The graph below shows:8-it e y+ba5ubcvwyl3 d(x3n the relationship between maternal age and the incidence of non-disjunctio:y 3 v5(tyxb-ad bw3i8n ulec+n. What relationship is suggested by the data in the graph?

  Which stage of meiosis is represens6f7m aa wbg(w*xp9v3ted in the diagram below?

  The diagram below shows chrox tuo/e93e tm1l t;4ysmosomes 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 nuf*j7( v, qhsbgp*.y4qtx(gne mber of alleles of a single gene which would be present i fp(sh(n, 4be.qgq7yt **j vgxn the nucleus of a cell as a result of each process?

  Which keyword is matched to the cnr0/.x4mx k5ti.1oyrg sab1u l3zx3rv : g8sz orrect definition?

  Which statement(s) about mitosis is/are (gn6 no 7k88u*cz,ux1cl acsatrue?
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 p7yyp;- xa p; n;yujgx(oints to a cell in anaphase?

  During which stage of mitosis does ts 21c rgn/ s)w7hgf+c0(ttvojhe nuclear envelope break down?

  Which one of the following transport proteins only carries our ru. + hmr0xx/u*ug,bt active transport?ugr+ ,rx.*hubxm /0ru

  Which process does notu( /4m)mskzd69zds vl happen in the shoot apex?

  Which type/s of memb xvb4r(e6 8rdjrane transport do/does not require energy expenditure?
I. Facilitated diffusion
II. Active transport
III. Osmosis

  The diagram below represents a cell with a diploid number of 4. Which staggk o1jp+n3 p mch(r*0sn)9kxu e of cell division is the cell curos9*ux nghm n(01p+pkkr 3 c)jrently undergoing?

  The photomicrograph below shows a root tip meristem. Which of t zxr(e ip,qk 87)jgt2ihe following sentences co7ji(rg,p k ztqix 2e)8rrectly defines a meristem?

  When does the random orientatiop nayf(:nh; x1 voq 8v103rdoyn of homologous chromosome pairs occur?

  Which process does not occur during meiosis?b rimq0oqqjp s /52 f6tl8uc1c 1h97sr

  If a cell with a diploid number of 36 undergoes mitosis3qobio7h1pg.yb u;f e61hy0z, how many chromosomes will be present in each daughter 370 y yeub6h1o.bhzq1gop;f icell after cytokinesis?

  The image shows a micrograph of1/iul tvfoe; 7 a cell.


What explains the appearance of the cell in the micrograph?

  Which statement(s) about homologous chromosomes is/are not tr+ qkk /y4:+neonjq9ix ue?
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 w bl (/o c)1eglzoy/u(g(qqc7dith Down syndrome.

Which statement is not correct?

  In the cells of a horse (E. caballus) during prophase I of meiosmda 1nxxq5*(jvaw+)ris I there are 64 chromosomes. Whxmaqx(dra 1*v+nw j)5at is the haploid number of chromosomes?

  Which arrow is pointing to a chiasmtm f9gii (3.ow(3u pjza?

  The diagram below reprem* .tn9gf )dcnsents the structure of a shoot apical meristem. Which row in the table correctly identifies the processes occuring in*mf) ng 9c.tdn the structures labeled in the diagram?

  How does meiosis promote6qk q7tq0gjs 5 variation?

  Which of the following statements+ gnuc5i .x 5-bmydy1o 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 prod9a nhf31* zytfuced 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 the formation of seco :ph9l0nftr46n8dx kvndary tumours from primary tumours as a refd0nkvlx:6h tn p849r sult of the movement of cells?

  How many chiasmata are yh *vihkd)e +dbfg+n72 .b ih8present in the diagram?

  Which statement is a similarity between cytodh2zp; zll+nz 0i:w x(kinesis in animal and plant cells?

  Which stage of meiosis is matdjhd6zo 5.x n6ched to the correct description?

  Which statement(s) are true o m leki *5oo;up6eu11hf meiosis I but not 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 fi nh,opvaud:/u/8v 9d zrst meiotic division. This results in the formation of one large cell and one small cell. What is the fate of the large ca 9nou8/z,udpd: hv/ vell?

  Which row correctly describes diploid and haploid cell:;+l.exq(1 f +tbmyvmoos*:nbx tyr 4s in humans?

  The following table shows the diploid chromosome number of a range of spesvt(ma 4;-fh;f j/oxk q9:qxhcies.


Which of these statements is correct?

  What conclusion can be drawn fro:i,o s8e fx,gj3 jiru)d75akhm the karyogram below?

  Which of the following processes is cha+qk/.eqkrs8 yd7* eeyracteristic of the meiotic and not the mitotic cell cycke7/q.8s*edq yey+krle?

