The graph below shows the relationship between gixv;1j.f v3l maternal age and the incidence of non-disjunction. W1vvl; .ifgj3xhat relationship is suggested by the data in the graph?

  Which stage of meiosis6be 3u 4pkx9f:lnh pq geh5f1( is represented in the diagram below?

  The diagram below shows chromosomey5ue5 : z8dlcea 49ezks 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 genel: w2jshg2gsb .t*4re which would be present in 4jg2w*:sslg2rb het. the nucleus of a cell as a result of each process?

  Which keyword is matched to the correct defigrdn*(j2h/nw w r)be *nition?

  Which statement(s) abo;vc+3 fbr1a9gmtx8vp ut mitosis 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 pointsn xxz7ue.m)/g, 6,xrqxxr(yl to a cell in anaphase?

  During which stage of mitosis does the nuclear envelo: ns5 eagt65tm8)gcrr pe break down?

  Which one of the following tra/tco, )iilrcxnpxz(:f;:k7znsport proteins only carries out active transport?cz;:lnxpf7c(,t) x r/i:zkoi

  Which process does not happen in the sh0edarf qd* 5mq0h13rvoot apex?

  Which type/s of membrane transport do/does nw0*s4 yag n.r7s8aumvuj 7cx,ot require energy expenditure?
I. Facilitated diffusion
II. Active transport
III. Osmosis

  The diagram below represents a ce;a )2o,zfow4aohzjb 5l,1ho rll with a diploid number of 4. Which stage of cell division is the cell currently undergo,abz)w,f5loo2 a hho4 z1j ;oring?

  The photomicrograph below shows a root tip meristemavra (9d 3ptq:. Which of the following sentences correctly defines a meristemrva:3 d(9qtpa?

  When does the random orientation of homologous chrmzjc, 3 g8rol 2hhy;:aomosome pairs occur?

  Which process does not occur duplc.z9b:b (eb ring meiosis?

  If a cell with a diploid number of 36 undergoes mitosis, how.kujw :tnr +glhy5:v2t08a uomk.r)s many chromosomes will be present in each daughter cell after cytolh5a s vo+0r.yg:8:t. wjt)kumn k2 rukinesis?

  The image shows a micro:ffrx6 5qb/ly9a)vz7qa w8ptgraph of a cell.


What explains the appearance of the cell in the micrograph?

  Which statement(s) about homologous chromosomes i(bpbp 0 ;;ikao5u:hmw c0 v4vjs/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 individm 1k3 oid8mscq6j4y)eu3df7 nual with Down syndrome.

Which statement is not correct?

  In the cells of a horse (E. caballus) during prophase I rg 3x9rgr:h:dr; kxcm)x t:e5 of meiosis I there are 64 chromosomes. What isrxm5)h xrt:d3gxk;gr e r:c:9 the haploid number of chromosomes?

  Which arrow is pointingsli +3oaqdd4l: jbt8+ to a chiasma?

  The diagram below represents the structure of a shoot apicx+dc1fbo4y qrqbwpg)can211 *4fic9q sp1+u al meristem. Which row in the table correctly identifies the processes occuring in thebcfq sfcab21pd+*g)1nuo yc4q+9r1 pi q14 wx structures labeled in the diagram?

  How does meiosis pro+n w j :fo0rcd/r4nx6tmote variation?

  Which of the following sm h .xs3p wutzc8,8h/xtatements 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 chromosomesj. gvcms24fz-n:m- om .


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 describesy;:csbmdsru c g1+rycd0. 6- gm.4xd p the formation of secondary tumours from primary tumours as a c. g;d+mryd g1 bs:-xs pum4.06y drccresult of the movement of cells?

  How many chiasmata are presentdg:d2p6 3b fht in the diagram?

  Which statement is a similarity betweegxu(8fwx.ze5 n cytokinesis in animal and plant cells?

  Which stage of meiosis is matched 57pwpt9phs)t)bn:hdt f, 3fy to the correct description?

  Which statement(s) are true of meiosis I but not meiosi r+p7k0wol ns1feg5k+s 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 divib -w.,8q td.d bqqj3drsion. This results in theb3drjwtqqb. d 8- d,.q formation of one large cell and one small cell. What is the fate of the large cell?

  Which row correctly describt0ax kx7 anjh*1-,wuf4 zx7iv es diploid and haploid cells in humans?

  The following table shows the diploidockz +uar; d3sd;x(c0ao w, 03co(qrk chromosome number of a range of species.


Which of these statements is correct?

  What conclusion can be drawn from the karyogram bijdz+17r x3x :zn lcy0elow?

