The graph below shows the relati(sq8hx 3qxdp mlxx:*vpm7 ) g*onship between maternal age and the incidence of non-disjunction. What relationship i vxpxqmmg *x:plh *7q 8dx)(3ss suggested by the data in the graph?

  Which stage of meiosv6 fg:yl kwjw3. e0z2ais is represented in the diagram below?

  The diagram below shows chromosomes duri9b 9 n 8u6vl)omtz;obyng 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 allele o v-9be6ne69lbw7gk es of a single gene which would be present in the nucleus of a c6gbw-e n6 9 ek7lveb9oell as a result of each process?

  Which keyword is matched to the w ognc8qnh z-x+o* eue09w ,1qcorrect definition?

  Which statement(s) about mitosis is/are truyl o.o) 4.ld+m qfi0mke?
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, whicn lxvk m9-.ih,h letter points to a cell in anaphase?

  During which stage of mitosis does the nuclear envelope break dl 2 rkfn- g/a,4pf; xjfu)sf)yown?

  Which one of the following transport proteins only car2hldpg i2v .t)ries out active transport?hgt2d2pil ). v

  Which process does nlxbyg*01kvfz) 40a gwot happen in the shoot apex?

  Which type/s of membrane transport do/does not reqjd03w7 ft4:gvhb(u ntl y/ 9zkuire energy expenditure?
I. Facilitated diffusion
II. Active transport
III. Osmosis

  The diagram below represents a cell with a diploid number of 4.e7+n u8cvy :l /wpzb0x Which stage of cell division is the cell curxw 7 evzul8+:c0bpny/ rently undergoing?

  The photomicrograph below shows a root tip meristem. Which of the following s9*q6u14w(sgn ncljl qentences correctly defines a m*c( qgnjqw4s96ul 1lneristem?

  When does the random orientation of hppy i:motti:u3 zs*p 0x31-8ze*loyaomologous chromosome pairs occur?

  Which process does not occur during meioo5fs 9prpzj3+ sis?

  If a cell with a diploid number of 36 undergoes mm2() l rspnmm pdav8/3itosis, how many chromosomes will be present in each daughter cell after cytokinesisap 8pn 2 )mmsv(/lmrd3?

  The image shows a micrograph of a cell.h++o q7yj+mif


What explains the appearance of the cell in the micrograph?

  Which statement(s) about homologous chromosomes is/arce 6ll1q 9ei/ee 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 with Down syndm1/g3 hto5 5stui 6g(ynb wi(grome.

Which statement is not correct?

  In the cells of a horse (E. caballus) during prophase I of meiosi/wzpr(/ qw :gu. ay0vc3 waw*xs I there are 64 chromosomes. What is the haploid ncy/ /q*ww w auzg(0wa3vpx.r :umber of chromosomes?

  Which arrow is pointing to a chiasma?0spmo ncmt, ey v;14d7

  The diagram below represents the structure of a shoot aimr6f6ce ;6q we:4vqw wc15u vtw:6w dpical meristem. Which row in the table correctly identifies the processes occuring in the str t6:w5vmwd vci:4ecwqw61wqeu 6r6 f;uctures labeled in the diagram?

  How does meiosis promotorg 0-;8aem t*f:tgbmu2 8aj xe variation?

  Which of the following*: snf 1 oa:fjm:)( ckkgpzzr+br*:bh 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 ,s5mko 5tyg6c5k i80bm ayg9ffrom 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 jh+fml99f63ot e3;fi uib bj 5formation of secondary tumours from primary tumours as a result of the movement of cells?umebj9bfol69 + 5i;f3 jf3iht

  How many chiasmata are preseng.*jghi4 l* nkt in the diagram?

  Which statement is a similarity between cytokinesis inzeavq )-fd/-emv mtzp(2 *pz* animal and plant cells?

  Which stage of meiosis is matched to tv,xu3 yyyb9o ,he correct description?

  Which statement(s) are true of meiosis I but not mef5unej hx9v4z z dbk9m/,v, w/+vx* neiosis 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 divis hwjm-35z(h34ia mrws 9cuyn 8ion. This results in the formati 39mius3 rz-whnw hy 5acm4(8jon of one large cell and one small cell. What is the fate of the large cell?

  Which row correctly describes diploid and htx.c6.pa6 ntcaploid cells in humans?

  The following table shows the diploid chromosome numbnf gk bj)gob-:kl)33der of a range of species.


Which of these statements is correct?

  What conclusion can be drawn from the kapkfv/:u29/g-.srkii7 bzdb * q7mx;n7 csbl oryogram below?

  Which of the following processes is characteristic of the mr8 2/un suqj ti-n:/njn2zqd57 5cpnleiotic and not the mitotic cellu7 unirzt2qn nd5cnj-l:n /q /sjp582 cycle?

