The graph below shows the relationship betb + acb.p meeby:t/ytt*yi6 37ween maternal age and the incidence of non-disjunction. What relationship is suggested by t7a3by */.y6 b: t +becmtptiyehe data in the graph?

  Which stage of meiosis is represenhfx3x54lmw; za/7 xxl ted in the diagram below?

  The diagram below shows chromosomes1 ay /uuc3gvfo), xxh z0oj8+s 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 gene wh1u- ,z5lokw yj),rrtfich would be present in f,yt,k 5)1wojrr-z luthe nucleus of a cell as a result of each process?

  Which keyword is matcg3dmurezbp 4foe2a 3*b v2c;.a gtd6+hed to the correct definition?

  Which statement(s) about mh vjw-33dtcpkj0d; g 2:r *clfitosis 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 below, which letter points to a cell in ana; hvv 5-f0yew w2+eqkdphase?

  During which stage of mitosis does the nuclear envelope break a 6h/i*vg vzh8down?

  Which one of the followi klh. 6 r*awip18qrhg1ng transport proteins only carries out active transport?hr*1l1 h wga86r.kiq p

  Which process does not happen in the sv/2oq*1 8i wjf rez(we9s ps3hhoot apex?

  Which type/s of membrane transport do/does not require e +-ys; +o+s(u vjjsg4dezm,cnnergy expenditure?
I. Facilitated diffusion
II. Active transport
III. Osmosis

  The diagram below repre79dv (h5kw3w0ll wa qnsents a cell with a diploid number of 4. Which stage of cell division is the cell currently undv(95hnlwa3w0w 7dq klergoing?

  The photomicrograph below shows a root tip meristem. Whzix s; o(swn;h)x.s0hich of the following sentences correctly defiz()0xhohns.xsw; i s;nes a meristem?

  When does the random orientation oxo ;jglx0-( mkizabrpy (+vax 6,p.(g f homologous chromosome pairs occur?

  Which process does not occj2r6i gdi b;2f0-mzfsur during meiosis?

  If a cell with a diploid number of 36 undergoes mitosis, how r1+u(6w g2yj:wynnf k many chromosomes will be present in each daugu21kwrf :y( ny+j6ng whter cell after cytokinesis?

  The image shows a microgr(j/ lt4esi ql-aph of a cell.


What explains the appearance of the cell in the micrograph?

  Which statement(s) about hlp*5t61nka rew6zxa (4v f fei;c.hn;omologous 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 individlo/b n z7/(oym /h79cq;oigsdual with Down syndrome.

Which statement is not correct?

  In the cells of a horse (E. caballus) during prophase I of meiosi (qo rcl cghd88*/1uok; - ;x*j3oll3k ddevges I there are 64 chromosomes. What is the haploid number of chromqlcg*3r*/-d8 oe h3djeok8 (dxc;k1go l;u vl osomes?

  Which arrow is pointing to a chit;v(xfx)/x3e- r uo w+bg*pm zasma?

  The diagram below repre 1rn vik1t)xh; .tk:vssents the structure of a shoot apical meristem. Which row in the table correctly identifies the processes occuring invnkrsi; .vh:t1 t)1 kx the structures labeled in the diagram?

  How does meiosis promote jua;s g5lo2ju0+g2 kbvariation?

  Which of the following statements is/are corrw7 7a6zmyxv)v .l;a6w r lc1jiect for meiosis?
I. It is a reduction division
II. It involves random orientation
III. It produces genetically identical cells

  The diagram shows gametz,ht9cx e9o*v:p fq-vk2,wx/ew pux9es produced from two 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 22 durn90lkdr the formation of secondary tumours from primary tumours as a result of the molud 92 d2nkrr0vement of cells?

  How many chiasmata are present in the diagr* m ,xc :kj7hf6x5hggaam?

  Which statement is a similarity between cytokinesis in animal ac9p 9u (i7y 8iuxxx1awnd plant cells?

  Which stage of meiosis is matched to the correct description?le k apa,oz)*apy n )j/ffy2u()i 81po

  Which statement(s) are true of meiosis I but not meiosisnkzd9ch, 480j iy0nvc 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 resuy;sk+j 2xwzp9 lts in the formation of one large cell and one small ce k9;zps jw2y+xll. What is the fate of the large cell?

  Which row correctly descrrqu,vqjge (6 4ibes diploid and haploid cells in humans?

  The following table shows the diploid chromon5c3rzlhwr t .khk-*92ul2 nosome number of a range of species.


Which of these statements is correct?

  What conclusion can be drawn from the karyogram belf 5v,lr.q1rqq ow?

  Which of the following processes is characteriv6w6 /j sg4mn,/rs cw9ntio*hstic of the meiotic and not the mitotic cell c/ 6wvm6s9t*h 4/ijcr nno g,swycle?

