The graph below shows the relationship between maternb -i),hdf+qjd)lb8qdg- onb* al age and the incidence of non-disjunction. What relationship is suggested by jqfig*) qdod8+bnb-hd l),b- the data in the graph?

  Which stage of meiosis is represented in the diagram -q iy4mz ul:*mdd8-s8j o6yj)k , ccxlbelow?

  The diagram below shows chromosomegz756ptf yt7yeu-1cdde )r (:z6zg t fs 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 num ruh yoysn b)g..)0xq/3d )cwnsnan27 ber of alleles of a single gene which would be present in the nucleus of a cell as a result of eaqu 7co) hs x)b03nr/awy d.ngnns)y.2ch process?

  Which keyword is matched to the correct defini5g 7mx; h0z;q7tu eboftion?

  Which statement(s) about mitosis is/are true? +t 0/7pfazec-lewz-q x)ng.a
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 anaphasb( 78(p zojnqke?

  During which stage of mitosis does the nuclear envelope break d(ozu2m +wzdh3 r ru8pyl* ml4*own?

  Which one of the following transport c tbigl **uif6ny ,*i/ ytc1 p(g5uwd*proteins only carries out active transport?*p*yi/5uc git*ilbgtfn cu( w61dy, *

  Which process does not happex7ib8tgf mm., n in the shoot apex?

  Which type/s of membrane transport do/does not require energyu8v48 zxhn rr-ug l e,(v4xc1h expenditure?
I. Facilitated diffusion
II. Active transport
III. Osmosis

  The diagram below repph..7kx qg1yh y kt.yi 5+:y okv*+jbpresents a cell with a diploid number of 4. Which stage of cell division is the cell currently undergoingy..*tpvk++ .:b qkphgy1 x7 kjhyi o5y?

  The photomicrograph below shows a root tip meristem. Which of the followi1ztqm qv )1na3mco-c3l .26ywo,ap dm ng sentences co dm6 3)w1onotz m1 lp 3m,qcyaa-qvc2.rrectly defines a meristem?

  When does the random orientation of homologous chromosome pai:zf2;- fh axysrs occur?

  Which process does not occur during meiox, qgtn m-l0a3eus(tc+81cq jsis?

  If a cell with a dipl e-6y,nrv:vl joid number of 36 undergoes mitosis, how many chromosomes will be present in each daughter cell after crn-vv 6y e:l,jytokinesis?

  The image shows a micrograph of a o7 c4ke +tn 3:6svzi p4j,pxovcell.


What explains the appearance of the cell in the micrograph?

  Which statement(s) about homologous chromosomes is/are nojzmix* 55r y1ot 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 Down syndrome-s xtn/u 89 lk .t+dg:sddzf2;fun1bg .

Which statement is not correct?

  In the cells of a horse (E. caballus) during prophase I of meiojf/ u/y i,mx(qsis I there are 64 chromosomes. What is the haploid number of fj(qy /mx iu,/chromosomes?

  Which arrow is point,tiw( /4o vkdjing to a chiasma?

  The diagram below represents the structure of a shoot apical meristem. Which rowe zxy(hvn+2(v vne2 h( zyxv+( in the table correctly identifies the processes occuring in the structures labeled in the diagram?

  How does meiosis promote variatioop v5 8v+ +lbnckyf:7en?

  Which of the following stayjfcg8 d)s( .fa2vb /c8php6ntements 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 two q6b* (hii v3of*9cwixhomologous 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 tumou946 czyvqg :g 52xtck o5foy8ars as a result of the movement of cells?fa8t 6ggkq9yxy45ocvz2c o 5:

  How many chiasmata are present inhr :,4s tfrdbt/fi1k. the diagram?

  Which statement is a s ;z da-ai(8tdsimilarity between cytokinesis in animal and plant cells?

  Which stage of meiosis is matcsxt x g-e)3x )a8p(xwyia86)r o2latohed to the correct description?

  Which statement(s) are true of meiosis I but not mey;8vqc7tfd 5piosis 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 mewblyg3 +gd0 l2iotic division. This results in the formation ofl 3+0wgy2db lg one large cell and one small cell. What is the fate of the large cell?

  Which row correctly describes diploid and haploid u*fs : z4w;-ffch2uoo993pikjtn9bh cells in humans?

  The following table shows the dipy8d 8g rh3mh:ploid chromosome number of a range of species.


Which of these statements is correct?

  What conclusion can be drawn from thi; m ad/ omh r0;us)1pcv xrky7-y8ot*e karyogram below?

  Which of the following processes is characteristic of thr rp-zg/mc9 iv:os0 o.e meiotic and not the mito zcog/pir-vo 09rm.s:tic cell cycle?