  The diagram represents a bud wuyz3ji 2 /n)prith a shoot 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 chimpaac dwl6iq8l36(cj5vyjwf((ozn4 d)h nzee (Pan troglodytes) is 48. Which row shows the correct chromosome number for different cell typ)64z wyl8ni 6j ((3dolwcf(qvhd 5ajc es and cell division stages?.

  At the end of which phase of meiosis I doeyx) r :m0/vs*cywn1v/a ds o2ks crossing over occur, and what is the ork n)*sc/yva sym0/w2vod x:1utcome of crossing over?

  Which of the following statements does not descril-;hdvdfrl 3 ,be a step in the sodium-potassium pump cycle in the nlr3;fd, dl vh-euronal cells?

  Which row in the table below i 6*usewpeku6)s true of meiosis?

Membrane transport is important for allowing particles to fy :65 tqfuue3move across the cell membrane andqu5yf uf e36t: 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 is4uk9)3kpdlqkthr9fim- fh*l1;g s ; 7ujb e/p 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 cyclik7kdj b3x) rw(ns during the cell cycle. Which d(3k)krwx jb 7cyclin is involved in preparing for DNA replication?

The diagram below shows )vtf7xry./wks28deok,cf9 m ;cvo z ;chromosomes 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 7z,lhk cc1xedd h.y: l5 ofqcgq t:7+9separation of homologous chromosomes?

  The mitotic index of throat tissues taken from 4 different pat+u grkzh7+(z zients is shown below. Which patient is most likely to u7zkrh(z+g z+ have cancerous throat tissue?

1.Draw a labelled diagram to represent the pltaa;hu.u) by /(3 vrhrocess of crossing over.

2.Compare and contrast random orientation and crossing over.

3.Outline the stages of meiosis.

  The image shows an abnormal hum8/d-bgw d lg:lan karyotype.


What is the abnormality in this karyotype and its cause?

The graph below shows the relative amount of DNAut 5ght3 fju xbi.x7i)1rmjpd5 6nk8. in one cell during one complete cell cycle. Each letter represents one stage of the cell cyj . iu 1)6xfubgi7 kr8tt35hp.mxjnd5cle.


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 isnch8( )vixps4*tz9 wt :kul0 y homozygous for brown, long hair and a female cat that has bl8txpy(4zhti k :usvl09w* )n cack, short hair.


Which of the offspring has a recombinant genotype?

1.Outline how polygenic traits can show a normal ft :-usken--m 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 non-sister 1;+k-yzc , dlk -io.4dykkyxtchromatids shown in the diagra-yk. dzo c,ykdk x1;ki -ly+t4m below?

  The photomicrograph shows a pollen grain from L. candiddkujnuz* ru d60z:9j 1um (Lily). Which stage of meiudu*njru61 kjd09z :zosis is shown?

1.Outline the events which would fe6vx dei;p*rzk *m1 1lead to an individual being born with Down syndrome, which is characterised by the presence of three copies of chromosome 26 xz*i *ve;1mredk1 fp1.

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 w2hl+ ft) b b1,oyxj 70kbygqx2as conducted on white onions (Allium cepa),lx+2ohbb yft0 k 1j)2x7,gqyb 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 cells can divide. The diagre-jc q354agdjp3*mmqams below show two cells from an organism with a diploid number (qej35ma4 jqgd 3cp -*m2n) 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 growl33 vdn w6w.()t e7ba bw.afj0enx,ooth.

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 nu+;qpi 5d nezp(ofl a;6mber of 8, in different stages of meiosis. Which row correctlyez6+pda;ol( pf n5iq; names each stage?

  The micrographs show jm*be w tq1.2gj br40.c 4rrnhfour phases of meiosis I in a plant. In what order do these phases oc.*emq4r0 jrg bc 1n .tbwjh4r2cur?

Mitochondria are responsiydtsfc d)bv8+skk3w;3av99oh * wy8w ble for supplying 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 from both parents.89bdy ww93av vo;)3h scyfw skt8dk+* 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 ckj x48b6, 6dbpoq:6 zobk0sufells in different stages of the cell cycle in four samples of lung tissue from four patients. Which tissue has the lowest mitotico :k z8xbsbpk0b 6j fq66d,ou4 index?

  The diagram shows the dom3:b.d ygy s74j3 j1vshjiyhd 3inant cyclin/CDK complexes at different time points in the cell cycle. Which cyclin/CDK complex j34jjg.y s3 id 7hyh1vb :sdy3activates DNA replication machinery?

  Studies have shown that gek8na ot-44bjqnes such as Cyclin Dependent Kinase 3 (CDKN3) are highly overexpressed int4kbojq -4 a8n 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 nn2u dg7 weoosa 2:6.pthe highest during the cell cycle ?