The graph below shows the relationship between maternal age and the incidence sa6g 6ahvrach+i 8k6. of non-disjunhaka.6i6 +8rv6gcsa hction. What relationship is suggested by the data in the graph?

  Which stage of meiosis is represented in the diagram belo6b sd+ez1 ; x+slt;isiw?

  The diagram below shows chrof+3jkta:)y vyd+ e x3ody48q smosomes 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 states the number of alleles of a single gene wha hd1-0 a)qwwu1 cn+2yqk 6w j.ypfis;ich would be present in the n.wu2 1qh ap6-+ );swyijk1f0a nyqc dwucleus of a cell as a result of each process?

  Which keyword is matched to the ccm haej4, lig(57ke0f91kxu q orrect definition?

  Which statement(s) about mitosis is/are tzdyt/tcal) qkdr-x( 15;+nt 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 celluw9*onk8ov+31f gckr in anaphase?

  During which stage of mitosis does the nuclear envel d;mmi ewrvj;ziee xg3bi,z/v/: .6y2 ope break down?

  Which one of the following transport proteins only carries oujdd :o(uxgp0b/x jv.(t active transport?v/((jbjxu o:x dgp d0.

  Which process does not h 1uzd)eb:e,+ yopy0 wnappen in the shoot apex?

  Which type/s of membranj .0 0cmrz)9ang *ytbge transport do/does not require energy expenditure?
I. Facilitated diffusion
II. Active transport
III. Osmosis

  The diagram below represen bhfr/ s55:6c3 kc4dogztgq1pts a cell with a diploid number of 4. Which stage of cell division is the cell currp rg/hc 6541z: g qcos3kfdt5bently undergoing?

  The photomicrograph below shows a root tip meristemhdk lz3 tt9l+ shp9,lqng(;3l . Which of the following sentencllsl n glhq +3z9h,p9(tk;3t des correctly defines a meristem?

  When does the random orient2+6o2rp5h:lis5u snd oa tzz6ation of homologous chromosome pairs occur?

  Which process does not occur during meiosise zeki-s(z zjsk/oc;)lod 5 osk38k7/?

  If a cell with a diploid number of 36 undud l,4k,ndx))usah-y ergoes mitosis, how many chromosomes will be present in eac-u ,u dds4ak nxl),)yhh daughter cell after cytokinesis?

  The image shows a micrograph of a cell. )5acsae *p6in


What explains the appearance of the cell in the micrograph?

  Which statement(s) apzknidbpajv2 ;x sv9(v4/ sun5 g -7i:bout 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 in.rgl;+gklzk cy 75 pg/dividual with Down syndrome.

Which statement is not correct?

  In the cells of a horse (Eg*unk42gyjcvj1e x4raii+hh; s2 c : 0. caballus) during prophase I of meiosis I there are 64 chromosomes.0: shkc*ryg v2ie aci;4 u j1xhjg+n42 What is the haploid number of chromosomes?

  Which arrow is pointing to a ch8jchrse,); wn)de g+t iasma?

  The diagram below repreo0xm.8jkj9ux sents the structure of a shoot apical meristem. Which row in the table correctly identifies the processes occuring in0j8m xxojku9. the structures labeled in the diagram?

  How does meiosis promote em+ltg 3 tub1.xe1d(gvariation?

  Which of the following statementsu3j((kj g rtug;3i:qy b 8)nmw 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 chromosomes.ngm 8 *k5ljg4;ghs3h k


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 f ta4nk sjy5t5mtxuu2k)+s 0.y rom primary tumours as a result of the movement tk.syt)5 +ja2us t u5k0 m4ynxof cells?

  How many chiasmata are present in the diagram? w fuh:qg 6(76unn6,(uuncg gluv*;xd

  Which statement is a similarity betq6pm,np .g2 m 3jnoz ()4kqgjcween cytokinesis in animal and plant cells?

  Which stage of meiosis i0yd12sp* owdgs matched to the correct description?

  Which statement(s) are true of meiosis I but not meiosi7 s*r mh:3vudnc1 /mq e0rn,fm,v/aqvs 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 d8;( hsn.yvvk0 ,oypty ivision. This results in the formation of one large cell(s p,yoyvvty h k.n;08 and one small cell. What is the fate of the large cell?

  Which row correctly describes nl7,tpyj4bov0l5ls: 0 zb :j ldiploid and haploid cells in humans?

  The following table shows the diploid chromosom )c2ss0hjlxyu5w/du, e number of a range of species.


Which of these statements is correct?

  What conclusion can be drawn from the ks2y a2j57mk 97:grs/pwmueq*xp ; vmxaryogram below?

  Which of the following processes is characteristic of theia6kq-2l .syu meiotic and not the mitotic c-6.k ualqy i2sell cycle?

