The graph below shows the relationship b7-trk6o4 dn6prc w0pjetween maternal age and the incidence of non-disjunction. What d6pp-j7wnrc4t60o rkrelationship is suggested by the data in the graph?

  Which stage of meiosis is represented in the di3 1m(7dmavmdj agram below?

  The diagram below shows chromosomes dur0avd mg.lqc/aw v2;0ig o48bhing 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 nak perm(vm;7g /o36 5x4jywdof alleles of a single gene which would be presene 7 ;wjv6k3( mxpm5a/ odr4nygt in the nucleus of a cell as a result of each process?

  Which keyword is matched to the cor m xo;ngy9zh,j /s-ob:rect definition?

  Which statement(s) about mitosis is/are trufsr.x6e7d*i *ya8 t sre?
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, whif m0eg,f(rv( mch letter points to a cell in anaphase?

  During which stage of mitosis does the nuclear envelope break dowxh/s)+ dukhtiobl * 6hj.3lt,n?

  Which one of the following transport proteins qk0if1kc- d/tonly carries out active transport?kt/cd0-i 1 kfq

  Which process does not happen in the shoot agwzc92,f oeryrdjc r 0uo4 xnz );1sdme-1t) 2pex?

  Which type/s of membrane transport do/does noq: i3ve6k6 /zpys1e put require energy expenditure?
I. Facilitated diffusion
II. Active transport
III. Osmosis

  The diagram below represents x:y0s,)7y x.mu- l+huns -bh/ggxyz s a cell with a diploid number of 4. Which stage of cell division is the cell culug0-x/yy,.gsmh7+xu y snh: )x- zbsrrently undergoing?

  The photomicrograph below shows a root tip meristem. Which of t w2 )w pjo9fi89jqgxk:he following sentences correctly defines a meristegi9ww 8f:xjqp29k)oj m?

  When does the random oriefjbds,you6 ms)+ 0k lg *,5ddontation of homologous chromosome pairs occur?

  Which process does not occur d 0jia*1q,rl e m7nhlln1wmsq*675fd kuring meiosis?

  If a cell with a diploid number of 36nzaf0axwij53* qu+ +y undergoes mitosis, how many chromosomes will be present in each daughwxn3 zi*yfja+ u 0a5q+ter cell after cytokinesis?

  The image shows a microgr (1oq 0entpptl +p6rkk io4,3zaph of a cell.


What explains the appearance of the cell in the micrograph?

  Which statement(s) ay uz+ y:1)6tovj,2ec 0pkqvkuk8a/gybout 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 invbnd*c50: zog dividual with Down syndrome.

Which statement is not correct?

  In the cells of a horse (E. caballus) during prophase I of meiosis I therjc+kq )/0 deb.s lj:mme are 64 chromosomes. What is thbmjs/eq c:kd)m0. j l+e haploid number of chromosomes?

  Which arrow is pointsnf gz+ded2 5pb5n; ;jing to a chiasma?

  The diagram below represents lqll,tuu-j)4 the structure of a shoot apical meristem. Which row in the table correctly identifies the processes occuring in the structures latlu)llqj, u- 4beled in the diagram?

  How does meiosis promote vari)l )ilkrm5(o36;*zoa rpip. 5.tj tq l1dqzwmation?

  Which of the following statements is/are correct fm/s4ohtr* t* bor 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. q (j(qxobki2)s/rm(di+m n :x7fx npv y*r/d1


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 formatcfku7 /n/9a kyion of secondary tumours from primary tumours as a result of the movement of cel/k y9 a7knf/culs?

  How many chiasmata are present in the diagram? hh ahfmhqi819k 9f(dwz7:)t,p opj2 p

  Which statement is a similarity between cytokinesisze-u iz3;,mcwtnvj.0 in animal and plant cells?

  Which stage of meiosis is matchedikle1.p 89djq k du;f3 to the correct description?

  Which statement(s) are true of meiosis I but notx 1sv; vo.ap;1h-mfy u 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 resultsdl)vh(j0 cnw q u (vou-j1kij5+d63tt in the formation of one large cell and one small o3+d(u k50ji-cdl t1juv t) wjv(qnh6 cell. What is the fate of the large cell?

  Which row correctly describes diploid and /j na-brha62q haploid cells in humans?

  The following table shows the diploivipby4 bk.rr;-:mwh,v8yjvc4hb 6yj4i z5t2 d chromosome number of a range of species.


Which of these statements is correct?

  What conclusion can be drawn from thei.w* v,bl1m kg karyogram below?

