The graph below shows the relationshi*,/d6lr4onpm o8bnb kp between maternal age and the incidence of non-disjunction. What relationshipobr84np k6*b,l do/mn is suggested by the data in the graph?

  Which stage of meiosis is represented in t5g+2n5l*ucwjdc tq3w he diagram below?

  The diagram below shows chromosomes during tx/y3fa2toy6;lb s ky/lm9 4xj )z(ml 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 alleles of a single gene which,,v*0 -jt2wklqyox/vg n/qey would be present in the nucleus of a cell as a result of each procest0 */q-nyqgoe/vvlk,w ,jxy2s?

  Which keyword is matched to the correct definiticvs3u4a )inkn ig5r ;:on?

  Which statement(s) about mitosis is/are truwvcp4 3w)s6(fq6vak7t zr;k vhl m2j;s2dc2l e?
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 letter pointsta. 10eu+x;b yx4f vvz to a cell in anaphase?

  During which stage of mjz 2qzcshc;2 m9 l4:i-*ww vspmpqpl o*-rz3(itosis does the nuclear envelope break down?

  Which one of the following transport proteins opx -p*ut x4cluuk,3 n8nly carries out active transport?tukl3,upx c x8- np4u*

  Which process does not happen it9wa9o;n5k wkypg tf 3x 5+m5fn the shoot apex?

  Which type/s of membf) :hb /pyd)psrane transport do/does not require energy expenditure?
I. Facilitated diffusion
II. Active transport
III. Osmosis

  The diagram below represents a g :wxl**z-gt sz(y1)fn19 r ykeeh e8ucell with a diploid number of 4. Which stage of cell division is the cell currently und ef)*y* er 1 8-u(lhy 9s:gkxztewgnz1ergoing?

  The photomicrograph below shows a root tip meristem. Which of the following sen)imhca**t c 1 m4+uqx r(ucn-btences corre1ux+(bi*) aqumrct *c4 m hnc-ctly defines a meristem?

  When does the random orientation of homologous chromosome m23*amz3zq o+x 0yhho pairs occur?

  Which process does not ocbnp ev6jb mwq8+s k yguh75 m9s99xxpnl) 2y.;cur during meiosis?

  If a cell with a diploid number of 36 undergoes mitosis, how many chromosomxid 9y* lx:;*oj h7.xeeo,hwk es will be present in each x lie7k:j* h9wdeh; .yo*xx,odaughter cell after cytokinesis?

  The image shows a micrograph of f f8;9f*ur+-ve acg ioa cell.


What explains the appearance of the cell in the micrograph?

  Which statement(s) about hofir8w7 of; 9 -a )w5wme fwg5*:rluvirmologous 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 2dvrf pozv 9212iaih0 with Down syndrome.

Which statement is not correct?

  In the cells of a horse (E. 9eyd nhh.dx 5tx.km5- q5jdiq h( qbbep;1r4-caballus) during prophase I of meiosis I there are 64 chromosomes. What is the haplob-q-55(t 91bqid.dn4;h xkxh y.jqrp5hd me e id number of chromosomes?

  Which arrow is pointing to a chiasma? y,-h7hz pr, mj+ qgyx4

  The diagram below represents the structure of aq -.(weq; ynx q0oz0gd shoot apical meristem. Which row in the table correctly identifies the processes occuring in the structureqg -.0e xdo;(zwn q0yqs labeled in the diagram?

  How does meiosis promo, 8xc2xj5w8 n6:citt.,9v txyv wnbrste variation?

  Which of the following stkdo1zblx/6xti8..w 1 utxt40l:9 jf gldj2jzatements 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 fromp uxkc fy .ef2l8.6x11 anb6wl 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 of secondary tumours from primary tumours.j9 f/2jj/ m xjx4as;t/kioea as a result of the movement of j/saxf2em4okt.j xi;/a9j/ j cells?

  How many chiasmata are preft fq h-u//tzm; ,1giasent in the diagram?

  Which statement is a similarity between cyti o:-tq7lfaz qf f2;o:z0dm 0qokinesis in animal and plant cells?

  Which stage of meiosis is matched to tv /t+i.9xq *)urltagnkww:7che correct description?

  Which statement(s) are true of meiosis I but not mct +(kxx2qh -keiosis 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 oocmt4 fuq8oc utx+0t;.ayte after the first meiotic division. This results in the formation of one large cell and one small cell. What is the fate of th8.t;t o4+axufuq 0 tmce large cell?

  Which row correctly describes diploid ax8;4( (mdmx(;mg5yy hzmxmdj nd haploid cells in humans?

  The following table shows the diploid chromosome number of a range oftz/o9 qke8ix(0 /zztk species.


Which of these statements is correct?

