The graph below showgzz 8 88 kydx/yupj61bs the relationship between maternal age and the incidence of non-disjunction. What relationship is suggested by t8yby8 /8 gujk61zp dxzhe data in the graph?

  Which stage of meiosis is reprqohy:l a6iv ,. u pvkzn,b;;u1esented in the diagram below?

  The diagram below shows chro .k*q +lmsr;+c swpe-omosomes 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 allell)c o bfd t,.m4,qgc(hes of a single gene which would be prhc,d,)f (lo qtbcm4 .gesent in the nucleus of a cell as a result of each process?

  Which keyword is matched to the correct tlwkq.3oo cn 2 r(e)9odefinition?

  Which statement(s) about mitosis is/auoxm9ac/85pj9/8sgrg0c l xe1y aj , dre 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 letter po. -bo of5qrsn(ints to a cell in anaphase?

  During which stage of mitosis does the l ;.6kc3hnch93ri,b -hw pngvnuclear envelope break down?

  Which one of the following tr-gichgpicbr :,t) / l)ansport proteins only carries out active transport?itcg)),-gpl :b c/hi r

  Which process does not happen otv)-- 5d k; os )yvxxl *kevb1iv/,wpin the shoot apex?

  Which type/s of membratsuvrj g.:yc f -9)cw2ne transport do/does not require energy expenditure?
I. Facilitated diffusion
II. Active transport
III. Osmosis

  The diagram below represents a cell with a diploig 5;f0fk2ewfol 7vb6 nd number of 4. Which stage of cell division is the cell currently undergob f56g2 ;lke07ov ffwning?

  The photomicrograph below shows a+ x7;+u sfy;sfe/*n 3komrtr w root tip meristem. Which of the following sentences;r;+nfk ws3+ /ts r7u*oefmxy correctly defines a meristem?

  When does the random orientation of homologous chromosomewdmy: sz7 4vm; pairs occur?

  Which process does not occur during m 7n;sxua30k +)ua2rcpcj ur5ieiosis?

  If a cell with a diploid number of 36 undergoes mitosis, how many chrom;vpz+(kdaz*mr.5 m n fosomes will be present in each d+k d(*mfnp.;zr5zvam aughter cell after cytokinesis?

  The image shows a micrograph of a cell.dzx v3(ha n/6rn4a/8ut os pa0


What explains the appearance of the cell in the micrograph?

  Which statement(s) about homologous chromosomes is/arebfej na0.mof77h,.di; b wq* p 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 D. 2u 0 ju dlym2 4m)30npidvkgdkrz()vw6-xemown syndrome.

Which statement is not correct?

  In the cells of a horse (E. caballus) durindpe0avc .(l a1 ,/mvixg prophase I of meiosis I there are 64 chromosomes. Whavp. ,mcd0 /xa1v ei(lat is the haploid number of chromosomes?

  Which arrow is pointing to:m fzo1.o8c 3v6qlei l a chiasma?

  The diagram below represents the structure of a shoot apical mer1 s7fzai:2 sgbkie /m.istem. Which row in the table correctly identifies the processes occuring in the structures labeled in mif1gbia s.7ezsk:/ 2the diagram?

  How does meiosis promote variatic,uya-tsqym y *v0/5son?

  Which of the followinu r8mx3i 9k0(tw3vz7t.tlm + yeq zm5pg statements 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 gaa 4oc0m9vm;qexo9iz p66 qa+wmetes produced from 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 zmphf0e.pm7tvf (dv,:e+ov .of secondary tumours from primary tumours as a p( .+e .h70vfdopfvmm:ez ,vtresult of the movement of cells?

  How many chiasmata are present in the diagram? -v jlgjmz)5(u(2 vnf .qub.ip

  Which statement is a simi*/dpq 2qg owlp*9nxu:larity between cytokinesis in animal and plant cells?

  Which stage of meiosis is ma7 3g.b*u/vcfu v)jnwz tched to the correct description?

  Which statement(s) are true of meiosis I but not mei g icz+(q4e +8ef)pgzjosis 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 shows5w5otg b :oal) an oocyte after the first meiotic division. This results in the formation of one large cel5b:aotg ow 5)ll and one small cell. What is the fate of the large cell?

  Which row correctly descrp/qri l8u/;dy ibes diploid and haploid cells in humans?

  The following table shows the diploid chromosome number of a range of species.mcw* y0av wq152hik g9


Which of these statements is correct?

  What conclusion can be drawn from the kary (2pioqmva/d : 2 fubdk0h7d1logram below?

  Which of the following processes is characteristic of the meiotic and not theg9a hfvi3j r .w7zaod78ug0; o mitotic cea .gw; hj0ovi7udz9 r7f ag3o8ll cycle?

  The diagram represents a bud with a shoot apical me9f0dem1 ov72 nownv+f.;hz qcristem.

