The graph below shows the relatec iww 5zq6 qrfc.(b7p e;++qmo8-eb aionship between maternal age and the incidence of non-disjunction. What relationship is suggested by tc7 f6bqq-q 5rcmezp+b e ;wi 8ow.+(aehe data in the graph?

  Which stage of meiosis is represx)by.bxbcyc 5 g/hh; 1ented in the diagram below?

  The diagram below shows chromosomes during mvf *: 1 mpj2 fa/xv5x-ckqd:tteiosis.


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 nq 5wn /+a,zh yrk5d9iw rin6o3umber of alleles of a single gene which would be presr wn5,ii/rhw zn kaq6o3d+59yent in the nucleus of a cell as a result of each process?

  Which keyword is matched to t1 p;m (g1siix o;cw)i-w0vgtohe correct definition?

  Which statement(s) about mitosis is/are true? xo mw-ew60d;q t;li 3o
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 lett53 (-ahh 1nh.iyibq sker points to a cell in anaphase?

  During which stage of mitosis does t*5 f1g 2ix;rk apwcca6he nuclear envelope break down?

  Which one of the following tr:/7x1ml b,nz/k bncggansport proteins only carries out active transport?/, bb1/cgzlm:7x nkgn

  Which process does n*yn2x0 e0n u3 f n.(ktilk,edcot happen in the shoot apex?

  Which type/s of membrane transport do/does not req / rsty6zpw65fuire energy expenditure?
I. Facilitated diffusion
II. Active transport
III. Osmosis

  The diagram below represents a cell with a diploid number of 4. Which stage oxy dqqpuo* )m511.: iw7k kyuqf cell division w op:i m1k*yy x5)udk.uq q17qis the cell currently undergoing?

  The photomicrograph below shows a root tip meristem. Which ofjqx36gt6i jr 0j73azb the following sentences correctlq6 7ix z 6jgjba0tr33jy defines a meristem?

  When does the random orientation of homologous chromoslx63o loud*r ,n5awp6 ome pairs occur?

  Which process does not occuc3e:k+.zd)dhp x ml z-iws6p)r during meiosis?

  If a cell with a diploid number of 36 undergo x k /bn1fo*b n(8fszzwsb4)j8es mitosis, how many chromosomes will be present in each daugh o14wxz8b(s fjnk)b8 /b fzn*ster cell after cytokinesis?

  The image shows a micrograph oc1nn*jd m x u71 l:ipz0wxlk5)f a cell.


What explains the appearance of the cell in the micrograph?

  Which statement(s) about homologous chr qgj;5ou3 au5aj41 nndomosomes 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 foryo j52rvc 79j9t x5cqwy3gh1e an individual with Down syndrome.

Which statement is not correct?

  In the cells of a horse (E. cabal 3rkstqr;,w5dlus) during prophase I of meiosis I there are 64 chromosomes. What is the haploid number of chromosomesrt3ksd , w5;qr?

  Which arrow is pointing to a 8 ) 8mgvep8tugro +juof4v ld;d *f6l,chiasma?

  The diagram below represents the structure of a shoot apical meristem. Whic 4ii1 x-l2pkq.zamg3q h row in the table correctly identifies the processes occuring in the structures labeled in the dix1gqi-z mk3.ai42qpl agram?

  How does meiosis promote variatiqpur ff *ux9dz/ g/4dv0+)gmion?

  Which of the following statements is/are correct fory. t(qf2gw5 czrsikzv9 u3 d;sc611nu 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 hoh y03h5yt69o 8a14whq s, ddtxikblc ,mologous 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 pri4 no7j2nq4cr:dv1r p umary tumours as a result of the movement of cell1ujc4r4 d7 nq2:vpo nrs?

  How many chiasmata are present in thf-5(ygb bn rhw7+lzpr7 a ie.(e diagram?

  Which statement is a similarity between cytokinesis in animal and plag4 2hi;. f1 tbm4.weznh*efnint cells?

  Which stage of meiosis is matched to tc+gp9 qegt*w +he correct description?

  Which statement(s) are true of meiosis I ue) c2 wvv9jv6nty x1+but 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 oocyte after the x8 9sn;yg*lwgd; 4m9wmp;o nyfirst meiotic division. This results in the formation of one large cell and one s gpgmy;;n94wm9 snlxy; *8 odwmall cell. What is the fate of the large cell?

  Which row correctly describes diploid and haploid cells in humans?pq9 zmcx/ ;x0xs k3(pe(sbph2

  The following table shows thex1uz*mde gl0 glladv 6.lzxyw6)g- 2 . diploid chromosome number of a range of species.


Which of these statements is correct?

  What conclusion can be drawn from the karyogramnhl dxxj-udeswk4*;t h:2 4/a below?

  Which of the following processes is characteristic of th +cap *udzuhg2u jg(8f /;qd(ge meiotic and not the mitotic cell cycle8p f+*gg ddhuj(2 q(ucz/a u;g?

