The graph below shows the relationship between maternal age and the incidence of w(to rg;2vjh8i;ycgdq)* r5h non-disjunction. Whatrj5*ir vg8)w(cgh dto2;y ;qh relationship is suggested by the data in the graph?

  Which stage of meiosis is represented in the diagram below? h17 hijd7nvtdbv9r4u *-3;x( xd ttor

  The diagram below shows bs d v9r5ms g:3zweo0ux,-fu 8sx;l6k chromosomes 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 ofxh gf0 s3yen1* a single gene which would be present in the nucleu1fy3gh0 *xesns of a cell as a result of each process?

  Which keyword is matched to the9pj4)8 . hjz8vr vgkbisb3 j0n correct definition?

  Which statement(s) about mitosis is/are t2mxf /u, pttr g6nfs(+rue?
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 o /j)ha(5ilxojz h4s8 to a cell in anaphase?

  During which stage of mitosis does the nuclear envelope br+m) i/i*b+; a dongdmgeak down?

  Which one of the following transport proteins only carr:b5;hd ;ryq)bm 5abww(q dg* bies out active transport? ;q:b;h ybbwd)rg(*wq5dbm5 a

  Which process does not happen /;uqv f t+uf cwm1.av-)v.bxk in the shoot apex?

  Which type/s of membrane transport do/does not require energy 3ht78 wdc m.od*nkeyhyd1 n a7f+6zd 3expenditure?
I. Facilitated diffusion
II. Active transport
III. Osmosis

  The diagram below represents a cell with a diploid number of 4. Whichxb+ j,k y ;.roza0gk*y stage of cell divisiong+zkk0 jxy* r.ob y,a; is the cell currently undergoing?

  The photomicrograph below shows a root tip meris);mql9znoq i o4j- l/ttem. Which of the following sentences correctly defines a meristeml9- /oijq lqt4z)n;o m?

  When does the random orientation of homologous chcwee/ /yb1e *;mgb4 a9/gmkx4mn,d qhromosome pairs occur?

  Which process does not occur d of(yk6mqkb :c 0ne8(rtgvr11uring meiosis?

  If a cell with a diploid nu isj, p)i)wit2mber of 36 undergoes mitosis, how many chromosomes will be present in each daughter cell after cytokti ijw),i2ps )inesis?

  The image shows a micrographl,4gi9x 7fkli 5;y ttq:jly7 e of a cell.


What explains the appearance of the cell in the micrograph?

  Which statement(s) about homologous chromosoahb d7;1b;pkbdw;i7m mes 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 with Downk,dnr*v l0gw 7 syndrome.

Which statement is not correct?

  In the cells of a horse (E. caballus) duringnhxlu/5d45d6 wm; ,ob0m ekmv prophase I of meiosis I there are 64 chromosomes. What is tm v5bo m,wxddme4/k5l6uh0 n ;he haploid number of chromosomes?

  Which arrow is pointing to a cra. +- )0kn)mk2e fu q(duxnjrhiasma?

  The diagram below represents the structure of a shoot apical h6:u,6-j clk iz*gbmh meristem. Which row in the table correctly identifies the processes occuring in the structjmh6,l:u-k hcgb zi*6ures labeled in the diagram?

  How does meiosis promote variation?roofgb bv//47 hc36sjg 9xun :

  Which of the following statements is/are corg j jujn-5h5ds9 xu-pc*+bp ;drect 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 two homologous chromosomes+z-viuaul4*a:.kt5* ylz-dskm 2c jh .


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 sepqhj) 1hat o 9 f:khf,+s g+vg,kw/hj-condary tumours from primary tumours as a revhf+ kh9+gt, oj) -wfhphj:k g1/sq,a sult of the movement of cells?

  How many chiasmata are present in the diagram? jf*6u( epyy8u

  Which statement is a similariy)xw jq622p(gst8 ptmty between cytokinesis in animal and plant cells?

  Which stage of meiosis is matched to the correct descriptlauq7i;5)qtx9 :n6ta c lueq7ion?

  Which statement(s) are true of meiosis I but no vbhgd.gdbt, *.53gf blg:2i yt 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 k + zp spebormq,b2wz4q+*g6:in the formation of one large cell and one small cell. What is the fate of the large cell? +b qq *6zrsb 4p:kgme+ o2z,pw

  Which row correctly describes diploid and haploid cells int)1 bg1gjbc aa d4b tuej17;f. humans?

  The following table shows0bqj-zk 5-fkf:fd 1hd the diploid chromosome number of a range of species.


Which of these statements is correct?

  What conclusion can be drawn from the karyogram belozo 8lpnup9 4m 7d7lc,dw?

