The graph below shows the relc:ve )by *ek gg0 v6k8qb4ehy;ationship between maternal age and the incidence of non-disjunction. What relationship is suggested by the date)bhe4qg b6 ek8c ;*vgyky:0va in the graph?

  Which stage of meiosis is representze ti:9+ c)kkned in the diagram below?

  The diagram below shows chromosomes during meie 4p kz9yukra,-o u89oosis.


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 si e6)dx xpu4 k,9hyb+3w jei3ibxo p)r(ngle gene which would be present in the nucleus of a cell as a result of ehb3 kioiypd, j (px4e )x96x+3w)rubeach process?

  Which keyword is matched to the correct defina4n) auw0en20j.wodx ition?

  Which statement(s) about mitosis is 4g0g q qhv1g7 (fx1grlpo;:oi/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 c hsyj epa4,9 30rlezy :2oy-fcell in anaphase?

  During which stage of mitosis does the nuc.lza20 dgm;rk3jgh d *lear envelope break down?

  Which one of the following transport proteins only carr+m;s 7qbkl8 uyies out active transport?+s8 uql;bkm7y

  Which process does not happen in the shoot-rol(3- dsj:t4bpr uf apex?

  Which type/s of membrane transport do/does i)g8d le0,ltznot require energy expenditure?
I. Facilitated diffusion
II. Active transport
III. Osmosis

  The diagram below represents a cell with gw+u5j(2 m 5+r:4gobkg aeir ja diploid number of 4. Which stage of cell de54+io:r 5r uj2gjamk g (gw+bivision is the cell currently undergoing?

  The photomicrograph below shows a ro pbj ,ch)e2di:ot tip meristem. Which of the following sentences correctly defines a meriste2cd)ehb ip:j, m?

  When does the random orientation of btrt d78*hkmp3 evy 5e,vn2n)6wzad+ homologous chromosome pairs occur?

  Which process does not occur durin6) xg4-c(ud.gnyn. sxi qxm ;lg meiosis?

  If a cell with a diploid number of 36 unu 1t 57n bz j-v:isbay7tbmj;j1d71 rpdergoes mitosis, how many chromosomes will ybm 5dvt 7aj 71s1tr1:u j-pb7bjzi;n be present in each daughter cell after cytokinesis?

  The image shows a micrograph of a :k, fqq*-aj/z 6 wyiual 4*zurcell.


What explains the appearance of the cell in the micrograph?

  Which statement(s) about homologous chromosomes is/are not t(x bhp2mymet331hc (urue?
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 individualm4tr9 o0fg81 vgskzx 8 with Down syndrome.

Which statement is not correct?

  In the cells of a horse (E. caballus) during prophase I or+.kfr4 ffpd/f meiosis I there are 64 chromosomes. What is the haploid number of chro.ff/+d rrpk 4fmosomes?

  Which arrow is pointing to a chias5 6zcc4sho/h xma?

  The diagram below represents the structure of a shoot apical meristem. Which rojl9bj2px/nh k6o wz66 w in the table correctly identifies the proce2lpn9j6h6 x/o 6b kzjwsses occuring in the structures labeled in the diagram?

  How does meiosis promotej qqw/ ei)lvu,h (147q)brch e variation?

  Which of the following statements is/are7d g/k )m.e lmdsaf.i qhyx21: correct for meiosis?
I. It is a reduction division
II. It involves random orientation
III. It produces genetically identical cells

  The diagram shows gap2 c6fek5 c0cbkdi/ .tmetes 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 the formation2rm *+f ls/ 9tipwd5ah of secondary tumours from primary tumours as ma* +sh5t/2drw9f il pa result of the movement of cells?

  How many chiasmata are presentm9j/ (c.o6js)otm ij y in the diagram?

  Which statement is a similarity between cytokinesi(ozf7b/p s+mps in animal and plant cells?

  Which stage of meiosis is matched kg)-3/eixwk1:x cvsp to the correct description?

  Which statement(s) are t c9kktd-8 ;dy*/ mrn;nbos p8true of 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 ooej6q 4nrs3yq ,cyte after the first meiotic division. This results in the formation of one large qrj q4,s3n 6eycell and one small cell. What is the fate of the large cell?

  Which row correctly describ1ln ure6y2yi /8.ge1 pk1w huoes diploid and haploid cells in humans?

  The following table shows the diploid chromosome number o towwb7k /gf:ey0h: )af a range of species.


Which of these statements is correct?

  What conclusion can pg u+gi p0hn6+qny 7t)be drawn from the karyogram below?

  Which of the following process 1)rmp bo/r9nzes is characteristic of the meiotic and not the mitotic cell cyclero/bp9)m1rz n?

