The graph below shows the relationship between) zlb4k 1mjwy0 maternal age and the incidence of non-disjunction. What relatiokjl1 b0 w)z4ymnship is suggested by the data in the graph?

  Which stage of meiosis is representeakop x;d-z bi (ua-tf()1wzz2d in the diagram below?

  The diagram below shows chromosom,*tjgsntn 5ax2 k/6owes 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 stater54ep;qo id0ks the number of alleles of a single gene which would be present in the nucleus of a cell as a resup0;k 4od 5reiqlt of each process?

  Which keyword is matched to the correc*uxqb .n; s:vut definition?

  Which statement(s) about a*yakl vwd *dcn/9,g*l3.iejk tc,8t 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;/ angwq2dj+4 u6ufm m points to a cell in anaphase?

  During which stage of mitosis does the nuclear envelope brvs v6on-qpyfc5 ,vu(c -/a 9rqeak down?

  Which one of the followql3 opfjv79p;:sxi tm40a,df ing transport proteins only carries out active transport?t sdao fm49:30x v7p;fl q,jip

  Which process does not happen ;1izi udn5t /lin the shoot apex?

  Which type/s of membrane transport do/does not require energy expetj z4qfnfvaq 8r9l7y8 5n) vl/nditure?
I. Facilitated diffusion
II. Active transport
III. Osmosis

  The diagram below represents a cell with a diploid number of 4. Which st89d sgf(wr-c nf 9pqa1b24nmoage of cell division is the cell c n2f4dcs (pmbf8 o1a -r9n9qgwurrently undergoing?

  The photomicrograph below shows a root tip meristem. Which of th38,nk* yxmw rqe following sentences yq, w*3 nxkmr8correctly defines a meristem?

  When does the random orientation of homologous chromosome pairs o0 3 7 (ji32ftdmeap(glfii9hvccur?

  Which process does not occur duringv tp aj.k7j tfb.vq45ctc;mo88v :e:len3uc* meiosis?

  If a cell with a diploid number of 36 undergoes mitosis, how many chromosomes wi(ohxde-; v46;h xkxlz ll be present in each daughter cell ao4;kh -6el(xd;x v zxhfter cytokinesis?

  The image shows a micrograph o .: r-nv.r,/*hr dty 5y:eu(dzf 0,twhysgwuef a cell.


What explains the appearance of the cell in the micrograph?

  Which statement(s) about homol2pwzw86 p8olu ogous chromosomes 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 individual with Down syndroxk2+g; ooobunil:*n,z4y4i j 4y dar9me.

Which statement is not correct?

  In the cells of a horse (E. caballus) duagtm4v ,w z y7,/cliz*6gbh)aring prophase I of meiosis I there are 64 chromosomes. What is the haploid ng a ga4,b*/lih,cvt z7m)6 zywumber of chromosomes?

  Which arrow is pointing to a c; 10t3 zocnexwhiasma?

  The diagram below represent 9j fe0(x bi8/lvx,vvks the structure of a shoot apical meristem. Which row in the table correctly identifies the processes occuring in the struvi9(v ejfx bkxl,0 /8vctures labeled in the diagram?

  How does meiosis promotb g)dm,f n8de-e variation?

  Which of the following statements is/are correct for meiosis? l,;my t 7zqf;,-q ezqwqk:j;k
I. It is a reduction division
II. It involves random orientation
III. It produces genetically identical cells

  The diagram shows gametes pd7s+r;*yh *ta dg5lopbf 2/sbroduced 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 formationq.t6/t t9yo* scsvyn( of secondary tumours from primary tumours as a result of the movement of *q6vs9yt ( tcyo .nt/scells?

  How many chiasmata are present itn 42o sm/f1gjik1.n uga/q n)n the diagram?

  Which statement is a similarity between c 9pvv hzbh 0ud91;hox s*d6sg6ytokinesis in animal and plant cells?

  Which stage of meiosis is matched to the cor7xbf;tf,, s ;ojn*wpu rect description?

  Which statement(s) are true of meiosis I but not z8 l 4zer 6c*)-kkdtv2 u(xtgfmeiosis 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 oocyv3tvxp*2420sx-c(cam e/ +pf mqs3va vis: jnte after the first meiotic division. This results in the formation of one larges va (3excsa:ms2pc 0/vvxt-3njvf + 4qpim*2 cell and one small cell. What is the fate of the large cell?

  Which row correctly describes diploid and hapf)0b cm,xk/rud 72 svrloid cells in humans?

  The following table shows the diploi7 .ldrq;b wypoy 937u65 trxxsd chromosome number of a range of species.


Which of these statements is correct?

  What conclusion can be n/ on,*a fgem8s/8 ca8pkwrn4s q3 rk+drawn from the karyogram below?

  Which of the following p5qp;h.ck*5blj5i pc r9/o agerocesses is characteristic of the meiotic and not the mitotic cell . gkpbccpe oh5l;5*j59/qiarcycle?

