The graph below shows the relationship between maternal age andn*t3 ow(8 cbwm the incidence of non-disjunctiomcbn3(w o t*8wn. What relationship is suggested by the data in the graph?

  Which stage of meiosis is representer6hvo,g8 nmt3 v14qom1csq t-dm4d.od in the diagram below?

  The diagram below shows chromosomes drio yexo- n7:6uring 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 n hkoio9z5:h :kumber of alleles of a single gene which would be present in the nucleus of a cell as a result of each proces:9: izk kh5ohos?

  Which keyword is matched tks:y ;-nht ,f - 1bm2ei*jmekco the correct definition?

  Which statement(s) abou,h /tajjdqq : (z9om0ut mitosis 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 ax 9 ox36j3/ 5ppbyldvcnaphase?

  During which stage of mitosis doek.y 94cayrvf / qyjb z*j1,0wis the nuclear envelope break down?

  Which one of the following transporz uz09wo;xyd 2t proteins only carries out active transport?ozd9yx w; u02z

  Which process does not happen in d+avdjd ;*p .ithe shoot apex?

  Which type/s of membrane transport do/does not require energy expenditurzxlf y;la ( :-wa*x zl/+au5bje?
I. Facilitated diffusion
II. Active transport
III. Osmosis

  The diagram below represents a cell with a diploid number ojrm. c:o;z o fx1-d;sqb xk50 -gomph;f 4. Which stage of cell divisi xb ;j mrqocp.0 xs-zmo1o;f5g ;:h-dkon is the cell currently undergoing?

  The photomicrograph below shows a root tip meristem. Which of q 00+oci5cvz zthe following sentences o0c zqi0zvc+5correctly defines a meristem?

  When does the random orientation of homologous chromosome pairs occur?gz;:n b2/cr2 :detb,wlmg; xr

  Which process does not occur 90+gcu 6u uu(pzt:sw aduring meiosis?

  If a cell with a diploid number of 36 undergoes mitosim( 2lh4s g4jfps, how many chromosomes will be present in each daughter cell after cytokinesis jh(2m plfg44s?

  The image shows a micrograph of a cei 9,y2sm dio*-0x jcgell.


What explains the appearance of the cell in the micrograph?

  Which statement(s) about homologous chromosomes is/are not t y iqkp28 gb/pgm.j 8ble8x8qn:g 6jx8rue?
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 D,, c qqa7;/ om:mgnxwkown syndrome.

Which statement is not correct?

  In the cells of a horse (E. caballus) during prophase I of meiosis I there t,r9 gjfu4t b9are 64 chromosomes. What is the haploid number of chromosomes?rj,bft4 99t gu

  Which arrow is pointing j: k4 3az8hvnvb6n8fn to a chiasma?

  The diagram below represents the structure of a shoot apical meristem.h 4(kyw0 :xro b ai*m-/vkt+yb Which row in the table correctly identifies the processesoa4k-kyyvxit:( bhwr0m+ b */ occuring in the structures labeled in the diagram?

  How does meiosis promote valw0 urf.no;a,riation?

  Which of the followingsjyd7r( fex :. statements 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 tw.xszd ) z92csdo 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 primary tu tc(:z2 wkj;n6wake u-mours as a result of thzw( :c w na6ke;t2k-jue movement of cells?

  How many chiasmata are present in thej 11qt93w zbse diagram?

  Which statement is a similarity between6gp -oc,rwpv/iqc1 +f cytokinesis in animal and plant cells?

  Which stage of meiosis is wwpu;* dklg6/ uu 1ly90 v7rpjmatched to the correct description?

  Which statement(s) are true of meiosis I but no wacnvr.h 5p9ct966rdt 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 division. This results +o:vxko5 ;x- ;vm hjszin the formation of one la5 s;+:komj vvz-hx; xorge cell and one small cell. What is the fate of the large cell?

  Which row correctly describes diploid and haplo59p suhh*wxuh:*+l mnhtvz 7-7v 8xtoid cells in humans?

  The following table shows the diploid chromos3i2 z54auisw oxxy2e ,ome number of a range of species.


Which of these statements is correct?

  What conclusion can be drawn from p,c totea4b,96nzq o(the karyogram below?

  Which of the following processes is chard ,v7yqa1g.jj1u,f3 6skdoyac 7zu5macteristic of the meiotic and not the mitotic cell c.amkjc75 ,j7ou 1sdd,3yfv6gu y az1qycle?

  The diagram represents a bud with a shoot r8vr) m9b 6ib3odm-dm 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 ch .3f)gla m0at-4hcsuvimpanzee (Pan troglodytes) is 48. Which row shows the correct chromosome number for different celll cmaatv-h0fs 3 4.ug) types and cell division stages?.

