The graph below shows the relationship between maternal age vd/w e.n unzwo8a.g:1emy:ev.ml 5f:and the incidence of non-disjunction. What relationship is suggested by the data in the graph?ewwn.zu./y edm58 :.omg::a fvevln1

  Which stage of meiosis is represented in the diagra8zl0sk+ko(1ncm8 pn8. gyqj cm below?

  The diagram below showyjau4uih;+bd j:87.np( t bt xs chromosomes 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 geet/.;v 8;,vpxcvovlpn dd 9)zne which would be present in the nucleus ozcvv ev)9 d t p;v;x.dn/po8,lf a cell as a result of each process?

  Which keyword is matche,;bke gps4a 0id to the correct definition?

  Which statement(s) about mitosis is/are true? ;vs9cv+(8 tcrt)s/2 hheatvien o52n
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 oaf:;v2by9eocwcch1o4 h 8myf/ e+;npoints to a cell in anaphase?

  During which stage of mitosis does tb1fd34rp 0;ssxqhg,mhe nuclear envelope break down?

  Which one of the followis.l 205jwmg llng transport proteins only carries out active transport? w5s m2ll.lj0g

  Which process does not happebr2/kva6* x;w np/(go fysi8i5 is5rpn in the shoot apex?

  Which type/s of membrane transpz t:;zk(k*jsa bv0lkuwct ,)1ort do/does not require energy expenditure?
I. Facilitated diffusion
II. Active transport
III. Osmosis

  The diagram below represents a cell with a diploid number of 4. W 6mo/hjp mbi;1hich stage of cell dimhj6iomb/p1 ; vision is the cell currently undergoing?

  The photomicrograph below shows a root tip meristem. Which of the following sentvh610 z;p:jvj vb .fp1lmjg/fences correctly defines a meris:hjv61 0bfvg lmfjj p;.zp/v1 tem?

  When does the random orientation ofw+dsou 6,4*efgub*n p homologous chromosome pairs occur?

  Which process does not occur during meios(x4dlm8a+rq z is?

  If a cell with a diploid number of 36 undergoes mitosis5pg4 ;ci)edsm , how many chromosomes will be present in each daughter cell after cytokinemcp;eg4 s5)di sis?

  The image shows a mi8oq 0 u,wp;d:t8* mrzre pw)fncrograph of a cell.


What explains the appearance of the cell in the micrograph?

  Which statement(s) about homologo j -kvy bgykcxx5rs jubyb187:q;ic.3/)r*s nus 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 with Down syndrome.7znh n2qv b 2c j2mxby+7ra5)d

Which statement is not correct?

  In the cells of a horse (E. cagm5n lv0 otk q9 vwdm/0:;cbo(ballus) during prophase I of meiosis I there are 64 chromosomes. 0qkb l:;0 /movmv9tc(ognw5 dWhat is the haploid number of chromosomes?

  Which arrow is pointing to a chiasma? qy02 t*l94wj-k wkgsv

  The diagram below repres/ utvki/2e:24wn+vju 1 knux/k o9gizents the structure of a shoot apical meristem. Which row in the table correctly identifies the p /2/uok 2n kuet u/9vk x1gwiz4:jnv+irocesses occuring in the structures labeled in the diagram?

  How does meiosis promote variatzw;6b 5qr5lbu ion?

  Which of the following statements is/are co2 b hcj9-:.n+d ;plkw5twmyjirrect 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 chromosomes. bkdno8ww 93wbqh7 /l/


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 sedp.ns 32qdcdp) 0b7dl condary tumours from primary tumours as a resullcbd q0d) p72.d3pdns t of the movement of cells?

  How many chiasmata are present in the diagramxb i3agol+z7jm0zo0r c) )0dt?

  Which statement is a similarity between cytokines, 2x30 p dv ficska :)gah.f)vke :cjvqf.r,m*is in animal and plant cells?

  Which stage of meiosis vv +cp))faupd*l*dn + is matched to the correct description?

  Which statement(s) are true ,o k5oszpn3.s+ wj gcyc/ 5rp:of meiosis I 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 firstqv0mxk2j84. tz 1t cmk meiotic division. This results in the formation of one large cell and one small cell. What is the .v8m1jkq20x 4 t zctmkfate of the large cell?

  Which row correctly descr / *k arm-plnpi:j-cnmv1h6t 6ibes diploid and haploid cells in humans?

  The following table shows the diploid chromosome onary3 ;g 0md9v+z w5vo/ s9zwnumber of a range of species.


Which of these statements is correct?

  What conclusion can be drawn from the kaepq ,i8px)5uoszn y3/ ryogram below?

