The graph below shows the relations0 ttx7w ftk t7ev5a2lm *ad*.chip between maternal age and the incidence of non-disjunction. What a7ct*x fe0mta5t.*72wkdvtl relationship is suggested by the data in the graph?

  Which stage of meiosis is represented in the d:. pgy fb te8dyrcb8m8vw (h:0iagram below?

  The diagram below shows chromosomes during meex+9 j9qie.h d.acc lyv *a:o/iosis.


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 ws7m3epf xmy* 3lfm11 tould be present in the nucleus om7xt1 p3yf3s*mmf l1ef a cell as a result of each process?

  Which keyword is matched to the correct defind, a iml+(up7bition?

  Which statement(s) about mito:u)ypd 0(dax jw r i6mr1cae59sis 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 point0ow)4o ncg y0gs to a cell in anaphase?

  During which stage of mitosis does q(q+ze 4 dkoir7 n5k(mv sdy3)the nuclear envelope break down?

  Which one of the following trans/fe cq g2*uqw5port proteins only carries out active transport?5 2ufgqecw q*/

  Which process does not happen in t a:cox kezcw70t1;n1 the shoot apex?

  Which type/s of membran3cih +pwg i)j*c95rl ve transport do/does not require energy expenditure?
I. Facilitated diffusion
II. Active transport
III. Osmosis

  The diagram below represents a cell with ahkp u rrr.v6:uo--8a(0f bi eov05m bi diploid number of 4. Which stage of cell divis-rrvik5ev :r0(h6 u8b a p.b 0uooim-fion is the cell currently undergoing?

  The photomicrograph below shows a root tip mpt4+uznq:c/ t eristem. Which of the following sentencq+tpcu n4: /ztes correctly defines a meristem?

  When does the random orientation of homologous chromosome pai.+ wwdu6;dzjee jw(a/3ba9)6/ hppq;wjgli rrs occur?

  Which process does nopl5n07q/, aigelw.a zk *cmz 4t occur during meiosis?

  If a cell with a diploid number of 36 undergoes mitosis, how manxp2q bxxaf7,t- e./zhy chromosomes will be present in each daughter cell aftbe xa h-x2xq7t pf.,z/er cytokinesis?

  The image shows a micriw uz xkq+frq+/,9 jhhz9( x.bograph of a cell.


What explains the appearance of the cell in the micrograph?

  Which statement(s) about homologous chromoso:kml0* fwir k/divyu,-t56p05s ja xkmes 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 o(03f )vdgqe.g.ytd )6a ntbrindividual with Down syndrome.

Which statement is not correct?

  In the cells of a horse (E. caballus) during prophase I of meiosis Id wlqov 7x/(0 /j hxt2n3.wh-mb1unfs there are 64 chromosomes. What is the haploid number-b2fh1 / 30nvh(7 onwl/mw qus.txjdx of chromosomes?

  Which arrow is pointing to ap2zf4fifp0u , chiasma?

  The diagram below represents the structure of a shpzi i. w7jba )3j+fu8fbncr(z8 : der(oot apical meristem. Which row in the table correctly identifies the processes occuring in the structuciji8(eu7f) prz+3 n:fza jdbwb8(r.res labeled in the diagram?

  How does meiosis pro+hh8jg hvz 7b3*h:n o yrx.z6rmote variation?

  Which of the following statements itx(b r) 8uf/oys/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 chromosomes.ih2+7lm:gp ,fft );u aue kp5)+ gpskowmsy.5


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 primary bruis9nb,t 3h 3 )iyyqj7q;a- tumours as a resu3usb qnr9yq)7a b3yt ; i-i,jhlt of the movement of cells?

  How many chiasmata are pc *i7wakp0bc ,l2v6idresent in the diagram?

  Which statement is a similarity between cytokinesis in animal anxx)m:b-p gp:jd plant cells?

  Which stage of meiosis is matched to the cor-wj,i0+(is l:of hg rj lwu p*7(5lbinrect description?

  Which statement(s) are true of meiosis I but not meiosd7 ut xe-sfs-ul) )u6ris 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 q-bz4 ok5 5viydivision. This results in the formation of one large cell and one small cell. What is the fate of th4vy5z o5bi-kq e large cell?

  Which row correctly describes diploid and haploid cells in humaaanwg4/sr60u ns?

  The following table shows the diploid chromosomd l)5bil.(vhqp4 pv ep;28w)*pdwfs m e number of a range of species.


Which of these statements is correct?

  What conclusion can be drawn from the karyogram bel4+lp9nq er)q 90jofceow?

  Which of the following processes is characteristic of the meiotic and not the mi-*a bw:pgwu+u / t jbca)+bi/itotic cellw+ :a/-b*/ uwbj+ pii autcb)g cycle?

