The graph below shows the relationship (cx67 tdm/wr ct*o,sxswuq r q1-r.l0 between maternal age and the incidence of non-disj 6cs-t7 ms(wwt/xlrqq d1x* ,c0o.rruunction. What relationship is suggested by the data in the graph?

  Which stage of meiosis is represent ze*9in zxfwvy ducsoaf.25 u -i+).6ked in the diagram below?

  The diagram below shows chromosom )w26 wge8fkkl+ebbb8 ,bfzl ozy./(d i;jhk1es during 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 the number of ala6,2 cyutd )hxleles of a single gene which would be present in the nucleus oau,cdy 2 tx6)hf a cell as a result of each process?

  Which keyword is matched to the 15e6w xbb. lidcorrect definition?

  Which statement(s) aboj/(+6rnyrdv l ut 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,wph+1*shdm( ugrd/c *a6 psb9 which letter points to a cell in anaphase?

  During which stage of mitosis does the nuclear envelope gsz gd;2he/ w0break down?

  Which one of the following transport proteins only carries out active trans).ix a(wvo/ .2cotneaport?/. o (iaet2x.wcnao )v

  Which process does not happen in -(l(nvgbaay o8 lh 99h 8vby.ythe shoot apex?

  Which type/s of membrane tra8: ynktl :y)entt 6*wknsport do/does not require energy expenditure?
I. Facilitated diffusion
II. Active transport
III. Osmosis

  The diagram below repk2yox060 fex0prnq .h resents a cell with a diploid number of 4. Which stage of cell division0p k6xr.qnfo2h0e 0xy is the cell currently undergoing?

  The photomicrograph below shows a root tw8 h+kqgk w)8 cndmmhx7,vg77ip meristem. Which of the following sentences correctl78 ,7hwdm gc8nhg)+7km xwvkq y defines a meristem?

  When does the random orientation of homologous chromosome pairs ocz-ad0;cb-ir te b(x l2cur?

  Which process does not occur duri; z(of (0 pmrtndhk)9lng meiosis?

  If a cell with a diploid number of 36 undergoes mitosis, how many chromosomua( ,n)uuoyl, hlo-(zriaki 5+l w/ (les will be present in each daughter cell after cyt(wk /h(z,, +lal)uri5u o oal-yi( unlokinesis?

  The image shows a micrographef kq7r 1/4qh(0wua+r shslgyz ,(q3q of a cell.


What explains the appearance of the cell in the micrograph?

  Which statement(s) about homologous chromosomedr6fj fee tbkb;;*/- ps 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 fq75a7)kahl.xtu u 3vwith Down syndrome.

Which statement is not correct?

  In the cells of a horse (E. caballus) during prophase I of meiosis :m/ukwya; i1jph93+jpt c0t0h (tjvcI there are 64 chromosomes. a01kjut (9pjchty 3;+0h:c mtw ji/pvWhat is the haploid number of chromosomes?

  Which arrow is point/v5pkzqf 9m;:teum )j ing to a chiasma?

  The diagram below repre 9u wf,0 vlhdmdn9m+(bsents the structure of a shoot apical meristem. Which row in the table correctly identifies the processes occuring in the structure,hfbm9+uwn ldm09 d( vs labeled in the diagram?

  How does meiosis promou+zy,wf+pqf, te variation?

  Which of the following statement) njqcr3;qix, s 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 two homologous chromosx)(-g b8lzie2a npdd w9m pkm ,9nmm4m.. gs/komes.


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 n ffo1cakea)0 0de1n/ of secondary tumours from primary tumours as a result of thk0 a0no)eff1nc de1/ae movement of cells?

  How many chiasmata arefj,21l 6:w;y z ohefsi present in the diagram?

  Which statement is a similarity between cytokinesis ,8ggsj9 n( l )z8hqnvwin animal and plant cells?

  Which stage of meiosis is matched to the correct descriptijra,x8:,n6q raq 0mbbon?

  Which statement(s) are tf)pgp8 n zr/q28.qj xomeq2 c*rue 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 oocyte :ge*l6x gll+v rnb3 ;sjw-9d mq2q.75xbhyljafter the first meiotic division. This results in the formation of one large cell and one small cell. What is the fate of the large ce.qj6xqb;m yw 2xh9g:vl7g -bdn lr+j35lls *ell?

  Which row correctly describes dy q(f wk3hi6v/v r4yo gtna*:(iploid and haploid cells in humans?

  The following table shows the diploid chromosome number of a range ofjjlbp:h*bua9qm k3 c/9l 0ryubjche))34a1 t species.


Which of these statements is correct?

  What conclusion can be drawn from the karyogram 3x xelduq4wo8vo3n(2v.ng s( below?

  Which of the following processes is characteristic of the meiot /bh1 /tqvb/vaic and not the mitotic celvta hb///qvb1 l cycle?

