The graph below shows them( a80gld7zx4 c1y k2nj p2wrs relationship between maternal age and the incidence of non-disjunction. What relationship is suggested by the data in the g0 sa82 gl4x1ycjzndp2(7wmkr raph?

  Which stage of meiosis is represented in the diagram ao2zmy3m bb ;npyz(//ll bt5 cj6:u d,below?

  The diagram below shows chromosomes during meio5v3yoj/3t abu wi3pu/ sis.


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 num7 z+5w+n q3ougv6( xfrz mjq.bber of alleles of a single gene which would be present in the nucleus of a cell as a result of eac + bvzq x6qz. 5nrm37+(ogwjfuh process?

  Which keyword is matched to the bvx6nv z8+ j5zcorrect definition?

  Which statement(s) about mitos b*48iyj0kafs 0.1zupy tcqgq/4f7xi is 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 let-hca*kn/jv/bv)(/g pjuc3 d7px v) mfter points to a cell in anaphase?

  During which stage of mitosi(bj./lzo, wf(9 ,gk*tsa mgov s does the nuclear envelope break down?

  Which one of the following transport proteins only carries out active transpo0tv y;q opt5neg op*/*rt?yo/*;p*ptn5gqt 0 eov

  Which process does not happen in the shootl+ r;j, pdx),7d 4aj gu(ywkdg apex?

  Which type/s of membrane tranns o6ph(.n71bz7+q qwm9mygvsport do/does not require energy expenditure?
I. Facilitated diffusion
II. Active transport
III. Osmosis

  The diagram below represents a cell with a diploxbv 4dls /(le3id number of 4. Which stage of cell division is t4s /d3xl( vlbehe cell currently undergoing?

  The photomicrograph below shows a root tip me: 1glfn.klx2r ristem. Which of the following sentences correctly defines a meristemrg k.l:x fl21n?

  When does the random orientation of homologous chromosome pairs occurq43:jishfvl )?

  Which process does not occur during meiosis imnzu01i-:dsx,7g/ fmsle*r0 lbhy5?

  If a cell with a diploid number of 36 undergoes mitosis, how many chromon / c-h)np :,l:-hgebb9jdnensomes will be present in each d/hc j:e9-nhb),bgdnnl e n:p- aughter cell after cytokinesis?

  The image shows a microgra9jzj 17(imyfd n v8,.axwx8y+j hq,q0lsfw-kph of a cell.


What explains the appearance of the cell in the micrograph?

  Which statement(s) about homolog 5jj,hbmjqz6.pq 61nm.b g ng;ous 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 individuai4gg4no6(poo. ,4vzgwk o*5 lk; vuxbl with Down syndrome.

Which statement is not correct?

  In the cells of a horse (E. caballus) dy+k2) 7aw4k( wi -x:kwqkztb;pbm2 ofuring prophase I of meiosis I there are 64 chromosomes. What is the haploid yf;x4k2 azo +kbw kiqwpmt2-(w7)k :bnumber of chromosomes?

  Which arrow is pointidmjimi4fz4yl1; i0o3sb2y ;t ng to a chiasma?

  The diagram below represents the structure of a shoot apical meristem. 9/n md ycu3,pdWhich row in the table correctly identifies the processes occuring in the structures labe ,p3d9mndc/ yuled in the diagram?

  How does meiosis promote variatio+bg- :udxrssd1 l -/x0 ima0xq9gg3wxn?

  Which of the followiszcp0(j 3 *wqs v-;t.mw6dmirng statements 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 gabkbzxxt k qz(a, wtby5:i:-d:-u;p*d.dwx 9 c metes produced 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 s6o+ , -wzetil qoz1/gof secondary tumours from primary tumours as a result of the movement o qwg+zoiz /-l61e,tsof cells?

  How many chiasmata are present in t .h3,px9 z1mnskoi+ bko eq 7ud9vb*0ahe diagram?

  Which statement is a similariz0qwx,fem *3j 20yf 9)wkqu+sbv) zmvty between cytokinesis in animal and plant cells?

  Which stage of meiosis is matched to the c8by2lfl4rr 7t9 h3m pv3wmxx3orrect description?

  Which statement(s) are true of meiosis I bujbg t7s3xj(3 ww9sr*q t 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 ov)2 jhk3bjsa+.yu7p p4 4mt miocyte after the first meiotic division. This results in the formation of one large cell and one small cell. What is the fate of the lar3)m sk 2vp .tamujj44yb i+hp7ge cell?

  Which row correctly describes diploid and haplo f*:k i4dzmrx(; efqu.id cells in humans?

  The following table shows the diploid chromosome number of a r5yv0p 1xv7k9f k;rtv nange of species.


Which of these statements is correct?

  What conclusion can be drawn fro kboh .gxody s)-dd 221(uac39bii-fpm the karyogram below?

