The graph below shows the relationship between mattik6l6p ,8 9jxq 2jewzernal age and the incidence of non-disjunctioi 9l266,wj kxe pqt8jzn. What relationship is suggested by the data in the graph?

  Which stage of meiosis is represen qf/y *:tb1k++s eb9l7lgxq dpted in the diagram below?

  The diagram below shows chromosomes during j;) l4y;0so gd4bkm xfmeiosis.


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 alswrs4n82y3bd9nz t6xleles of a single gene which would be present in the nucleus of a y6428 wdnz3ssx9tbr ncell as a result of each process?

  Which keyword is matchelxj.a o3zrdbb;hu.6 tto2)t38 ixen 7d to the correct definition?

  Which statement(s) about mitosis is/are trur 5db-3l8 /.lsepbz-nm u8wc ee?
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 im xsqmz omu;c++2ac mppg(: mb:+,b6rn anaphase?

  During which stage of mitosis does the nuclear envelope break downkkg dgo94ueh p sf9:zjg(551g?

  Which one of the follz268),al qvqt uxq )wo8*cguaowing transport proteins only carries out active transport?6vx,8tqg lwzaq* ))cauuq28o

  Which process does not hap r8yv zp:t,4clpen in the shoot apex?

  Which type/s of membrane transport do/does not require energy expendit nj/bpd)aw v5.tn+ 6jgpr8yo5 ure?
I. Facilitated diffusion
II. Active transport
III. Osmosis

  The diagram below represents a cell with a diploid number om*6 hs7.ajboa rfp8 vdg92f;uf 4. Which stage of cell division is the cella6*mspj9oar8g v .b7uf2f h ;d currently undergoing?

  The photomicrograph bfka zbl.)r4o* +m7flqelow shows a root tip meristem. Which of the following sentencelfq4)zkf7*.o lab+rm s correctly defines a meristem?

  When does the random orientation of homologar:guq*g vj/ fve8i( 3ous chromosome pairs occur?

  Which process does not occ.w8xadtu a 0 6y5ut9ifur during meiosis?

  If a cell with a diploid5ekvydi:r7 h tj/e3.z number of 36 undergoes mitosis, how many chromosomes wilhed ez:v75yi/ 3tr.kjl be present in each daughter cell after cytokinesis?

  The image shows a micrograp . l 4dvg(vriao/y,kg/h of a cell.


What explains the appearance of the cell in the micrograph?

  Which statement(s) about up4sdfzf ::8 zhomologous 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 individual with Down syndromkih).4 oy6zy te.

Which statement is not correct?

  In the cells of a horse (E. caballus) during prophaxc6b0a q4+uv pse I of meiosis I there are 64 chromosomes. What is the haplqb6uv 0c+axp 4oid number of chromosomes?

  Which arrow is pointingk/l*c( -kt .02zc 6ru nxuvxcw to a chiasma?

  The diagram below represents the structure of a nj:a rfbb d++.shoot apical meristem. Which row in the table correctly identifies the processes occuring in bb+a f:j+ .rndthe structures labeled in the diagram?

  How does meiosis promog j4t1teo a5lbcbb *3 xw+rp:8ba3wi2te variation?

  Which of the following statements is/are correct faq7/8cs9jo qe htiv* ;or meiosis?
I. It is a reduction division
II. It involves random orientation
III. It produces genetically identical cells

  The diagram shows gametes produ8,1 (r/byxf b i0zl.(q j ;promsz,vnnced 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 j9ujsn8)2gqo of secondary tumours from primary tumours as aj9)2qsj 8u gno result of the movement of cells?

  How many chiasmata are present in the dytl t5k3+vq+d /s*du yiagram?

  Which statement is a s8 nb3fpz:vh *a:z)k dwimilarity between cytokinesis in animal and plant cells?

  Which stage of meiosis is matched to the correct descript-u lrik)y 0ha. su nvg2fg32)og6.xn zion?

  Which statement(s) are true of meiosis I but not meiosis /4vlf2r3lsh o 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 -fzs1t qni7g( meiotic division. This results in the formation of one large cell and one small cell. What is the fate of the larg 1nqsf (-ztgi7e cell?

  Which row correctly describes dip/kk gji)a *kho,23ed cloid and haploid cells in humans?

  The following table shows the diploid chromoso (w tln2wr3*m)2; :jjxacw 3 j5hkejbyme number of a range of species.


Which of these statements is correct?

  What conclusion can be drawn from the karyogra mq3/em,tcdo., ux0is sm yr d:/xy/w*m below?