  Which of the following processes is characterist 0xoky*(s*x)ow v8sc hic of the meiotic and not the mitotic cell cycc wx) x(0o*sy*kvo8shle?

  The diagram represents 4uukufcu :l*) 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.qpekv/ f 18ko1 Which row shows the correct chromosome number for different cell types and cell d op/ fe8kk1vq1ivision stages?.

  At the end of which phase of meiosis I does crossing over occur, q:7ym o86 l0(fujgkqwand what is the outcome of crossw7qg 8fol6:0kuyqm(j ing over?

  Which of the following s+h2dp7 s fh-ratatements does not describe a step in the sodium-potassium pump cycle in the neuronal cell-arhh2 pd f+s7s?

  Which row in the table below is true of i279vttel*mfm6qk s9 meiosis?

Membrane transport is important for allowing pav)xx1 je gm- 0j,/mwnhs1 )-,ircdcrlrticles to move across the cell membrane and respond to changes in tx x1vm /rs-i,mlr nj)e ch)-1wgj0c,dhe 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 cells.eow:f h ua:aw;q ky.:(

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 venz v)n;f7dbyuz -18 during the cell cycle. Which cyclin is invold;z7 fv-unybnz1 v)8 eved in preparing for DNA replication?

The diagram below shows chraurrf+o0 f+ 5a;- daqdomosomes 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 meiosismopy,twdpa mr2 eilvp6//7v 8t4jz ;) involves the separation of homologous chromosomes?

  The mitotic index of throat tissues taken from 4 different patientu/atgxe vii g*u1 0)+fs is shown below. Which patient is most likely to have catvgixfig)* 0u ea1 /u+ncerous throat tissue?

1.Draw a labelled diagram to repr0j)mh n62+ v0:fcoejatbsxsnq ;/, ts esent 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 karyoj hf.w+ia krps,9d* rgg. w8:otype.


What is the abnormality in this karyotype and its cause?

The graph below shows the relative amount of o u+r mwav(gi9;n)fzycfg()uly4z;0 DNA in one cell during one complete cell cycle. Each letter represents one stage of the cell cyclagc+nuy;ygr m zw(if4 ;0vuzo lf)(9)e.


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 maliy:q,* rs 4qra yym4h0e cat that is homozygous for brown, long hair and a female cat trqmqry y s:0 y4a,hi4*hat has black, short hair.


Which of the offspring has a recombinant genotype?

1.Outline how polygenic traits ce5n )c- avxv5tan 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 resulj1.o xhsn+a x wzfh ,zg3lb/4:t from the crossing over of non-sister chromatids shown in the diszhonh1ag j3zx/.b4 ,xl+: fwagram below?

  The photomicrograph shows a pol3oz nydt0vfl p*e6c1 /len grain from L. candidum (Lily). Which stage of meiosis is shown?t/ ze3lp1y*0 cvnfd o6

1.Outline the events which would lead to an individual being born with )dn27rux it7cDown syndrome, which is characterised by udxt)72ni7rc 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 measuring plant growtj nb28vxqgr4p(np +3i(pww y2h. A study was conducted on white onions (Allium cepa), under controlled conditions v2 brp(4ygjnp8xq+3pwn2i( win 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 waysosrdf 9ta:k a7.m6vf 2 in which cells can divide. The diagrams below show two cells from an organism with a diploid number (2n) o sa6fr:d7fkm. 9ta2ovf 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 expr0k h9f; kxg8fwaxq,v0ession 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 di3.rfam2 xfvo,m1d)r wfferent stages of meiosis. Which row correctly names each vff amr 2,3o.1rwdm)xstage?

  The micrographs show four phases of meiosis I in a planmdb.)5 nllm wa t:u87.6fo chjt. In what order do these phases bf hmn7c.awj d5:)tu 6.l8 moloccur?

Mitochondria are responsible for supplying metabolic energy in euen+iu ga 9l2p(lmb e 2:msfc l6r74b(wkaryotic 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 patternnabrwcg74 lbl2m l:( 6+ ifu2eep9s m(s 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 cell cycle rb (t9uxar* 9pw h/eo8in four *xapt b/ehrr(8uw 9o9 samples of lung tissue from four patients. Which tissue has the lowest mitotic index?

  The diagram shows the do;gf7/os j; 9uwhef)ghminant cyclin/CDK complexes at different time points in the cell cy w7hjs ;gho/u;9f)g efcle. Which cyclin/CDK complex activates DNA replication machinery?

  Studies have shown that genes such as Cyclin Dependent Kinase 3 (CDKN3) are hi/w-p21gh n8u* i nqlvrghly overexpress wnpqigh8 uvr*/n1 l-2ed 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 hig3ts-uc/22 byhxv2ar y hest during the cell cycle ?