  Which of the following pokw r: akb(s(8rocesses is characteristic of the meiotic and not the mitotic cell cycaw(bs (kr:8ok le?

  The diagram represents a z7wdep62pq94kh0or 10/amm2x qshep 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 trohsli7x pht1w0kh ;l7 aeyp1n:2qt +c3vwi0 h+ glodytes) is 48. Which row shows the correct chromosome number for different cell types and cell division 07ti3yit c1 hlh+1 k: p2+7 pqalwhwh0x;vens stages?.

  At the end of which phase ou*h7 d ,3u2l*vjenu. tv0 ejqhf meiosis I does crossing over occur, and what is the outcome v *7uevj.2qtuh j l*u0nehd,3 of crossing over?

  Which of the following statements does not describe a step inz2rt628 p w :hxltq6ea the sodium-potassium pumrh2:6lzq te xw8tp62 ap cycle in the neuronal cells?

  Which row in the table belo: ozbjy8ma) u.w is true of meiosis?

Membrane transport is important for allowing particles to move across the cell h5ctxqj2 (/ da67hqr)fwfp8rmembrane and respond to changes in the chemical composition of the extracellular flht5cf/) fr2 h p(arqxj86qdw7 uid.

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 rea dbl1 x+v7r7agulated 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 showe ,pb kg4s3a2xzw rt.3s the concentrations of different cyclins during the cell cycle. Which cyclin is involvedp2 3.twbg4x3k sre az, in preparing for DNA replication?

The diagram below shows chromosomes during mei qb9y: lbzttw )xqy)):osis.

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 meios wn96js0ix+s 5fxle 2et8 x5 lclg3dv,is involves the separation of homologous chromosomes?

  The mitotic index of throat tissues taken from 4 different patients is shown be y2-dk f2 r2n6ddeqr(elow. Which patient is most likely to have cancerous throat tissr2d 6e(kre y2d2qdn- fue?

1.Draw a labelled diagram to represent the process of crossing over. pina sul*4,l58yo ocw o* *c*j

2.Compare and contrast random orientation and crossing over.

3.Outline the stages of meiosis.

  The image shows an abnormal hqe i;c );1j55z u8yssl*xtbj puman karyotype.


What is the abnormality in this karyotype and its cause?

The graph below showi:x75qk b7*li p ao0zds the relative amount of DNA in one cell during one complete cell cycziapd iobk50 *7qlx:7 le. Each 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 a cross between a male cat that is hdkuh7 xjgqa, ( )zut0yn0zy1;omozygous for brown, longuz07gx,h (u njayzk1yt;dq0) hair and a female cat that has black, short hair.


Which of the offspring has a recombinant genotype?

1.Outline how polygenic traits can show a nw(cplqv84p66q48coik i4c6hrk *w l9 sopwe* ormal 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 show,pvf * ; sie8x6ts.lsin in the diagram belp;sl sxi8t6is*f v.e ,ow?

  The photomicrograph shows qv4dvy)0g6eq +; jerd a pollen grain from L. candidum (Lily). Which stage of meiosis is 0jqg;eq vd 46ydvre)+ shown?

1.Outline the events which would lead to an indi,./ii(e+c igv )vu trividual being born with Down syndrome, which is characterised by the presenct/rigvc , ()+iuvie .ie 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 co )9aid arlsx t 5d3/,*utc0alchxuy//nducted on white onions (Allium cepa), under controlled conditions in a lab, to investigate the xayu9/i auds/a ,rht0l /x d3)cltc5*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 dmf2(8 ci)qi i5 q)ufykiagrams below show two cells from an organism withkyiuci) iq) q82f 5mf( 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 expressionp7+h chje5l6 rzv *mh7 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 staggmnli.;:h /wu. yvg /ajv+d)s es of meiosiahl)wgsi.n//dv:vu+gj ; ym. s. Which row correctly names each stage?

  The micrographs show four phases of meiosis I in a plant. In/ 1a1axst c5r9nf3g tm what order do these phasertm 1 sat35anc fx9/g1s occur?

Mitochondria are responsible for supplying metabolic energy in ,7gq(o zauk4 16tm ubzeukaryotic 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 u1ob (z6uqa, 4zgkt 7mof 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 in different sta0o -0pfoh0cjk 4jls at h61kk:ges of the cell cycle in four samples of lung tissue from four patients. Which tissue has the lowest mitjaj ph01oo06 h-:k kk4c0lsf totic index?

  The diagram shows the dominant cyclin/CDK comp887 u3ovy rws,u:qfjllexes at different time points in the cell cycle. Which cyclin/CDK u3 qwf8ro7,luv: jys 8complex activates DNA replication machinery?

  Studies have shown that z aug.) yi5/yfgenes such as Cyclin Dependent Kinase 3 (CDKN3) are highly overexpressed in cervicali ug)zy 5y.fa/ 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 cyc *st*la;* k2 xq4l ,hzhqy2ycvlin E the highest during the cell cycle ?