The graph below shows the relationship betweennws/ko;0 /cx*1hi u9 nqeh.dwhxe:( m maternal age and the incidence of non-disjunction. What relationship is suggek/uc1 w d ;n.q0 h(smw:9nxe*ixoeh/hsted by the data in the graph?

  Which stage of meiosis is represented ine,,l6vtkasn)u3/b emkuo87 x the diagram below?

  The diagram below shows chromosomes du.dlrl1 o -pmxi,0ka5c oida61 ring 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 thy.5ny u 81a6k:wm44 eb nrzgmwe number of alleles of a single gene which would be present in the nucl8w.bw4zyak mnmyr gu16en: 45 eus of a cell as a result of each process?

  Which keyword is matched to the corbjldl,uh;3wt k e29zxbdzm n 8 *x3-q5rect definition?

  Which statement(s) about mi9wfrw ,53ub :glehi4 vtosis 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 po.fg;wk h9noqq mv3.s/tx; w (wints to a cell in anaphase?

  During which stage of mitosis does the nu:zn11jee) tic clear envelope break down?

  Which one of the following transport proteins only carries out active upueexo9/ h7: transport? e9xhuu:7oe p/

  Which process does not happen;w7m ,ivx qlx - 2bpl7.:a0 xme td;msb+l4zub in the shoot apex?

  Which type/s of membrane t: p .ntmyvz* ikgoqs3q1f4d:j5z i44.l /lzc nransport 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 stage4th. xw(*sm idu ma:jf7tug. 5 of cell division is the cell cmwah7gtu .5: *.jfu t(is 4mxdurrently undergoing?

  The photomicrograph below showsyex t:2pa78 xs a root tip meristem. Which of the following sentences correctly defines a mee7xx2p ytsa 8:ristem?

  When does the random orientation of homsfc cxr bl b c/*d;wx;jq8:-:-hugg)gologous chromosome pairs occur?

  Which process does not occur tc y2j 8vq4op-during meiosis?

  If a cell with a diploig/j+:fex2 hdad number of 36 undergoes mitosis, how many chromosomes will be prdxjg+:hea f 2/esent in each daughter cell after cytokinesis?

  The image shows a micrograph of a celw w 0n4ty tr0d/.j9 *.tfekekyl.


What explains the appearance of the cell in the micrograph?

  Which statement(s) about homol)z 1 4hkv far8hqd(xg(ft:,me*yjhx )ogous 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 sylpxu m,n/fz1z1 h. o)f.uwa1c ndrome.

Which statement is not correct?

  In the cells of a horse (E. caballus) during pro vo;jl93znbvxr pjk:0m/7 e-ophase I of meiosis I there are 64 chromosomes. Whpv /09lzx7jnmvj e b:ko-;o3rat is the haploid number of chromosomes?

  Which arrow is pointing to a l2 tg a6a,7a r5 nhnba05 o(4uqhjn/yuchiasma?

  The diagram below repq xg/t na:fo;8resents the structure of a shoot apical meristem. Which row in the table correctly identifies the processes occuring in the structures labeled in the diagragqoax /n:t ;8fm?

  How does meiosis promote variaq8(q v :ew6hdlj5*ex 3in vkltq(1 q7btion?

  Which of the following statemenc+usm4 ay p.7nts 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 tw0te s ,iv.qmobk5wh)u ep :+1po 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 for51 bq8j)v --,6-rxpbsa*tia zuvq ipkmation of secondary tumours from primary tumours as a result of the movement v--v,abbq* ias 5xi 6t)krzpq u1-jp 8of cells?

  How many chiasmata are present in tht9,rdbx5;aqrf r d2 or*d 9h3ee diagram?

  Which statement is a similarity3 f2 36ict r6.lzl vuqn:oj0mb between cytokinesis in animal and plant cells?

  Which stage of meios7u2j d,npkcy) is is matched to the correct description?

  Which statement(s) are true of ;bkg. (a d sko3c5,mk w4t.wstmeiosis 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 sj ixb0 q/bs :+lk)2z :vndd7eoocyte after the first meiotic division. This results in the fdd bl i+27q0j:)xsvn/zk e:sbormation of one large cell and one small cell. What is the fate of the large cell?

  Which row correctly describes diploid and haploid- 55d dcchd(ij cells in humans?

  The following table shows the dnnn(p w3.+egsiploid chromosome number of a range of species.


Which of these statements is correct?

  What conclusion can be drawn ( h7:7 mb 0a6dem (r:rsvtgolifrom the karyogram below?

  Which of the following processes is characteristic of the meiotic ,e;+a/p 3c/ksrf.i -3s qtjliq z drh.and not the mitotic qlqteipj.id/.s/f c3sh3 -r;zrk , a+ cell cycle?

