The graph below shows the relationship between maternal age and the incidencen+ozekqscy;nl;: ; q 0n1z ci1 of non-disjunction. What rk+o;q0;1e: 1; n nzclyc sznqielationship is suggested by the data in the graph?

  Which stage of meiosis is representedluac3p;.; xx rr)6 1qwvetgo vw*st70 in the diagram below?

  The diagram below shows chromosomes during meiosis.;1 y n8ypfg)30uy yj-rag8mw u


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 allele+jx-qw4xm tcra o53pt .z*u85tbtnp - s of a single gene which would be prt tt5 jn5px8.+* -qxuwrpb mz4c3ta-oesent in the nucleus of a cell as a result of each process?

  Which keyword is matched to the qu *f6gitv45fr(yl y(correct definition?

  Which statement(s) abo :/a)/n1fad o0 fju.l19vvy3 mibvd jxut mitosis 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 anaphq: v1mr,8fg.)qjh an/yln;bk ase?

  During which stage of mitosis does the nuclear envelope5v5gnyyk : -;p prjij1 break down?

  Which one of the following transport proteins only carky-9sbjk h0+ kb iadr9bd:k-3ries out active transport?9-+ rk3kka:0sbd dijbb-hy 9k

  Which process does not happen in the wce 7ndrvw*z9f(j1 2pshoot apex?

  Which type/s of membrane tr5ijzjz: 6rr a;ansport do/does not require energy expenditure?
I. Facilitated diffusion
II. Active transport
III. Osmosis

  The diagram below represents a cell with a diplot-7z n+omp *mnsfc 0:1f8qbrqid number of 4. Which stage of cell division is th-b +nf1:7qm sptz0 8cqorfm* ne cell currently undergoing?

  The photomicrograph below shows a root tip meristem. Which of the s 2l um4,o:jjofollowing sentences correctly d ,l mojjo:us24efines a meristem?

  When does the random orieny)d2gb9. ycpcawk. hm y*/rr/ kw+(e ktation of homologous chromosome pairs occur?

  Which process does notp/inpn 4i *( cznb(vi1:jo ff9 occur during meiosis?

  If a cell with a diploid nuyju61vd2 (e)b k;8xdm a:nx;ybq nba: mber of 36 undergoes mitosis, how many chromosomes will be present in each daughter cell aftery) ::a6qe(axbudvn bkb;2dj 18 mn;xy cytokinesis?

  The image shows a micrograph of a celhhnd 2n x su:jpk3+/k3l.


What explains the appearance of the cell in the micrograph?

  Which statement(s) about homologous chromosomes is/are n3gdfgm8. 6 w0xj 7;w ctjvr.9nbaa 1i;efacy0ot 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 wxfysu, 4nmzb38+w gw1ith Down syndrome.

Which statement is not correct?

  In the cells of a horse (E. caballus) during pr7s*qd-4 l 6/w b9 zdkuu;idyfuophase I of meiosis I there are 64 chromosomes. 7; uszdbdld 4f*yq9w iu-k6u/What is the haploid number of chromosomes?

  Which arrow is pointing to a chiasma?v yvx)v6en f9()avx kfy*+i2n

  The diagram below represents the structure of a shoot apical meristem. Which ;,;qum5fakidoqut- rr s *.s:row in the table correctly identifies the processes occuring in r uui:,*.rkt5f oqdsam s;-;q the structures labeled in the diagram?

  How does meiosis promote va*gwg5gx6j 7ui5fun+ 0i plc9z, idi2 iriation?

  Which of the following statements is/are correct for meiosis7wv7e9 kapcz9?
I. It is a reduction division
II. It involves random orientation
III. It produces genetically identical cells

  The diagram shows gamfi7 trasn 8i81etes 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 formation of secondary tumours from primary t2 .xoe5ffidbe lzp+*9umours as a resule95+pf2xd i fb l*.ozet of the movement of cells?

  How many chiasmata are present in the(dw *y59 blto2gtlr7d l 2ve9s diagram?

  Which statement is a similarity between cytokinesis in animal and plant v xp/wd s*(t o)r;+sqyxqz d(x as)7*bcells?

  Which stage of meiosis is matched to the corr ghvw4h .6/ gru61awnkect description?

  Which statement(s) are true of meioszi+(wkrc x5 r(is 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 aftym961zuv7 5nf9 k w npltud1:p aily)1er the first meiotic division. This results in the formation of one large cell atp nn 1vz)61k1fluypd9l m :w5 y7aui9nd one small cell. What is the fate of the large cell?

  Which row correctly describes diploid and haploid cells ind s-kf. xs45bj humans?

  The following table shows the diploid chromosome nu fb il:45g7uygh4do1fmber of a range of species.


Which of these statements is correct?

  What conclusion can be draw 1wt3g ;mab:zbn from the karyogram below?

  Which of the following processes is characto2ql(f4;gg48l(dk0a z * lv wdkj 8lbieristic of the meiotic and not the mitobd z(wfda4ig2k(4k 08 lll;q*lj vgo8tic cell cycle?

