The graph below shows the relationsr(ea*ow i8tq,hip between maternal age and the incidence of non-disjunction. What relationship is suggested by the*( ori8wt,qea data in the graph?

  Which stage of meiosis is represented in the diagram below?.kky9oz zga/q+uj(l;

  The diagram below shows chromosomes during meveuw, et fjt/( 7+r3rciosis.


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 orgooz8 y)ou:k1g ;d .t)v.g qjf a single gene which would be present in the nucleus of a cell as a result of each pvj:u.k odg ry q1ogz;)) 8ogt.rocess?

  Which keyword is matched to the correctjc* hj4c 4 7dhbh91fpo definition?

  Which statement(s) about j/u prsu7g 24s +)btwomitosis 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, wgrvpm+um(g 4p-bb 1*dhich letter points to a cell in anaphase?

  During which stage of mit-bfx/l-olq +0/uv thz ;9 cpymosis does the nuclear envelope break down?

  Which one of the following transport proteins only7 ur9vf8tx jnfax/v) *k9 ;izx carries out active transport?fn*f9vji9zk a/r7; )ux 8xvx t

  Which process does not happen in the shoot ap.6ch 5hu4x/dcr *bgk sex?

  Which type/s of membrane transport do/does not require energy expenditure? gb r vk+dk.l,.r*t.kg
I. Facilitated diffusion
II. Active transport
III. Osmosis

  The diagram below represents a cell with a diploid number of 4. Which s57rdl ,uc nvl;tage of cell division is the cell currently undergoing? lu7c5nvr;l d ,

  The photomicrograph below shows a r qsj- fk7z4qe wq5sul(pr.a)i)tz(y9oot tip meristem. Which of the following sentences correctly definesp5l) uqzfjsq4 w9z t(karqis. 7- (ye) a meristem?

  When does the random orientation of homologesj, -x3,tscz37hoh0y nq8mf ous chromosome pairs occur?

  Which process does nimqb1zoo(g,sbyfc 067vc c; * ot occur during meiosis?

  If a cell with a diploid number of 36 undergoes mitosis, how many chro9k34/;46cmv+hkosq fy u eezzu jr;(jb6 p-jvmosomes will be present in each daughters3 j v6pfkue 64(jj;qk;byevz+u4mr /c9 o-zh cell after cytokinesis?

  The image shows a micrograph of8 wn a*1fmoo;m9/beiw4r/cb q a cell.


What explains the appearance of the cell in the micrograph?

  Which statement(s) about xrb2 gd(y8 8 :-4dyrsrng:ku4)vkxm yhomologous 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 individuaog.vy5 q(s2gjl with Down syndrome.

Which statement is not correct?

  In the cells of a horse (E. caba 6 bd hcxbk-5z vhy 0fqg/y)e;wzk(7w,llus) during prophase I of meiosis I there are 64 chromosomes. What is the haploid number of chromok,y;qb( kgzhvwc) b yz5xdh 0-/7f6wesomes?

  Which arrow is pointing to a chiasmaepkx9z21f0r s ?

  The diagram below represents the structure of a shoot apical meristem. Which ip7ae b ,n6b)+d01ybbzxz n0 drow in the table correctly ident pny0 +)eb6b 1ni,zb d7x0abzdifies the processes occuring in the structures labeled in the diagram?

  How does meiosis promogkih l7aw18 tb2,s9 sjte variation?

  Which of the following statementsl2hzxei0-dvh f(rqat/ slu/ sb ;k;fr560i6m 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 7e kzhn2 l.3ritwo 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 tumours from primarif8 tzp:s:a 75uyegt 4y tumours as a result of the moveat4pz: f5ue7t si :yg8ment of cells?

  How many chiasmata are p -wje xnc96c gg82oq,cresent in the diagram?

  Which statement is a similarity between cyto7fnf 3ho,ovyy.k w5 um7n19q pkinesis in animal and plant cells?

  Which stage of meiosis is matched to the co +bh 0m+dqcom7r hbf():9vw mbrrect description?

  Which statement(s) are true ok/ 4 tdwga4bbp)( -wxff 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 t p8o:3cdujyv (he first meiotic division. This results in the formation of one large cell and one small cell po83v( yudj:c. What is the fate of the large cell?

  Which row correctly describeo g6 q4*gb n(i)t i60q:rzuvjts diploid and haploid cells in humans?

  The following table shows the diploid chromosome number of a range of species. y txz t +j4k(5sp6pii4


Which of these statements is correct?

  What conclusion can be drawn from the*e6 ag*:be- fufo ms;p karyogram below?

  Which of the following processes is characteristic of the meiot ff4zb9 v2 +*h+xz8m r-hxmvawic and not the mitotic cell cycl vh-+2 vffrawxz8mb 4*m hx+z9e?

