The graph below shows q.y0- lsgdso9 ) :pwmtthe relationship between maternal age and the incidence of non-disjunction. What relationship is suggested by the data in the grapywm-sdgt0 qp:o l)s.9h?

  Which stage of meiosis is represented in the diagram by(pu,2fjb eq7zdc 1cye :6j+1roue/below?

  The diagram below shows chb8,v .m 2syuvkromosomes 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 )hu- s6dh64amnx 7qlcgene which would be present in the nucleus of a cell as a result of each procesmqx hu- 6s76)ahlnd4cs?

  Which keyword is matched to the correct defin)v5vnk3 gerua a,u,7j ition?

  Which statement(s) about)+au yuku 2 vr)wws-bemf 187a:wn1 qf;djxs0 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 beekevy19 g4r 4ytuv10 blow, which letter points to a cell in anaphase?

  During which stage of mitosis does the /q;8gorz(xtxk3s ((-c *;srv nwqjnb nuclear envelope break down?

  Which one of the following tra d4j)( mtt,qnpe(w2zansport proteins only carries out active transport? qt4w( za(j 2tpdnem),

  Which process does n3wh8 nnwm6f i lnvrk:;wv3xd q,;*jy)ot happen in the shoot apex?

  Which type/s of membrane transport do/does-*yf ( zasuv n2l6wx;q not require energy expenditure?
I. Facilitated diffusion
II. Active transport
III. Osmosis

  The diagram below represents a cell with a d *w, y ,gnlndo-l*wonx*4g a5giploid number of 4. Which stage of cell division is the cell currently underg*n noo4l l5*,ynwag* x-g,dgwoing?

  The photomicrograph below shows a root tip meristem. Which of the fol6 (mvho9fc1b5kjr ,u llowing sentences correctly dek f5c vu6lmb jr9,1ho(fines a meristem?

  When does the random orientatib2ppf*7 fhc;hjgqh2 .on of homologous chromosome pairs occur?

  Which process does not occur during meiosit:6-z+ 6un yalylz,j ws?

  If a cell with a diploid number of 36 undergoe j wl., bwfe)m2- n:+-;ljzwvozgx5afs mitosis, how many chromosomes will be present 2-j og bwefx;v w5lz)lfmj+.wan z,: -in each daughter cell after cytokinesis?

  The image shows a microgral;s rk(iucx))(zy.p0,ixy w kph of a cell.


What explains the appearance of the cell in the micrograph?

  Which statement(s) about homologou9( rvlvx.y *w khg9hzu;uh7c9s 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 indiv+nr;sh zr f+;lidual with Down syndrome.

Which statement is not correct?

  In the cells of a horse (E. caballus) during prophase I of meiosis I there ars.i,olo1wly -2gk0cp e 64 chromosomes. What is the haploid number of chromoso1ok l2,p.yl 0wgosc-i mes?

  Which arrow is pointing to a chiasma l9dwkhq 21e1y)(kdfs?

  The diagram below represents the stru(bs4zqdf9: 9wpfeq; /f9wa rfcture of a shoot apical meristem. Which row in the table correctly identifies the processes occuring in /9a ;f9:fdeq swff(wqrpb49zthe structures labeled in the diagram?

  How does meiosis promote vari:s/ch:sl gxrnnubo9c51h+,b ation?

  Which of the following statements is/are correct f6ve0i3ml0ie uu : o*bior 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 cfy1zmv,4kq fs4x46ly 3 kzi3ahromosomes.


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 ofi t9a) a:5w2mjgu)hep secondary tumours from primary tumours as etp:iwmu9 j )a5g 2a)ha result of the movement of cells?

  How many chiasmata are presenth ,bneqh frc-e, g-)/b in the diagram?

  Which statement is a similarity between cyt4qz 3foom4x ld5 go/,yokinesis in animal and plant cells?

  Which stage of meiosis is msh1g.cspu qh91 m-iv 8atched to the correct description?

  Which statement(s) are true of meiosis I but not meilg2i2r6h s us fa mt:9dhn,,.oosis 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. hi1rvegm am4 d8c, z0z k6)8qpThis results in the formation of one large cell and one small cell. Wha 0c41,m g a6) z8dmqzkhirep8vt is the fate of the large cell?

  Which row correctly describes diploid ajbl5o8(c zetoh+ugmy ss2 )w7z1a (9mnd haploid cells in humans?

  The following table shows the diploid chromosome nuuyx3.2 1)drqezioz 33c ac m)cmber of a range of species.


Which of these statements is correct?

  What conclusion can be drawn from the kzcl)jw4hrp2vbf ( j 5.lwk02 daryogram below?

  Which of the following processes is characteristic of the meiotic and not the 0yq*s ;abo -.l3mt uya xcd3;ymitotic celu;mocy*033d-sqy aty a.;x bll cycle?