  Which of the following processes is characteristic of the meiot4z zb8fp/owk1(ms* eric and not the mitrzz 4/8bfo1espwm* (kotic cell cycle?

  The diagram represents a bud with a shoot apical mer+ugpoook pm1 ,6px7; eistem.

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 troglmlht d)c i 2-t9mm +3bw7:ovqlodytes) is 48. Which row shows the correct chromosome number for different cell types and cell division l 32h7molt+:9bdi- mwm)cqvtstages?.

  At the end of which phase of meiosis I does crossing over occur, ayef1q* f vm07ind what is the outco q*imfe1 y07vfme of crossing over?

  Which of the following state0s7 7lukq rpw6ments does not describe a step in the sodium-potassium pump cycle kpwrsu077q6l in the neuronal cells?

  Which row in the table *ol b1s(,1mv2yeuw h5dmys(cbelow is true of meiosis?

Membrane transport is important for allowing particles to move 5 g e-zp--8kcgbk8ne:s w,wz qacross the cell membrane and respond to changes in the chemical composition of the exg8-5- g8:ewsq kzne,zb pwkc-tracellular 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-2)*oy myw e.dryrdw0 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 cov- pl. ecp8fy+j6,gda ncentrations of different cyclins during the cell cycle. Which cyclin is involved in prepari+dl.,gpc vap-fy 8 e6jng for DNA replication?

The diagram below shows chm1lsl+xq 9g w;q+8uv /xhk r7mromosomes 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 3niv-yx q*; :3rmmyfm of homologous chromosomes?

  The mitotic index of throat tissues taken from 4 different patients is.luwa b ,fd7 hbw+ydb+5 g+id: shown below. Whi h+i+5dbb:f+bw,7yd .ldu wa gch patient is most likely to have cancerous throat tissue?

1.Draw a labelled diagcwxs:3r 4b05p q h0swdozrnzt:h873 rram 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 hu39z pnk 3gdont9e*f 5yman karyotype.


What is the abnormality in this karyotype and its cause?

The graph below shows the relative +ku*p u hckc7wb/ ,jzm oy-t1+amount of DNA in one cell during one complete cell cycle. Each letter represen1bc*k o+tw-yh+uu jk7zpm/c , ts 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 cph)i1-5(fuj zk n 9gy9fvi5/bqbc u,f ross between a male cat that is homozygous for brown, long hair and a female9 i(1fvufkp5fh-zuq 9 cjb ,)g5bi/ny cat that has black, short hair.


Which of the offspring has a recombinant genotype?

1.Outline how polygenic traitsrj5r-8:rgbpvh+ m *,yq4ue k z 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 overfm;i;so j xg(: of non-sister chromatids shown in the diagram: ;mjxg oi;(fs below?

  The photomicrograph shows a pollen grain from L. candidum (Lily). Which stag,1x oe3 06l4ofweky yae of meiosis is 30y6l41x,e ykowaoef shown?

1.Outline the events which would lead to an in 4dd0uz-u st9qdividual being born with Down syndrome, which is characterised by the presence ou49du zqts0-d f three 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 st +qclx1b3ay b-udy was conducted on white onions (Allium cepa), under controlled conditions in a lab, to investigate the efqc+x1 bl a3y-bfect 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. p9 ( e6;c1uyf.xzroy x( ffdb;The diagrams below show t y 9p(1f6ycrf( ;xxdouz.;febwo cells from 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 expression1xkbii*qu*35 7k hxhn hgf(h; 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, inx/fao veku 79f gv)o38xr/ 0kmx7ou**orf 0jq different stages of meiosis. Which row correctxq)//oegm0 ff*7 o 3fo 9 8 *uk0au7oxkxrrvvjly names each stage?

  The micrographs show four phases of meiosis I in a plant. In what ordov-/ ob/)sa sder do these pvs doas/)/-bohases occur?

Mitochondria are responsible for supplying mei*c21q d1a fxs)hapg1tabolic 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 speci1*f dsq) ia1c g2ha1pxes, 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 n874woeauc v3 mo7wj4.n*kc tkumber of cells in different stages of the cell cycle in four samk4uwmtw8 vao .e 4cj377nokc*ples of lung tissue from four patients. Which tissue has the lowest mitotic index?

  The diagram shows the dominant cyclin/CD w1ngm 5z4zu/wK complexes at different time points in the cell cycle. Which cyclin/CDK complex activates DNA replication/uz wgz4wm5 1n machinery?

  Studies have shown that genes such as Cym54 fo/ai0fq1 o4fb kpif 5u.fclin Dependent Kinase 3 (CDKN3) are highly oo5i1 ffp ofu0a4 5qf4/ikb mf.verexpressed 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 concentrrhm8 ji47sc x)ation of cyclin E the highest during the cell cycle ?