  Which of the following processes is char);tvd mk 0 9jueml:h5bacteristic of the meiotic and not the mitotic cell cycle?m )vu;d: 0mlbh jk95te

  The diagram represents a buv0 5v;h7v, ;m v u0cknbuytjdav4,t+td 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. Which row shows thh m *;22jyun(*; i2errk 5 wn,koyoiiqe correct chromosome number for different cell n;reh **iwn252u(ojy2kmko ;i, iqyrtypes and cell division stages?.

  At the end of which phase of meiosis I does crossisg/- 6p-sjlr7w3 ufc rng over occur, and what is the outcome of jpr-fs u/r s-lc w76g3crossing over?

  Which of the following statements does not describe a step in the sodis3bm59 8xkc zll54r zjudzm .*.7xxwgum-potassium pu *5zw x4z3 .m7xgu9lbz.sj8 xdk lmcr5mp cycle in the neuronal cells?

  Which row in the table below is true of np*p+ (3ag +l, etwmihpy8i0tmeiosis?

Membrane transport is ,ddsrrk w95, cimportant for allowing particles to move across the cell membr 59wrck,rdd s,ane and respond to changes in 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 is regulated in cel a7y smnh9wyy(6) vzc4ls.

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 differew rwy(fq ;-dwv.3v mj,nt cyclins during the cell cycle. Which cyclin is involved in prepar-d w;(fjw yv. ,3vrwmqing for DNA replication?

The diagram below shows chromohmar4v9hkb joe) ;- b3somes 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 separatiot *1ecu6xde f/h 74ouyo hi+-sn of homologous chromosomes?

  The mitotic index of throat tissues taken frods dst+v:s2 m0 h:l0 o lf:kj(oo70i ;rkdkcp)m 4 different patients is shown below. Which patient ik7c;l0hs:(2+ ktso v p0k o:ld)djrmio0d:s fs most likely to have cancerous throat tissue?

1.Draw a labelled dia9jax*1bprfz 93 -md9jdih-kygram 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 human kary ui1:7h z;7i f;pun3 c,dxpoxtotype.


What is the abnormality in this karyotype and its cause?

The graph below shows the relative amount of DNA in one cell during o2 z3dfotnk7w90g bus9ne complete cell cycle. Each letter represents one stage of the 2 0dnzgfuk7t bwo993 scell 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 hor 4oly mnu 9pg2g32wh.mozygous for brown, long hair andrl.w9 ng3 omghu2py2 4 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 distribus1( 5z*gmyz cmtion.

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 chromatidqu4izn4b-c0at 6c 6.) jrkf ufs shown in the.zb6f t 64cfrq-cuiuna0j 4 )k diagram below?

  The photomicrograph shows a pollen grain fl,f .0oh4kjsa)hyrhn 6b: 8xbrom L. candidum (Lily). Which stage of meiosis is showo4h6)0n.klj a bh hsxf8:, yrbn?

1.Outline the events w e* huodkp7+bwu)g( c3( ypu +f*wiv:ufddn(5hich would lead to an individual being born with Down syndrome, which is charactun* c:gu o+*(7 +vf(pfdb)kuy hi3 de5wpwu(derised 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 mea2xitox9t n (o0z*w 2qfsuring plant growth. A study was conducted on white onions (Allium cepa), under controlled conditions in a lab, ttq92i nwx0x t*z( ofo2o 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 diagramso37g mti ztr)0 below show two cells from an )tm30 7gtirzo 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 of4xr7 p+ mtv.yk gene expression 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 showe,suj1iuzf/og)em7 y3bqr .q.-kfl* a cell, with a diploid number of 8, in different stages of meiosis. Which row corre-eq lg)sjf1. uo 3qy, r zku7e*mi/.fbctly names each stage?

  The micrographs show four phases of meiosis I in a ploq1bh:+j6 acwp- 6bgzant. In what order do these phases occ 1p6q-bhbzcw o6+j a:gur?

Mitochondria are responsible for supplyingykn de- 5zf0yfd*k,lhfu 76 :n metabolic 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 eukaryotic organisms, inheritance patterns of mtDNA found in hybrid cells, which are the result of sexual reproduct:0* dlffhd y5 7y,uzn efkn6-kion 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 ceo,egq+yr + . jdir,+nllls in different stages of the cell cycle in four samples oljq+y i +.,+dn, eogrrf lung tissue from four patients. Which tissue has the lowest mitotic index?

  The diagram shows the dominant cyclin/CDK t4j luxw .+6*tr* ljgscomplexes at different time points in the cell cycle. Which cyclin/CDK complex activates DNA .sglluj4*w+rxt t6*jreplication machinery?

  Studies have shown that genes such as Cyclin0z1fvo q 5g0ai Dependent Kinase 3 (CDKN3) are highly overexpressed in cervical tumourg0 v1oq5afz0i s.


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 hiyw p lqm4o u1.5e-l3u9bzr3w qghest during the cell cycle ?