The graph below shows the relationship bew1pt .stm ;dz2tween maternal age and the incidence of non-disjunction.zt. ptm1d ;ws2 What relationship is suggested by the data in the graph?

  Which stage of meiosis ic,w.qqkjh7 :s s represented in the diagram below?

  The diagram below shows chromosomes durib pskef,nd* ea7182l*q wewb1ng 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 achdbb //h9l( gene which would be presentd cl( /abhb/9h in the nucleus of a cell as a result of each process?

  Which keyword is matched to the correct definition 3bgcfgpzt-c szr6 zf,3ua -9-zw29gu ?

  Which statement(s) about mitosis is/are 39ca af8s+pm7uwjf /dn2;pne 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 below, wa lq 4/9-wl:rq xp0om5qspncb ,am2b/+z, lsphich letter points to a cell in anaphase?

  During which stage of mitosis does the nuclear envelope break down?nx+vi4etunr-n) (w c-

  Which one of the following transport proteins only carries out active tr rqe9 l9j)cuc.rzvq; 9ansport?;) ev999qcu .rrjqlcz

  Which process does not happen in the sk6 (wso) a7ya p9+t7f-shh-jo0fawythoot apex?

  Which type/s of membra jz qo7k43etw3ne transport do/does not require energy expenditure?
I. Facilitated diffusion
II. Active transport
III. Osmosis

  The diagram below represents a cell with a diku*d*4k ux /myb:-wmoploid number of 4. Which stage of cell division is the cell currently undergoing-/yk mmbu4w od uk:**x?

  The photomicrograph below shows a root tip meristewhb w ;2o;ge p d+nfay:/rej+w3cv/+jm. Which of the following sentences correctly defines a meristem f +n;epe+cj3v+/ oh:gj/2d wbrayw;w?

  When does the random orientatioe ,fh)ja4t q(nn of homologous chromosome pairs occur?

  Which process does not gq9qhcq +cw7:r+v5njy /h7 cyoccur during meiosis?

  If a cell with a diploid number of 36 undergoes mitosis,v *46z6 adtnci how many chromosomes will be 64 c a6itzd*nvpresent in each daughter cell after cytokinesis?

  The image shows a microgaj8jye+:zwcr:0 (g)n nh2 iwgraph of a cell.


What explains the appearance of the cell in the micrograph?

  Which statement(s) about homologous chromosomes is/are not true e-bz4wb8g b1,wflm 0t?
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 s*oilw7ye .k 7is3ig(individual with Down syndrome.

Which statement is not correct?

  In the cells of a horse (E. caballus) during prophase I of meiosis I there are 6bmt1 euiq k3ed r70+;u4 chromosomes. What is the haploid number of u0br q;1k e+demui37tchromosomes?

  Which arrow is pointing to a cz4o7ahhi5yw 4 hiasma?

  The diagram below represents thej2 h+abyc trejp . .tfc8:z1z0 structure of a shoot apical meristem. Which row in the table correctly identifies the processes occuring in the structures labeled in +e htczaj8.b1j 0:. f2ztr pycthe diagram?

  How does meiosis promote variationz:/xati w)uf /?

  Which of the following statqq.jfo v35 vwplq:9s1 ements 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 from wxa/nq ivk8,6rau zbb ; :30wxtwo 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 p*bm-0jduyg**; 4mjanx nms +kui0hi: rimary tumours as a result of the movement of cellsa;h bmgm0i0d-*4sj *nn+x *ui: kuyjm?

  How many chiasmata aro 89 3;x /wwcplonpyf2e present in the diagram?

  Which statement is a similar 53hgy, p:tog8grqmp xp 1,oz2ity between cytokinesis in animal and plant cells?

  Which stage of meiosis is matched hscn3z l-pb.8f. 6l r7dear k9to the correct description?

  Which statement(s) are true of meiosis I but not meiosis II? :8p bkph 4mai l1;h8gw1f ;5p wvhd8cn
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. Thizlllc 5+,dt h3wm9:zp zo9h ;qs results in the formation of one large cell and one small cell. What is the fate of thel3mo59 zhztlhq;zdwc+,:9l p large cell?

  Which row correctly describes diploid and 0e3 phbt tc:k2haploid cells in humans?

  The following table shows the diploid chromosome number of a range of ss8tq7 5 f.sdmlpecies.


Which of these statements is correct?

  What conclusion can be drawn from the voa36 q)l7 z8i/ mhsvokaryogram below?

  Which of the following processes is characteristic of the meiotic and not the mpl)g u * -lg;5uoaz-tq u;hcr,itotic cell cycuug ;,ra-pthlog; l)uc*qz 5-le?

  The diagram represents a bud with a shoot apfqb p:jwdlza s.z38h)ib7rfx39 6 ya 7ical 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 rj*ti x3x)xiy/ 3ixjx4zk 9+mlow shows the correct chromosome number for different cell t4xjx/3) xyxim+jik*z 9 itx3lypes and cell division stages?.

