The graph below shows the relationship between maternal age and the incidenc. zm 2cnq.bl7fe of non-disjunction. What relationship is suggested by the data in the grl72.fqz m. cnbaph?

  Which stage of meiosis dobw:a 2un0 5tis represented in the diagram below?

  The diagram below shows chromosomes during meiosidy8:j5x bttp,s.


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 wou46dt) qyq. mi9 mj2pmtld be present in the nucleus of a cell as a result of each procestydmtj42)p iq mqm.69 s?

  Which keyword is matched to the co (wuwqsn1f, )7drju4n rrect definition?

  Which statement(s) about mitosis is/arjy92+n- oooc ae 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 anqqct 8a bd5b(1i;dh:j ciw0adcfs :0+ aphase?

  During which stage of mitosis dou *p3nzlhzc 7-es the nuclear envelope break down?

  Which one of the following transport proteins only carries out active trans4g;l;7ekttxslw z.z6 port?6xtzst4wgk .7 lz; e;l

  Which process does not happi;mt iw,( /ryfen in the shoot apex?

  Which type/s of membrane transpozw7h n jibnqu 2of)/ k(p/-df 2zy69rsrt do/does not require energy expenditure?
I. Facilitated diffusion
II. Active transport
III. Osmosis

  The diagram below represents a my cbw4h ;i*fr70oni6 cell with a diploid number of 4. Which stage of cell division is the cell cu4cfrb;m0ni* o6 i7hywrrently undergoing?

  The photomicrograph below show;wq mx(iq;w .iux.d h;s a root tip meristem. Which of the following sentences correctly defx xwdh; iu.iqq;mw. ;(ines a meristem?

  When does the random orientation of homologous cls/lo y *l,fu5hromosome pairs occur?

  Which process does not occur during b3d28a) hxe6qayw7zcmeiosis?

  If a cell with a diploid number of 36 undergoes mitosis, how many chromosoma*qr(f ,x9ulees will be present in each daughter cell a,lu ex9*(r fqafter cytokinesis?

  The image shows a micrograph xia2 y6u cf:a6pif a*d1o7m:dg h6ym5of a cell.


What explains the appearance of the cell in the micrograph?

  Which statement(s) about homologous chromosoqb ))pmdhz(; rmes 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 wi qg4w2 ,-dtjrb tk1x8*vmk2bvth Down syndrome.

Which statement is not correct?

  In the cells of a horse (E. caballus) during prophase I of meiosis I there are 0l jo1 kbt dz0sn; 4fgyy-b(lq 9,m*be64 chromosomes. What is the haploid number of chromo9z ,sbjn(0e yf;1-o bd*lq 40tglmkyb somes?

  Which arrow is pointing to a chiz+ nr l8e)9fkugraa vpw ()i 0y9,7lweasma?

  The diagram below represent-*/ol p47aq javbew8y s the structure of a shoot apical meristem. Which row in the table correctlb8o-y/*qp4al ej7v w ay identifies the processes occuring in the structures labeled in the diagram?

  How does meiosis promote ( qnnpr)ba,px8h*g miq q29;y variation?

  Which of the following statements is/are correct for meiofr qs-j1z e4 *thct:cp)d7i 5wz13vgkw/b 6uhsis?
I. It is a reduction division
II. It involves random orientation
III. It produces genetically identical cells

  The diagram shows gametes produced from tw81vh,74l. ,effyqph + albwha o 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 0gme6k*wouv; 3p oxp+ tumours from primary tumours as a rep* p+vx0e;u3mw o kg6osult of the movement of cells?

  How many chiasmata are p vzv-:x2zbqb9resent in the diagram?

  Which statement is a similarity between cytokinesis in animal and pl 6ef7 t2w+r)*izwm1*gugaxobant cells?

  Which stage of meiosis is mat(a;px 6 q5lanvasbi+who1) u;ched to the correct description?

  Which statement(s) are true of meiosis I but not meiostjs3 l, 1zuz3jis 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 meiot(u -u o: qr9akq2sm0alic division. This results in the formation of one large cell and one small cell. Whatq:qr ualo 0m-kau( 2s9 is the fate of the large cell?

  Which row correctly describes diploid and haploid cells in human8j19whau s)tq s?

  The following table shows the diploid chromosome number of a range of spel)ca+e b)o7y zcies.


Which of these statements is correct?

  What conclusion can be drawn from the ka,i.3cpfa(d 8 )nk hqqis* mda8ryogram below?

  Which of the following processes is characteristic of the mw4pul 4agcs:(nv;f q :eiotic and not the mitotic cell cycpcl:(uq f;sw:v4a 4ngle?