  The diagram represenfz95e8p h * mfrhux)(vts 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 troglodyte:gbs* ;ne j79pymfg7 co9d3oys) is 48. Which row shows the correct chcm:y99op *e;7dbfgsy oj n7g3romosome number for different cell types and cell division stages?.

  At the end of which phase of meiosis*y3sf-wi,sc0stc. jk I does crossing over occur, and what is the outcome ofck, cw-s*ssyit3 j .f0 crossing over?

  Which of the following statements does not describe a step in the sodiuz*f2x0m dwt6:t3mib+l0ucc7 jj:ap r m-potassium pump cycle in the neur:cbzcilj x7w+r 0 d2fpamu* t0m 6jt3:onal cells?

  Which row in the table be+-uqtp 1rs. wmlow is true of meiosis?

Membrane transport is important for allowi q gn *uo zn wsm-scot2,)klmq*y+w6(:ng particles to move across the cell membrane and respond to changes in the n +u6 sc* mwz2wqnqtls:o (o)-gkm ,y*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 regucf y5 xcav,mfd;tull 0m)/) o)lated 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 different cyclins during the cell ,frn :kmznj.u33 j)2r eb ywc+cycle. Which zucb32+y,jw:f.n m3j r )r nekcyclin is involved in preparing for DNA replication?

The diagram below shows chromosomes durin*j;iq mcdd ,;gg 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 inve.bycu c f: l;odnj). epg2s(.,jyfd. olves the separation of homologous chromosomes?

  The mitotic index of throat tissues taken from 4 different patients iko: oue1p+)iv s shown below. Which patient is most likely to have cancerous throat tissuio+v ok 1e)p:ue?

1.Draw a labelled diagrsd v+zj (s+etbp b/t/n3ube/s13a x+p am 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 hum p;whyk/hr43ban karyotype.


What is the abnormality in this karyotype and its cause?

The graph below shows the relative amount of DNA in one cell durih15c n 2:7uifdz9 gr 2dgival+ng one complete cell cycle. Each letter represents one stage of the cell c2h+: i1dfv9n5cgzga ri27ul d ycle.


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 shob-r/ 9 fdq6mlfp;ua93* xv f0zxfi9wtws a cross between a male cat that is homozygous for brown, long h pwvf -;6fxbm/f9zxfdt u9r03 iql9*aair and a female cat that has black, short hair.


Which of the offspring has a recombinant genotype?

1.Outline how polygenic trarj0w z(s3 ,y09 o dzn9wcjky)uits 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-sister chromatids shown n;+l6ui .k 6obfiik2uin the diagram below? obn.iiki u;2+k6 f6ul

  The photomicrograph shows a pollen grain from L. candidum (Lilu :k (padet)dje- 8( f-qiyhuwxj-lp7a)0on /y). Which stage of mjnap- htuqkl(do u-0(e dx) )ai 87fye/j:- pweiosis is shown?

1.Outline the events which would lead to an individual being born with Doj*kx vns1 24hewn syndrome, which is chan hsxj k2v1*e4racterised 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 measuring plant growth. A sd( q6jk p/4 lfpbysvqf:1;z d.zq9g7ztudy was conducted on white onions (Allium cepa), under controlled conditions in a lab, to invesspd .q;d bz6qlkj/ (4 z7v9y fgp1fzq:tigate 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)3+ mudbul xzh+w:f8u ; dzt8f divide. The diagrams below show t: flzxm8wfudb3t 8)hdu ;+u+zwo cells 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 expressid ifb46 2+k82jj -mt2gs,hg gxafkgc 6on 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 stav1f(t /rp63aoxj tdu4ges of meiosis. Which row correctly names foja rv6xt1 (upd /43teach stage?

  The micrographs show four phases of meiosis I in a )- 77wqs-nqzdhyp 1qnplant. In what order do these phases occz1) qdqh7ny 7pnsw q--ur?

Mitochondria are responsible for supplying metabolic energy iv w4i 2q 0vujh583edjpn 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 reproduction between two different yeast species, could20id5e8jjq3v w p uvh4 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 tn/(i*rvl7tny) clcj9 +6lbtr he cell cycle in four samples of lung tissue from four patients. Wh n6(vctct/r ni r+bll*97l)yj ich tissue has the lowest mitotic index?

  The diagram shows the dominant cyclin/CDK cv2tos3 j,x4xsntltt sp/* t *;omplexes at different time points in the cell cycle. Which cyclin/CDK tt;4 js2s/t,oxs3 tl*tv nxp* complex activates DNA replication machinery?

  Studies have shown that genes such as Cycu2k duh6* ;kmp b.zv0wap(.*tqh lry*lin Dependent Kinase 3 (CDKN3) are highly overexpressed in v h0*u(pplmk ykd .z*;h2 *.uwq6ab rtcervical 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 hiyxg q qmmdoj (;26zrnqa2(:l8ghest during the cell cycle ?