The graph below shows the relationship betwee pjllwvk;(xn9d 4t6m1n maternal age and the incidence of non-disjunction. Whavw1;l4kxd( 96 lnjmtp t relationship is suggested by the data in the graph?

  Which stage of meiosislunr74 a az4e.bzh3t; is represented in the diagram below?

  The diagram below shows chromosomes d3pa m pen8-.9fnk:s2exd p /rluring 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 numbescg-o on x 68cp3+fzr+r of alleles of a single gene which would be present in the nucleus oonx8ccog- +36 p+zr fsf a cell as a result of each process?

  Which keyword is matched z2 w p2bqs3lv(gou4e(to the correct definition?

  Which statement(s) about m+z)je*69k 3kp n9ndhug t5yc gitosis 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 ledf*zaq . -89 oslofep*tter points to a cell in anaphase?

  During which stage of mitosis does the nwt7 0 2gista(duclear envelope break down?

  Which one of the following transport pra u+sr/(zrj2hoteins only carries out active transport?a 2(+rsh/ju rz

  Which process does not happen in tu/ d*),tcd /ife u-c) hsk5ehnhe shoot apex?

  Which type/s of membrane transport do/does not require energssiw xe 1mix;:;o*x-n u2u;xcy expenditure?
I. Facilitated diffusion
II. Active transport
III. Osmosis

  The diagram below represents a cell with a diploid number of 4. W*um ;erzz 6k;xhich stage of cell division is the celur*k;m;xz6e zl currently undergoing?

  The photomicrograph belo;/vmiuzyt9ad1 f 7k7t w shows a root tip meristem. Which of the following sentences correctly defin vz7tyk1 9 fmi;uatd/7es a meristem?

  When does the random orientation of homologous chromosomey dh,t;7n:c kat aau;+ pairs occur?

  Which process does not: ,6u6q-boyq00x hqethjbmj- occur during meiosis?

  If a cell with a diploid numbp a .vk+l9y;f ejt,j0ier of 36 undergoes mitosis, how many chromosomes will be presel,90pyet+jvfaik.; jnt in each daughter cell after cytokinesis?

  The image shows a micrograph of a cemx 3br1hog 8qe)hp:1ull.


What explains the appearance of the cell in the micrograph?

  Which statement(s) about homologou1zlkk+io4tu 1,ezqcd/dlk ,+s 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 forhrmz 1tf0rig-d+f6 /,n oq,rhqf; vl * an individual with Down syndrome.

Which statement is not correct?

  In the cells of a horse (E. caballus) during prophase I of meiosis I ttu3s8 csjud/ +1/brajbt; ew. here are 64 chromosomes. What is the haploid number of chromo.t+u1r3/jusaj 8tdb esbwc; /somes?

  Which arrow is pointing to a chiasmak5 2vqu oyo+rb/ 65cx1x 9cl*bcw pr1x?

  The diagram below represents the structure of a shoot apicmi w//1vt0 .l z5 -)sk*e5ivhugngqojal meristem. Which row in the table correctly identifies the processes occuring in the structures labeledmz5ln1/vq/jkw -g0)5u.*o tsig vie h in the diagram?

  How does meiosis promo ts* lpisjao0 69/hb-ote variation?

  Which of the following s)luuft06n-)dm k/r: w+h6z4ua pl oce tatements 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 twogw/hr i h;p3/n 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 of secondary tumours from primary tumooi:dqfu;c/kec4p 0 k:urs as a result of the movemeceq/p d; uikk :40of:cnt of cells?

  How many chiasmata an* 1)jscd -x1hh f0fhto py niuue1+33re present in the diagram?

  Which statement is aa3j6u/wtj no: s9tzru25 prj9 similarity between cytokinesis in animal and plant cells?

  Which stage of meiosi0pldj;mv ahga8 m: w0r;6s 7iexjn((bvut a78s is matched to the correct description?

  Which statement(s) are true of meiosis I but not meiogk-omj-ff,g 5 3yj/mlsis 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 after the first meiotic divisionao)w r(- t:7ykmm0h zi,nedy- ui;o.alho19 e . This results in the formation of one large cell ;iok - .o9 -m ), eidryeahaou710zlyhw:mn( tand one small cell. What is the fate of the large cell?

  Which row correctly describes diploid and haploid cells inas5m5 bi xcyab *ch7mj4 v8gl:fl)6v7 humans?

  The following table shows the diplo yh ve+i7 wks,+qen57oid chromosome number of a range of species.


Which of these statements is correct?

  What conclusion can be drawn from the karyogram below? p;j(k+ gnw8u n

  Which of the following processes is characteristic oy.8 bu/c4qw wulcqwi lnib,,m0( .p: af the meiotic and not the mitotic cel.,q/u la b .pi0nqu(m8 ,y4i:wbwlcwcl cycle?

  The diagram represenzu .pf/vzlkds/26yn /ts 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.pvxl wll zp1z-d0lt(78n6 uu ;zt5+ o xl0itt0 Which row shows the correct chromosome npnttl i-(twx+lz;70utz60zoulx pvl dl 5081umber for different cell types and cell division stages?.

