The graph below show0 n 63t+o1 roddo0cv kong/br1s the relationship between maternal age and the incidence of non-disjunction. What relationship is suggested by the data invcoob+ 1ro n6do0 gk0r/1dn 3t the graph?

  Which stage of meiosis is represented in the diagm:wqozo - zbvg49:cr 6ram below?

  The diagram below shows chromosomes during meta8(vnc(6 x lmiosis.


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 would be s x*gw. os.sedx n6,ls..m8ee present in the nucleus of a cell as a result w,xs8n o e m.*sdss6gel.. .exof each process?

  Which keyword is matched to the correct (e9ke:ma(eylw b )b 5tdefinition?

  Which statement(s) about mitosif*f *ieqs) dmz40he6fs is/are 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 points to a cell in an+:e;phm v kveeo+5*hnaphase?

  During which stage ot ydr*zu.s3yav4+ /3nf ig rs4f mitosis does the nuclear envelope break down?

  Which one of the foll romc: *audp.2kjc trc1+.2lbowing transport proteins only carries out active transport?krlb1a+ d*m 2c:c.uj.or t2 cp

  Which process does not happen in the shu5n ypnad2k97r c b(h9 f3uou+oot apex?

  Which type/s of membrane transport do/does not s kd,im )9ybm:require energy expenditure?
I. Facilitated diffusion
II. Active transport
III. Osmosis

  The diagram below represents a cell with a dga;5w98w9e ) ih3ca ed rfit los28b8uiploid number of 4. Which stage of cell division is the cell )sae ri3g88h2ec95oatfww; 8lu 9bi dcurrently undergoing?

  The photomicrograph below shows a root tip meristem. Which of the following se d s-+ougl,c( ksxi.2 utt+93vlz7bpintences correctly defines a meristem2, i7tbt-lxg+z9 us c3p(sd l+ukvo.i?

  When does the random orientatiordvv87i f*f s/a2;lbt n of homologous chromosome pairs occur?

  Which process does not occur dl .9inq1 k x/7qpoen 7kmg9mg 0j.1dlduring meiosis?

  If a cell with a dip1zz.(y zd-nicz4+c-yxczq 8jloid number of 36 undergoes mitosis, how many chromosomes will be p q x-8z-c.j4cnz1zzy+zyd(ci resent in each daughter cell after cytokinesis?

  The image shows a micrograph 3:w4bll *:p.,wga lzy)ysuxmof a cell.


What explains the appearance of the cell in the micrograph?

  Which statement(s) about homologous chromosomes is/are not true3*p( ymkj2i. zd+l vbq?
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.pg96slv61bmg ,; zuly9hyxr dg w)w: with Down syndrome.

Which statement is not correct?

  In the cells of a horse (E. caballus) durinfwmj25um.5bv g prophase I of meiosis I there are 64 chromosojumbf .wv 552mmes. What is the haploid number of chromosomes?

  Which arrow is pointiymh a4uo9e- re u2/pd9ng to a chiasma?

  The diagram below repr jkvnc l4d6,n+ ; )ocmm0fdp7lesents the structure of a shoot apical meristem. Which row in the table correctl vnl)m0fp+c;7 no jl4mdk6cd,y identifies the processes occuring in the structures labeled in the diagram?

  How does meiosis promote variatvdoom3r+u: )1:a ylgg ion?

  Which of the following stateme,en0khus2v s4csk; ba9 tk) w(nts 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 chromoxq)b*d:t4wmb y,k3 nw somes.


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 tu8wv m,fc5f-rmeup2v rzuo , ,7mours from primary tumours as a result of the 2r- ev mpo,fc 5 uuwfr7,mv8,zmovement of cells?

  How many chiasmata are present in th myug*+p 9icesc/at6(e diagram?

  Which statement is a similarity between cytokinz px 8ezwjl484hjr,1gesis in animal and plant cells?

  Which stage of meios56pmnpe k+l85/kutu gis is matched to the correct description?

  Which statement(s) are true of 8ewf/ tsycc54meiosis 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 first meiotic division. vyad/i/)gub - 3tr7)qmgt d ;uThis results in the formatiogrdquv)mt)3g - t u a7/y/;bdin of one large cell and one small cell. What is the fate of the large cell?

  Which row correctly describes diploid and h c:c:w1wo,lvkaploid cells in humans?

  The following table shows the diploid chromosome number of a range/kjs- ty17dzx (d)dfn of species.


Which of these statements is correct?

  What conclusion can be drawn from the karyograr(u)w, th)pkcbhor+ ;m below?

  Which of the following processes is characteristic of the9v*4rz b/hxc e meiotic and not the mitotic /c*xrv9 hbz4ecell cycle?