  The diagram represents a bud with a shoot u.xi l9ulxce1 )mj) -yapical 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 4bv1 2 hgqqcr6k (sz4.w8. Which row shows the correct chromoso6g sr 4bwk21qh(cq.vzme number for different cell types and cell division stages?.

  At the end of which phase of meiosis I does croxk6exu b:8v0s) oqqr)ssing over occur, and what is the outcome of ub ))x 0qor :vq8ksex6crossing over?

  Which of the following s vd8.rcu+szs4ts lf 8,3hzn.s 0u 8bsmtatements does not describe a step in the sodium-potassium pump cys4 .8n3husstv8z crsm. 0zlfb+ u8sd,cle in the neuronal cells?

  Which row in the table below isiy*3ne1dhx 7bvsy- fh96u4ps true of meiosis?

Membrane transport is important for allowing particles to move across the cell mj sch*)f vf72iembrane and respond to changes in the chemical composition of the extracellular flu fhs ic2j7v)f*id.

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. l+k98g, phibd 0co-wn

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 c6a2/ecsi ijy*id g+ e ;p/v1cba p;5hqoncentrations of different cyclins during the cell cycle. Which6 vqj +2i;cpepgecah5*i/ad1s i / b;y cyclin is involved in preparing for DNA replication?

The diagram below shows ch6i:o- qum9p7 j:9a tq6zafos g7afxz2romosomes 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 separat x:(z4vcffr o.ion of homologous chromosomes?

  The mitotic index of throat tiseqgoknt(,ic8bqe,m+3(of r9 sues taken from 4 different patients is shown below. Which patient is most likely to have caq q3(fo,c8g ( on+b9me,kietrncerous throat tissue?

1.Draw a labelled diagram to represent the process of crossi.(b7a -whvgbky b23p 8ln6uscng over.

2.Compare and contrast random orientation and crossing over.

3.Outline the stages of meiosis.

  The image shows an abnormal human k 3e-/ dx6cp +ujs yp;x6,cwrnaaryotype.


What is the abnormality in this karyotype and its cause?

The graph below shows the relative amount oi39 mhoqi94aaf DNA in one cell during one complete cell cycle. Each letter repi94 h9aa iqmo3resents 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 homozygqd-(4ospn: xb, xzoz *ous for brown, long hair andooxs-q:( xpd z bn4*z, a female cat that has black, short hair.


Which of the offspring has a recombinant genotype?

1.Outline how polygenic traits can show a normal distribution. c )swu 4/cduj(

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*ya3 ;qo- oi dl6eflx6er chromatids shown in the diagram xyo 3e qaf;-*ilo6d6l below?

  The photomicrograph shows a pollen grain from L. candi 2h+a -ju0onzedum (Lily). Which stage of meiosis is shoznoaju2- e h0+wn?

1.Outline the events which would lead to an individualv8a oh(yex7rtmv .4i : being born with Down syndrome, which is characterised by the presence of threeayhexmoiv vt(8 4r:. 7 copies of chromosome 21.

2.Explain how meiosis increases variation.

3.Outline the stages of meiosis.

The mitotic index is an indi 60dj;j nyve):ao gr)srect way of measuring plant growth. A study was conducted on6rjseo);v nj:dyg) a0 white onions (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 in which cells can divide. ;-x 4ca5nqd u r1-bz pw7zk;ucThe diagrams below show two cells from an organisrw7-4kpuxzc-1q5 ; cz ndb;aum 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 expression in stem growme .s hb6we.r*th.

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 dqd:ysz5m +nb:iploid number of 8, in different stages of meiosis. : +bs:d5zyqnmWhich row correctly names each stage?

  The micrographs show four pb fo)sxr7 ) -yj.i*eyuhases of meiosis I in a plant. In what order do these phases or-)7x* y)fbeus. ijy occur?

Mitochondria are responsible for supplying metabolic energy in eukar 3pwy0 u+2katxyotic 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 cellk02xp at+wu y3s, 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 950*zneoq 5z kgx )utd:0rfw3m*bp z gthe cell cycle in four samples of ldgg :5ux*zmp3bof09tzzk 0 5)e*n rqwung tissue from four patients. Which tissue has the lowest mitotic index?

  The diagram shows the dominant cyclin/CDK complexeqma;z1 smd shb )9g45;-gtlm 9rbvb/ es at different time points in the cell cycle. Which cyclin/CDK complex activates DNA 1m/ ssvzbma ;rb9m -5 d94t bg)hlegq;replication machinery?

  Studies have shown that genes such as Cyclin Dependent Kinase 3 (Ch3c ;ijm:8c-. uy0 az zshni9mDKN3) are highly overexpressed in cervical 8 sia 3chu.0m:i-mhz;9jn ycz 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 h ;sm(ssgf3g .ei6, fwb8jb7mkighest during the cell cycle ?