The graph below shows the relations 6*wgtq94mblv 1,zh pvhip between maternal age and the incidence of non-disjunction. What relationship is suggested by whvqg zmb1l4v* tp,96the data in the graph?

  Which stage of meios oop) cf9,yhh;is is represented in the diagram below?

  The diagram below shows chromosomes 199hufkrml2 mdq1-b 9a nt/drduring 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 nu, )n6euafv0 u)8h r3iaivbg a5mber of alleles of a single gene which would be present in the nucleus of a cell as a )u0 a 5vi, 8nefr) uah6agbv3iresult of each process?

  Which keyword is matched to the correct definitioe5( *wlpa/a3tp:eu .0z kp eprn?

  Which statement(s) abou9jp*0do avk6pt 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 points to a c-0fsg:up.i52gzl: y1o, 2ovdajd tow ell in anaphase?

  During which stage of mitosis does the nuclear enve *ioosvsu8n. 3ba:9nv gj3w6jlope break down?

  Which one of the following transport proteins only carries out active transpob/l 5-hjf; dfswe a6v3rt?svflwd 63ajh5; f/be -

  Which process does n oj/:r5c-ray)w )n nhxot happen in the shoot apex?

  Which type/s of membrane transport do/does not require energy e0,vst(o a v:9l(hzx jdxpenditure?
I. Facilitated diffusion
II. Active transport
III. Osmosis

  The diagram below represents a cell wit hzfz;-qc gq4:h a diploid number of 4. Which stage of cell division is the cell cur-z h:qc;gf4 zqrently undergoing?

  The photomicrograph below shows a root tip meristem. 6gegbvqb86w0a c9d v/psy9 c9Which of the following sentences correctly defines a meristem 9 baec qvb/ gd89c66wgvy0sp9?

  When does the randome1dwy*v9 (/vumes5re orientation of homologous chromosome pairs occur?

  Which process does not occur during meio.0sic;wtc,g)bt;*i 6 g/ntyu upkxi 6 sis?

  If a cell with a diploid number of 36 undergoes mitosis, how many chromosg kt6szec )2h(omes will be present in eagzck26ts )he(ch daughter cell after cytokinesis?

  The image shows a micrograph of a c5uog.sfc rje3bl54/ i ell.


What explains the appearance of the cell in the micrograph?

  Which statement(s) about homologous chromosl)92mf fzq;blgak7u /omes 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 syndr72y e(f lev(s41 iq)ddoxi1f vome.

Which statement is not correct?

  In the cells of a horse (E. caballus) during prophase I of meiosis I t2oy s ipq+ma1przae hy ym3g+ i9:)*/-wc(knvhere are 64 chromosomes. What is thepva1y +s: h2o/k9ye-(i)qm*nap z yr mci wg3+ haploid number of chromosomes?

  Which arrow is point *vyrd +a+e*nh4l*czfr8j6ohqb6 ,qeing to a chiasma?

  The diagram below represents the structure of a shoot aphv-dh rjp0x meg*gid 6a ;+-y9ical meristem. Which row in the table correctly identifies the processes occuring in the structures labeled in thehyghe+ra6d-0 ; vp9xm jid*-g diagram?

  How does meiosis promote variationvcyr; r l 203stj8,xpt?

  Which of the following statements is/are correct for mei04 tcfw: dsjnnt: j+b+osis?
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 cu-uo1ss hrz( 1hromosomes.


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 second)8 b-goanxm tdj8ca, ier6sm-3 yu6 n3ary tumours from primary tumours as a result of tmi syxj 38n3gau)n6r-aeo 8cm,-t6d bhe movement of cells?

  How many chiasmata are presenuk md, 4li/ke9t in the diagram?

  Which statement is a similarity between cytokinesis in animal and plant celv+snf,o (0d4vyu 0rvvxsu8o 7ls?

  Which stage of meiosis is matched to tynnot/d b83m6 he correct description?

  Which statement(s) are true of meiosis I but not meiosi22h)f5xcbz yif1j c n)adqm;ir;rs64 o* ax6cs 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 diviqge ck yx56f2*sion. This results in the formation of one large cell and one small cell. What is the fate of52 eqxg *6fkyc the large cell?

  Which row correctly describes diploiiussvc0,7 hgcz v l)v+h f3*(od and haploid cells in humans?

  The following table shows the diplo;z85fnaeo ihja d .i (ba4xs-(id chromosome number of a range of species.


Which of these statements is correct?

  What conclusion can be drawn from the4;jt1d8ka ( pd0uzk nq karyogram below?

  Which of the following processes is characteristic of the m7v4qj r /vq9zmeiotic and not the mitot 7m vqjvr4qz9/ic cell cycle?