  The diagram represents a bud with a shoot ap0e-onb6wxtb. w( 20 qosn.d cuical 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 -t09p5jxtde7iudn *e s i 5c(gthe chimpanzee (Pan troglodytes) is 48. Which row shows the correct chromosome number for different cell types and cell division stagesxcnst5p0 ujidi *t(g5e 7 de9-?.

  At the end of which phase ofc7l/ gzao3hw07-iiu i meiosis I does crossing over occur, and what is the outcomiawug7 zh73ii 0lo/c- e of crossing over?

  Which of the following3tk9mz7qwa , w statements does not describe a step in the sodium-potassium pump 9q3 z,wwatm 7kcycle in the neuronal cells?

  Which row in the tabl7c9 .b5 vjs;nx p+dirlv4l6 vhe below is true of meiosis?

Membrane transport is imporo*hx/mk n (6ykxos l.am 26c.,)yuudttant for allowing particles to move across the cell membrane and respond to changes in the chemical composition of the extracellular fluisy.mo6 nd x* .)uhak6/ol xu2m(, kytcd.

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 l tgz xllhv4q.6,l4 fl9 4giatt;d*)c is 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 concentraqucf/5q3mpb+ r 4( h8w imeo0mtions of different cyclins during the cell cycle. Which cyclin is involved in preparing for DNA replication? 3/8cbwior0hf4pqequ m(m +5m

The diagram below shf dt9 v52+9 frx esl9t.:.:iil gqwysuows chromosomes 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 z s o4-k1wpt s tsq:t);ok0kj3separation of homologous chromosomes?

  The mitotic index of throat tissues takex/b dkq -0bs(gn from 4 different patients is shown below. Which p( 0-b bxd/ksqgatient is most likely to have cancerous throat tissue?

1.Draw a labelled diagram to represen8i9xa - rchhn,qmzm89 t 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 kaxv2ocv 8wta.su;mj **o i9fo3ryotype.


What is the abnormality in this karyotype and its cause?

The graph below shows the relative amouiabyg 6 ,l.rn,mtu7s50im q 4eu3cqx*nt of DNA in one cell during one complete c5 *gx s4m3q7ci ar0,bt u6myqieu.l ,nell cycle. 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 between a male cat that is homozygous foyq lf0p)/xhl ,0i5ss ,dsg /hzr brown, ) x,ylp issfl0qd,h /z0/ hg5slong hair and a female cat that has black, short hair.


Which of the offspring has a recombinant genotype?

1.Outline how polygenic t9zu of)*z1l4*kuz 5 nzr8tpikraits 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 czy ic;awz-m83++6s3 wnrrtkn hromatids shown in the diagr8 wkma sn +33z6-yc+ irzn;wrtam below?

  The photomicrograph shows a pollen grain from L. candidum (Lily). Which sxn3h w17fpp kvv;+:u01ais xotage of meiosis is shv7;hpn p1wxf:1u+0 o3iks vxaown?

1.Outline the events which would lead to an individuv g t/z g. 3qar5,x1ufll20volal being born with Down syndrome, which is characterised by the p. 13 l, fg/lt5zxl2ug rvqavo0resence 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 measun*2.kr)edm8q)yuq vs ring plant growth. A study was conducted on white onions (Allium cepa), under controlled conditions in a lab, to imq qke *n8)syru.)dv2nvestigate 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 whicr .pv6e/apf qst;m8,t h cells can divide. The diagrams below show two cells fromta/,se; qv.rp8p6 fmt 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 eflr,6wor;hn 3cj9c w8 xpression 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 diploid8cplrw;ydrn l 5.nw w *c4),sye+ lgr( number of 8, in different stages of meiosis. Which row correctly names each spnwll4 c5yrwe crrdl8;g+,(yw).ns* tage?

  The micrographs show four phu vxpqes4 )6l-ases of meiosis I in a plant. In what order do theseq-s4upv6x)l e phases occur?

Mitochondria are responsible for supplying metabolic energy in euk1h*q:aw gh*r( +n/edd *tjyxoaryotic 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 fo: dxy/+1rdetnhw*q( ohj*ag* und 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 inwq 8wgb3x3syv;7qy*i four samples of lung tissue from four patiw ;8qiwyg bxy37s3q*v ents. Which tissue has the lowest mitotic index?

  The diagram shows the dominant f*q qai pn2vsy dgixn8z2.z7 7b/lvxr;9*b )zcyclin/CDK complexes at different time points in the cell cycle. Which cyclin/CDK complex activates DNA replication dz v9vlann7 b bi*yz /f8q;7gq i xxp.2*)sz2rmachinery?

  Studies have shown that genes such as Cyc/i7oa xbq8 0eilin Dependent Kinase 3 (CDKN3) are highly overexpressed in cervicalo0q7 ab/8ixei 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 concentratiomsc2:h5ibrffw98. wz n of cyclin E the highest during the cell cycle ?