  At the end of which phaspgkw.y 9ymlnb3 8u3 sl.(p +yle of meiosis I does crossing over occur, and what is the outy.pl 3+y3lk( pm bwlgn 8su9y.come of crossing over?

  Which of the following statements does notib0 ;jwz: o/ox describe a step in the sodium-potassium pump cycle in the ni:;/xjo 0bwzoeuronal cells?

  Which row in the table below is true o b.a/ 3h0rsjbtf meiosis?

Membrane transport is important for allowing particles to move acr;qy8h cym,)c39t srpzoss the cell membrane and respond to changes in the chemical composition ohq )mry ys;3c, tc8pz9f 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 regulated in sv:i/iurdajejh1 50+8m. yz d 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 cp8gfco9ca 9s4-.huk2, fg uyh1o) dgtyclins during the cell cycle. Which cyclin is involved in preparing for DNA replicatiot)och 21-sc9a8yfg d94uh k.gu,og fp n?

The diagram below shows chromosomes duri,m pr6 )kauz +a*ulxy.ng 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 homologous chromosomb8yx2y/qc 1v;jh n )sbes?

  The mitotic index of throat tissu x5fm/se-l bkhr- w2*les taken from 4 different patients is shown below. Which patient is most likely to ha/ fwl5ek-x* h2l-msbr ve cancerous throat tissue?

1.Draw a labelled diagrvc md,j)me ce) j8gl42am to represent 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 karyotypu+yb 4- taqq66utfru4 d2b6qs mr1vb)e.


What is the abnormality in this karyotype and its cause?

The graph below shows the relative amount of DNA in (6vk4u1blxd )la- xpe one cell during one complete cell cycle. Each letter represents one sv-xul64le( 1 kxp a)dbtage 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 betwv,q. jah r/j .y*gp n68dycnn,0vq5kr een a male cat that is homozygous for brown, long hair and a female cat tjh,c68kr0y . .d* v ,jag/qr nn5nyvqphat has black, short hair.


Which of the offspring has a recombinant genotype?

1.Outline how polygenic traits can scp,kgy-cy-e8 ki1kz -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*s2hyjjo f)40ay(uhh9hr fs- crossing over of non-sister chromatids shown in the dia hs-0ju rh(j yf)ysa2o9 *fh4hgram below?

  The photomicrograph shows -v 1q 4lpp)ieha pollen grain from L. candidum (Lily). Which stage of meiosis is ip-p14qv )lehshown?

1.Outline the events whichp.*dct- sw3aa would lead to an individual being born with Down syndrome, which is characterised by the presence of three copies of chromosome*aaw p.c-tsd3 21.

2.Explain how meiosis increases variation.

3.Outline the stages of meiosis.

The mitotic index is an indirect way of measuring plant g,afhzy k2k8 p8rowth. 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 p88z2hfayk ,k 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 tx /a l1hjm*tq8(z, 7vy* cskbfwo ways in which cells can divide. The diagrams below show two cells from an organism with a diplofmv,*tjz 7b/k *y1hq8xla(sc id 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 stem gro ryz eqt- ul8sw(o0zs .5ota+)wth.

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 ak/ ,kvx*o o0qv diploid number of 8, in different stages of meiosk,o v/x0 *ovkqis. Which row correctly names each stage?

  The micrographs show four phases o,f la,ivoim 8m)x,ynsl*-a rpcf 5lb9 v9(t,jf meiosis I in a plant. In what order do these phases o, n-iif5vaf(xlp)a st l9l,j9,m ,rv by8c*moccur?

Mitochondria are responsible for supplying metabolic enen .(-0a k 3mvv7zgpgm8lgv v-krgy 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 from both parents. It has been suggested that, in some eukaryotic organisms, inheritance patterns of mtDNA found in hybrid cells, which are the resul-g8mzl-vm73v n(g.vg 0kakvp t 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 diff2(zra)8qcjy loc b +,rixd :fn rbl98)erent stages of the cell cycle in four samples of lung tissue from four patients. Which tissue has the lowest dlz:c(n9rrbc8) 2ya,rib + o )fljxq8mitotic index?

  The diagram shows the dominant cyclin/CDK complexes at different time poqmoi hv4bg xsz5v-dx3l*,t); ints in the cell cycle. Whi ;x,s4dih3oq*5zbmg) vt- xl vch cyclin/CDK complex activates DNA replication machinery?

  Studies have shown that genes such as Cyclin Dependent Kinase 3 (CDKN3) arekca7 j 2ap+ f;tsx4cbcyh5:m3 highly oveccb5a7 +h k jm;pfcsya :3tx42rexpressed 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 during the cell cycd,ux cwa-uq2 )le ?