  At the end of which phase of meia qq p0+zbt 2kpe1r+n+osis I does crossing over occur, and what is the outcom 1pekrq2 0+pbq+tz+nae of crossing over?

  Which of the following statements qw32 eqqem3 /wpm +u8bdoes not describe a step in the sodium-potassium pump cycle in the neuronal celpuwew2e3mb/3qq +8 mqls?

  Which row in the table below is true of meid l( .(:c bqdxl0p+b+ 5icjwphosis?

Membrane transport is important fom /;bi:;7kqdcreu5p; ce t ti8r allowing particles to move across the cell membrane and respond to changes in the 7 qce:;d km tr8 ;bieic/utp5;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 regulated in c vew.0n7 idu(qa+f;rccpp 4 p:ells.

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 khj/y1:qxgt;p73rz5s x8n .iu 5tiyvof different cyclins during the cell cycle. Which cyclin is involved in preparing for DN3t5j 7is1ig:; uv rhx xny.pz8tkq/y5A replication?

The diagram below shows chro3 iw;j6dcplgl7ips8edk+ . 1s.m ,ztymosomes 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 involve6oidqv ix 5pm882yr4xf 6ih7 pg7xd5is the separation of homologous chromosomes?

  The mitotic index of throat tisspq1b + q;g97rhjtpm (ques taken from 4 different patients is shown below. Which patient is most likely to have cant p9 p(;bhqjg+ q1qr7mcerous throat tissue?

1.Draw a labelled diagram to reobuw9 7ih;gds.9yr udn o5w,3present the process of crossing over.

2.Compare and contrast random orientation and crossing over.

3.Outline the stages of meiosis.

  The image shows an abnor/0xuzmv r-n4mvr0wofmj b( l ) sw.6+xmal human karyotype.


What is the abnormality in this karyotype and its cause?

The graph below shows the relative amount of DNA in one cell during o(;jhc6v w o*mfr +w:cene complete cell c ojm(*r6cfwc;+e vw :hycle. 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 mald2ry 4m *trod5rqs mos+ )7e)je cat that is homozygous for brown, long hair and a female cat that has black, sh m7)ero qtmyo5r)+s jrd*42s dort hair.


Which of the offspring has a recombinant genotype?

1.Outline how polygenic traits can show a nor ;p6 btm,n0zumr ys)j;g e5s+dnj6zy2 mal 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 cros)f +o-v 4ggzbuua1.*kmd wh f9sing over of non-sister chromatids shown in the di b-9 4uk* u1hw.gdfam)zof +gvagram below?

  The photomicrograph shows a pollen grain from L. candidum (Lily). Which stagk ;bs.cfivcr/x06kij 2(izi ) e of meio/j(c; viibk2) c .i6i0krxzfssis is shown?

1.Outline the events which would lead to an individual beingt;lg cs43sy .ji6.zmr- gj3i 4*mvorj born with Down syndrome, which is characterised by the presence of three copies of chromog.r*4r;g4tj 33j.js vz- l6my co misisome 21.

2.Explain how meiosis increases variation.

3.Outline the stages of meiosis.

The mitotic index is an indirect way of measuring plaek 7o1s .dqro k03edojc.b0.h nt 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 mitotic index of the roots. 1cko.s .e dj eo 3k07dh.qrbo0


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 cel) .g(odsoha4lls can divide. The diagrams below show two cells from an organism with a dipo(doslh 4ga.) loid 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 grj-xm l0/s;c eoowth.

2.Outline how growth is controlled in the shoot apex of plants.

3.Explain the process and applications of micropropagation.

  The diagrams below shyk-3jr qv,rvmy7 z+ j1ow a cell, with a diploid number of 8, in different stages of meiosis. Which row correctly names each strv 1m73j ,+-jvzy qkryage?

  The micrographs show four phases of meiosis I in a plant. In whau2qvy5ky9xe 8 t order do these phasqxuke9 8yy2 v5es occur?

Mitochondria are responsible for supplying metabolic energy imc7x6w(ix7r n n eukaryotic cells. In most eukaryotes, which reproduce by sexual reproduction, mitochond(xr xm76ni7w crial 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 cells in different stages oftw qr/y 2cmrf;1p1 o we(urf7; the cell cycle in four samples of lung tissue from four patients. Whicf rmr;r1fep1(2;ocw uty7q w/ h tissue has the lowest mitotic index?

  The diagram shows the dominant cyclin/CDK complexes at different time jfx6id pp:o)( points in the cell cycle. Which cyclin/CDK complex activates DNA replicatio:ipxd(6jfp ) on machinery?

  Studies have shown that genes such as Crbfz 204spl* h+ud86a(bk) ox2gtyyb yclin Dependent Kinase 3 (CDKN3) are highly overexpressed iobb+b gy4ha208 u)f6dlp2 zkx*ytrs (n 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 cell cyczb8dho(s*raeh) 0 + frle ?