  The diagram represents a bud with a sho +fr)ykl79vrql9fe)4 qfrdf 1ot 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 rqbkb ./v50eho *swmg 025 raw48. Which row shows the correct chromosome number for different cell typesk0b mhaobrgqes 02w .5w/*rv 5 and cell division stages?.

  At the end of which phase of meiosis I does crossing over occur, and +i8ii52 o pmdvwhat is the outcome of cro pmv82ii5+ido ssing over?

  Which of the following statements does not describe a step in the sodium-potassi5wq+t3ss:eyd ji) m+vum pump cycle v j: tm)35dy qiwess++in the neuronal cells?

  Which row in the table below is tcf) pg9maor/-d v7/ix rue of meiosis?

Membrane transport is important f cftpjsi7ai ehq us)5(4/.tq 0:g (lrbh;3hvx or allowing particles to move across the cell membrane and hjqght ii4f3rc b((.ap;h:7 x5v e/qu 0ssl)trespond 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 re/w 1/y f 1bbt:xo/yg2*o ixblegulated 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 concen lg54u v:pb8: dbom;wmtrations of different cyclins during the cell cycle. Which cyclin is involved in preparing for DNA replication gmp:;oblw8vb4 m:du 5?

The diagram below shows chro66epn2p-tzh i mosomes 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 cvhu4rrk 2i4d(pv nbo r.sb72)hromosomes?

  The mitotic index of throat tissues taken f-*gl by7od0e 53qlk jlrom 4 different patients is shown below. Which patient is most likely to have cancelgd5y qel -3 0b*7kjolrous throat tissue?

1.Draw a labelled diagram to represent the process of crossing ovb- 8m1/wu vaqwer.

2.Compare and contrast random orientation and crossing over.

3.Outline the stages of meiosis.

  The image shows an abnormal human karyotype. prr-* zt +c)me*xr g7q


What is the abnormality in this karyotype and its cause?

The graph below shows tdoq 0.u,nb 30ht izo9yhe relative amount of DNA in one cell during one complete cell cycle. Each lebtz i,qon0yod93hu. 0 tter 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 cro4ma 29:dydg mkp.t pm:ss between a male cat that is homozygous for brown, lo2yt9km 4.gpp:d :d ammng hair and a female cat that has black, short hair.


Which of the offspring has a recombinant genotype?

1.Outline how polygenic t pf w8(2 zpnpwxuzm/d7 g4i27xraits 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 crossing over of no7bpyd:e7mu a2fi)pl/ n-sister chromatids shown in the diagram below? )d/7iumb e2 y7lf :ppa

  The photomicrograph szt vk1/uxs7pji/ /-jchows a pollen grain from L. candidum (Lily). Which stage of meiosis is p/ijsut7jkc- v x1z// shown?

1.Outline the events which would lead to an individual beizoo)irn mee(2i b5 u6-ng born with Down syndrome, which inieoou )r2bz-m6e i(5 s 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 o6tqkj71 6r/knn;n9g xud. kj.l iaa:measuring plant growth. A study was conducted 61;a/x:.jkr t7j.9n u6nia ong kkqdlon white onions (Allium cepa), under controlled conditions 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 dia1dwh* 4.x0 x)ii bxjgngrams below show two cells from an or01dn*wix.4 h)i b jxgxganism 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 growtzpsve0l6 c9t) d7o1hth.

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 8,92 ;b/6v*n6bvct neymjwa36j zvwk+fp b, ys6 in different stages jn66m*2k6zyp/c tjwvb bwvys+;a 3 fe6, vnb9of meiosis. Which row correctly names each stage?

  The micrographs show four phasefx wi4 nr(7wpcl6)c l2s of meiosis I in a plant. In what order do these phases oxf7p6w () 2il nc4wlrcccur?

Mitochondria are responsible for supplying metasjx0.myw ;a8a8gb1/rq d did5bolic 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 in 8m5sw /yrdjgaqai1 8.;xdbd0herited 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 number of cells in differentc,an)g:b o6 buhw1ea- stages of the cell cycle in four samples of lung t-h a6b ngbuw ac1e,:o)issue from four patients. Which tissue has the lowest mitotic index?

  The diagram shows the dominant cyclin/CDKmn82;cy f)fvs complexes at different time points in the cell cycle. Which cyclin/CDK compl8n;2fv m fcsy)ex activates DNA replication machinery?

  Studies have shown that ge(/,gxs y l) ojq.gl(5azim j0rnes such as Cyclin Dependent Kinase 3 (CDKN3) are highly overexs(jgaqjo5 izg0/yl (m r,.x )lpressed 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 concentra(vwx dd ie*:*. ne s*4vtqegx8tion of cyclin E the highest during the cell cycle ?