  Which of the following processes is characteristic of the meiokc+n(tc52 yy ctic and not the mitotc 5n cyyk(tc+2ic cell cycle?

  The diagram represents a bud wit9 ph1 eav.k/uih 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 chimpanzee (Pan troglodytes) is 48. Which row show8 ;/s (a.+ihx6on oonwbyp bh/s the correct chromosome number for different cell types and ch o w8b+ya//b.oins o 6hxn(p;ell division stages?.

  At the end of which phase of meiosis I does crossing wr5oxd(nv 3(exi*u, uover occur, and what is the outcome of d u,3wr nx(*ov(u5ie xcrossing over?

  Which of the following statements does not de6 8rn(u .+f tcob+nyqzscribe a step in the sodium-potassium pump cyclz+. 6+tyonf b8(u rqnce in the neuronal cells?

  Which row in the table below is true of meiosi3mo/s b* :u9dnzvzap+ s?

Membrane transport is important for allowing particles to move across the cel o vlcm2+)7:a:lk rd/ufm5af nl membrane and respond touao+ n fac7/mmf)v:k2r5lld : 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 is regulated in csz o mkniw82 ddpkec7 5b, kjhoi.12/,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 cyclins durignau, 7u8d 5g,taz mo.ng the cell cycle. Which cyclin is involved in preparing for DNA rega,oamu5 ,7 zutg8.dn plication?

The diagram below shows chromosomes during )c,s4mdk 3rpud -c,us 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 *g1f2e4yow+/qh)p l0lvv d uwj o.-kq separation of homologous chromosomes?

  The mitotic index of throat tissues taken ft*2,xn8jubs e rom 4 different patients is shown below. Which patitu2s*j,be xn 8ent is most likely to have cancerous throat tissue?

1.Draw a labelled diagram to represe6g +z3 + lvhzbej4cpw+nt 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 kar,kbrw2m:0 gl oxx 1fn:yotype.


What is the abnormality in this karyotype and its cause?

The graph below shows the relative amount of DNA in one cell duri h ,wcke)8hy/:1nong ung one complete cell cycle. Each lett en :c,yh /gw8oku1)nher 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 thatv99 (nlvfq 2wv; i-pbc is homozygous for brown, lo -l9fnvqci;bv pv2(9w ng hair and a female cat that has black, short hair.


Which of the offspring has a recombinant genotype?

1.Outline how polygenic traits can show a normal distribution5nyr f -q sk21;mvm8gy.

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-sismrer ( ikr*/u1ter chromatids shown in the diagram below? m*rik/( u er1r

  The photomicrograph shows a pollen grain from L. candidumlo + mvydu8-r. (Lily). Which stage of meiosis is show+ur .mvyd 8lo-n?

1.Outline the events which would lead to an individual being born w/:lj8-amusf h m.d,nsith Down syndrome, which is characterised by the presench m,lf.nms:d/ausj 8 -e of 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 measurrs)hupis+2w 1g* qjy- ing plant growth. A study was conducted on white onions (Allium cepa), under controlled conditions in a lab, to investigqphrs 2g*y1uiw- )sj+ ate 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 di7 a).d;ujb dttr ,j gzwaa:u;7vide. The diagrams below show two cells from an t,agjuab;j7w .t )r; z7uad d: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 expn 8nj:u2 rr/sdression 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 8i c:ed9tnc1e f7 dkro1j772li, in different stages of meiosiodtd77cr 97f li2:ei jecnk1 1s. Which row correctly names each stage?

  The micrographs show four phases of meiosis I in a p5te1lib/ w 9solant. In what order do these phases occu eol59i1w /btsr?

Mitochondria are responsible for qo3cc6lb d )8x*hjv5 zsupplying 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. It has been suggested that, in some eukaryotic organi)qj3 zocx v58 dcb6l*hsms, 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 cells in different stages otg3ky6 0 n5iubf the cell cycle in four samples of lung tissue from four nit3 y06ukbg 5patients. Which tissue has the lowest mitotic index?

  The diagram shows the dom,vw0jh o* 90vm 1dh9+wup i8i fxq+ovlinant cyclin/CDK complexes at different time points in the9,quii h dpm o1h9* +w8vjfvv+wolx00 cell cycle. Which cyclin/CDK complex activates DNA replication machinery?

  Studies have shown that genes such4t,s7 /6hgrcl*g4hw*fv1 d vwqh(qoa as Cyclin Dependent Kinase 3 (CDKN3) are highly overo,rhv* tqfw6qhc4/7lwad(4 *hv1 g sgexpressed 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 the3yd )2d)o wpwsg22zps7 uwtw: highest during the cell cycle ?