The graph below shows the relationship between maternal*4h:ghq2owknz81 gu z:ark 2c age and the incidence of non-disjunction. What relationship is suggested bh*wgzk1zrg2q:2ca 4oh : 8kun y the data in the graph?

  Which stage of meiosis is represented in the diagram bek hj0 fo.+ol;d07+ pljb9w hiwlow?

  The diagram below shows chrom)sf 4w vwgj ();mkvko /j8*stjosomes 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 nqyw.ioa l2+c ;c1:e3np2jrb alleles of a single gene which would be present in the nucle1nc2o :pl3 +cq j.rie awy;2nbus of a cell as a result of each process?

  Which keyword is matched to the correct definitiont1pj+bq51,uy.k dc cxaht,cj0o pr l7/ (;hio?

  Which statement(s) about mitosis is/are true?)oe)xca 9++q opntv.p
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 below1zt)g ;zyr 7lt, which letter points to a cell in anaphase?

  During which stage of mitosis dv6 b-oz*nx5ryoes the nuclear envelope break down?

  Which one of the following tran ,nf0zk7ewuhe( 5,wowjo;/bmsport proteins only carries out active transport?b w5 , wmunk0(ofzj7oee,h; /w

  Which process does not happen in the shoot apex--ni +o2yk luw?

  Which type/s of membrane transpor* tnee81prulr)pw5fb -m g.-zt 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 stxwv9z,z1 muvzhd :l 1)age of cell division is the 191 dh :zw)xz,vmluzvcell currently undergoing?

  The photomicrograph below shows a root tip merite/n sp/a4z8xstem. Which of the following sentences correctly defines ntpsx /ae4/z 8a meristem?

  When does the random orientation o-8f31ss fuaz xf homologous chromosome pairs occur?

  Which process does nqqnhca( 2,5ah3g v vsu.om 99not occur during meiosis?

  If a cell with a diploid number of 36 undergoes mitosis, how many chromosomesx1kr1d*vzc 3i will be present in each daughter cell after cytokinesisir3cvzd*x1 k1?

  The image shows a micrograph of a b/3p bedlk;l.ccr6 +n uhy76hcell.


What explains the appearance of the cell in the micrograph?

  Which statement(s) about homologous chromosomes is/are not true? djivfd,g 04vs;5ztdm7r7 bh g kp-68r
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 individg*4 o)9kfs gitual with Down syndrome.

Which statement is not correct?

  In the cells of a horse (E. caballus) during prophase I of meiosisv;i/-8hr6z1w5uhp lajzjfd; I there are 64 chromosomes. /ilvp- hz;1r dfzjwa8; j h6u5What is the haploid number of chromosomes?

  Which arrow is pointing to a chiasmi 3 bukx)fw+xr o65ia9a?

  The diagram below represents the structure of a shoot apical meri 8co hqfzahmrv+kh4w2 :2e*/bstem. Which row in the table correctly identifies the wqfchz/a oh 2 8e* rmv+4b2kh:processes occuring in the structures labeled in the diagram?

  How does meiosis promote vari 2jb.zhm0ao1uxv ll) /iwk +4vation?

  Which of the following statements is/are correct for me p+bvespp/,x by ml20-iosis?
I. It is a reduction division
II. It involves random orientation
III. It produces genetically identical cells

  The diagram shows gametes produced from two homoh5iu rbt vz7ba6;dk6 epy ,t9(logous 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 seconddl igk gh8c:,g8tkssz*r p36 .ary tumours from primary tumours as a result ofs8:6,d 3glikkpcs8 tg. ghr z* the movement of cells?

  How many chiasmata are present in the diafd,qu(h nrriq 0s (v76gram?

  Which statement is a similarity between cytokinesis in animal and pym3.j lej6 z7hp4n b6plant cells?

  Which stage of meiosis is matched to the corrlii/hdp a- z.;ect description?

  Which statement(s) are true of meiosis I but not meiosis IIq 0,ac-nmzael8u. k ./oy, 0uqz gd:hp?
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 meioticds 3yutwfcn,( ;h1b/ r division. This results in the formation of one large cell and one small cell. Whatbnwc rf/3utd yh,(; s1 is the fate of the large cell?

  Which row correctly describes diploid and haploid k7er n3xqji83ow cn73ypbjh/l2p7 7 u cells in humans?

  The following table shows the diploid chromoo0/b4r5by1wjw le3 - go 8gjqvsome number of a range of species.


Which of these statements is correct?

  What conclusion can be drawn from the kotg1x6tla jp,y) co3m)-g,km ri2 vi6aryogram below?

  Which of the following processes is charactei,d5v fa3z :ozristic of the meiotic and not the mitotic cell cycle, zi3zdo:5af v?

