The graph below shows the relationship between maternal age and the incidenceed2:o m/am/)z*;p .hjo 4ojjmw9p tyc of non-disjunctiomwe)mopmtj2 *oj/; p yjz c:9h4d a/o.n. What relationship is suggested by the data in the graph?

  Which stage of meiosis is represenf0,+ 2wo9px5s nlk prwted in the diagram below?

  The diagram below shows chromosi0 1v6exauv;v(zls* e omes 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 single ge(f-xs2ej o4iymjv0 5 soy.at 3ne which would be present in the nucleus of a ceof0vj3e5( 2 sa-.tmi4y jo xysll as a result of each process?

  Which keyword is matched to the correct defini20thfb2if*oni 3h gyiny5,: r tion?

  Which statement(s) about miibkld; jegh 1g9q;b. p v1wm7(tosis 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 be:wd sjoi;g1pg7iui:g(l u1c -,iia1 slow, which letter points to a cell in anaphase?

  During which stage of mitosis does the nucle i l8,nho0cwd8ar envelope break down?

  Which one of the following transrfg ld:0+q hdd*.x bf)port proteins only carries out active transport?0 d+ fxd hdl:*fgq.r)b

  Which process does not happen in the shc*f33rjpc ) wu4v xri6k3 ,fra8:2usb qbv m5root apex?

  Which type/s of membrane transport do/does not require energyeii:xa f4js+i t,5xj o8j0qx+ expenditure?
I. Facilitated diffusion
II. Active transport
III. Osmosis

  The diagram below represents a cell with a diploid number*dr-omn1nqbi3p bsa e,mm 5, / of 4. Which stage of cell division is themn5p,n/o -r*m dba3sq, e1mbi cell currently undergoing?

  The photomicrograph below shows a root tip me 8bo:i:ch*b,p2 rellf/mc .* vhprp 2zristem. Which of the following sentences correctly defines a me ch zlr*le.r/2c2fi8*m p,bhpp ::obvristem?

  When does the random orientation of homologous chromosome4xba qni94 wa8 pairs occur?

  Which process does not occur during me7n8v+ brbs: /p 5:w, sm)yptth y5jsitiosis?

  If a cell with a diploid number of 36 undergoez)w:+slgojo)0 ybtko ag: ( p3s mitosis, how many chromosomes will be preso)g:yzk a)0spogw:+ tlbjo3(ent in each daughter cell after cytokinesis?

  The image shows a micrograph of a ce)m52n7vz x4f a ews5fmll.


What explains the appearance of the cell in the micrograph?

  Which statement(s) abvwliqu ip /(111xec/qout homologous 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 individual with Down syndrome lu l+*fg0(xic.

Which statement is not correct?

  In the cells of a horse (E. caballus) during prophase x/; kpstzn4u8 I of meiosis I there are 64 chromt nsk;8pz /ux4osomes. What is the haploid number of chromosomes?

  Which arrow is pointing to a cqv blk5bn./mp4q 77sy hiasma?

  The diagram below represents the structure of a shoot apical meristem. Which c.2y -p g/4a40tmwrzh,s t+u u j8etxry.uy2lrow in the table correctly identifies the proy/u .8y gsc4pr-utr e4jtuw,2l+z 2 0tyxa.h mcesses occuring in the structures labeled in the diagram?

  How does meiosis promote vaz uufgjh)/yos5 -ad zb:o1bom 4*/n,.gy tjo5riation?

  Which of the following statements is/aredp1j. ) qiawh0 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 two homologous chromosomes. ehz m) y11+epov;so5 s7aol 4j


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 f mmpde) /li5ozgt1( 8vrom primary tumours as a result of the movement of cells?o8 ( mp/5mde l1vgz)it

  How many chiasmata arbfi77+ kkr 2hlpvphf7q58w fft*3tl:e present in the diagram?

  Which statement is a similarity between cytokinesis in ax6 zdwb*y z*jelm :61m:eif 0x4 4jfsxnimal and plant cells?

  Which stage of meiosis is matched to the correct dqj0cbbh9urr )q -1 +tfescription?

  Which statement(s) are true of je+vq; ec 3fl/* jnk6zmeiosis I but not 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 resbbx ko2lq,te ,i m.;/hults in the formation of one large cell and one small cell/tx,hloe2 ,;i.b k bqm. What is the fate of the large cell?

  Which row correctly describes diploid and haploid ceb nbe3 zo ,.7;upg :i)o4cv2mpkopufra9/ os.lls in humans?

  The following table shows the diploid c mq mz0d1p/opkvd9qko).*3w chromosome number of a range of species.


Which of these statements is correct?

  What conclusion can be drawn frog (vzns2 j44mfm the karyogram below?

