The graph below shows thd a(b+e* bcp-be relationship between maternal age and the incidence of non-disjunctioe+ b b(b-d*acpn. What relationship is suggested by the data in the graph?

  Which stage of meiosis is represented in the diagram be vu+13axsf : plkb +61.qr7n y8lzbztdlow?

  The diagram below shows chromosbaesu n*3kpq c8(1 (46qd psixomes 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 g0us zrck:/74 ssg:ayrene which would be present in the nucleus of a cell as a resulakgz 07rsyc:s4 s/r:ut of each process?

  Which keyword is matched to tt ia ri ryn/r9+0dk7r,he correct definition?

  Which statement(s) about mibb7u c+ ngo5u+t)n3tutosis 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 poi; zbp5h q0owz ynws4-(nts to a cell in anaphase?

  During which stage of mitosis d6jet g3we:*6 v(gat emoes the nuclear envelope break down?

  Which one of the following transport prd c:b5t8 lmw6moteins only carries out active transport?5 6wbt lm8cd:m

  Which process does not happen in the shoot acsmqk:f xc :irgo90/5 pex?

  Which type/s of membrane transport do/does not require enerc48iep z.u j*pgy expenditure?
I. Facilitated diffusion
II. Active transport
III. Osmosis

  The diagram below representsxg6 gxjqd/0zhc6 z).*s nys 0f a cell with a diploid number of 4. Which stage of c x*60js gdgz q6fc .ny)zh0xs/ell division is the cell currently undergoing?

  The photomicrograph be+ba1ozpv5)y i low shows a root tip meristem. Which of the following sentences correctly defines a meristep+5bz vi oy1a)m?

  When does the random orientation of homologous chromo1ss/cp,s(uiya 9gd7xiqug)i5-* )f pub; e nasome pairs occur?

  Which process does not oc2f:x9*q ww2 jzb*a rafcur during meiosis?

  If a cell with a diploid number of 36 ung8ezwq-nmgv 86 g 1,addergoes mitosis, how many chromosomes will be present in each daughter cell after c6 ,e1dg 8qwzvgn -g8maytokinesis?

  The image shows a micrograph of a92lb pmo ,i4n p3iyzlsw5b j)- cell.


What explains the appearance of the cell in the micrograph?

  Which statement(s) a h*/ *3 ua-any7*uijeq2/ zfomhnp- fvbout homologous 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 wit ;8us7svjm*o/ue19o )lroo -z(cbn(qfke -bqh Down syndrome.

Which statement is not correct?

  In the cells of a horse (E. caballus) during prophase I of meiosi))( hbxwu 1;biz ast )ofuk9i9s I there are 64 chromosomes. What is the haploix)h)s o1)a 9(uk9ubw ibi z;ftd number of chromosomes?

  Which arrow is pointing to a chiasm vv j5jckv7 nn6v3/gs-a?

  The diagram below represents the structure+k62cqb5q 7lfk bmq: x of a shoot apical meristem. Which row in the table correctly identifies the processes occuring in the 2+kxml6qfcq5 kq: 7bb structures labeled in the diagram?

  How does meiosis promote variatifuv. wb* 5k6weon?

  Which of the following statements+zr4j:edlf j:dv agv / ;nlj., 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 gamete k vqd /iz3cdwo) ,z313nray8ls produced 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 formation of secwm;v /wju4z*t6fyf( dondary tumours from primary tumours as a result of the movemfw(f6vmwzduj/ ;yt4* ent of cells?

  How many chiasmata are present in the diagramc9k2uvrb/ lx+?

  Which statement is a similarity between cytokinesis in animjk*j9azjsjm -/+rjc rf59i;ral and plant cells?

  Which stage of meiosis is matched to the cordyuc6rny kjnlb)( 944re. )jy es:f z+rect description?

  Which statement(s) are true of meio r6 a.jgagayw y2o6z pr)x-kfuck+g t ;/45i1usis 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. This resul*apdb7hf neg* 0/*rw)hb8 t ysts in the formation of one large cell andenarp7*0)b*w 8yd g/*hfs tbh one small cell. What is the fate of the large cell?

  Which row correctly describes diploid and hap6e psyh ) ;z.x/gop;o;h2nt 2 ooja3pnloid cells in humans?

  The following table shows the diploid chrgij i)27tv9e77 y k1vvgz, mlyomosome number of a range of species.


Which of these statements is correct?

  What conclusion can be drawn fromlnnw;7vx(gq) *z/tx s the karyogram below?

  Which of the following pr++ xgr1na ;vpfocesses is characteristic of the meiotic and not the mitotic cell cyca++f rgpn1xv;le?

