The graph below shows the relatioc6c8yg /mpjaxt5 eks8+7ley/nship between maternal age and the incidence of non-disjunction. e6gm 8+5/k7jl8xeyay/ps ct cWhat relationship is suggested by the data in the graph?

  Which stage of meiosis is represented in the diagramy(, c;lrexikztn8 55oo64f ub below?

  The diagram below shows chromosomes 6 pnyqq-h:pf+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 gene wuxvx.:w05o j ohich would be present in the nucleus of a cell as a result v .xou ow0:jx5of each process?

  Which keyword is matched to the correct 6 -n liu4x 5l; ahe3+hx*oqmtzdefinition?

  Which statement(s) about mitosis is/are true? cs4q gi 8s(gy7
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, whiz+ :evvo qm/mqk t86re( 4v/aoch letter points to a cell in anaphase?

  During which stage of ; o2 dfemrg ;f-da:j6l0ew:jhmitosis does the nuclear envelope break down?

  Which one of the following tra bjaz6 z:om)y;nsport proteins only carries out active transport?z 6;oy) zm:baj

  Which process does nam 3gjae* 5c*9kzdwi 2ot happen in the shoot apex?

  Which type/s of membrane transport do/does not require en p( 3g+-k wgww .87ttlsf.a5hg1;b9ktybmpls ergy expenditure?
I. Facilitated diffusion
II. Active transport
III. Osmosis

  The diagram below represents a cell with a diploid number of 4. Which stage o8l ofa91s19ts (ti0asn:wid hf cell division is the cell currsafol1(t: 80aiw1 n9t sih 9sdently undergoing?

  The photomicrograph below shows a root tip meristem. Which of the following a jbpc p3o/4:xgo h3)7cfdq 9;yh vd/ i0sy+etsentences correctly definvcs9h3i ba+f/t)g0d:ypydc;/4h ep jo 3o x7q es a meristem?

  When does the random orientation of homologw6mhe2/w a r.z9)jx-sidy4ii2 j9a nmous chromosome pairs occur?

  Which process does no)zhws3 )e/kkvt occur during meiosis?

  If a cell with a diploid number of 36 undergoes mitosis,yzhpptr7lc4nxut9 :jwl(*965yk s i3 how many chromosomes will be present in each daughter czkxpt4p39(yjsu97*y:6ilhrl 5 t wncell after cytokinesis?

  The image shows a micrograph of l48dd+ d/aca,6vk vg4rpek 7b4zht 8oa cell.


What explains the appearance of the cell in the micrograph?

  Which statement(s) about homologous chromos+vw88um/vt j1r nke 6vomes 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 individuwjqf2tpfe56g08 /mu8 cjn5qm al with Down syndrome.

Which statement is not correct?

  In the cells of a horse (E. caballus) durin,tk9 l5 w:zaucg prophase I of meiosis I there are 64 chromosoml5wz9:ukc at, es. What is the haploid number of chromosomes?

  Which arrow is pointing to a chiasmkiq+q5 4d j 4ez hn,xbkl:8k f(gi7m*ha?

  The diagram below represents the structure p m8h(x gkd7b4of a shoot apical meristem. Which row in the table correctly identifies the processes occuring in the structures labedk4 mbg(x8 ph7led in the diagram?

  How does meiosis promote variationplq r:, gg 6zv,w8atx2y3z. qu?

  Which of the following c 1-o6fgz:xs qstatements 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 chromost-frw3pm g (btdra (6*tuw/x 1omes.


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 tumours from p1ecmq;c 9)ozgx5gwk h/rxn 3lf) k6 r)rimary tumours as a result of th)g;lqc/g x)kh 6x3cr1wm)znf 5 rk9oee movement of cells?

  How many chiasmata are present in the diagraz c1xq9xz8 :gdm?

  Which statement is a similarity between cytokinesis in animal and plan umtvh d4(-ej/t cells?

  Which stage of meiosis is matched to the correct 3:o* (kixi xbcdescription?

  Which statement(s) ar6*ohe:;j6vzh llmau 6e true 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 first meiotic division. Thisg+7o1bzj (ndk x)rq 4i results in the formation of one large cell and one small cell. What is the fate of the large celz4d i(7jkgrb1nx )oq+l?

  Which row correctly describ37j gp ob-* .kbnd.fytes diploid and haploid cells in humans?

  The following table shows to3jc-:ozw, l9r k56 l pkfk weu;z4.dthe diploid chromosome number of a range of species.


Which of these statements is correct?

  What conclusion can be drawn from the karyogrank /:xm s,(zsrhd4p(um below?

