The graph below shows the relationship between maternal age+ pqwyq2 *z,bu6aqge / and the incidence of non-disjunction. What relationship is suggested by the data in ta ey /+6pgqw,zbqu* 2qhe graph?

  Which stage of meiosis is represek 9 sxomu/u0a9nted in the diagram below?

  The diagram below shows chromz )c1:kr 9 xtydf8rg-c1f:hfr osomes 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 n6 mgprel 9qsw38 u-:ewumber of alleles of a single gene which would be present in th- eqlps8693 w rw:gueme nucleus of a cell as a result of each process?

  Which keyword is matched to the correct ds+ ippo v2kud 1z3rfk 45f)z0:pokr2i efinition?

  Which statement(s) about mitosiqp qdd f ,x jk4m6.6l8(ijq;rde:ebw6 s 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, yq, ,kez) rrfb yt0og49ap9 o+which letter points to a cell in anaphase?

  During which stage of mitosis does the nuclear envelope break d u ha.7dg16zuxown?

  Which one of the following55 urx ox d*ps),ggx4dyl/; d8f(myvl transport proteins only carries out active transport?58 4oy (dl gy/xd fulvrm p,x5gx*)ds;

  Which process does not happ1z6q5cwrm j:h(t q/t den in the shoot apex?

  Which type/s of membrane transport do/dx(;b+4yama i goes 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 stage orc +jmv 6(jj wuopq*))cdkv(3f cell division is the cell currentl6*(rj3o wvm +d)jv(cckpuqj ) y undergoing?

  The photomicrograph below shows a root tip meristem. Whgvm3:0 c8er hxich of the following sentences correctly defines a merir0g8mveh x: c3stem?

  When does the random(evkfnb m x5x1:/ v;mu1l2 z+tlrw0h7 /hdzoh orientation of homologous chromosome pairs occur?

  Which process does not occur during 79gtbr c;xr lcyj/u*(meiosis?

  If a cell with a diploid number of 36 unm27ms z7* rwb: cbyh4mdergoes mitosis, how many chromosomes will be present in each 7*my2 m4zh7r:bsmwbc daughter cell after cytokinesis?

  The image shows a micrograpdhw s4hzg z-tl a:u+.+h of a cell.


What explains the appearance of the cell in the micrograph?

  Which statement(s) about homologou l:(u5nn 7:xjkm e5rhcs 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 synd5r i .u fmqvu3+j/h9trrome.

Which statement is not correct?

  In the cells of a horse (vr d .hjjde92od15oi 1E. caballus) during prophase I of meiosis I there are 64 chromosomes. What is the haploid number of chromosomes?rvhdjio.2od1jd e 195

  Which arrow is pointing to a chiasma?y6 mjv / vvj mc+31fubr0beh*1:co*wi

  The diagram below represents tb dgjk/v cn156he structure of a shoot apical meristem. Which row in the table correctly ide6/n 51jb vgdkcntifies the processes occuring in the structures labeled in the diagram?

  How does meiosis promote varixv5 h fur1g5*py1 fai5ation?

  Which of the following statements is/are.;x no27ha,: oqdwdl3kko x6v 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 chrom;n+ks,8sgp cm ni y/y*osomes.


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 3 fa7hz*ba*auwd 56k; ttczj; of secondary tumours from primary tumours as a75*c;khzzwt a*a; dj bf36 tua result of the movement of cells?

  How many chiasmata are pre1+0gs wo*wv1z zsa))fbikxd) sent in the diagram?

  Which statement is a similarity between cytokiv5ia6;*5 ay+xv oq j.0fvo9ywrv//h zj(b euynesis in animal and plant cells?

  Which stage of meiosis is matched to t(2 ) yeyw5t5jo gqzlv/he correct description?

  Which statement(s) are true of meiosis I bu ,xyc0 -de+ci e:sh)dpt 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 oocyk4 77g5le +o*mpbfzh7vnt :id te after the first meiotic division. This results in the formation of one large cell and one 7bt7g4m:l 5* 7vodzf+h i peknsmall cell. What is the fate of the large cell?

  Which row correctly describes diploid and hap2;osifch*d/p6nto5t vl4p :tt3 b6z ploid cells in humans?

  The following table shows the diploid ch q3 9m(gv6mf )lq /d.es4aecvvromosome number of a range of species.


Which of these statements is correct?

  What conclusion can be drawn from the k731jl j /s8bxd qp :)y.f+4 xqdizovasaryogram below?

  Which of the following processes is characterist(kzzf3zg+)(dfr i )poic of the meiotic and not the mi)3rz) o+gkfz(i(p fdz totic cell cycle?