  The diagram represents a bud with a shoot apicc.sk)ln)ur:ji.- sdy al 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 chim3) bkclajq z35.as(3 y-o2.hqy nabixpanzee (Pan troglodytes) is 48. Which row shows the correct chromosome number for differento z..aq y3qi(3k- ax32jbsynlh)abc5 cell types and cell division stages?.

  At the end of which phase of meiosis I does crossing over occur, and what y4/qskj.pu5h1;7bzq*e7js5 u hu xcfis the outcome hf;c415uyx q/e7 5jpu hqkj.sz*ub s7of crossing over?

  Which of the following statements does not describe a step in 0p*rrtv( 4a fmthe sodium-potassium pump cy fp rm4t0a*vr(cle in the neuronal cells?

  Which row in the table below is true of meiosisq87zl)4loxj bl4x -st?

Membrane transport is imporyc3v:*m ka .iotant for allowing particles to move across the cell membrane and respond to changes in the chemical composition of the extracellular flui y *aci:o3k.mvd.

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 regw5p 7epyj0f4 oulated 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 et44w1 arc6q(d +gdij cyclins during the cell cycle. Which cyclin is inv icw(6ag e+jd1qtrd44olved in preparing for DNA replication?

The diagram below showsdv,hwi)l9h/it/te -bln ju+ 0 chromosomes 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 homologouefv;mas z6/9z )(tq vus chromosomes?

  The mitotic index of throat tissues taken from 4 different patients is shh 1u s;kkl v20iz ,*bgksqd13yown below. Which patient is most likhs,v;u k* db 121s3zkkil q0ygely to have cancerous throat tissue?

1.Draw a labelled diagram to represent the process of crossing ov6hv k1y- pu 76nqcron ;+uken;er.

2.Compare and contrast random orientation and crossing over.

3.Outline the stages of meiosis.

  The image shows an abnormal human kar9jsq kv-cz)7 uyotype.


What is the abnormality in this karyotype and its cause?

The graph below shows the relative amount of DNA in one cell during one comyrvhaf8xc0 mz oy 6p5o+6vt*k,j 1o +kplete cell cycle. m++ yz6v1 oko8r0xjoap5vfcyt* h,k6Each letter 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 a59dctnu*zn / ,ds0:way 1ytg y cross between a male cat that is homozygous for brown, long hair and a female cat that has black, short hair.5*g,w du ts/:zyctnyda0 1y9n


Which of the offspring has a recombinant genotype?

1.Outline how polygenicf).o m+ n,zh5wy bocy5 traits 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-sisterebri3 hi0g n g(o2:,j+ q0/t,rs gqjto chromatids shown in the diagra ojij+t,q3bh2 r0/sgte0qgr: gno,(im below?

  The photomicrograph shows a pollen grain from L. candidudl2im6j k/qj+m (Lily). Which stage of meiosisilk2j6/qdj + m is shown?

1.Outline the events which would lead to9vke+tr vr)b6 an individual being born with Down syndrome, which is characterised by the presence of three copibr6 ke+)vt9v res of chromosome 21.

2.Explain how meiosis increases variation.

3.Outline the stages of meiosis.

The mitotic index is an indirect way of measuring 4ix z+u ;u6dbio 4b)kpplant growth. A study was conducted on white onions (Allium cepa), under controlled conditions ;i6obiu4 kdp4+ zuxb)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 whijgb7ye+: ax b3-ad4ewwb -q-ech cells can divide. The diagrams below show two cells from an organism with a diploid number (2n) of xgj7eb dw-q-+4e b-waaeb y:38.


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 expressionka.tvl q,m;m/e p2w i6 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 stniy d;8l .f,g9.5zxd ot.jsjfages of meiofdgy ,oj 5 .9z.l.t8df;ixs jnsis. Which row correctly names each stage?

  The micrographs show four phases of meiosis I in a plant. In what order 8rr; 3wy;kto/ il,7tnvf g3lr do these phas;8/iro3t l7;r 3twn,fklgvy res occur?

Mitochondria are responsible f tb9ry hqvcg7z1i4+o3or supplying metabolic energy in eukaryotic cells. In most eukaryotes, which reproduce by sexual i1 97+vozgrqhy c b4t3reproduction, 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 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 cellsdcl0064 bsml80n b uaz;vyr 0h in different stages of the cell cycle in four samples of lung tissue from four patients. Which tissue has the lowest mitotic ic 0n0d4sruva l60ly ;b0bzh8mndex?

  The diagram shows the dominant cyclin/CDK complexes at differed f:drz7wdsj4z5a v wns380z 5nt time points in the cell cycle. Which cyclin/CDK complex adsjfw34swz8 znd z05:7d 5ra vctivates DNA replication machinery?

  Studies have shown that genes such as Cyclin Dependent Kinase 3x;w6d4ci.rhi 2;xs pg (CDKN3) are highly overexpress 2isiprcx4gx6. ;;hw ded 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 xibibbh/jjwyt) 9m6:l/ +4+pl q/ iuy3cjkh* highest during the cell cycle ?