The graph below shows the relatiw-*eb/adz2 * )ch ugbgonship between maternal age and the incidence of n/g *da *2zgbhwbu e-c)on-disjunction. What relationship is suggested by the data in the graph?

  Which stage of meiosis is represented in the diagram belo; x jobceo+a5i v+.0n7qtaa0qw?

  The diagram below shows chromosomes pd-av +sr k,4ogtv1 ,xpf+5jnduring 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)pyx v( l2(+qqh-.exd5:zub qn2q9slzz9mkd which would be present -:pqz( emq( s.kzxxdv2n9 29blq5)zqhuydl+ in the nucleus of a cell as a result of each process?

  Which keyword is matched to the correct definition?9mmpcnp8:l3; tl5s y k

  Which statement(s) about mitosis is/are true? y d;d4 ipgnf9oqf7p9,
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 anaphast x:b zz5bft;05 y.k8tvuwuo8 e?

  During which stage of mitosis does the nuclear ensxy-s+upmo)i *v3fw diz +/8*ja mcl :velope break down?

  Which one of the following transport proteins only carries out active transporhd6a)0-jq +4 bpqd54 fb*8 nwkiifu fot?of *fj0pawd dn5kf+ u)4bi i 6q-bhq84

  Which process does not happen in tmh) xn x+;gvc2;t d5mf4vw.rr he shoot apex?

  Which type/s of membrane transport do/does not requipu6e3fk,v:j*n+f pb rre energy expenditure?
I. Facilitated diffusion
II. Active transport
III. Osmosis

  The diagram below rep; r6xlvrygku6gs3/ 7m u3uow4g wr (4eresents a cell with a diploid number of 4. Which stage of cell division is the cell currently xrg wgl 46 r(r4k;emo6vu7u33ws/u g yundergoing?

  The photomicrograph bel ksy iy86xw0gc/d0 +iaow shows a root tip meristem. Which of the following sentences correctly defines a meristemgw i+scxi0 y0/ k86dya?

  When does the random orientation2uy opkgtn6e 3isi)7 2 of homologous chromosome pairs occur?

  Which process does not occur duringv12x7 zp.ix/kqxc,kc meiosis?

  If a cell with a diploid number of 36 undergoes mitosraz6v99qbbl,s: s g o0is, how many chromosomes will be present insl:,6r zqb0sav9bog9 each daughter cell after cytokinesis?

  The image shows a micrograph of a es wn: 1e j7xxsgt+v;9+mm55b i lz.oicell.


What explains the appearance of the cell in the micrograph?

  Which statement(s) about homologous chromosomes is/are not tri4p)r mjd+nt)j5 s; kkue?
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 Do-p*opz6 hj3 7 d0cathzg u.j+wwn syndrome.

Which statement is not correct?

  In the cells of a horse (E. caballus) during propvu jx tax)s0yd)s++) m hhn8v,r)wu3whase I of meiosis I there are 64 chromosomes. What is the haploid number of chromosomesxum)8 )3sunawhh)0r sjv+w+tvy, d x) ?

  Which arrow is pointabu a x6r-w,,5c x8(hrd/hche ing to a chiasma?

  The diagram below represents the structure of a shoot apical meristem.9 jeeyyhd y8v *:b*lb; Which row in the table correctly identifies the processes occuring in the strlvj;b8 yehyy* db9e*:uctures labeled in the diagram?

  How does meiosis promo/sm/ ns-jurm. te variation?

  Which of the following statements is/are correct for meiosi7sm9 (7xhhw pqs?
I. It is a reduction division
II. It involves random orientation
III. It produces genetically identical cells

  The diagram shows gametes produced+we, k95,kj(dode euu from two 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 formation of secondary tumours from p -w+xzfm)sb+ d/mu 5qvrimary tumours as a ms-+wb)ufm / z5vqxd+result of the movement of cells?

  How many chiasmata are present in theihzbbopvu/:8 oq*y t)hk fgg87+x(k xn43d y3 diagram?

  Which statement is a similarity between cytokinesis in animal and plant cells?1yhe34n bg)lk

  Which stage of meiosis is matched to the correct descsajru) u3 c.n8l7fok9ription?

  Which statement(s) are true of meiopz-p1 jv-kr2 ksis 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 fir7g; poznv/ik a: br3y8st meiotic division. This results in the formation of oi vzn;y /:3a7r8gpkbone large cell and one small cell. What is the fate of the large cell?

  Which row correctly describes diploid and haploid ce1n(3pi )4md4ecaoo u qlls in humans?

  The following table shows the diploid chd y8m9b35yrknromosome number of a range of species.


Which of these statements is correct?

  What conclusion can be drawn fr;6ei2)5 i p-oas xahstom the karyogram below?

  Which of the following processes is characteristic of t 8ga;+j(i;oifpabkw-r m j 2w36m:yv jhe meiotic and not the mitotic celljf - 2agboi8+vi;;wk3a :wjj6y(pmrm cycle?