  What conclusion can be drawn from the karyogram below? v t b5q1m k:4s:lib8pb

  Which of the following pro 29.o xk23 9mz.th.si yznnun(ephgd1cesses is characteristic of the meiotic and not the mitot1 k.2y9 .ms.zgp2ht oih9zxen(nnd3u ic cell cycle?

  The diagram represents a bud with *t s5 ez3i m/5a7t wyw-tijuv4+kt 3bsa 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. Which row/:i(rpiao8ydw t4lv 5 shows the correct chromosome na/ 8pi i(rd:5w4lyvt oumber for different cell types and cell division stages?.

  At the end of which phase of meiosis I does crossing over occur, and whaj 8gjqd 2jw72vs* b i-kjc5.cjt is the out 22ijd- s *k gcvbcj75jq.jwj8come of crossing over?

  Which of the following statements does not describe a step in the sodium-hc.dwv 2o+4l 9arw 4stpotassium pump cycle in the 2tw4asc9l4.v+ hrw o dneuronal cells?

  Which row in the table bel re/g hu8mx4)vj 6t7mxow is true of meiosis?

Membrane transport is important for all9gaiew k2e6wkwd3z 2.owing particles to move across the cell membrane and respond to changes in the chemical composition of2dk.za we92w3we ki6g 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/)p0vrm3q;rcvwt9 s,zx dfa x;535 uozcn+yc 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 a:uj khz /kt x1d6yz06during the cell cycle. Which cyclin is tzkdz/6 akx y1hj0 u:6involved in preparing for DNA replication?

The diagram below shows f54uo39pvs nv1v:bm ys)e wp6chromosomes 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 ttzifr61yh ll8:q h2 t6he separation of homologous chromosomes?

  The mitotic index of throat tissues taken fr7ee m7b: z z f4ng4::rjhkpat1om 4 different patients is shown below. Whi4:b eak zpm4fnj7:z7 tr1eh :gch patient is most likely to have cancerous throat tissue?

1.Draw a labelled diagram e,-d9 f dn:ufhlg(-ege,v:ws to represent 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 humanrfm1j ;q479q50ybh .khqr5abyed ;rw 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 crj( w6c )sn)xdomplete cell cycle. Ea s))nwc6 djxr(ch 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 homozygous for brow 8i9ni; ,+inn; vvlbemx ,fd2dn, long hair and a female cat that has black, short hair8lnei; i29+,mv ;nidd f,v bxn.


Which of the offspring has a recombinant genotype?

1.Outline how polygenic trgs0 b 6z:capy5aits 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 crossibizsg 6 mi h 3-;+2nzgy(lgcp;ng over of non-sister chromatids shown in the diagrs6b + l(-g;; iy2zzpgcmh3ing am below?

  The photomicrograph shows a 2x2le7 mcs4y cdze;t :pollen grain from L. candidum (Lily). Which stage of meiosis is show:mc 2s4;yxcdtzeel 7 2n?

1.Outline the events which would lead t dmf;jq:ax5a *0neg q+o an individual being born with Down syndrome, which is characterised by the presence of three copies jxg0:qfd;a5*+nea mqof 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;6d ;xn it z)pu)fjt.a. A study was conducted on white onions (Allium cepa), under controlled conditions in a lab, to investigate thu )fi) za;x;jt6tn p.de 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 lmf5owxdv + xw7z393n which cells can divide. The diagrams below show two cells from anow7w 9 nz+x35mv 3dxfl 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 expressido; t0e*c/(nmp. gsllon 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,; aujhw77bq1 whlfz0 v) ed+(p in different stages of meiosis. Which row cor7wq;01 )ab(uhvwzh l+ epfj7d rectly names each stage?

  The micrographs show four phases of meiosis I in a plant. I*k1 ks 3zlx(4 pbjzkdw +rhi-/n what order do these phx*lk1 +zi(ks-d3z r 4b whkp/jases occur?

Mitochondria are responsible for supplying metabolics bqok*wk4+ymz c+3y3 energy in eukaryotic cells. In most eukaryotes, which reproduce by sexual reproduction, mitochondrmzbq3wyo3 + sk4yck* +ial 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 z g 0yulh,bk;q 3/bd2pnumber of cells in different stages of the cell cycle in four samples of lung tissue fro puzbdk,0bl3qh /y;2gm four patients. Which tissue has the lowest mitotic index?

  The diagram shows the dominant cyclin/CDK complexes at different time p.*0 , grvcvzrgoints in the cell cycle*g,zcvrv.0g r. Which cyclin/CDK complex activates DNA replication machinery?

  Studies have shown that geneg b p:gbpw-mr 45o05g4lak s*ts such as Cyclin Dependent Kinase 3 (CDKN3) are highly overexpressed in cervical tumouobr-g55gb40wa sgtl:*p mk4prs.


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 cyc p/o1x +c, w1vwvjoe2dle ?