The graph below shows the relationship between maternal age and th1xk/.36jjodx3pcjxe()f h1i pkyd04/h un khe incidence of non-disjunction. What relationship is suhji/y3f d kx(h1ojukh xnj)p .0dxp364e 1/ckggested by the data in the graph?

  Which stage of meiosis isjxx;umt;ne:smfb*z z6d+wc1/y--gn dx z0 m 0 represented in the diagram below?

  The diagram below shows chromosomes+,ypp z5-vr xw-3 sugy m2jnw8 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 alles;1 f46us9chj9u w.5glgyhnules of a single gene which would be present in the nucleus of a cell a6ygsj 9;lg4w s9uf hhc51unu .s a result of each process?

  Which keyword is matchem+pgnf i :5wp3d to the correct definition?

  Which statement(s) about -jq2rgxeh+5c4hjtg4l8bs,xj x4 d 4ymitosis 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 beloo*8u jdadl6k(x / 3jxpw, which letter points to a cell in anaphase?

  During which stage of mitosis doe 4(qfz ay7bki*8s )gfjs the nuclear envelope break down?

  Which one of the follot1xdmx* wn ugq:bo6 + 9kdw:2rwing transport proteins only carries out active transport?o9g wdwrmu6x1k:xn+d *b: t2q

  Which process does not happen in p/8 kt wkeew66 )sg4kj,m5 tnfthe shoot apex?

  Which type/s of membrane transport do/do59kwx,lvri( ok atwc( 4/xs;qm5c9ries not require energy expenditure?
I. Facilitated diffusion
II. Active transport
III. Osmosis

  The diagram below represents a c suoc8-5b5e wx3 efxl7y9: bdqell with a diploid number of 4. Which stage of cell division is su875bldofqcb 9xe3-e yw:x5 the cell currently undergoing?

  The photomicrograph below shows a root tip meristem.8onj9r..wmhik91 jj p Which of the following sentences correctly defines a meri8 9 hwkj1jpm9r n.j.iostem?

  When does the random orientation of hsm 56*69dh.tih up8jlo (n isfomologous chromosome pairs occur?

  Which process does not occur during meiosils 9wlq6 pmg*p:2xg :is?

  If a cell with a diploid numbere,kvpi ;gg+s6 of 36 undergoes mitosis, how many chromosomes will be present ingi,+ 6gke;vsp each daughter cell after cytokinesis?

  The image shows a micrograph ofs lpeqt6ebzm:. mm5tw (ldl )m)). mn- a cell.


What explains the appearance of the cell in the micrograph?

  Which statement(s) abozcylp06elt)/ gh-0ibut 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 individ0f -ygvlo0 (u 4ktwkv)ual with Down syndrome.

Which statement is not correct?

  In the cells of a horse (E. caballus) during prophase I of6x1 u oyokd)8)i.0xt xrol2cg meiosis I there are 64 chromol8c10 y x io6)xrdgt.2kxoo )usomes. What is the haploid number of chromosomes?

  Which arrow is pointing to a chiasma? n xm9bzc uap7j; dk oa.ce*h:o.i;7*q

  The diagram below represents the structure of a shoot apical meristem. Whrrga,n 2ttc3bik9hh5d*) 8gj ich row in the table correctly idenh djgn 3r25,g* rcikb)taht98tifies the processes occuring in the structures labeled in the diagram?

  How does meiosis promote v. wk-kafa qm5jt/a+9msu) wb(ariation?

  Which of the following statements is/are correct fem(rp bth xv28mld /*6y:b+ dtor 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 5 k;pi,)w lxyohomologous 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 primary tumours asj ti sha(t)3y wv;-37uwl-mbq a result of the moveme(tmh tilw-wq7s;3 )yub3aj-v nt of cells?

  How many chiasmata are presentone)m4.nm 1og gwnmb k*6 )5um in the diagram?

  Which statement is a similarity between cytokinesis in animal and plant cellx4s/ rkgwstr36ek 1 g0s?

  Which stage of meiosis is matched to the correct descriposc jts u+.,yfbpgid) l5 wr+ 4:-l.khtion?

  Which statement(s) are true of meiosis I but not mefd+ f se/ 5hv3pir8xoimo4(*n ;zb6jjiosis 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 mlr i1,zkb;ft*cdw8i36qt:x -rg 6 ac results in t*iiqad6 8k x;rgw3-6l:tzm, rbf1cc t he formation of one large cell and one small cell. What is the fate of the large cell?

  Which row correctly describes diploid and haploid cells lkrl 7za34xgrh3 .- lpin humans?

  The following table shoqh mde x;mjco q-;o/*mf/e 4o/ws the diploid chromosome number of a range of species.


Which of these statements is correct?

  What conclusion can 5 q, isxmx+5jnlrff5h 3(n i4zbe drawn from the karyogram below?