  The diagram represents a bud with a sho1wgyvndt.xi,9 t(b e;m.jf/ iot 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. Whicv ;*wzs8hsjv78d r xqo0lm 5g,h row shows the correct chromosome number for different cellvs50 v,o;r hq * swgzxmld8j78 types and cell division stages?.

  At the end of which phase of meiosisj2pwd :,mm8p2 . telfrkpn/3o I does crossing over occur, and what is the outcome of cross,.pr28k/3tfmlmoj2 pdw p e:n ing over?

  Which of the following statements does noormf7v8k7cb 8- t yf-uz+x u;ft describe a step in the sodium-potassium pump cycle in the neuronal cexf-+ mc8f8rb z77-uu;vfkt yolls?

  Which row in the table below is true of meios 3cbgyy9qanji)6k-ev2 crgy:-a04 pfis?

Membrane transport is important for allowinp4t,hh20pt s ug particles to move across the cell membrane and respond to changes in the chemical compositsp0uh2tp4,ht ion 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 regulate 2pt9f*beahog1a+ a 9ad 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 ya+c wc /qqx8-the concentrations of different cyclins during the cell cycle. Which cyclin is involved in preparing for DN/8-q cxacy+qwA replication?

The diagram below shows chromosomes durq5 j8ck3q7njd c8wcl3 ing 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 separ k+ (:aofimvp;1m mlc6ation of homologous chromosomes?

  The mitotic index of throat tissues taken from 4 different patients iox,)tooo54;t 1jl im is shown below. Which patie5 oxjlmtoio,;o)4 1itnt is most likely to have cancerous throat tissue?

1.Draw a labelled diagram to represent the process of crol; f2:3 y9g k4lg ta+(cogqxri1fk(vhssing over.

2.Compare and contrast random orientation and crossing over.

3.Outline the stages of meiosis.

  The image shows an abnormal human ka lcdg(/un:j*v ryotype.


What is the abnormality in this karyotype and its cause?

The graph below shows the relative amount of DNA in one cell during o oy-mk8f1 z1aane complete cell cyy1ma 8f1- akozcle. 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 p8lj. jw jtm8g m-eb(,male cat that is homozygous for brown, lolbejmg p ,jt.8w-m j(8ng hair and a female cat that has black, short hair.


Which of the offspring has a recombinant genotype?

1.Outline how polygenic trr u1:wgbk2 x,e:lwvl ,aits 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 snb*kmwwfjhkt 1-3 (eb*pv6e 1hown in the diagra**eb1 (kpnmbk-f1jt6ew 3vwhm below?

  The photomicrograph shows a pollen grain from L. candidum (Li6u)zx6q1:ka eawb d*ac /sqw6 ly). Which stage of meiosis is shown?a6:zak1xqe w 6d)q6/us cbw*a

1.Outline the events wh0(k1 vgtm + qhdcti5y;ich would lead to an individual being born with Down syndrome, which is characterised by the presence of three cop 1k 0m(q5+c;gv dhttyiies of chromosome 21.

2.Explain how meiosis increases variation.

3.Outline the stages of meiosis.

The mitotic index is kbndds1 9)) 8dzmuod ,an indirect way of measuring plant growth. A study was conducted on white )b,1m nsk dod89)zuddonions (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 ( ;e7;iifoi; az8f ha,4jwdvf in which cells can divide. The diagrams below show two cells from an organism with a diploid number (2n) off f v;a;(joi ;4e7fd,i8 awhiz 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 7p;lsyrfk*0-iskvk cv5kg0k7zqf6) expression 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 differr fi* e+e-3znxent stages of +* fin3rxz-ee meiosis. Which row correctly names each stage?

  The micrographs show four phases of meiosis I in liralf-+*vd. a plant. In what order do these phases-ldr+* ia.f vl occur?

Mitochondria are responsible for supplying metabolic energy in euk h, an:oydrz/4aryotic 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, y/oz r4n,ha:din 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 ofrl5r 6 y -qo1rhqn/:s( yv.g/ z/5, yecshellm cells in different stages of the cell cycle in four samplegsc/l/ry5hy e rre,h/ :(qmq- 6zvlo1.nl y5ss of lung tissue from four patients. Which tissue has the lowest mitotic index?

  The diagram shows the dominant cyclin/CDK complexesc- t58p-mmg el8qjuh /j*4cwz at different time points in the cej-huw5cl*e8 /cpmgt 4mq8-z j ll cycle. Which cyclin/CDK complex activates DNA replication machinery?

  Studies have shown thag bkprx7avlxf. znu9. r/j1( :t genes such as Cyclin Dependent Kinase 3 (CDKN3) are highly overexpressed in cervica(17a./9 x furrjx.nkb pvg lz:l 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 Ea/ 39nix 0f10d*bmcxgmr* vbj the highest during the cell cycle ?