  Which of the following proce ay9 kvmj9d+u-fvg3-g sses is characteristic of the meiotic and not the mitotic cell cycle?kj u9 a-ym 3d+f-gvv9g

  The diagram represents a bud with a fmv61u unwdfijg/)9 )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 chuw3rqh :x3cq ,j1vxdnt*wpe. s9w f( +impanzee (Pan troglodytes) is 48. Which row shows the correct chromosome number for different cell types and cell division stagn3x:,(wsx tqwj.q9w31 *fde urhpc +ves?.

  At the end of which phase of,9xdha ov 0sjq ks*v39 meiosis I does crossing over occur, and what is the outcome askd3xovjv*9 h s0q,9 of crossing over?

  Which of the following statements does not describe navki50hn9+qn9 evb9 wo0o lk d4n1s1 pt;;xfa step in the sodium-potassium pump cycle in the neuronal cells?e41; okv090txb9inn k;s vf w9nd qahnl+o5p1

  Which row in the table below is true ohp z .xjw/p0y4f meiosis?

Membrane transport is important for al n*l4k5zaz*wl lowing particles to move across the cell membrane and respond to changes in the chemical composition of the ek5na*ll *z wz4xtracellular 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 e+w;2tw(ap w6x6j.dlmpsz eepco -4 )is 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 differer,t;ur:( qds7jkg3 ws9n2up unt cyclins during the cell cycle. Which cyclin is inp(nuus9twkqsdr3,jg; ur :2 7 volved in preparing for DNA replication?

The diagram below shows chromosomeqclzjf- wqe)k b1-/(ws 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 /ms3b5x* pmu.oveqc11fztb* involves the separation of homologous chromosomes?

  The mitotic index of throat tissues taken frompuy9e9ybi -pul2:,w f c5fp ;r 4 different patients is shown below. Which patient is most likely to have cancerous throat tissu29u l f:i-;, rw5pfpy u9ecpbye?

1.Draw a labelled diagram to represent the process off,8hq hzxul n) v- )osda558 wy2eq+cx crossing over.

2.Compare and contrast random orientation and crossing over.

3.Outline the stages of meiosis.

  The image shows an abnormal human karyotype.r+nm p9 ;wflwn;cw o69b- 3dod


What is the abnormality in this karyotype and its cause?

The graph below shows the relative amto/ae1* ;r)m1z wff zdount of DNA in one cell during one complete cell cycle. Each letter represents one stagrzwdaetom/* f1 fz; 1)e 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 te q7bviq ,:p8hhat is homozygous for brown, long hair b v8iqh7q ep:,and a female cat that has black, short hair.


Which of the offspring has a recombinant genotype?

1.Outline how polygenic traik9gg. 91uj2fjdw s7c3 beeu x1ts 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 non-sister chromatids shown in)l l: kwvp+l3ck9q- ks -s+llcpv :)k qk lwk39the diagram below?

  The photomicrograph show gea49 ws;cer;s a pollen grain from L. candidum (Lily). Which stage of meiosis is4ar;eg w e9;cs shown?

1.Outline the events which would lead to an individual being born with Down syx8awd / d)uq6sz eqid3g +ax++ndrome, which is characterised by the presence of threesqae6 3 +zqx)w gdu8d+xi/a d+ copies of chromosome 21.

2.Explain how meiosis increases variation.

3.Outline the stages of meiosis.

The mitotic index is an indirect way of gr i-q.nxq*k(ts+l: n measuring plant growth. A study was conducted on white onions (Allium cepa), unl nkq q r(ti*:+n-xsg.der 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 cells can divide. The diagrams bexn63ghs l7,x ulow show two cells fx3g7,6 xshnu lrom an 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 ouiq-w juz( vxi8;j-6.bsw90 j0ztsfy f gene 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 )9 2fugonmj 4). xwxtya diploid number of 8, in different stages of meiosis. Whij.9 my)t4 f ox2uwgx)nch row correctly names each stage?

  The micrographs show four phases of meiosis I inbo5j qra 5zm54 a plant. In what order do thesemao455j5r qzb phases occur?

Mitochondria are responsible for supply,4xy.,f sbghyzd kt/8ing 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 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 paren,xzh y/tsb.g8y 4fk,dt’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 c6oj/r0qm k,ii 5 zf4kzells in different stages of the cell cycle in four samples of lung tissue from four patie4kjifzoiz qr/ 6,mk0 5nts. Which tissue has the lowest mitotic index?

  The diagram shows the dominant cyclincfp zhgb.: .;l/CDK complexes at different time points in thg;clzph fb..:e cell cycle. Which cyclin/CDK complex activates DNA replication machinery?

  Studies have shown that genes such as Cyclin Dependen jc)p gnm8in 9dmu84.ot Kinase 3 (CDKN3) are highly overexpressed in cervical tumour8mg ij8ud)ncnop m9.4s.


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 oiwf: 7zdqbvv/v - hp34f cyclin E the highest during the cell cycle ?