  At the end of which phases + uqo/.j b/pt,a/mkm-b4jxx of meiosis I does crossing over occur, and what is the outcome of crossing btj4 qjm/. x/x/+sb ,ap-kumoover?

  Which of the following statements doesf 9l:elcxqgw3va 4v lsjq71; ; not describe a step in the sodium-potassium pump cycle in the neu17qwq j c9lv gl3v:xe;4a;lsfronal cells?

  Which row in the table below isn/yzp43 n) h24c p dwowv2w0zr true of meiosis?

Membrane transport is important for allo, - sg:zol z5k+u6lmxmwing particles to move across the cell memb:zuoms6+g5xzl k ,-mlrane and 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 is regulated in cells.9au 0 ;dzpgrozx/u +..tyt 6fg

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 during t0orh58*lnhqo f:wkr) he cell cycle. Which cl:ohw5r *0nf)r8h k qoyclin is involved in preparing for DNA replication?

The diagram below shows chroovmj9t ie6oer g0qg-2xhol i+gp( ; arz ;k.(/mosomes 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 ofegp h.fzepb)akj pm5 ) hr10*bcx7l86 homologous chromosomes?

  The mitotic index of throat tissues tay -wd;ht)dh.b5 7abnv ken from 4 different patients is shown below. Which patient is v )w;h.n5hadbyb t 7d-most likely to have cancerous throat tissue?

1.Draw a labelled diagram to represent the processrkh (:cgcv )c/ of crossing over.

2.Compare and contrast random orientation and crossing over.

3.Outline the stages of meiosis.

  The image shows an abnormal human karyotypepz7v9gie9ug x3tywhp:;s c+ o81us f).


What is the abnormality in this karyotype and its cause?

The graph below shows the relative amount of DNA in one cell dtyctf:n 7 9had( o+ip,uring one complete cell cycle. Each letter,y+c ah:i 9o(fndpt7t 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/-aglfi;.hc-jmv ffm 8oj4g: cat that is homozygous for brown, long hair and a g .m-ffi;-4 hj/oj8lf: cgmavfemale cat that has black, short hair.


Which of the offspring has a recombinant genotype?

1.Outline how polygenic traits can show a normal distributio6;w pjoy y4 p2hqqcb81n.

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-se47ebfeadc(a :h1 ke5a*d.5k mplm v2ister chromatids shown in the diagram below? ae da (kfdheb41.vap5l:e 2 m*7cm5 ke

  The photomicrograph shows a poll.: fzkq(.o1xcm9th uh t80(rq xu1d7 glyb5 cden grain from L. candidum (Lily). Which stage of meiosis is 1(umt g:dto7h 0c9x1 ul b8ck5rhxd(qy.f.q z shown?

1.Outline the events which would lead to an individual bi/shi q*u1 7kweing born with Down syndrome, which is chara1iush/ki* 7 wqcterised 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 indvf9t kl +wj.tys04ah +c0+ebxsxm9( rirect way of measuring plant growth. A study was conducted on white onions (Allium cepa), under controlled conditions in a lab, to investigate the eff0hjs t4xf+ewtya99v (rm lx+ sb +k0c.ect 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 cell5lk h,nc63-4hfv rtsk/m bhu47eb -ej s can divide. The diagrams below show two cells from an organism with a diploid nuk h-644h,h ke5-mb fuc7e3/bjt rn lvsmber (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 eba+mszeiwvcjcsngvl - 5w(-5.9 b y0f):h 2a 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, with7pv5 oedms,kxq(z7* w a diploid number of 8, in different stages of meiosis. Which7wv oxe7 ms(zkq,p5d* row correctly names each stage?

  The micrographs show four phases of meiosis I in a plant. In what order do thec*p*mhb 1xrgb;x ,1yyse phases occur? xy;*b* h1mybxp,1cr g

Mitochondria are responsible for supplying metabolic energy in eukaryotic cellck bb)m+uqoel 4v2; r1s. 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 result4l);2mue krqbv obc+1 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 of txrvn6g w.igiw, sux6ym6 +y ag(v:o0+ he cell cycle in four samples of lung tissue from four patients. Which tissue has the lowest mitotic igx :vxog us+yn6wiya.+ gwv6rm6,(0index?

  The diagram shows the dominant cyclin/CDK complexes at diffeqb qcws1o(p7. rent time points in the cell cycle. Which cyclin/CDK copb7c(1 oqs .qwmplex activates DNA replication machinery?

  Studies have shown that genes sasma mf v:js571z t2gzub*v :*uch as Cyclin Dependent Kinase 3 (CDKN3) are highly overexpressed in cervfa*5:js:msma1v 7t2v g*zb uzical 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 during the cell cycfk72n2. p3r qwb 1cgpole ?