  The diagram represents a bud with a shokju: -lcsxt 36ot 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 the chimpanzee (Pan troglodytes) is 48. Which row shows tn8*atv* 7 (nwdvdpcgj0k s: ( rgdw4u7he correct chromosome number for different cell types and ce nptd4 nugwscd7( *vr (ak*w0v:dg7j8ll division stages?.

  At the end of which phase of meiosis I does crossing over occu/7c+ frzfuu-mr, and what is the outcome of crossing o-zfmf c ru7/u+ver?

  Which of the following statements does not describe a step in the sodium-p+zs8/l vy/ua/v2 fw ucotassium pump cycle in tuyflsa/28 /vv+ wc/z uhe neuronal cells?

  Which row in the table below is true of meiost(-*xzxfh.lm ms m -a4kr 34yjis?

Membrane transport is important for allowing particles to move across tx:7lpqg(n gh :he cell mpg g:(q hnx7:lembrane and 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 -e ulq9xtt2i* is 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 concentrationw/(: :ubo a32bn-lrd:fnynkrs of different cyclins during the cell b: r: -unnr/b loywka:3f2d(ncycle. Which cyclin is involved in preparing for DNA replication?

The diagram below shows chromosomes durin6u7qg:323ivsatyl+a0p ugk qy /ucs(g 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 meiosiswqmcmf2 t2wj98y3bb+f/h i3y involves the separation of homologous chromosomes?

  The mitotic index of throat tissues taken wa9b*u ;7lr j mn8kw(efrom 4 different patients is shown below. Which patient is most likely to have canceroumb8k9wuj( er*;a7 n wls throat tissue?

1.Draw a labelled diagram to represent td/7cs)khqiv gr1yc+-uze : 6 e1au(ofhe process of crossing over.

2.Compare and contrast random orientation and crossing over.

3.Outline the stages of meiosis.

  The image shows an abnormal humena;vu 76l 1ejan karyotype.


What is the abnormality in this karyotype and its cause?

The graph below shows the relative amount of DNA in one cell during onew.il8pcu a4ba61dxjze *f :s5v)dxirf 0w4 )l complete cell cycle. Each letter repres.jz :da bflexui5 w1v84sx*)4 6 pcfl0rdw) aients 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 sho 9x1gd -ck htf4t0ckf6ws a cross between a male cat that is homozygous for brown, long hair adc tfkh04f1g9t6-kxc nd a female cat that has black, short hair.


Which of the offspring has a recombinant genotype?

1.Outline how polygenic tra codz1pa tcob,6l 18-vi4i 6naits can 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 result from the crossing over of noq;wfkqx;z2.w jo ba;p 24e/cvn-sister chromatids shown in the ; owjw 2b 2 4;zvaqcq;fkx/p.ediagram below?

  The photomicrograph shows a pollen grain f2 lmh+2 +jacszdri8s 2rom L. candidum (Lily). Which stage of meiosi2 dj+z rc2a2l s+hi8mss is shown?

1.Outline the events which would lead to an individual bc),-j/alg x b 2vaqm5veing born with Down syndrome, which is characterised by the presence of three copie gamjcx)2,v/q-l5 vbas 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 was cond1mni,,*qm+xlm g h2 kjucted on white onions (Allium cepa), under controlled conditions in a lab, m,lx g *j1ik+hm2,nm qto 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 cellch 0b i.fm29vz*qei9 vs can divide. The diagrams below show two cells fr29.cb0zihmqv fi9v * eom an 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 expression in stemy* o+muz:k*1vbp ecy n8 si75y 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 l7:kxy4wj4rcvq8 cg3 of 8, in different stages of meiosis. Which row correctly nam8vl :wxkrycq44g3 c7jes each stage?

  The micrographs show four phases of meiosis I in a plant. In what order do u x g2-5yzafjxq o)j1:these phog 2xjx q5-1:f)yuaj zases occur?

Mitochondria are responsible for supl0 k-xg m2w*zpplying 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 inzx2 k-gw m0l*p 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 tblv+52+sfl:2j;9 evf(fazh5 jlcyvcell cycle in four samples of lung tissue from four patients. Which tissuejvhbcvyf5t:l+fs;2l2j+ av5fl9 (e z has the lowest mitotic index?

  The diagram shows the dominant cyclin/CDK complexes a h2p qjty6kr09*l s d17h.s9u:d mkerut different time points in the cell cycle. Which cyclin/CDK complex activates DNA replicationqd9h l0dj6t:9e ur1sku rky27hm.*sp machinery?

  Studies have shown that genes such as Cyclin Dependent Kinase 3 (CDKN 0o6f1jh pl(ko3) are highlh1o(06 jop flky overexpressed 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 sflxtv)lweqrtt 5:4n:, n- g6 highest during the cell cycle ?