  The diagram represents a bud wap skp8pl/hyvb6yk7c +sjo2hw*+; 6 sith 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 trogldccybm 6esj2w.2x6li h6uo /*odytes) is 48. Which row shows the correctse6 xomi*j uyl2.66b 2hwcc/d chromosome number for different cell types and cell division stages?.

  At the end of which phase of meiosis I does crockdn) zw0u3 zowo/5.tssing over occur, and what is the out)k0. wu5 z/coz o3nwdtcome of crossing over?

  Which of the following statements does *j6mh1iw (ljs not describe a step in the sodium-potassium phim(j jsl6w1* ump cycle in the neuronal cells?

  Which row in the table below2f atbnox1; u4vnq5v cjk/ ,s,zt w)3m is true of meiosis?

Membrane transport is important for allowing particles to move across the c.s ju 5nj my3c(jzs(n*ell membrane and respond to changes in the cheminnsu*yjm5c3zj ( (.jscal 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 regulated;7 zb+bm*8znvqg6.jp gyehzwnn 36 (h 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 dupb3q,3 bt+ qraring the cell cycle. Which cyclin bbrp+q 3q,3atis involved in preparing for DNA replication?

The diagram below shows chromosomes during meiosis.g 9b ge* +ooir43ehrj(

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 inlckl(-,2l cd hvolves the separation of homologous chromosomes?

  The mitotic index of throat tissues taken from 4 different pathwbi p ,(0tk7xients is shown below. Which patient is most likely to have cancerous thrh0t(7ix,bkw poat tissue?

1.Draw a labelled diagram to refgdh.d2+ j.o kr;1vvq present 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 human kary/ow 3*mfqy 3kaotype.


What is the abnormality in this karyotype and its cause?

The graph below shows har+9 xleye *b1u0in: the relative amount of DNA in one cell during one complete cell cycle. Each letter represents one stagl9 eb+0:xuna 1* heyire 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 sho., : *ar 613adk orso8sunyzymws a cross between a male cat that is homozygous for brown, long hair and a female ckoz. u roa ,ry1y6*m:dn3ss8 aat that has black, short hair.


Which of the offspring has a recombinant genotype?

1.Outline how polygenic traits can show a normal distribution. 9y d/ zme2oqr:/qzx/b

2.Outline the differences and similarities between homologous chromosomes.

3.Explain why expected and observed Mendelian ratios may differ.

  Which gamete can result fro k+b),+q ls3 ppzg6hmrm the crossing over of non-sister chromatids shown in the diagram b6+pqzl+bmhg3psk) r, elow?

  The photomicrograph shows a pollen grain from L. candidum (Lily)1mo2 bi 75bwnu1drjl7 ;qza. n. Which stage of meiosis isd2 bo1uqi1zw. bj5 nn;m7 lar7 shown?

1.Outline the events which would lead to an individual being rzs+e*joc.d6 v/ 9v boborn with Down syndrome, which is characterised by the presence o+ o9*.ocj srzvd/v b6ef 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 growta7 dj-/u 4pfe df-q9zuh. A study was conducted on white onions (Allium cepq/ 9f-fzaj4 7upe-dud a), under controlled conditions 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 cellsrt5p13 6hd:0omy bw qc can divide. The diagrams below show two cells from abmhpc y q1o3t:d5 06wrn 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 gb kh( )lyv4p0cene 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 different stagql;w; d h8e8sqwe(bu1es of meiosis. Which row correctwuwhqe ;8d1( 8sqle; bly names each stage?

  The micrographs show four phases of meiosis I in a plant. In what order do t)a3tbm+6dnjlt w+ yuy+j2/ ikhese phaseukd)tmyjyn i 6baj++2 /twl +3s occur?

Mitochondria are responsible for supplying metabolic energy in eukary46m*( u1j6em rxlrvkg otic cells. In most eukaryotes, which reproduce by sexual reproduction, mitochondrial DNA (mtDNA) is inhe rm*6 kv6g4lm x1rjue(rited 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 number of cells in difi+zjxku)m3etn /c n orto qij b/-:) ho29o(8nferent stages of the cell cycle in four samples of lung tissue from four patients. Which tissue has the lowest minr2)j: mbh o8 i)ntxeoonkz3(/j +/9i cqou-ttotic index?

  The diagram shows the dominant cyclin/CDK s f53*ztx09zmimqssa h:wc(f64 2ytv ;pblb.complexes at different time points in s zlz5csa.06fmtb:f *3q9mb 4y h w(;vsxit 2pthe cell cycle. Which cyclin/CDK complex activates DNA replication machinery?

  Studies have shown that genes such as Cyclin Dependent Kinase 3 (CDKN3) ar1zwib7r gbb* *n0pla *e highly overexpressed in cervical tumgiw pl*b nbb a*7z01*rours.


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 cycle ? m:: b yjtis0+b