The graph below shows the relationship between maternal agdl 1/macp 01ri5tr5o )hwkye8s1v ;i 40hszzfe and the incidence of non-disjunction. What relationship is suggrh 51zt )vw del5;hypik11iscz0f 0mso8ar4/ested by the data in the graph?

  Which stage of meiosis is represented in the diagraea vir(-6iad 6m below?

  The diagram below shows chromosomes durw-. x*dmc -tjjem/ :kfk,t dx9ing 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 singl(x xg;e )/adyre gene which would be present in the nucleus of a ;y aex (rxg/)dcell as a result of each process?

  Which keyword is matched to*rqr )u1xi o0a/fk ii4tvn; /m the correct definition?

  Which statement(s) about mitosis is/are truyg nq-n gc;:m4e?
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 to a ce2 x0jcka 7dz2)(mbxowll in anaphase?

  During which stage of mitosis dcb oin ri( :p3oupp74j db;+i-oes the nuclear envelope break down?

  Which one of the following transport proteins only carri1o,gu fo)wwz5.eio1 q es out active transport?ofz .g1q),wwo 1oei5u

  Which process does not happen in thepaacpf1,79 9/j2ijoojax9edof ;.. g+din j j shoot apex?

  Which type/s of membrane transport do/does not require energyk s-i. r-x ctj(autf 8a6a;7zl expenditure?
I. Facilitated diffusion
II. Active transport
III. Osmosis

  The diagram below represents a cell with a diploid0j,h7 fgqmt8g 2,rl cw number of 4. Which stage of cell division is the cell curreqj0m8 ggr,7f, 2th cwlntly undergoing?

  The photomicrograph below shows a root tip meristem. Which o+ek/ehf9 kq2 if the following sentences cor e9iqhf2k/+kerectly defines a meristem?

  When does the random orientation of homologous chromosome pa8vnwi. wr9il,irs occur?

  Which process does no:a k gwqz 5,fbrs(gf+1t occur during meiosis?

  If a cell with a diploid number of 36 undergoes mitosis, how many chromosomes4lekxi,gb uu1+, u uu5e/+xpu will be present in each daughter cell afteruu5 iuex,1uxg,u+plke /4+bu cytokinesis?

  The image shows a micrograph of a cell.m*iw;jle r .w,


What explains the appearance of the cell in the micrograph?

  Which statement(s) about homologous chrom4codrc ,hlb3f ym-z q8u0 94tgosomes 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 Down4q (p9 jogkh:+dsakx9 kl3b; f syndrome.

Which statement is not correct?

  In the cells of a horse (E. caballus) during zc y9fkoroz8 0i;ym6; prophase I of meiosis I there are 64 chromosomes. What is they;c zmooi08k9 fz;y r6 haploid number of chromosomes?

  Which arrow is pointing to a chiasma?o;y +engi h9 k+.v5c( vi iv:v-8leily

  The diagram below represents the structure of a shoo.i 9h4np 88larnvy+ ugt apical meristem. Which row in the table correctly identifies the processes occuring in the4.rpnv yh+8u8na lgi9 structures labeled in the diagram?

  How does meiosis promote variation5 j)3w hgkqe u+l1 )a6+.,xdmwgnfket?

  Which of the following statements is/ards 5 s ;h4ntr+uph+h)4 gq6pi)n7ezs pe 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 tw(ygnwr e3 ,5 :gf)gr7gg.sgm io 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 tumoqtp x,gsis rbqm4:m 0o.s*,k. urs from primary tumours as a result of th ob s*.iq0tpkxm ,s.gmrs:q 4,e movement of cells?

  How many chiasmata are present in wgjyit y3+idy8on ey4,8sd25the diagram?

  Which statement is a similarity between cytokinesisa)r,4 d9zzbyy 9qce y9 in animal and plant cells?

  Which stage of meiosis is matched to the mlps7.j mz(bs.10smisz-q3 q correct description?

  Which statement(s) are true of meiosis I but not4nbk )k d;wkm3r:hz s) 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 resk)k h 8eaxeojz7t n 1t.*tla31ults in the formation of one large cell and one small cell. What is the fate of the large cellt1xkajtt ohk78 3 nz. *1)aele?

  Which row correctly describes dqfes o 6t:re55iploid and haploid cells in humans?

  The following table shows the diploid chromosome nhv6scvj(q zo r/,6gk :umber of a range of species.


Which of these statements is correct?

  What conclusion can be drawn favy)8 8 ;tjaai b 4e:h/r0iwogrom the karyogram below?

  Which of the following processes is characteristic of the meiotic and not t4 c:yhlv0hdre ,ashss 6v-;gnx m)a,9he mitotv9):slysxn0s,rm ;c h aa,hevg4-6 h dic cell cycle?

  The diagram represents at,7*aifpclw v.oa8 s5 bud with 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 (Paf 9wxgsv mv:5v)-ws:a3y0sokc a.o5an troglodytes) is 48. Which row shows the correct chromoso9caas:m )wa.sg5:wv5 3vfvoy x0-ko sme number for different cell types and cell division stages?.

