The graph below shows the relationship betweenzonrqy15cfwfex, ;a// l9 m/h maternal age and the incidence of non-disjunction. What relationship is suggested by the data in ;o1r/cl,m zxfw/y ehaf9 /q5n the graph?

  Which stage of meiosis iqe1;shz e, .zus represented in the diagram below?

  The diagram below shows chro57 plv n/j*6 rq;ksifumosomes 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 alleles of a single g6xoot74;;p- +egm opgrhxr4g ene which would be present in the nucleus of a cell as a;rp e;gxhtr+om xg4 4 7gp-6oo result of each process?

  Which keyword is matched gefg dz/pw+ z)-l,g4/kyb6hlto the correct definition?

  Which statement(s) about mitosis is/are tw v9 :kmrg;*gtcw6 2ahrue?
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, whi(eow7r)m a:alch letter points to a cell in anaphase?

  During which stage of mitosis does t3u9.,h5 c4sm vpk bmnjhe nuclear envelope break down?

  Which one of the following transport proteinpxf8;y2m+/ culox zp-s only carries out active transport?f pxm-2/oly8 p+xc ;uz

  Which process does not happen in tfw;iw2udprv .b- r) j.cr 7k+pax: m*jy w;x7che shoot apex?

  Which type/s of membrane transport do/does not x grea2 s:.nbe-v-2:k bz1jyprequire energy expenditure?
I. Facilitated diffusion
II. Active transport
III. Osmosis

  The diagram below represents a cell with a dip* 4 y;lfm9txqf//p iugloid number of 4. Which stage of cell division is the cell currently undergoing/tq4yx iu *fpmlf;g/9?

  The photomicrograph below show8n w+w1b7zrpab 6 tmei/:iq0ls a root tip meristem. Which of the following sentences correctly defines a mern1z:qit bb7m/w8 w+ e0iap l6ristem?

  When does the random orientation of homologous chroqr3*x0l c e/vkmosome pairs occur?

  Which process does notnt lj3ej5.x 1huug.z, occur during meiosis?

  If a cell with a diploid number of 36 undergoes mitosis, h0 3x v;cfsqjl nb40hz7ow many chromosomes will be present 7cbh0 f4jnqx z3;vs 0lin each daughter cell after cytokinesis?

  The image shows a micrograph e (jq7e )d9 ;t(e: wr-mrmovxmof a cell.


What explains the appearance of the cell in the micrograph?

  Which statement(s) about homologous chromosomesoab o g68b-m*mf7apmt o9kv77 efhdp05 6dvr/ 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 utk h1g4 dgq16ivt0p+individual with Down syndrome.

Which statement is not correct?

  In the cells of a horse (E. caballus) during proph 4 jf0udzk)w2vio h /hz27hhf ;m8u+hdase I of meiosis I there are 64 chromosomes. What i 8zh4hf7+0dmu zw)id k2h/ j; vohfuh2s the haploid number of chromosomes?

  Which arrow is pointing to a ch 1zwhu ;:g;m*a feuyn b6q/u4ziasma?

  The diagram below represents the structure om+i. 71qmfht3j0qsn,/jp sz of a shoot apical meristem. Which row in the table correctly identifies the processes ojoz/.1i tqqh0,np3mm sfs7+j ccuring in the structures labeled in the diagram?

  How does meiosis promote vaat63x yem he7.riation?

  Which of the following statpr6 x)0n( oubtements 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 two homologous chru* ;ap3dsk07 cxg5metomosomes.


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 tumour56g rqx .cbmjo+ny/3h s from primary tumours as a nmc6xyrjohq3 g+/.5 bresult of the movement of cells?

  How many chiasmata are p( v.w:b q/dxrx7k gz.dresent in the diagram?

  Which statement is a similarity bet-i2v t9k/; rlqx9inq)cy7f ryween cytokinesis in animal and plant cells?

  Which stage of meiosis is matckmv(c/iqup (+hed to the correct description?

  Which statement(s) are true of meiosis I b8t2- aiyyo0wa5stpw (ut 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 fi bnose*ubyl+e 5*jt77g3/ k etrst meiotic division. This results in 7b*y73t bon +ts5kgulej/ee*the formation of one large cell and one small cell. What is the fate of the large cell?

  Which row correctly describes diploid and haploid cef.l yus lj,b eh+;5tg(lls in humans?

  The following table shows the diploid chromos v0vuaexa(vsp/b jtg w7u/8/ )du 5-svome number of a range of species.


Which of these statements is correct?

  What conclusion can be drawn from the karyogram below? aj8d9 * kxnm2umwddps4yg +t) .w0k2j

  Which of the following processes is characteristl;)cf l8 bnpiu9wij5co) 27bv ic of the meiotic and not the mitot;)wc i8v 7l9n5 jbpc)uoi2lb fic cell cycle?