  The diagram represents a bud with a shoot apical meristem.9 ea2qjs:f c/d

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) is1;bry mc:ohwjlebq,:y+ vh- / 48. Which row shows the correct chromosome number for different cell typescrqhmoyl yew ;jv-h1/:b+ : ,b and cell division stages?.

  At the end of which phase of meiosis I does crossing over cbz:*w3xww b)occur, and what is the outcome of crossing ovwz3xw):cb *wb er?

  Which of the following statements does not.*vmf1bug i .h describe a step in the sodium-potassiuui *..hb1gfv mm pump cycle in the neuronal cells?

  Which row in the table below is true of meiosi hq+i *6hjax7 vopi7qy-/0bau 3hv+ejs?

Membrane transport is important for alloy(k l lciv2v( 0t:p(itwing particles to move across the cell membrane and respond to changes in the:y0k (v( vic ltl(it2p 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 zoq6+-9 drxn/um-blqis 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 thn)seq ts61if /e cell cycle. Which cyclin is involved in prepf1ni/ et s)qs6aring for DNA replication?

The diagram below shows chromosomes 0m).uwutjbo3hogcw cg;2ovz88 5 c5 hduring 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 meiosir9bq p ac-if;)s involves the separation of homologous chromosomes?

  The mitotic index of throat tissues taken from 4 different patients )4q9p v ms yxbe-1wmh8is shown below. Which patient is most likely to have cancer1yqe m )9wbh4x8m-pvsous throat tissue?

1.Draw a labelled diagram to represent the processfc 05-1nrglzh:2,qy7fe zaati v8+rtb ;v y.r of crossing over.

2.Compare and contrast random orientation and crossing over.

3.Outline the stages of meiosis.

  The image shows an abnormal humg,2q h*bh-n n-fk wkx9an karyotype.


What is the abnormality in this karyotype and its cause?

The graph below shows the relative amount of DNA in one cell+bjz6i 8f*hot during one complete cell bh6j *if+toz8cycle. Each letter represents 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 shows a cross between a male cat that is homozygous for brown, ub7i8s0yq ;jl los iubl7j;0y q8ng hair and a female cat that has black, short hair.


Which of the offspring has a recombinant genotype?

1.Outline how polygenic trait1(5m n.(cev: gdhju-p v k lmi2hed.u-s 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 eemiwh9r+ik 5, .a /xynon-sister chromatids shown in the diagram below?a9 / kixei+e hmyw.5,r

  The photomicrograph shows a pollen grainric4.fd b 1 t)flt58dasu tc6fv( 4m,n from L. candidum (Lily). Which stage of meiosis is sh dd nv4fmcbltfu18 a5t(rtc f ,4.)6isown?

1.Outline the events which would lead to an individual being born with Down synn u /- b)vua(mjaio)l.mp: o7qdrome, which is characterised by the presence of three jmu/b- vmioa7.: nalq o()u)p 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 stupvg 40ozol14 v-qz. hbdy was conducted on white o1zzo4oqv0gb l phv.-4nions (Allium cepa), under controlled 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 celdt+vdi m5t;b -;iy )dals can divide. The diagrams below show two cells from an organism with a diploid numad- m;+vtd) y5iit d;bber (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 euzgr;3e 4d p/nxpression 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 cell, with a diploid number of 8, in diffe qp;5s1rdjou5 ,p js;mrent stages of meippju;5q m,s1d5 or ;jsosis. Which row correctly names each stage?

  The micrographs show four phases of meiosis I in a plant. In what or6bd 9klj0 b2mjder do these pha6m9ldj b2jkb0ses occur?

Mitochondria are responsible for supplying metabolic energy in eukaryotic k29yvptlv8hl85 u-*+1hfw hn0egn pn 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 hasfk h1 8-nn plg 58hyv2euhv+ ln0t9*pw 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 i6(a.y7+c ht diys u1 kvwt.gq;n different stages of the cell cycle in four yc1(6ti+hqg;kvu.7 ytad ws. samples of lung tissue from four patients. Which tissue has the lowest mitotic index?

  The diagram shows the dominant cyclin/CDK complexes at different time points ,mszzd0dd ; 3jin the cell cycle. Which cyclin/CDK complex activates D d3sz0 ;dd,mjzNA replication machinery?

  Studies have shown that genes such as Cyclin Dependenfyr1xsd (e7xz6y (7x ft Kinase 3 (CDKN3) are highly overexpressed in cer7yxsz6( 7xxyfr1(f devical 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 ofmpxm dk-kc,x2r g-e1 s fuz6m 5-*0xcu cyclin E the highest during the cell cycle ?