  Which of the following processes is charactskrp3h2yq u3e-) 3gtg eristic of the meiotic and not the mitotic cell cycle2gk 3y-tgher 3spqu3)?

  The diagram represents a bud with a szxh 4q/yg0x q7skug95hoot 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 chimpanzee (Pan troglodytes) is 48. Which rw5x brf 84n9uxow shows the correct chromosome number for different54xbw8rnuf9 x cell types and cell division stages?.

  At the end of which phase of meiosis I does cro-kqg 6om g1dj5ssing over occur, and what is the outcome of crossi-mjod5gqkg 1 6ng over?

  Which of the following statemenqhn2:m4io hja0cn * 3xts does not describe a step in the sodium-potassium cxa:j*mn0h42 3h o nqipump cycle in the neuronal cells?

  Which row in the table below is true of meiosisc18rkfk bn0 ;b?

Membrane transport is importg szt e bi5uz+2.(e*)z f r n2lhnyf-.mrut,p.ant for allowing particles to move across the cell membrane and respond to changes in the chemical compositioner i2ezz-.rytzus ,.m.h)n 52bfltgu+p*n(f 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 regulated in c7eq4(fh ,lxzj ells.

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 c1af1l6 hkjbs-yclins during the cell cycle. Which cyclin is involved in pr1- ajlb 6kf1sheparing for DNA replication?

The diagram below shows chromnvqwr ae8jz ) ke7.wp f;e423cosomes 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 chromr tewb:ny5/w wqvf8**osomes?

  The mitotic index of throatvcu f);)u gju9 tissues taken from 4 different patients is shown below. Whichc)j);uf 9vugu patient is most likely to have cancerous throat tissue?

1.Draw a labelled diagram to represent the process of c3 x( mvwtss:)xrossing over.

2.Compare and contrast random orientation and crossing over.

3.Outline the stages of meiosis.

  The image shows an abnormal human karyhu r 5xd4:4wpkotype.


What is the abnormality in this karyotype and its cause?

The graph below shows the relative amount of DNys44 mhl1g q55ewc5 zy2ard 0gA in one cell during one complete ce4z 55cal15h4rygsq2 g w edm0yll cycle. 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 q7tkc5 hyz;;nhomozygous for brown, long hair and a female cat that has black, short kzctn; yq;75h hair.


Which of the offspring has a recombinant genotype?

1.Outline how polyge4, )pk(cpw) x6ilyw brnic traits 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 noxab. :lv/3oor vo j:t(p6vk, dn-sister chromatids shown in the diag vv/ bvdo.ol tk,px:ja:o( r36ram below?

  The photomicrograph shows a pollen grain from L. cc.:4aps ) vr*;nh szyoandidum (Lily). Which stage of meiosr.;*: nc)vayshsoz p 4is is shown?

1.Outline the events which would lead to an individual being born wta1swkhh ei+u-dbeo2xso* m s+-7u: 1 ith Down syndrome, which is c1sokoh*ei t72xsdausuh+e -m:+1 b -w haracterised 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 indirect wa(d7rz4l c)/vbm9x0lknw hp 1iy of measuring plant growth. A study was conducted on white onions (Allium cepa), under controlled conditions in a lab, to inv/znc70i1mb kl(94wrplx) h dvestigate 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 diagrams42z.4zrogfyj ,sth;6 v; ibx igo5j3p below show two cells from an 4,3zr;g6 ofio5.2h;j 4yp bzjx gs ivtorganism 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 of3g1zn)2bq 3ntv mnf v9(pi7yb gene expression 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 numb3-uq7jaf42yt x 4ki*dc8e ypf er of 8, in different stages of meiosis. Which row correctly names each stu3afqi74 *8k-jxd feyy4p2 ctage?

  The micrographs show four phases of mkd (usrzfm.s16* mf1ueiosis I in a plant. In what order do these phases occu.11m( fuuz6d fks*rsmr?

Mitochondria are responsible for supplying metabolic energy in euka1n2 fyb/yak cu u827fcryotic 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 reproductib/ f28kuau7 cycfn1 2yon 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 diff(de)c pa uvtmg ex5(7tmzg)1:erent stages of the cell cycle in four samples of lung ti(eg d57t1()a:v m )uzgetpcxmssue from four patients. Which tissue has the lowest mitotic index?

  The diagram shows the dominant cyclin/CDK complexes at diff 3ezeki)bhj(r6j (pv;v. lqj-,n j;ojerent time points in the cell cycle. Which cyclin/CDK complex ac6bl; )vznk; pqrj j.e, (-jeiojv3hj(tivates DNA replication machinery?

  Studies have shown that genes such as Cyclin Dependent Kinase+m c bfor)e60w 3 (CDKN3) are highly overexpressed in cervf6cr)+emo b0wical 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 vl6h+ h6lfs1gh+q n7 le(al7zduring the cell cycle ?