  At the end of which ph gvl4 (k: m75xfp.ed ef7yv(j 8rxk+chase of meiosis I does crossing over occur, and what is the outcome of crokveh:pg5(jl c.x xdfe v7+ m(4ky87 rfssing over?

  Which of the following statements does not describe a 8vimp v1 zgd( cg(2b1luu6p/z step in the sodium-potassium pumpzl pz/g 8mc(61 2vgu v(i1pudb cycle in the neuronal cells?

  Which row in the tabl3arjm)en*ol6 8q-s go e below is true of meiosis?

Membrane transport is important for allowing particles toz6jno3g) x 8(bcx + e5nciqxu )r.x0cv move across the cell membrane and respond to changes in the chemical composition of the extracellularex+rx nj0u6c . )5(3 xiccq)gbv8zoxn 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;docyt6qmltqs(- gq7s 5 ay,qy/x20d 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 therx1v wkaxb2;: -zxdp.cv m)m : concentrations of different cyclins during the cell cycle. x ;bc2mp zv.wxd )kv :r1x-:maWhich cyclin is involved in preparing for DNA replication?

The diagram below shows chromosomes during;n)kp*8hf d du*czvj8 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 t:f/; jlw3b zxtd3rx1 xhe separation of homologous chromosomes?

  The mitotic index of throat tissues taken from 4 different patients is shown bel6* a d)l(p q+yt(hp c6,rqahztow. Which patient is most likely to have cancerous throat tisshp (* z(qrhc,+tla pad6yq)t6ue?

1.Draw a labelled diagram to represent the process of crossing ov *k eol2q-ocoq6kw+a.d o*q t4er.

2.Compare and contrast random orientation and crossing over.

3.Outline the stages of meiosis.

  The image shows an abnormal humanahu4:yg- i(ntvfar: b y(fj4e+:oo 4c karyotype.


What is the abnormality in this karyotype and its cause?

The graph below shows t4pirh;ll0 w; ihe relative amount of DNA in one cell during one complete l4;lrhwp0; ii cell 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 hoho4- o-8ekttu ba 10ofmozygous for brown, long hair and a female c 4 oot-1- 8ftkhb0oaeuat that has black, short hair.


Which of the offspring has a recombinant genotype?

1.Outline how polygenic traits can show a nsioktf;o md:2 b0ww;x.:1nl t .hc1tqormal 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 heoxwkx; 2:-2ya6p wvcrossing over of non-sister chromatids shown in the diagram 6p;w-y vew ah2xkx:o 2below?

  The photomicrograph shows a pollen grain from L. candidum (Lily). Which +5;bc: 4otfpow fc7x hstage of meiosis is shownpox5bt ;f+:wc hof4c7?

1.Outline the events which would lead to y:f hyrco3nr,nk e :,.an individual being born with Down syndrome, which is characterised by the presence of three copok,yyrn,: 3.hn re:cfies of chromosome 21.

2.Explain how meiosis increases variation.

3.Outline the stages of meiosis.

The mitotic index is an indir i36 pa*.4d 9j/qmobk+ag gpndect way of measuring plant growth. A study was conducted on white onions (Allium g3a/9m aikpb+g *4ddj6on.pq cepa), under controlled conditions in a lab, 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 divide. The diagramdyg9 b8 sjap (wf(;1kb, wf)zds below show two cells frompk 1 ;jafsyd8()db(9wwbz,f g 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 eqkcpq:2(*nj n; q xvlo1-wm;mxpression 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, w 4*tp -mr, le2xp6peizith a diploid number of 8, in different stages of meiosis. Which row correctly names eachipelpzxe2- * 4,mrp6t stage?

  The micrographs show four phases of meiosis I in a plant. In whj90vtp2w h un lj(/,enat order do these pljt09n( /j,unv2he wphases occur?

Mitochondria are responsi0d8dqiv32qv fgt sw+o8 /,jw xble for supplying 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 organisms, inheritance patterns of mtDNA found in hybrid cells, which are the result of sexual reproduction between two different yeast species, could be influenced bq+/wxs fj83tq 08g,d wd vv2ioy 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 s : pbl,k5;sy jm)joc;ntages of the cell cycle in four samples of lung tissue from four patients. s5 oym nk;plcbj,)j: ;Which tissue has the lowest mitotic index?

  The diagram shows the dominanuuh*op:vw 16ra*; ekl9l7eh i t cyclin/CDK complexes at different time points in thel7uu*6*9 hlvrekwh ea o;:1 ip cell cycle. Which cyclin/CDK complex activates DNA replication machinery?

  Studies have shown that genes such as Cyclin Dependent Kinase 3 (CDKN3) are highq6y kg7f-rj 59iw x2lply overexpressed in cervical tumourspfgk2jlrq 9i-x576 y w.


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 highestqbvj ofv6h( /r+n bg91 during the cell cycle ?