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 chimpanzeekyphvuw)3i053c2 z/lkt(e ir (Pan troglodytes) is 48. Which row shows the correct chromosome number for different celwk3pikuey( 5 /2 zhlc)t0rv3il types and cell division stages?.

  At the end of which phasdx4qs,d clp9e3q 4q ,ge of meiosis I does crossing over occur, and what is the outcome of pe44 9,qsxd , qcqgl3dcrossing over?

  Which of the following statements does not descr70gj4-r.h:fj y zk8 7 juulqwuibe a step in the sodium-potassium pump cycle in the u70: jj8ghy uw rfzk4q-l.j7u neuronal cells?

  Which row in the table below w 7lyu;ye7p0v is true of meiosis?

Membrane transport is important for allowing parth; 7if u z kg7m924:gavm,gjweicles to move across the cell membrane and respond to changes in the chemical compositioue4gg m9f7: 7jkhazm2,g ; ivwn 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 i x/)yms0 a+rj9vedrx -s 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 difw.yelb2:p3kge. y5 vh2 qsf(:qbmd/tferent cyclins during the cell cycle. Which cyclin is involved in preparing for DNA replica bmt w :yl.(v s2ek.5bhp:gy/dq2qf3etion?

The diagram below shows 0fj :9nx zp;5yh 4w4 wvler*ilchromosomes 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 h 4 8tsxchjiq56omologous chromosomes?

  The mitotic index of throat tissuevau-9 p rujnw9 4;i0bxs taken from 4 different patients is shown below. Which uuvr0-;jp4abwx ni99 patient is most likely to have cancerous throat tissue?

1.Draw a labelled diagram to represent the lk)f)kb cxr1vs l)zz: se1 8/wprocess of crossing over.

2.Compare and contrast random orientation and crossing over.

3.Outline the stages of meiosis.

  The image shows an abnormyy0r l7+s tb9 lj6otd4-0uz8i;ubhmp0rp9 umal human karyotype.


What is the abnormality in this karyotype and its cause?

The graph below shows the relative amount of DNA in one xx8cc: ,dk/2nmg.olv cell during one complete cell cyclex,lmgv.dx8k /2c nc:o. 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 bet.jrofw q8mwpef9 mjn6 o47*;b8 r )ezvween a male cat that is homozygous for brown, long hair and a female cat thatb r48 jwrwj9.qfnem7; o m6zv)pef8*o has black, short hair.


Which of the offspring has a recombinant genotype?

1.Outline how polygenic traits can shdxyn dadrd cm*na1y(uo695: 9 ow 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 crossing over of non-sist7m/fdq 8j zd7hrh/r2ter chromatids shown in the j8rqhz/m277t df /rdh diagram below?

  The photomicrograph shows a pollen grain from L. *)gcqpb8tl 0u/ f62cf*mp/ulog3l 9u 3jilc jcandidum (Lily). Which stage of meiosis is l*u3gc/p ilog2369j*fljctp0cb8 u f) qu/ lm shown?

1.Outline the events wh- 9kt fnv t.kj.u2wx,kich would lead to an individual being born with Down syndrome, which is characterised by the presence of three copies of chromosome 21.,2kkv.kut-w f9tx nj.

2.Explain how meiosis increases variation.

3.Outline the stages of meiosis.

The mitotic index is an indirect way of measuq/ qdlgkp 6n+7ring plant growth. A study was conducted on white onions (Allium cepa), under controlled conditions in a lab, /7pqkdnq+l6 g 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+qqd1fikg 4-e. The diagrams below show two cell i41f qqgedk-+s 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 exf mn,8fhfxmu1fyxr+ (c-r m2 )h6tr/upression 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, in different ;ha8 w.w;pp icsq41esdj+oj* stages of meiosis. Which row correctly names each stds+hp opsqjc i;.aj4w8w *1; eage?

  The micrographs show four phases of meo4wbm 1v.41 ewrkvsf3 iosis I in a plant. In what order do these phases occur kov1 e31fwwb4r vs4.m?

Mitochondria are responsible for supplying metabolic energy v 42choq3v/zq*d-dq ein 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 reprodqv*o23d qez4 cq/ hvd-uction 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 stage48 g;spsho pc7vl jq(2s of the cell cycle in four samples of lung tissue from four patients. Which tisch4(qps 8 vl;js g72opsue has the lowest mitotic index?

  The diagram shows the dominant cyclin/CDK compl;p-qr/x e hlz)exes at different time points in the cell cycle. Which cyclin/CDK cpq zxh-)el/; romplex activates DNA replication machinery?

  Studies have shown that genes such as Cyclin Dependent Kinase 3 (CDKN3) ara*nclp7e 4)u:5wanqs e highly overexpressed in cervical tumours)n7ql es4*:p5ac awnu.


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 concentrag hrsp (97gm qcbvh )zfx9qe1.zu;(,vtion of cyclin E the highest during the cell cycle ?