  The diagram represents a bud with a shoot apical meristem. rg xg/1m6+e ep -9afeynmz)/ v

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. Which row shows isn-a,+. eo ltthe correct chromosome number for different celle. olit+n-s,a types and cell division stages?.

  At the end of which phase of meiosis I does 7iw2s +,d9ic ub/ugahwv 9q3i crossing over occur, and what is the outcome of hv/w+,ua2cisqb7 g9 w3 iid9ucrossing over?

  Which of the following statements does not djyi6 s/ :e9 0 g*uelnro84d5.rzdautpescribe a step in the sodium-potassium pump cycle in thn4lp86 0 e9uj g5tsydz u:rr.diae*o/e neuronal cells?

  Which row in the tablemc*v*/qc og) k1f(quwxm9 j7o below is true of meiosis?

Membrane transport is important for allowing particles to move across t wfp43;j( jmknhe cell membrane and respond to changes in the chemical comjwmn(3k jf;4p position 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 reghc)ij j:qf2j:bb j9uwi(6am/ulated 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 concentratb 6q1n6a;*t6yx+iatkm4v mm aions of different cyclins during the cell cycle. Which cyclin is involv mtt q6;y*n +4bam6am1v 6aixked in preparing for DNA replication?

The diagram below shows chromosomes duringkg /6+fj*njui ocf0r3 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 invd 7yg b 1sil-r: gonkadi((;h4olves the separation of homologous chromosomes?

  The mitotic index of throat tissues taken frobtidh(ymar 5)/2i0ts xh; hfou 5r/g.m 4 different patients is shown below. Which patient is most likely to have cancerous throaa 5ho/di;is u/t0r2mgth(.h x )y brf5t tissue?

1.Draw a labelled diagram to represent the process of crossing over.bh (n;j oj,dr:zm(,k x

2.Compare and contrast random orientation and crossing over.

3.Outline the stages of meiosis.

  The image shows an abnormal h- ppaax4 )rqa-uman karyotype.


What is the abnormality in this karyotype and its cause?

The graph below shows tbg 9ry:mbgy 6y4 1wkr2 u);inihe relative amount of DNA in one cell during one complete cell cycle. Each lekmy1 y;bg6w9y u)r:g2nri bi4tter 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 homozygous2 nis dr0rqzw( v;f8;a for brown, long hair and a female cat that has black, shovf s d0qi;;82ra( wrnzrt hair.


Which of the offspring has a recombinant genotype?

1.Outline how polygenic traits can show a normal distribution. n3:5onmruuhcu(p -2rw xu3:w

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-sistex pa)n q i3c48z,hmk.er chromatids shown in th3 nqm4x),8.kic eaph ze diagram below?

  The photomicrograph shows a pollen grain from L. 8yuq);/s lgtocandidum (Lily). Which stage of meiosygt s8;luo )q/is is shown?

1.Outline the events which would lead to a. voj3jh1h w.nn individual being born with Down syndrome, which is characterised by thejv .o.1 jwhhn3 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 measuring plant growth. A study was zcq0 sqnm4iz 7)xd0a0 conducted on white onions (Allium cepa), under controlled conditions in a lab, to investigate the effect of soil pH on the mitotic index of the roots. 0qsz )0zxmnqaicd047


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 below v,ammkiwmna *1i;g m: xg:a8je+7) uvshow two cells from an organism with a diploid number ua:7iex*1,mv:m ami; a+g wgm) jk8v n(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 expression ;zd xg/ gp63rqin 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 5m47ee *- ,qs +oizbf juk /pi,jhu+uhyuf:q(number of 8, in different stages of meiosis. Which row correctly names eac,-p+7f yh fzj/i+h:esuiu(m u5 qk4b oj*qu,eh stage?

  The micrographs show four phases of mf/ 13etvv ots)eiosis I in a plant. In what order do these phasee)t1of3 /tvv ss occur?

Mitochondria are responsible for supplying metabolic energy in eukaryv 1lmlhri* .)30v*oct ei ,ud )red0mpotic 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 reprodv301 htddir m .li)**)ueor,lve m0c puction 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 the celxbuv , 5ph ,s w2yms,zbdjh.57l cycle in four samples of lung tissue from four patients. Which tiud,7b.z2 vpwmh,55,sby hx jsssue has the lowest mitotic index?

  The diagram shows the dominant cyclin/CDK complexes at different time points a8 cf426dwsegin the cell cycle. Which cyclin/CDK complex activates d248 ag6swecf DNA replication machinery?

  Studies have shown that genes such as Cyclinsmi4wqv sw +4 21pe5c0*ytzz x Dependent Kinase 3 (CDKN3) are highly overexpress50qyicx * wt+z2w1m4s v4ps ezed in cervical 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 the cell cycz/vdpu: j.az sp4e -m/le ?