  The diagram represents a bud withagmkby -bap+zn73 h;9 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 chlzd71w rtin51 kf7 5 ( plx6k60zdtmo,bqwf*cimpanzee (Pan troglodytes) is 48. Which row shows the coz51d(icb5fpr dtxln0*l,kmt 7 wzfo66 k71qwrrect chromosome number for different cell types and cell division stages?.

  At the end of which phase of meiosis I does crossingn,t.wp oy0vdk4d: h. l over occur, and what is the outcome of crossin4ph: 0kdy., ovn w.tldg over?

  Which of the following statemg r /p72sijyi)8rhvz2 ptd mvynj i34gbb-**,ents does not describe a step in the sodium-potassium pump cycle in th2g )j2iynzii*s/ y,vvt3 7gjp *r8hb-bp4mr de neuronal cells?

  Which row in the tabhpzi1s7l w6g3 vy*g x1le below is true of meiosis?

Membrane transport is important for allowing particles to moyym( s(q*; m+ocnr .ogve across the cell membraneqgnm*( (o r; o.m+cysy and respond to 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 regulas b,s3h 5gvs6rted 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 during the cn -g)i)i b;qqj /zgy3s7+ofv qell cycle. Which cyclin is involved in prepainz7)qvs foqyg /q3j+-gb ; )iring for DNA replication?

The diagram below shows chromosomes during meiost 9wi9zi v b4k9bvg)f:is.

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 separationxrd 7-f m .p.u(x4ll nh0qnnlu5xv.1o of homologous chromosomes?

  The mitotic index of throat tissues taken from 4 different patients is shown be. pdlbl30dx-r6/ qvd hlow. Which patient is most likely to have cancer /hxld6-dqb0v3d.lprous throat tissue?

1.Draw a labelled diagram to repre8u lu0wvn- )xwsent 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 karyotype. 5uiy*)pym(w y


What is the abnormality in this karyotype and its cause?

The graph below shows the relative )- l w ;3he.vzfwgw4omamount of DNA in one cell during one complete cell cycle. Each letter represents on-mwg;w4efz. l3) vohwe 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 a cross between a male cat thate32i+lu kbqwce g.e u5tm7+e; is homozygous for brown, long hair and a female cat t keil+eeq5.+7uucwemg3;2b that has black, short hair.


Which of the offspring has a recombinant genotype?

1.Outline how polygenic traits can show a normal distribution. jxas ;3v 1* dxxivbo;en z)svn*u99-x

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 nor0uha a fnc+9lrw1git ;q.,, dn-sister chromatids shown in th.+ lq 0d9a, r;ghi,nfwc1rt uae diagram below?

  The photomicrograph shows a pollen grain from L. ca6rv;, yfym5(d0 ,yiqce o(jick gezb)q y*8v5 ndidum (Lily). Which stage of 8 db vyeqoq5y,y0 j5iziey(v;cmc grf(k6) ,*meiosis is shown?

1.Outline the events which would lead tgxne; zmsp6 4-o an individual being born with Down syndrome, which is characterisz4e ;xpm-n gs6ed 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 plant growth. A study was vj1 , ,4hx8woc3pboq* hhw/z zconducted on white onions (Allium cepa), under controlled conditions in a lab, to investigate the eff*jh 1/ zp hq8h4b3 x,wzoow,vcect 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 diagr2ut ila 5mvs.ln81v+i ams below show two cells from antl2i.salnmi8 v u5 1v+ 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 gene expression in stem fah+mn*. 2hcegrowth.

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 differen; xwqb4v( y/7uq. lwbe hbc7u+t stages of meiosis. Wh evyh+/x ;c.u 7b(u4qbw q7lwbich row correctly names each stage?

  The micrographs show foi66y6 gj mnt f 941yy w4ce8w(mg7rdvour phases of meiosis I in a plant. In what order do theset(f 6v146 n7y8rdwmym9eg w4 g 6oijcy phases occur?

Mitochondria are responsible for supplying metabolic energy in eukaryoti*dlvvcy *w7q.c cells. In most eukaryotes, which reproduce by sexual reproduction, mitochondrial DNA (mtDNA) is inherited from only one of the ld*7wyq.*vcv 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 hazad/;en+5a in different stages of the cell cycle in four samples 5eahn;za/a d +of lung tissue from four patients. Which tissue has the lowest mitotic index?

  The diagram shows the dominant cyclin/CDK complexes at different time poinv c4mrz.fb07,4 +irxy pj1 tcxm mg+n8ts in the cell cycle. Which cyclin/CDK complex activates DNA repli4 ,ft0nmmj+17 rmv grb+84.iczc xpxycation machinery?

  Studies have shown that genes such as Cyclin Dependent Kina55 d,z,oqbnbkh- iy0nse 3 (CDKN3) are highly overexpre izn-q5 ,koynb0d b,5hssed 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 h16/cri wngd :vgw. 4dwighest during the cell cycle ?