  Which of the following processes is characteristic of the meiotic al vkx )h*(37nzkw:/vlep ci(wnd not the mitotic cell cycle?i3(lnc*h7:e p(kzv xk vl/w)w

  The diagram represents a bud w*n eto+xe 2h 7f-caaos vaefktk(1;,1ith 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 chimpj*)nmrvk5 5g36brf zaanzee (Pan troglodytes) is 48. Which row shows the correct chromosome number for different cell types*j zbkv3f5r)6ma g5 nr and cell division stages?.

  At the end of which phase of mw+noh0 enw;- teiosis I does crossing over occur, and what is the outcome of crosw0oe-h+tw n ;nsing over?

  Which of the following statements does not describe a step in the sodkra(tq2ihg1*7 ow; we o7k +kzium-potassium pump cycle in the neuronalk+hgi*7 t7ow w2( qkor;k1aez cells?

  Which row in the table bel hu; n4quqoj9(dbr8: mow is true of meiosis?

Membrane transport is important for allowing particles1/jctr-y k lo ee2 4u56ek)iyw to move across the cell membrane and respond to changes in the chemical composition of the extracey6uoij4k) t /ec l2yrke1-w5ellular 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 ina(-m;w.k2rmubjcl r8 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 diffiflm1 /zt0lo )erent cyclins during the cell cycle. Which cyclin is involved in preparing for DNA rl o01l f/tizm)eplication?

The diagram below shows chrf)mrmxw71 21w1lvkk comosomes 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 chromosomes?oon-*p r*km :ph ckn*2 ewxk/(

  The mitotic index of throat tissues taken from 4 dil7hl8uvi-w8f j:)d /) xxxeopfferent patients is shown below. Which patient is most likely :)x/ u wo- fx vl8jxl)7diphe8to have cancerous throat tissue?

1.Draw a labelled diagram to(k6:xn ry(yz jl- wvg, 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 karyotype.yt2,huliur1j5k -)zhs33 f ghjym 1e;


What is the abnormality in this karyotype and its cause?

The graph below shows the relative amount of DNA in one a(4tubzc1 dfm0lx i7,cell during one complete cell cycle. Each letter rebalf0 4x im1(u,tdc7 zpresents 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 between a male 5td ,r5u4 pyv xto7)tlh :tm6rcat that is homozygous for brown, long haix 4: )vytuhl7rtm 6,5r pdto5tr and a female cat that has black, short hair.


Which of the offspring has a recombinant genotype?

1.Outline how polygenic trais7i8ebn/q f (st5b. kkts 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 non-sist /2u73/bns4cundqzq jk wm 1pt ;l:4joer chromatids shown in l d//zknj 3uu w:41jcm4 n 2stq;op7qbthe diagram below?

  The photomicrograph shows a pollen grain from L. candidum (Lily). Which stvrdcp,/ v,um; p ec0:ov0ya:wage of m0py0v/ c:; cvpuode ar :mw,,veiosis is shown?

1.Outline the events which would lead to an individual being 8q35l. 3n)ytvpov:/hqeswi c born with Down syndrome, which is characterised by the presence of t5lp)3 . qyiwnv3o8sh/:etcvq hree 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 growth. A study was co:dgkj88+u6 k7audv ov3 u6rsg nducted on white onions (Allium cepa), under controlled7gvu:kk v3+ rsdo 88u6udjag6 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 diagrams belytpt3+zp .l u 4 y,zo0(ymdq*aoap )q1ow show two cells from an organism with a diploid number (2n) of 8z 1p4.pq tt zo+q )p*(d0ayoy3lyamu,.


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 expressibhr7wot, bq,4 gn* 9:9qvvpyh :v.ijuon 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 nu)t/p0z 0lkm jimber of 8, in different stages of meiosis. Which row correctly names e/jlt)0 k zm0ipach stage?

  The micrographs show four phases of meiosis I in a plant. In what order do thmw 3 ds*8l:ske34epl maw-ns *ese phasew ls8n e3p*demwask34- *slm:s occur?

Mitochondria are responsible for supplying metabolic energy in eukaryotiw (6byn :rrmc,c cells. In most eukay6cw (,rbr: mnryotes, 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 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 in oz6i ;ofv80awfouraoio8fvz6w 0; samples of lung tissue from four patients. Which tissue has the lowest mitotic index?

  The diagram shows the dominant cyclin/CDK complexes at different59qm 1s1h)ij qjvtd8 d time points in the cell cycle. Which cyclin/CDK complex activates DNA re5 m1q9hqjid)8 djs vt1plication machinery?

  Studies have shown that genes such as Cyclin Dependent K)lu*twngs+ s 5inase 3 (CDKN3) are highly overexpresse+tls5 s)gw u*nd 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 during2 p*g pk/gg/qc1up- yp the cell cycle ?