  Which of the following pp9z ,r j01y fwvt/-jutrocesses is characteristic of the meiotic and not the mitotv,-ju/ztj fy wp 0rt91ic cell cycle?

  The diagram represents a bunii(lfco o81 4d 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 (Pan troglodyte g8q9*56s zvrvvm2kfx s) is 48. Which row shows the correct chromosome number for differenv m 9s8*2zg5rvvk x6fqt cell types and cell division stages?.

  At the end of which phase ofsnvann2 4: -cw4;y- icwskzy2 meiosis I does crossing over occur, and what is the outcome of crossing over yc - :si ;aw4csvyknz2wnn24-?

  Which of the following statement, 0elic)s8ym 8psyg1ottb8i5 s does not describe a step in the sodium-potassium pump cycle in the netyc)81t8i y gpl, b8ossiem5 0uronal cells?

  Which row in the table below is tru*di1pr9p(;qj syzkgk5m6xe *e of meiosis?

Membrane transport is impn4fukz)k, -j wedl*y; 6 yil2m8ozs ;uortant for allowing particles to move across the cell membrane and respond to changes in the chemical compositio4dwy-zumf;*u,)ln2ksk 6 j yio8 le;zn 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 m q-e34lzl7gte 6rs /gcells.

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 show,zcm,(z k0 qyas the concentrations of different cyclins during the cell cycle. Which cyclin is involved in preparing for D,kyzc,q0m (zaNA replication?

The diagram below shows chromocjc; n lhim uhk(oo4;:o:j.p 6somes 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 chqk pkhw7 2*b(uromosomes?

  The mitotic index of throat tissues taken from 4 different patients isdd:*qis0. j2ej im+55a mnbkb shown below. Which patient is most likely to have cancerous t m5 qa +ekd bji0m5*.d:sib2njhroat tissue?

1.Draw a labelled diagram tspxs/;dc ee +2jca;m+o 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 hu9yckg-d p)gd 4man karyotype.


What is the abnormality in this karyotype and its cause?

The graph below shows the relative al31u2- kmnao32:i1g nzn equ cmount of DNA in one cell during one complete cell cycle. Each letterkauq:2 nm3lc2u3nnogie z11- 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 maku:*o 2j jxdnt;c*f*pc 8z,hble cat that is homozygous for brown, long hair and a female cat that has blahxb:8z, jc;pu f*j dn o**kt2cck, short hair.


Which of the offspring has a recombinant genotype?

1.Outline how polygenic traits can showh+:mixv)v;uf2fy,z s , t7qsy 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 non-sister chromatids q p7al)2inc/ 8pxuk7tshown in the tp 7cpnl2ku) ix8aq/7diagram below?

  The photomicrograph shows a pollen grain from L.0()l20flrw(xb bqq mn candidum (Lily). Which stage of meiosis is s2l0r(xnb0)w qqlbmf(hown?

1.Outline the events which wou+u(y:b) 4q luwv 8fexuld lead to an individual being born with Down syndrome, which is characterised by the prese(efx uq:b u)+8wvu4 lynce 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 measuring , ikhd p)2s/, 8fiyzvql d8eob*tzx92 plant growth. A study was conducted on white onions (Allium cepa), under controlled conditions in a lab, to investigate the effect of soil pH on the mitotic indextyfo*zxkq8/ez98) ,l2 did bs2,ihpv 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 e.j u;mfok** +m0 fyasare two ways in which cells can divide. The diagrams below show two cells from an organism with a diploid numbem*o f0+s m*kuaj;ef y.r (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 exprei:7 hs tx--xj,;oqdcm ssion 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, in different stagesf,oc 37mk5petn:q ahygs-:0a of meiosis. Which row correctly names each stag,0nk3tf e:ycqo: m gpsa-ah7 5e?

  The micrographs show four phas 3c1vn5 hlk/hses of meiosis I in a plant. In what order do these pha1hcl/ vk35 snhses occur?

Mitochondria are responsible forf+xi8jrg b2;p 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 eukar8pi x fg+jr;b2yotic organisms, 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 of thevr -/hbtf-e 7f cell cycle in four samples of lungtrvb-e f/7 -fh tissue from four patients. Which tissue has the lowest mitotic index?

  The diagram shows the dominant cyclin/CDK complexes au j k)xntn6hiv+21 cq.t different time points in the cell cycle. Which cyclin/CDK complex activa+j6tnukx )hc.nv i 1q2tes DNA replication machinery?

  Studies have shown that genes such as Cyclin Dependeohjm g51t mtdj)/o5 +/ (m) ) vqjaum,lvubfl*nt Kinase 3 (CDKN3) are highly overexpressed in cervic ,f v+amg udqtm ovlmomtju5/b( j)) /*l)51jhal 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 concentrai ra3/pwkose4 fh ,4t7tion of cyclin E the highest during the cell cycle ?