  The diagram represents a bud with a shoot apical meumz2w/ iy2 jv)gekr6 6ristem.

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) icu a9skqrka.;wgp3** s 48. Which row shows the correct chromosome numberwakc3r ;* psu*kag.q9 for different cell types and cell division stages?.

  At the end of which phase of meiosis I does crossing over occur, an*5v)i pi aweyz)(hz. td what is the outc)*( i)z wtvezyhai5 p.ome of crossing over?

  Which of the following statements does not describe a step in / /ed5qhmlae8the sodium-potassium pump maqh /de8e5 l/cycle in the neuronal cells?

  Which row in the table below is t4g4hlntckf52bptw /z 9*wb:y rue of meiosis?

Membrane transport is im yq64fjf j3to*portant for allowing particles to move across the cell membrane and respond to changes in the chemical compositiooft64jqj fy *3n 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 regu )mn(qx qwv-;l2ud(tpglb gwxa,; q,7ni/ i1ulated 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 nvzg 39,g r+ trov.rm1the concentrations of different cyclins during the cell cycle. Which cyclin is involvedgm1r. 9z g+,tv3vronr in preparing for DNA replication?

The diagram below shows chromosome udcs5 u00ypc 7p9donrt2u..ts 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 involves the separation of homologousm 0q3jv y8i*sk chromosomes?

  The mitotic index of throat tissues taken from yv3 u6u r / x7u7m/fjqo:hc-vv4 different patients is shown belo/7qh6v3ufvxou u-:y r/7 m cjvw. Which patient is most likely to have cancerous throat tissue?

1.Draw a labelled diagram to represen;ca(yf;ad,okd8aa thq .m :6nt the process of crossing over.

2.Compare and contrast random orientation and crossing over.

3.Outline the stages of meiosis.

  The image shows an atlaz*+g6r.t i bnormal human karyotype.


What is the abnormality in this karyotype and its cause?

The graph below shows the relative amount of DNA in one cell during one completmcnq .47he(:mjwzpze1w gt-*e cell cycle. Each letter represents one stage of.z p hw7we*:-q4c1t j(enm mzg 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 shox-m7kif.q mm8ws a cross between a male cat that is homozygous for brown,.ki- qfmmxm7 8 long hair and a female cat that has black, short hair.


Which of the offspring has a recombinant genotype?

1.Outline how polygenic traits can shsl2it0pj z 2e: okk(w-ow 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 thec6,ikxj9 k k7axgw/b * crossing over of non-sister chromatids shown in the dia,9xbj k7xak6iwk/*c ggram below?

  The photomicrograph shows a pollen grain from L. candidum oijwq z(k*zecc9 31a:(Lily). Which stage of *(q k e:zw91azioc3jcmeiosis is shown?

1.Outline the events whicq. wd1;5sx s ujo4wq7hizf-j7 h would lead to an individual being born with Down syndrome, which is characterised by the presence of three copies sq-q7 7fjuww;5ihsd xzj.o14of 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:l4qq5c*yi 9ly3zaw t was conducted on white onions (Allium cepa), under control4iy: l*lca9 3zq wt5qyled conditions 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 diagrt lvbwz7yd -cag03mt )(ep8p) ams below show two cells from an organism with a diploid number (2n) ofv-( ycp)t g0t 8la)e7mdpw3zb 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;d;.ubt3*x 3fz h hmdi 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 cell, with a diploid number of 8, :kat q3p3hy4sin different stages of meiosis. Which row correctly names eachqp :hsakyt334 stage?

  The micrographs show four)0oj8pdynar2*9sa k ns:h4yz phases of meiosis I in a plant. In what order do these phases osanzpn:)yj9*h rydo2 ask048 ccur?

Mitochondria are responsible for supplying metabolic energy in eukaryotic lp)i;y4a(u gb6ownh/py u 2w, 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 organisms, inheritance patterns of mtDNA found in hybrid cells, which are the result of sexual reproduction between two different yeast spec )yog;p4 uw p(lbi26ahn/ yw,uies, 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 stagz v q/)b e-o24nf,rzw m4ksbg6es of the cell cycle in four samples of lung tissue from four patients. Which tissues4onz/g )z wkerb 6qvbm f4-,2 has the lowest mitotic index?

  The diagram shows the dominant sp ) xb+yspas3kt,- 9v f-ul8jcyclin/CDK complexes at different time points in the cell cycle. Which cyclin/CDK complex ac)ksbyp atjv39+s- s-fx 8p ,lutivates DNA replication machinery?

  Studies have shown that geneb/s4 uiicd+) us such as Cyclin Dependent Kinase 3 (CDKN3) are highly ov)s+4 ucb /diuierexpressed 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 cyclin E the highest duringyg;(,wj0h kl1)fw i nz the cell cycle ?