation of homologous chromosomes?

  The mitotic index of throat tissues taken from 4 different patientsyu5g:a 0nz/7/zas lfb is shown below. Which patient is most l/7z aygfbnuz5a:s /l0ikely to have cancerous throat tissue?

1.Draw a labelled diagram to represent the pb*eyo txq7d .2rocess of crossing over.

2.Compare and contrast random orientation and crossing over.

3.Outline the stages of meiosis.

  The image shows an abnorrr5ol54z jq dvo**rp,mal human karyotype.


What is the abnormality in this karyotype and its cause?

The graph below shows the relative amount of DNA in one cell durin8gtx-u/f o6 eog one complete cell cycle. Each letter represents onfo 6gxu/8e o-te 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 malevwlgb3gwh; ; / cat that is homozygous for brown, long hair and a femal;gvh wlb/g ;w3e cat that has black, short hair.


Which of the offspring has a recombinant genotype?

1.Outline how polygenic traits can show6o :06p:t a kouvclxh(gj+dt 6 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 noyuc 0*3,.e-ec+suoace, i wyg-m+rn,4jj obyn-sister chromatids shown in the diagram be,ae uye++roby *ejs jogiw.yuncm3,0 c c-4-,low?

  The photomicrograph shows a pollen grain from L. ca(ww9 eq)ka8e(gegu 7sndidum (Lily). Which stage of meiosis is shgeew9 au(g)8keq (7swown?

1.Outline the events which would lead to an individual being born with d-j1sqrreo4a x d.rs6fm 35v6Down synd635 .qrvsa1xo-dsmj 6 r4f rderome, 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 an indirect way of measuring plant growth. A study w e7.invha *sa-1vt0v+2grcyl-b/v a was conducted on white onions (Allium cepa), under controlled conditions in a lab, to investigate wc71 t/2nsg*ay+lvvv. 0 air-ehba- vthe 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 celrsq; a7n*eetct5 tzr2c tch0v2 +oys 6-y9k+ nls can divide. The diagrams below show two cells from an organism with a dipcvro 9r -+sy570e q;n k*a nzt 2t+2st6hyectcloid 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 sti62+ 5ms ryw e-ri;ruiem 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, with a diploid number of 8, in difdam lzel(1 g*.ferent stages of mei m1zal *(dlge.osis. Which row correctly names each stage?

  The micrographs show four phases of meiosis I innmtk60ld :kc4 a plant. In what order do these phases occ dkt 4km:0nl6cur?

Mitochondria are responsible for supp yu5dl+g lwl+v;57 syjlying metabolic 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 frvwy 5l+j 5yu ld7s;g+lom 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 ofuop xt1 e9,)(waa7ty ko)ho( r cells in different stages of the cell cycle in four samples of lung tissue from four patients.9ae,tr1(houwop k)ty7 ( )x ao Which tissue has the lowest mitotic index?

  The diagram shows the dominant cyclin/CDK complexes at dmb/zl /9dse5 uifferent time points in the cell cycle. Which cyclin/CDK compl e/9dlmbzsu /5ex activates DNA replication machinery?

  Studies have shown that genes such as Cyclin Dependent Kinase 3 (CDKN3xv2+ u9po 2stg) are highly overexpxpsv+ o2 tg2u9ressed in 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 cykj.hyml au: wv+03j a4clin E the highest during the cell cycle ?