  The diagram represents a bud with a shoot apica+inol-t5n+qgrxd2;s r sm96a -3yno gn ) yc2il 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. Which row sho 1/bcws)xekv9 f stnko-lrs:.aiy2), ws the corrkv,)9bts-k :.ae/o 2wx1 ryicfs)slnect chromosome number for different cell types and cell division stages?.

  At the end of which phase of meiosis I does crossing over occur, anduomkz(vnq/;yi+7 iq- what is the outcome of iq zm/n+ik( o ;uq-y7vcrossing over?

  Which of the following statements does not describe a step in the sodium-potassik(iumgqp9otgr3 x02 3ks6-equmk t2 qrk6 gpxg0m33soque-9( i pump cycle in the neuronal cells?

  Which row in the tabl*mni 3bb/vnrko(/sl ,e below is true of meiosis?

Membrane transport is important fo h,zrf+ytk; a-r allowing particles to move across the cell mtyrh,- f;zak+ embrane and respond to changes 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 regun, t:iqkg9rczwx :/ )jlated 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 conce:tv vfewx;d-dk9a4e(57hmvontrations of different cyclins during the cell cyc4eo w7edv 9(5x:;h-a mvkdvftle. Which cyclin is involved in preparing for DNA replication?

The diagram below shows chromosomes during meiosis.r2c e /k/jju a4k3w mi8ijom5e+uki+(

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.xcz ,w7zgigo. lli,+ the separation of homologous chromosomes?

  The mitotic index of throat tissues t32cz: dz3va;ovu c +qgaken from 4 different patients is shown below. Which patient is most likely to have cancerous throat tissu2 3qud:v ;cgz+3 covzae?

1.Draw a labelled diagram to represent the process of crld4 w7nec(4,q*sius)jjj 5z m ossing over.

2.Compare and contrast random orientation and crossing over.

3.Outline the stages of meiosis.

  The image shows an abbpmhdpp6+j;67jxxg;uyw-5 ns/j :tunormal human 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 c21r-lg 4ndlcvomplete cell cycle. Each letter represer1d2vc4nl g-lnts 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 bet -rgt)zgo5, sf +c-ztti/wsr )ween a male cat that is homozygous for brown,or5 r+,t- i)s wg/st-fzz tc)g long hair and a female cat that has black, short hair.


Which of the offspring has a recombinant genotype?

1.Outline how polygenic traits can show a normal distribution.*dyndany:y w .,c4*l cinl0-y

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 shown exn/ ym6yhx(r84g:f nin the diagra xne4:hrm (/yfxy 6ng8m below?

  The photomicrograph shows a pollen grain from L. candidum yjx9bk n0a: w)(Lily). Which stage of meios0j ) nyw9bk:xais is shown?

1.Outline the events which would lead to a/w/q i r;ek8qsn individual being born with Down syndrome, which is characterised by the presence of threk/ ;eq8qws i/re copies of chromosome 21.

2.Explain how meiosis increases variation.

3.Outline the stages of meiosis.

The mitotic index is an indirevlt n- )6y670wggddmo ct way of measuring plant growth. A study was conducted on white onions (Allium cepa), under controlled co 7wvmo-g6ldy06d)gnt nditions 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 are3b pj99*i0 po-e dqvdl two ways in which cells can divide. The diagrams below show two cells from an orppqbie *99-0ddj o l3vganism 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 genee00mj(,*zykrk un; vg 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 cels9,)it6q v8djfq p em8bb 6fv3l, with a diploid number of 8, in different stages of meiosis. Which row correcf)8qt s6mqbijbvp 6f,v9 83d etly names each stage?

  The micrographs show fou) q5p(gq*m6b8rsact0qzb g:zk0) r c nr phases of meiosis I in a plant. In what order do these phases oc)z: )rm8sqk *6c g0qnbbc(zatr 5gqp0cur?

Mitochondria are responsi+)k qetmrak c1q+bd d.h1*tp3ble for 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 parentkddc. 3 +kbetam q*h +)ptr1q1s. 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 number of my1y/a qsxzo9.4;ye bcells in different stages of the cell cycle in four samples of lung tissue from four patients. Whbomy;qae/ s x .4z9yy1ich tissue has the lowest mitotic index?

  The diagram shows the dominant cyclin/CDK complexesu l-* ,xp c3:4u-ktsli+qaby wsvg /u; at different time points in the cell cycle. blui*pt/ss;l 3uaw:gx- k +uv4-,yc q Which cyclin/CDK complex activates DNA replication machinery?

  Studies have shown that genes such as)18 aypcm snjg+*b1 0cyyb z8g Cyclin Dependent Kinase 3 (CDKN3) are highly ove )sy0g1gzbnym y +8p 1b8ac*cjrexpressed 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 thea,s*3refhks)(kxize/ ry4: n highest during the cell cycle ?