  The diagram represents : /sc./tluzls a bud with 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 troglodytes) is 48. Whichb.5:k)m* 9fdmh:bvha l;d weo row shows the correct chromosome number for different cell typesw.d): : dbh *;9kehamv5moblf and cell division stages?.

  At the end of which phase of meiosis I does crossing over occur, a (i/*5p4m* wdujv wmilt7vl.o nd what is the outc(pmm/ *jw4l 7iuod *tw .5ilvvome of crossing over?

  Which of the following statements does not describen /9;vlt1gyb6k,za qp a step in the sodium-potassium ;nt1zypbk a 9qvg6l /,pump cycle in the neuronal cells?

  Which row in the table below is true hqdzr1z+j8 po *b-)fiof meiosis?

Membrane transport is importazva8 f36 efdlas1w3k, nt for allowing particles to move across the cell membrane and respond to changes in the chemical compositionz 8 1f3dl6vaw,3fs eka 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 ret/2 ady;b 3ufigulated 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 co: v70dc-vqaa 6zxt l*z o8. t9ti.vdvtncentrations of different cyclins during the cell cyc: d7-v0zvivldtqt. 6to vac*az8x.9 tle. Which cyclin is involved in preparing for DNA replication?

The diagram below shows chromosomes du (o- yorz a :zw5-.ovvd.yfo,gring 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 homologous chr .2(grerb, ab4mmrz3romosomes?

  The mitotic index of throat tissues taken from 4 different patients is shown b*dt2mcu4l,e +bg e am;elow. Which patient is most li te c+ d,4laume*;2mbgkely to have cancerous throat tissue?

1.Draw a labelled diagram to representp 49 l9k)txi 5 po5/ft;jzmsar 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 w j)x/u(o/lm0 tswt.svu60k phuman 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 completec j4rwl6 5gsav9,/r; uun b-cj cell cycle. Each letter represents one stage ofla; 56jc vc,u-4rb /wgs9jrun 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 magnsa ix zd/n5(2 . wqcyygfj+o25,v8qle cat that is homozygous for brown, long hair and a female cat thagxnyjqs+ny gf iao2wz 28.( 5qv,5/ cdt has black, short hair.


Which of the offspring has a recombinant genotype?

1.Outline how polygenic traits can show a normal distr 5.v+ogfgoll1) vk2w x2k*jdhj01 taribution.

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 crossin rjhc:s( 5gxx( 4gltu,:8kciug over of non-sister chromatids shown in the diagram xgk8l cgr4 i5 t,s u(uj(hc::xbelow?

  The photomicrograph shows a pollene +4modmw;ke) grain from L. candidum (Lily). Which stage of ;4mkw +od)eme meiosis is shown?

1.Outline the events which would lead to an individual being born wmcn)q3e0e),v y;mi p eith Down syndrome, wh yee;ep)i,30mq) nc mvich 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 w9bk 4o a:zcu(gay of measuring plant growth. A study was conducted on white onions (Allium cepa), under controlled conditions in a lab, to investiga 9zk:agc4 ob(ute 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 waysun + yy/a7r;5 ks-bjiq in which cells can divide. The diagrams below show two cells from an organism with a diploid number (q7yuj;5s+in k-byar/ 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 gene expression in ste;md)gy; y,ilcm 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 num8b9 g8z kdbzk(ber of 8, in different stages of me9kkbz8b8d( z giosis. Which row correctly names each stage?

  The micrographs show four phases of m.581fsd ioucdtz)m/w1ai1yz eiosis I in a plant. In what order do these phases occur1a)s 5.cddf8m itz1wuzo1 i/ y?

Mitochondria are responsible for supplying metabolicnw l b,,8k*w/i1snhkd 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 betwee/,nis* 1wk l whdk,8nbn 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 different stages of the cell cyck)v9u2g7k 8ajiu/sb t/v xt- tle in four samples of lung tissue from four /-/xv97ktt8 vu i2ka stgbju) patients. Which tissue has the lowest mitotic index?

  The diagram shows the a3sy3h4 sg*-t8ml e tddominant cyclin/CDK complexes at different time points in the cell cygs3sd3 ylam*4eht8t-cle. Which cyclin/CDK complex activates DNA replication machinery?

  Studies have shown that genes such as Cyclin Depenr k4b+8x-ex4b8je-wd ,bokf +g mqu ;kdent Kinase 3 (CDKN3) are highly overex j;4,-mxbrgob-d+xewf 8kbekk8 q+ 4upressed 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 highest during the cellu/ amp-m:hd8sn1gjh8 cycle ?