  The diagram represents a bud with a shoot apical meristem. 9 z;e1v pp3ime

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 / fxvrp9:-7joyx +lqc(Pan troglodytes) is 48. Which row shows the correct chromosome number for diflxyf- 7q +/oxrj:c 9pvferent cell types and cell division stages?.

  At the end of which phase of meiosis I does crossing over occur, 4tg z7b ptr00nand what is the outcome of crossing ovetnb7t4z0pr 0g r?

  Which of the following statements does not describe a k-l xbj0 r8jvoczx9+) step in the sodium-potassium pump cycle in the neuronal cellslj+rx8-j)z0xv 9 ob kc?

  Which row in the table below is true of meiosis?czuk).dy:xa 6 cali0/

Membrane transport is important for allowing particles to move across theo2 fln63rxe;5cvub f.8wr 51ut1szeu cell membrane and respond to chv6zbrw1;1c furn u.xtfe53u2oe8 s l5anges 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 r p1,d f1je-mc hcd41ieegulated in 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 the concentrations of different cyclins during t*s lbs2-dp52bdye t0 2yced s5he cell cycle. Which cyclin is involvt *2l 2e5d05dc b2ebdpssysy-ed in preparing for DNA replication?

The diagram below shows t*; cdb)qq;kfchromosomes 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 o-+yq0 fl, uy8;zhqjtuf homologous chromosomes?

  The mitotic index of throat ti qws pf ,sh3sf7 g2m2ul.uvd.(ssues taken from 4 different patients is shown below. Which patient is most gul 7p2w 2sfmd.(.h3,qvs suflikely to have cancerous throat tissue?

1.Draw a labelled diagram to represent the process of crossdi kqn.gj0ew ,e ;bv9q;:0mthing over.

2.Compare and contrast random orientation and crossing over.

3.Outline the stages of meiosis.

  The image shows an abnormal human karyotype. .7.eq0gpw pej


What is the abnormality in this karyotype and its cause?

The graph below shows 6-w4v0w bvduerh0m + nthe relative amount of DNA in one cell during one complete cell cycle. Each letter represents one stage of the cvh 6w+0d4bemru vnw-0 ell 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 showq*ero;axgb u0+uk90ws a cross between a male cat that is homozygous for brown, long hair and a*u+;w kre0gqo9xu b0 a female cat that has black, short hair.


Which of the offspring has a recombinant genotype?

1.Outline how polygenic trkkpcv xr g;40+um*(ea aits 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 non-sister chromatids sho9t 7 bd)aps mjni;/;mcwn in the diagrap/n;c saji)b;7tm md 9m below?

  The photomicrograph shows a pollen grain from L. candidum (Lily). k 3)o:3vxtfug )de/:hy g jwg;Which stage of meiosis ie: gotwkyu j xf) gg;)/v3dh:3s shown?

1.Outline the events which would lead to an individual be zhimi,-f; z5;c6ha 3 indutm2ing born with Down syndrome, which is characterised by the preseztm3ic;-ufh6 2h zm , a;n5diince 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 o9ki oz k+yx6-i n mq3g kte)9:n9kmo1qf measuring plant growth. A study was conducted on white onions (Allium cepa), under controlled co6ii)n+:q3kzy -q x nm9geotk9o kmk91nditions 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 diagrams ykq-kn3 2-g+7uy*p ykt7ohw ubelow show two cells frq3u+y-2 ywkghoktp 7u yn*-7kom 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 expressi*p+lvfd*cpvcl q,d, ms*b x)+on 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 diploi0 g2dqbcdn:m ,fa7 /ied number of 8, in different stages of meiosis. Which row correctly names eacq,0n7fi: em/db g2cad h stage?

  The micrographs show four phases of meimrgnz r/c2+ j3 m,tl)aosis I in a plant. In what order do these pc/2r zr mt,al)j+gnm3 hases occur?

Mitochondria are responsible for supplying metabolic enebs n qbt svx.(0t9sw0;rgy 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 hybri(vqs bss.0btxw0 n9t;d 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 jtdkuf 9;-cv0 in different stages of the cell cycle in four samples of lung tissue from four patienv j9- ;dftuck0ts. Which tissue has the lowest mitotic index?

  The diagram shows the dominant cy;+ *hc0 evp5ljvo,jo tclin/CDK complexes at different time points in the cell cycle. Wj;v0lp,+co5oje t *vhhich cyclin/CDK complex activates DNA replication machinery?

  Studies have shown that genes such as Cyclin Dependent Kinase 3 (CDKN3) au 6 -w /)79ahi7mr wi9tctddazfl*o 1pre highly overexpressed in cervt m )*fi6u77w9h91o/ plrdat-wcdzaiical 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 2p0k)a sej:lfroh. k*the cell cycle ?