  The diagram represen 0yae6l6 eq.n0m cu-sy+mu+rv 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. /*lqhh8 zevf 88ek:yte)l4 ibWhich row shows the correct chromosome 8l4h z*e8ebq v:kf8t/el yi)hnumber for different cell types and cell division stages?.

  At the end of which phase of meiosis I does crossing over occur, and d3lc07z yw6u fwhat is the outcome of cru3fd76 yl0wc zossing over?

  Which of the following9,ql-xn 3u6h n; q2xfc1fwxjm statements does not describe a step in the sodium-potassium pump cycle in the neuro m -cjun6w;1ffx3xlx, 9nq q2hnal cells?

  Which row in the table below is tru ,t 1,y,vtxigkzxcy1 8e of meiosis?

Membrane transport is+de 1iz/ tvwfd71n4 uk important for allowing particles to move across the cell membrane and respond to changes ivuwfz7/1tkdne +4i 1dn 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 isb ub+t y15hm1n regulated 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 dur5 7w:bqy,v.zsam2 v cding the cell cyclazb :scm7 5qwyv2,dv. e. Which cyclin is involved in preparing for DNA replication?

The diagram below shows chromosodz te j),eok:q:z6cf*s o8b.z mes 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 the separation of homologous ch(y n p f (s/mdiacr2r7s87t0 oty.fqk4romosomes?

  The mitotic index of throat tissues taken from 4 different patients *tn2 qccan ):xz g3+apis shown below. Which patient a )2c *pnaczt:gxq+n 3is most likely to have cancerous throat tissue?

1.Draw a labelled diagram to represent the process of crossin4bh;a2w x8lbsu f,5ry g over.

2.Compare and contrast random orientation and crossing over.

3.Outline the stages of meiosis.

  The image shows an abnormal human karyotype. 2r *zeq/escl4


What is the abnormality in this karyotype and its cause?

The graph below shows the relative amount of DNA in one cell during o uam6z(7qbn: , drxh6dlh,- ndne complete cell cycle. Each letter represents one stage of theddl7rbnq (:,d m-hx6 hnz6ua, 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 homozy ,1eip .m6hqkajag9u;lj ((jrgous for brown, long hair and a fea;9rqm1hiu.,( jjp 6 e kjg(almale cat that has black, short hair.


Which of the offspring has a recombinant genotype?

1.Outline how polygenic traitsxbn 6 n/)a; ;h;qdagedwz5 ,jh 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 fr 9e pzk7r:j*m: r.d)2moude9d k dwrj1om the crossing over of non-sister chromatids shown in ther 1 jpm*u r97ze92ok:)wkded j.drd: m diagram below?

  The photomicrograph shows eb9c/k7 sxo8zkyk g/vo,6)m ha pollen grain from L. candidum (Lily). Which stage of meiosz, )9kgve bx8/ omokyhsk7/6c is is shown?

1.Outline the events which would lead to an individual being bornre -j8vo4mf ry:ctj.x8 f0m b5 with Down syndrome, which is characterised by the presence of three copies of chromosome :c850ff jtmerxrm8-vojyb .421.

2.Explain how meiosis increases variation.

3.Outline the stages of meiosis.

The mitotic index is an indirect way ofkr 59bv-g6ao c measuring plant growth. A study was conducted on white onions (Allium cepa), under controlled conditions in a lab, to investigate the effect of soilkv6-ar5cgo9 b 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 bel5 4 nxbcgsi.3 aegi:6kow show tw53:g6iineb4ca ks.x go cells from an 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 grow 3; fsw2g:bzsv4db 8vqth.

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 cellyg ,jofctt+dff5 67e;, with a diploid number of 8, in different stages of meiosis. Which row corre ;+6d tjfo7ftg cfy5,ectly names each stage?

  The micrographs show four phasesg+)blxn+r uf: of meiosis I in a plant. In what order do these phases occur? :+xunb+ r) gfl

Mitochondria are responsible for supplying mevnj*6s6g go7xj1h r pfsw6 6f/tabolic energy 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 that, in some e 6nsg76fxjhg6vwf*os6rp/j1ukaryotic 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 numbezw ab/s9o);grr of cells in different stages of the cell cycle in four samples of lung tissue from four patients. Which tissue has the lowest mitotic indg) z;9rwbo/asex?

  The diagram shows the dominant cyclin/CDK complexes at different tim.b o.r lh1oiq6e points in the cell cycle. Which cyclin/Cbq.hi6 .olo1rDK complex activates DNA replication machinery?

  Studies have shown that genes such as Cyclin Dependent Kinase 3 (CDKN3) n olfug6zgj7y+ .z- ;bare highly o-;.og+bz7 fzgj y unl6verexpressed 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 highest duri;x,zhxb by r8hxu*/m6 ng the cell cycle ?