The graph below shows the relationship besguf3ju/ yax;n6 0qe9 tween maternal age and the incidence of non-disjunction. What relationship is 3uxyf9gqj 0/nsu a e6;suggested by the data in the graph?

  Which stage of meiosis isc o+w7, jdrq st0* k.5ijoo/nb(5jejb represented in the diagram below?

  The diagram below shows chrk 83wj;fw4r ksomosomes 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 d( 7:dx5kcofbn46fqosingle gene which would be present in the nucleus of a cell as a result of x n5 ( do4doff67bq:kceach process?

  Which keyword is matchqj/),ppqd (el ed to the correct definition?

  Which statement(s) about mitosis is/are tf weyua+:37ha 5rac+qrue?
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 belo4fh1nl .odiw q)xdq 9-w, which letter points to a cell in anaphase?

  During which stage of mitosis does the nuclear envelope breawq1fjz9 s d5 wt0y(b(zk down?

  Which one of the following transport proteins only carries our6: j)aydmdm jp,dbv,7y1 a 2lt active transport?m:dl ydya,m72 rjj1v6da )b,p

  Which process does not happ,gfhlrghd5 ;( j:x;; qer djnu11 j4zten in the shoot apex?

  Which type/s of membrane transport do/does not require energy exu w2a*u 2exqb*rbt1cg6-3 9u8wlu xf dpenditure?
I. Facilitated diffusion
II. Active transport
III. Osmosis

  The diagram below represents a cell with a diploid number of 4. i gz1.)y njeh(Which stage of cell division is the cell curren( yez1 igh.)jntly undergoing?

  The photomicrograph below shows a root tip meristem. Which of the followim o8; (rheyag/ng sentences correctly defo;re/gam( y8hines a meristem?

  When does the random orientatio+n4yv usp-cj +n of homologous chromosome pairs occur?

  Which process does not occur dusl(6t gd62:aht (gnq9 /ars ulring meiosis?

  If a cell with a diploid number of 3 y3v 3g3wh vdcet,vb/26 undergoes mitosis, how many chromosomes wilgv23hw 3 yb3et c/vdv,l be present in each daughter cell after cytokinesis?

  The image shows a micrograph o*fb6j isnl)8 b4gc;h9pfcm: p f a cell.


What explains the appearance of the cell in the micrograph?

  Which statement(s) about homologousqvywu xb 54s*7l1auvem f60d) 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 i a(chn9 fxhl0 rdbz6-1g0rh) zndividual with Down syndrome.

Which statement is not correct?

  In the cells of a horse (E. caballus) during prophase I of meiosis I there are 6-y1(ue na26(fxqv5oge+; tyte l3 tlg4 chromosomes. What is the haploid tgyt5el-fequex ;6vy gao( 1tl32n+ (number of chromosomes?

  Which arrow is pointing to a chiasma 2hdgt d-e6go-(aki2i?

  The diagram below represents the structurk 9ra* :7oyg5srl:vg g3 (raaae of a shoot apical meristem. Which row in the table correctly ir7v(yg5aro:l9a 3 aga k:g*r sdentifies the processes occuring in the structures labeled in the diagram?

  How does meiosis promote variationj4v9s rc) j6a8.wdy(0b+-v7 +nmpxzx dqbfa d?

  Which of the following sr bswb 9 wjcviitg72kt,lkmm,).9 q92 tatements 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 pr74 bdm 6rple*2aovm+yoduced 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 primary tumours xqq w:p( 8som-d v6+vuas a result of the move-q+pm vsvq(u6x: w8doment of cells?

  How many chiasmata are present6 *jz *bbn)a3y dk+fhxzqq6w 3 in the diagram?

  Which statement is a4;gbs(/ acja l similarity between cytokinesis in animal and plant cells?

  Which stage of meiosis is matched to the correct descriptao5 3bplr qq.wxdf f2*9g5c safc*c0:ion?

  Which statement(s) are true of meiosis I but no h*bgm.jdsdo (co/ /d(t 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 the7nol.7i g1 czu59k2ro+reo ns first meiotic division. This results in the formation of one large cell and one small cell. What is the fate of the lgru9lo7skzo . n5 +21nrcie o7arge cell?

  Which row correctly *wpalkw-eqb0-r dv0x .4kyy -describes diploid and haploid cells in humans?

  The following table shows the diploid chromosome number of a rangna6q)3fki e0x9 pd. f0wg8ko ge of species.


Which of these statements is correct?

  What conclusion can be drawn from cmfyx bflph*2 5 0mq 9jvz37:cthe karyogram below?

  Which of the following processes is characteristic of the meiotic2k bxiyvchu-04iv 2 b: and not the mitotic cell2yvi-2ib4k0v:hc xub cycle?

  The diagram represents a bud with a shoot apic6zxz( dmc2nm +al 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 48u) e0pfzj*,p d. Which row shows the correct chrom,u*fjdezp)0 posome number for different cell types and cell division stages?.