  The diagram represents a bud witn4 n84pk cd5t:ulnd +sh 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 chi1f(s0e )eyv2gb gm3c2zacn d6mpanzee (Pan troglodytes) is 48. Which row shows the correct chromosome number for differentyg2fe(sz ec a20d6b)3g1m nv c cell types and cell division stages?.

  At the end of which phase of meioce -7 yqp0j**novx7gzsis I does crossing over occur, and what is the outcome of crosv o*7g0e -x*jp yqczn7sing over?

  Which of the following statements does not describe a step in the sodi 0 p(whp;kq(fbum-potassium pump cycle in the (f;(whk0qbp pneuronal cells?

  Which row in the table below is true of meiosis?8q(9m hmob7 pv

Membrane transport is impohnij( i+-(uy*b-ipa ortant for allowing particles to move across the cell membrane and respond to +-nu( opyh*(ij -aibi 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 regulateqh7fp4;m3l 3m1*rnt ps7k5 3bdwcuc yd 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 cye0 uy k(u.fz0p5hbc/nj/v8o pclins during the cell cycle. Which cyclof(8u vh.yp uc/jnez5 bp00k /in is involved in preparing for DNA replication?

The diagram below shows c74a-*r-lik.z qyv gc dhromosomes 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 involves the separation of hoi m0lz+ l/t*homologous chromosomes?

  The mitotic index of throat tissues taken from 4 different 9 h4opcszi-9:iqi+aapatients is shown below. Which patient is most likel:oai 9i9ca+ -sp q4hizy to have cancerous throat tissue?

1.Draw a labelled diagram to represent the process of cqdf;34oc, xc orossing over.

2.Compare and contrast random orientation and crossing over.

3.Outline the stages of meiosis.

  The image shows an abnormal human karia p-k(nc0x2 0xd gpm:yotype.


What is the abnormality in this karyotype and its cause?

The graph below shows th xub97;zof6t3iv) tdv e relative amount of DNA in one cell during one complete cell cycle. Each letter represents one stage o;t7)o ifu6vtxv 9z3dbf 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 +ayay 7uh14z kthat is homozygous for brown, long hair and aak +yhz 7y41au female cat that has black, short hair.


Which of the offspring has a recombinant genotype?

1.Outline how polygenic traits ca jnb08l0piov54xrg f 5n 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 noaef8qx v1i-)on-sister chromatids shown in the diagram below? aexivq 1)f-8o

  The photomicrograph shows a pollen grain from L. candidulwe83( 5g-gfr n jack:m (Lily). Which stage of meiosis f:c-g(a 3rkwj len 58gis shown?

1.Outline the events which would lead to an individual being born with h efjqacf3w6u7r;v-tv01zh 9Down syndrome, r6uhae- q1hv ; 3ft 0zvwjf9c7which 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 way of measuring pjl 14bmh a7d:t+bbb-d lant growth. A study was conducted on white onions (Allium cepa), under controlled conditions in a lab, to investigate the effect of soil pH on the -lb1 tj4+bhdab:bd m7 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 twompj55 ukmu ox 7p9a97b ways in which cells can divide. The diagrams below sh79u5o xaumpkm pjb5 97ow two cells from 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 of gend y ;d.guzjk48e 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 differe w0no0y/ *elze(rg3pc nt stages of meiosis. Which row correctly name*c/r ezgwno p(y0l3e 0s each stage?

  The micrographs show four phases of meiosis I in a plant. In wrhqx5t*pzo6 g 9- ifn9hat order do these phases n9- hxpr6g*zqo5f i 9toccur?

Mitochondria are responsible for supplying metabolic energy inb1m b39n5 o ldx 1hd3fiwj(*up 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 inherh 1imd (p593buob*jl3dnw 1fxited 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 )d kchz vzs12kka91 s(cells in different stages of the cell cycle in four samples os2zskavkkc )1 h d19z(f lung tissue from four patients. Which tissue has the lowest mitotic index?

  The diagram shows the dominant cyclin/CDK complysp5au+-6;-tlpf of mf- 2 gtdexes at different time points in the cell cycle. Which p -og;yst -6l+ff tp dma5-f2ucyclin/CDK complex activates DNA replication machinery?

  Studies have shown that genes such as Cyclin Dependent Kinase 3 (CDKN3) af1v0o, ppc. yngem;wmx y08 yy(s;cz2re highly overexpressed in c80f;oycyp.z02 vp myy,x(1; gmcesnwervical 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 g+t(x)n2qj tp highest during the cell cycle ?