  The diagram represents a bud wi4zvak 16q1a w:v w vyvd1 3/yp4axf;vmth 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.yw; yptz2h-wrr g4e23tlm6q) Which row shows the correct chromosome number p 4)t -6g whlme2q;yy3 rrz2wtfor different cell types and cell division stages?.

  At the end of which phas:i+s hg:opb/j-:y vrhe of meiosis I does crossing over occur, and what is the outco:hbhrsoyj:vg /:+ip- me of crossing over?

  Which of the following stat vr4 wd.m;3wwdements does not describe a step in the sodium-potassium pump cycle i4 3dwrd ;wm.vwn the neuronal cells?

  Which row in the table below is true of meiosim2h8gzdt/ 2vp s?

Membrane transport is y-1sf7x(ls+unvh1bu important for allowing particles to move across the cell membrane and respond to changes in the chemical composition of the extrac-s7v xynub1su(h l+1f ellular 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 w*m2 -k, x:nb n(y9o tlw9amfzregulated 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 the celgm9u gku03fh*l cycle. Which cyclin is involved in preparig*0hu9fgk m3u ng for DNA replication?

The diagram below sh1k0loy a0dysga3l 5ffk2/ rf 8ows chromosomes 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 thet/ 4t/3njrkue r;j kawkv9o v0b01a0e separation of homologous chromosomes?

  The mitotic index of throat tissues taken from 4 differenz8kyv6vw0 (io t patients is shown below. Which patient is most likely to have cancerous throat tissueo zi vv86k(yw0?

1.Draw a labelled diagram to resis6 qumd3o, p.pj c,dn2nl- 0present 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 h, alh j kq7p75p/kocy4uman karyotype.


What is the abnormality in this karyotype and its cause?

The graph below shows the relative amount of DNA in one cell during one cz8h49w 9pq 9tryfy0xp omplete cell cycle. xpyw89p9h 0 fy9rz4qt 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 homozygous for b2pwd) fu 5kqt*rown, long hair and a female cat that has black, sh* kwdtq2)p5fu ort hair.


Which of the offspring has a recombinant genotype?

1.Outline how polygenic trabk3z yu 5z7z9rlf6wd 4e(gr,rits 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 ca v7asb5-.n.hvdkk 7 non-sister chromatids shown in the khvndk- vs7aca.b.75diagram below?

  The photomicrograph shows a pollen grain from L. candidum (Lily)f5 .)ii8dcdx.cne-fkpcm+ qm t- 9 h*m. Which stage of meiosis is- tm) kqf*-9.c5.hi m+c8i fecpddnmx shown?

1.Outline the events which would lead to an ind( u(ag yuxsi;h (ar7m(:1xwerividual being born with Down syndrome, wharhu17 u(; (msgeryi a(xw: (xich is characterised 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 indirect way of measuringiozan.lvyi d4(g n .3, plant growth. A study was conducted on white onions (Allium cepa), under controlled conditions in a lab, tn z nl.(i goi4d.y,av3o 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 u 1ztqlr h e+off7r7;3below show two cells from an organism with a diploid number (2 q+ f;7ur73efh1rolz tn) 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 expression ixdc xw -s,o(1w v5o;fbn 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 sho24kf8n*9wgeinoxo) hx) c t3(e cmvd, w a cell, with a diploid number of 8, in different stages of meiosis. Which row correctly names each s(f3 ))xt ,c og8donke* ihe9mv24n wxctage?

  The micrographs show four phases of meiosis I in am5w *ath vn64u plant. In what order do these phases 5vutna*6 hwm4occur?

Mitochondria are responsible for supplying metabolic energy in eukary8uu-az2u a; hlotic cells. In most eukaryotes, which reprau- zu28;ua lhoduce 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 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 nu k+ *629pyi/y ym8c vexpg*hammber of cells in different stages of the cell cycle in four samples of lung tissue from four patients. Which tis/ya6yp8my hc2vmxi *k9g* +ep sue has the lowest mitotic index?

  The diagram shows the dominant cyclin/CDK complexes at different time p4g-ra0hy . fq4dr7y ggoints in the cell cycle. Which cyclin/CDK complex activaty gy4g aqr74r-.fd h0ges DNA replication machinery?

  Studies have shown that genes such as Cyclin Dependent Kinase 3 (CDKN3) ar;e2w bfz8y v 3-ptbdkaf(v;)ee highly overexpressed in cervical tf)fazb e;b;-vvd2y 3tp8e kw(umours.


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 concentrati 7 zvt)yra+bl,, r,vjt)kg0eyon of cyclin E the highest during the cell cycle ?