  At the end of which phase of meiosis I does crossing over occur, and wh,wv uru/tc (r mz5n0g1at is the outcome 1c truzur/wv,mng5( 0of crossing over?

  Which of the following statements does not describe a step in the sobnvxffi(js b5)7 ylm /5pybl5 +pw:.odium-potassium pump cycle in the 5job:). nylil+ffb5/ 7yb mw p(5psxv neuronal cells?

  Which row in the table belowo7i1u nv,7 cjc is true of meiosis?

Membrane transport is important for allowing particles to move across the celgl0gi a:qd lexp0; x0:xl i5 ;1ukdw,dl membrane and respond to changes in the cheiapl : u ,;xe0xklgdg q5d0;d:0w1 lximical 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 is r.)bl/auq y9h eegulated 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 th+vge8zg4j/ o i(xw ty,e concentrations of different cyclins during the cell cycle. Which cyclin is involved in prepar gwxtzi e48+vjo(yg/,ing for DNA replication?

The diagram below shows chry f-wg3 n3w2dyomosomes 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 homologous chro,eevql- t6yvr+b1jwoeut :*1 mosomes?

  The mitotic index of throat tissues taken from 4 digqyw) z)(1pmg fferent patients is shown below. Which patient is most likely to)z1g)p(gwy qm have cancerous throat tissue?

1.Draw a labelled diagram to represent the pro:1fryknn( 9a ccess of crossing over.

2.Compare and contrast random orientation and crossing over.

3.Outline the stages of meiosis.

  The image shows an abnormal hu d+l5r vcq.vpp3m3tr/9f gji vj+z.i 3man karyotype.


What is the abnormality in this karyotype and its cause?

The graph below shows the relative amount of DNA 9 h9exw x9o6uein one cell during one complete cell cycle. Each letter represents one stage of the cell xw9oe6u 9xe9 hcycle.


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 malks/6vib wwja0 +0z/obv;2iy4 vvdq *he cat that is homozygous for brown, long hair and a female cat that has black, short hair. ;vq40 wbvoa/ b/wyi0s 6*+ kdv2zhv ji


Which of the offspring has a recombinant genotype?

1.Outline how polygenic traits y+y sk v -7-py3cbi0ggcan 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 the3b: hxk4vzy z0 crossing over of non-sister chromatids shown in the diagrhz:kx30 yvbz4 am below?

  The photomicrograph shows a pollen grain from L. candid.*d72 wxtsk*sbrn)qfc9+da s n*d u3tum (Lily). Which stage of meiosis isdr)x c .dfka **sst*nu2d b7qnw +9ts3 shown?

1.Outline the events which would lead to an individual being born witgve ;k efywc * k7fe0l/beqwtpd2w8)m. .-;rih Down syndrome, welfv e/d.k;mf0wbwwqgct*7 e-.; r p)keiy28hich is characterised by the presence of three copies of chromosome 21.

2.Explain how meiosis increases variation.

3.Outline the stages of meiosis.

The mitotic index is an*xblu7)cdpio9 r2ae9 indirect way of measuring plant growth. A study was conducted on white onions (Allium cepa), under controlled conditions in a lab29xae *7ducp r 9)oibl, 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 divgn37db:jcf: b0z- ,ysa q1md yide. The diagrams below show two cells from an organism with a diploid num0 :bjsfzd:dny,c1a 7mbgyq3 -ber (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 expressions cjz q6ez-lfo,dj,c1 pib 6rh9+uc: 9 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 d6ya(p),oweo ,wd m hl8iploid number of 8, in different stages of meiosis. Which row correctly names each a ,wyom),l(h6e pd8ow stage?

  The micrographs show four phases of meiosis I in a plant. In what ordeah-vv10 x - hphlt.z+nr do these phases oczh- vv+-lxtn h.a 0p1hcur?

Mitochondria are responsible for supplying metaboliv:ur ;n/;omw q)6xkz gc 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. 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 bwznk ;qrou/ v:;g)x6 me 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 oq9 5e5fluq/c )5aepuin different stages of the cell cycle in four samples of lung tissue from four patients. Which tisu/) pue q9f55ace ql5osue has the lowest mitotic index?

  The diagram shows the dominant cyclin/CDK complexes at different time points d lyw9-0covos1zx zgaj-n3 s+07 0s fhin the cell cycle. Which cyclin/CDK complex activates DNA replication oo 3sj 1+ -z70gyn90hczw-sva xdlsf0machinery?

  Studies have shown that genes such as Cyclin Dependent Kinase 3 (CDKN3) are hig(it6i7 g(jp8 m5a grzehly overexpressed in cervical tumour(tg8p7ig(rei6z5 ja ms.


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 n 4 .zm:ute)y+foi:evof cyclin E the highest during the cell cycle ?