  The diagram represents a bud with a shoot apical m. axov( tw.js9xa5b2 nnby 7r1. oqc;deristem.

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. qoi74dd,xr;f ijj l.- Which row shows the correct chromojo,; l7. -j i4ixfdqdrsome number for different cell types and cell division stages?.

  At the end of which phase of meiosis I does croerm1uyq(qy,2 *ew 0nn,i u1gxssing over occur, and what is the outcome of crossing over0 2y( wmy1eurqnqxe1 guin*,,?

  Which of the following statements does not describe a step i8yv5/;panji i n the sodium-potassium pump cycle in t8 /;v pi5niayjhe neuronal cells?

  Which row in the table below is true of meiosis?izo/ 4xz4wu fa hfa548

Membrane transport is important for allowing particles to move across34c2kdvdugwxl97*k x/ u( hkd the cell membrane and respond to changes in9kwuu/h4( d3ckl kxv2dd g*x 7 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 i df.6d*8 ltuc .pa*:g;j1mf,fu z opyis regulated 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 )j8 v l+ mbkjpb.)oe2m8 xp7 ;w3juw)j6 rlaueduring the cell cycle. Which cyclin is involved in preparing for DNA replicatioe+j)aw p8)7;b6m mo j2.b wlj8ulr3j e)uvxkpn?

The diagram below shows chromosomes during meipt)l3rm cc2 2xosis.

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 homol5q93 vvhmyh7d t1m/gzm 7mh7cogous chromosomes?

  The mitotic index of th t27c xmt)r2pzs+)qf hfr6 9jzroat tissues taken from 4 different patients is shown below. Which patient is most likely to have cancerous throat tiss+rfc )rzz97s t xqp2f m)t2hj6ue?

1.Draw a labelled diagram to represent the process of crossing ov oz8:bl ts y0mrb-:z+ber.

2.Compare and contrast random orientation and crossing over.

3.Outline the stages of meiosis.

  The image shows an abnormal human karyoty3-t 4n(pttajype.


What is the abnormality in this karyotype and its cause?

The graph below shows the relative amount of DNA in onqktqgrz l)i c 6+3.s:ae cell during one complete cell cycle. Each letter represents one stage o3kc )l6zg.s:arqi qt+f 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 th9ry;r fxfu57 4ajv:h: 8 pucuwf0r;that is homozygous for brown, long hair and a female cat thatr4t8uxj5vfu;a:h9y r7w ur0h cf:;fp has black, short hair.


Which of the offspring has a recombinant genotype?

1.Outline how polygenic traits can show a normzwn,qf8a51 k20 qjmgpal 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 cro0arhpmlqlo+3r 6 e-dww/z ,2yssing over of non-sister chromatids shown in the diagram belowoy adre,l lm z26 /pw-03qhr+w?

  The photomicrograph showiowxgq 9+kbi6, ,p3a7gdiech 6zt4p/ s a pollen grain from L. candidum (Lily). Which stage of meios4k, gaz3o7i+q pid 6gcw h9,e6tpb/xiis is shown?

1.Outline the events which would lead to an individual brt uib0 7axrjs ((;ae+eing born with Down syndrome, whicb+ as(r70ie;jxu a (rth 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*c g8gsh n siiguhz/ocf ) cb,;o06c+2 way of measuring plant growth. A study was conducted on white onions (Allium cepa), under controlled conditions in a labicfs nzobh6+ 8cg ;20,ghg su)cc*i/ o, 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 +ywr lnrrc bh*/3pa7 v uee(;3diagrams below show two cells from an organism with a diploid numb /3e+e rruvrc; pwbn(7*lhay 3er (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 x d o8v)x0fml- l5raj: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, with a diploid number of 8, in differentdg*b e6eim 86e stages of meiosis. Which row correctly names each stage?m6e id6gb8 e*e

  The micrographs show four phases of meiosishjw p9m bcpx. .vit8;, I in a plant. In what order do these phases occur?..bmvxij ,ptwcp98 h;

Mitochondria are responsible for supplying metabolic energy inua9dg+zkiz .9 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, inherit 9z+.a9zdkgiu ance 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 diff8a v5sd vxm(*cerent stages of the cell cycle in four samples of lungc5*(m asvdv x8 tissue from four patients. Which tissue has the lowest mitotic index?

  The diagram shows the dominant cyclin/CDK complexes at dif9ai wkj )m5e (z3og6yuferent time points in the cel9mio3ya(5 u)e zkgwj6l cycle. Which cyclin/CDK complex activates DNA replication machinery?

  Studies have shown that genes such as Cyclin Deph kz+bsc9zspv5j9, * cendent Kinase 3 (CDKN3) are highly overexpressed in cervical tcbspch9 skjz5z + v9*,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 concentration of cyclin E the highes f:l*s)kbk pl9t during the cell cycle ?