  The diagram represents a bud with a s x; u8z6uqhqd(p- 0mpvhoot 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 trogl4;;8v*t in4 kc4yjoh cpwm62+xtz.een4iwx codytes) is 48. Which row shows the correct c8cyeexh44t pvi;4i4c j+ c mw*x t;zno6w.2nkhromosome number for different cell types and cell division stages?.

  At the end of which phase of meiosis I does crossing over occu/ox17jv a5 ( (h ,ge2 q7notc j1hn1bstmp5apcr, and what is the outcome of croc11 n5sq5xj2tv7,o/jnecot7p(gm1h b ap a(hssing over?

  Which of the following statements does not describe a step in the sodium-p;boa fh747iy* zu3xus hf,vygyp *5e2ti+;s yotassium pump cx ys;t*iebsh4y,+3 y5ypzfuio7uv a7f;*g 2 hycle in the neuronal cells?

  Which row in the table below is true of 6:h ts3k mug iu j:+yvwoda5f24 se3w;meiosis?

Membrane transport is important meq u c cn-;962vg3pq,c.nkze for allowing particles to move across the cell membrane and respond to changes in the chemical composition of tzcgn 2;m 69cv-. euqnkqce3p ,he 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 regulax.0 ,r7m59tspaj pgyrted 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 cellyv7g./:pts n ,fpzi.o cycle. Which cyclin is involved in preparf/ ,.zn7tgoi:yvs pp.ing for DNA replication?

The diagram below shows chromosomes during mei 1:ss s m)6tja(scynqo(k54 pnosis.

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 o g6c;v+fr/ gcthe separation of homologous chromosomes?

  The mitotic index of throat tissu xs8bag1w(6 j f 58rlqbn)p2yqes taken from 4 different patients is shown below. Which patient is most likely to have cancerous5n8 2q)jrbf1gpq w 6b say(l8x throat tissue?

1.Draw a labelled diagram to represent the process of cebyg 18+gr(q bz5kf p3rossing over.

2.Compare and contrast random orientation and crossing over.

3.Outline the stages of meiosis.

  The image shows an abnormal human karyotype. z3c8whrfhl4jxt :17a


What is the abnormality in this karyotype and its cause?

The graph below shows the relat) slb7o- *bxdt (abjg-ive amount of DNA in one cell during one complete cell cycle. Each letter reprb(jdb *t gxo)--bs7laesents 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 fo0my)1z wm3t71tkfua cross between a male cat that is homozygous for brown, long hair an1f0mo m)uf7w tktz31yd a female cat that has black, short hair.


Which of the offspring has a recombinant genotype?

1.Outline how polygenic traits can show a normal distribution.w./nh adlt-g1

2.Outline the differences and similarities between homologous chromosomes.

3.Explain why expected and observed Mendelian ratios may differ.

  Which gamete can result froonu i:t:ry/m(m the crossing over of non-sister chromatids shown in the diagritr: ym( :nou/am below?

  The photomicrograph shows a pollen grain from L. candidum (Lily). Whichwf(5k6u cm4 /d(fptjt9 7 sthmlyw4v6 stage of meiosis is s(( yjm5t tsfp966 cw4l t7/wk fu4dmvhhown?

1.Outline the events which would lead to an individual being born witwqco 02:-/ lud f6qvpe;)8aeu rb6p ych Down syndrome, which qf -:uoq p/pc);e6yrauc8lb6v e0wd2 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 way of mea 70oxontjd /y-suring plant growth. A study was conducted on white onions (Allium cepa), under controlled conditix 7tno/o-yjd0ons in a lab, to investigate 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 ways in which cells can divide. The diagrams below n,)vwiw/7hu eshow two cells from an organism with )vewi,unw7h /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 stlpk v,7 z;dg h54:w1mtrn0edjem 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 ak2jgg3- in,xq)hm2j y cell, with a diploid number of 8, in different stages of meiosis. Which row correctly names each n3 hm)gj2kx iqy,g 2-jstage?

  The micrographs show four phases zx)b2 inhq z7 z:r45u2 z 5wg/ven:srnof meiosis I in a plant. In what order do these phases occur?gnzu4)bvn5enzx:q/ir zw zs:r225 h7

Mitochondria are responsible for supplying metabolic enerj8eo4 lel8 ;z ike*3*xjqs v1lgy 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 th348*q;v oej jkll 8z el*es1xiat, 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 of the cv(c0q6aihph21cmis wdzu +q61 j ,m2i ell cycle in four samples of lung ti, j2 zq26+cvpwd 10 iiscqah6m1 hium(ssue from four patients. Which tissue has the lowest mitotic index?

  The diagram shows the dominant cyclin/CDK complexes at diffe5oh: 9ocw qwu/rent time points in the cell cycle. Which cyclin/CDK complex acti oo u/wh9w:c5qvates DNA replication machinery?

  Studies have shown that genes such as Cyclinb7t 4y+elp5h*mornn8f0q vs, 5dk )je Dependent Kinase 3 (CDKN3) are highly overexpressed in cervical ,+bpt sq)d5m nl58 oj0*e7eh krnf4yvtumours.


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 xh)1cxidf wrtyeq6aao215 79dn/c m 2the highest during the cell cycle ?