  The diagram represents a bud with a shoot apical ;t-lxq r/cv*mj;5 at/bi q-d0* yfpu omeristem.

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 troglodytes8 :z/j+yiiwo fxjfrz0lb8a j l:,dp .,) is 48. Which row shows the correct chromosome number for different cell types and ce,/fay 8 :d08zpi,r i+xj .lbjz:jlf woll division stages?.

  At the end of which phase of me/e. d2 qarlaixqdhei9nw+2 3 ,iosis I does crossing over occur, and what is the outcomer.xi2d,i2 el+3qn w9qdea ah / of crossing over?

  Which of the following statements does not describez gcm 35s7dpy7 a step in the sodium-potassium pump cycle in the neuronal ceyg5 m pcdz7s73lls?

  Which row in the table below is tru whetw+w9zit /j:(jj) e of meiosis?

Membrane transport is in dok3av m20hyj5+hh5;zc ds 5mportant for allowing particles to move across the cell membrane and respond to cha j+5s ; kzyhoacdmnh50hd v325nges in the 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 regulated in cellsp;wlggl+/r /u.

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 cyfij+ ;a4s;7n n nesbz;clins during the cell cycle. Which cyclin is involved in prep47; bz;jnasn +fi esn;aring for DNA replication?

The diagram below shows chromosomes during7zim5e;f z*r v/a;jnejxhm5qrs*)r )q. r b e6 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 sep3s d5r8 8dcw k:w,zmudaration of homologous chromosomes?

  The mitotic index of throat tissues taken from 4 different patients is shia.vv 5)du v8hown below. Which patient is most likely to have cancerous throat ha.5)u vi8 vvdtissue?

1.Draw a labelled diagram to represent the process of od kq2 utvetx8+,;f4 r5w2rmgcrossing over.

2.Compare and contrast random orientation and crossing over.

3.Outline the stages of meiosis.

  The image shows an abnormal human karyozzk +-zl+op .ctype.


What is the abnormality in this karyotype and its cause?

The graph below shows the relative amount of DNA 8-t(,n oag eojba(4iein one cell during one complete cell cycle. Each letter represents one stage of thb(a-8et ,ag(o jo4ine e 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 ma*nga8 -hpj- *o5h wd+at1ra egle cat that is homozygous for brown, long hair and a few*o -japnhgag 5tea1r*8d +-hmale cat that has black, short hair.


Which of the offspring has a recombinant genotype?

1.Outline how polygenic traits can show a nor3c,94u6 grudsf: rymimal 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 8ds8xv48lm r bchromatids shown in tb84dv 8rsx8lmhe diagram below?

  The photomicrograph shows a pollen grain from L. candidum (Lily). Whi*( l65)saz*xogsb fpo 7hk7tz ch stage of meiosis is showngaxo5)6 t*zh*s (b7zflps7 ko?

1.Outline the events which would lead to an indiv ok 8mbo:1y5)aigw gl+idual being born with Down syndrome, which is characterised by the presence of thr wy1oog8i+ lb) 5:magkee 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 wasej) uw7 +3b gkiu3/avxt,2tx g conducted on white onions (Allium cepa), under controlled conditions in a lab, to tujw+ )3t xg237,vix/ ebagukinvestigate 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 below smj ,s3h2wlkk+how two cells w m2jl3k,+hsk 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 *m(rrb( fv .nfk:h8uhgene 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 sho6*l 9 ; efyf8xutrk:j +nc9number of 8, in different stages of meios 9 ucyfhr*:o j9n sex+tf;l6k8is. Which row correctly names each stage?

  The micrographs show four phaeqwfe/npo -)*ses of meiosis I in a plant. In what order do these phases occnp-w *q)/eofe ur?

Mitochondria are responsible for supplying metabolic ene 41ruitywz ) i12i/cwdrgy in 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 spe21 riz/wdt ii)cy 4wu1cies, 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 ce (w0; vxuy2npzlls in different stages of the cell cycle in four samples of lung t nvyw2;pxzu(0 issue from four patients. Which tissue has the lowest mitotic index?

  The diagram shows the dominant cyclin/CDK complexes at difklo eodm,*b0ibe(ml8-j1x h y()s 5qcferent time points in the cell cycle. Which cyclin/CDK complex activates DNA replicaticmbb0 (ydolk h)18 em,ij5* q -(esoxlon machinery?

  Studies have shown tu c,6;21 vr(3ljwdf i)dygdbk hat genes such as Cyclin Dependent Kinase 3 (CDKN3) are highly overexpressevk2)bwd (ud6,;cflry 1j3gdid 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 thel v f)vprh,(8b highest during the cell cycle ?