The graph below shows the relationso+l:sv4v5 wqf hip between maternal age and the incidence of non-disjunction. What relationship is suggeste:+q5o wvlvs4f d by the data in the graph?

  Which stage of meiosis is represented in th+w)+4si:otd q-g ftn xs1u.ib e diagram below?

  The diagram below shows chromtqim4ot0+h 7j 2i7hljosomes 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 gene which would drfi 4u)/3:bd viuhleb3h jgj07q5c6be present inbiu5ub gl / i0c fje3j4d:6vd)3h7hrq the nucleus of a cell as a result of each process?

  Which keyword is matched to the correct defini( )m3g( 8pm+a ahnfmxvtion?

  Which statement(s) about mitoss*f ve e5b/n(sis 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 cell in anaphas;j xj; 7sn7b4 ybjvda)e?

  During which stage of mitosis does the nuclear envelope brejxgc1lv1 ;xfx+r3mq2 ak down?

  Which one of the following transport proteins only carries out active transpo / ymgchk.)m)p4s7oxcv- j ag3rt?yc 4j s.-7)cmx3g)gmv /ph kao

  Which process does not hap3dkvkvhax4v -:65 au vpen in the shoot apex?

  Which type/s of membrane transport do/d)ntn(r no xls)(luc ,4oes not require energy expenditure?
I. Facilitated diffusion
II. Active transport
III. Osmosis

  The diagram below represents a cell with a diploid numbe :.6d*mc nhtbzr of 4. Which stage of cell div*z.m6 t:d cnbhision is the cell currently undergoing?

  The photomicrograph below fwk2 e nn7:nibh:l+f)shows a root tip meristem. Which of the following sentences correctly defih bn +7wfl )n2ne:k:fines a meristem?

  When does the random orientation of homologous chromosome pairsa9/)9lneh ay5 3b:mnt xzrq8s occur?

  Which process does not ojg)huo4fpz222e+gsf s za( /e ccur during meiosis?

  If a cell with a diploid number of 36 undergoes mitosi wt:g-w r-*p98fwr tais, how many chromosomes will wf: agrw -i9*wtt-8rp be present in each daughter cell after cytokinesis?

  The image shows a micrograph of a cellsg*ygx,bj mrg/c+;- k.


What explains the appearance of the cell in the micrograph?

  Which statement(s) about homologous chromosomes is/are not trqvz)rkgi5n* - ue?
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 4jhbev0+9c l*rim 18 8okcclman individual with Down syndrome.

Which statement is not correct?

  In the cells of a horse 6upu2 1c/trlc (E. caballus) during prophase I of meiosis I there are 64 chrom1t2c pclu/u6 rosomes. What is the haploid number of chromosomes?

  Which arrow is pointing to l 9.xqt/wvdjof((br; a chiasma?

  The diagram below represents the structure of a shoot aptumav6 11qe 2rical meristem. Which row in the table correctly identifies the processes occuring in the structures labeled in the 62tv euq1am1 rdiagram?

  How does meiosis promote z1 bhw8y5 kelcmg 7bpz*z-5y8 u6do5vvariation?

  Which of the following statements is/are correct for meiosi8 tybb-, ufg:vs?
I. It is a reduction division
II. It involves random orientation
III. It produces genetically identical cells

  The diagram shows gametes producedtuu d5-o 5l h,rvevp(e(3xf/m5a v8wy 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 tq 5,ew (d3qo7z ov.-jwufvl0secondary tumours from primary tumours as a result of the movem3q,zjed -7(lvo 0v.wo 5qutwfent of cells?

  How many chiasmata are present in the diagr.1;aqru c *mwmam?

  Which statement is a simis :g;78zr yuum fbms :v5g+-gklarity between cytokinesis in animal and plant cells?

  Which stage of meiosis is matched to the correct 2ltjbv+ko :2rdescription?

  Which statement(s) are true ou 4ua 8 2ukgmj1bl*zk,f meiosis 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 thof:3m7)f+ evo8ak l ale first meiotic division. This results in the formation of one large cefoma 3)7lvk a+ el8f:oll and one small cell. What is the fate of the large cell?

  Which row correctly describes diploid and haploie9t;bba-v ,j h ()hulwd cells in humans?

  The following table shoj51d1avxi-,v -,nuj hi ;olagws the diploid chromosome number of a range of species.


Which of these statements is correct?

  What conclusion can be drawn from theuh dh +x6gtiq wbt0.1j9xhr5+ karyogram below?

  Which of the following prrdxk ;zqb(+q5 ocesses is characteristic of the meiotic and not the mitoti+ zq(bkd xq5;rc cell cycle?

  The diagram represents a bud with a shoot apical merist/8ey06 5bl0ydz mnlrxem.

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. Wt u :kehm5kr1 / /laqo,nk*bi.hich row shows the corrba /nt:/mkkq uoe ki*h,rl.51ect chromosome number for different cell types and cell division stages?.

  At the end of which phase of meiosis I does crossing over occur, zoc.m z p(xmy;56dmddkwo+ byy y0 k:c2. mr32and what is the obyzy kyo0dy wd +dcxm r2.mp3( 5zk :6.mo;2mcutcome of crossing over?

  Which of the following statemec95an w 73v9fhep5,a5f v- rm/wjygrf nts does not describe a step in the sodium-potassium3fvj 5ah7c 9r5f9rwpvm5wy f, a/e-g n pump cycle in the neuronal cells?

  Which row in the table below is true ogk+a c,8,qdll f meiosis?

Membrane transport is important for allowing particles to move ac0c m3t)t(b wsbross the cell membrane and respond to changes in the chemical composition of the extracellular fluc)(s3btbw m0t 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 / u ba 72cd e,quyc;x82d/fx/r5jfq liin 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 deu(xb4w/)s 09:n:tm bhyxhb huring the cell cycle. Which cyclin is involved in preparinxbu w hby hnxm)4:0htseb/:9( g for DNA replication?

The diagram below showk1* ni k+j-ze*z56jn u jqtwlkby -f7(s 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 separation of hom i03vz6eidio xq1 4bd)ologous chromosomes?

  The mitotic index of throat tissues taken from 4 different pat )m vu;0u r92p6d(s + dk ;*abg8hwgzcyutvrw;ients is shown below. Which patient is most likely to have cancerous throawt0*2hrg(aup;bsg )rdm8 y+z uu c; 6dk wv;v9t tissue?

1.Draw a labelled diagzv ( tsjf6n,*mufd *h4ram 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 hukj9 eqb9m t10zman karyotype.


What is the abnormality in this karyotype and its cause?

The graph below shows the ra2 7ft. .s5l i3u rgqimh u7-/tifxdj7elative amount of DNA in one cell during one complete cell cycle. Each letter represents one stage of the cell cuj32/f tqimgxd 7 l.7ah7firui-ts .5 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 shows a cross between a male cat that is homo.o8fhq yvsf( s+6.n9gvpr9 qqzygous for brown, long hair and a female cat that has black, short ha9 so(qv 96 gyfq+rp sh.nf.v8qir.


Which of the offspring has a recombinant genotype?

1.Outline how polygenic traits can show a normpdw0ovjx i8hm3.5shomul2 xt,c 999 r al 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 overha//s py 8vbe9 of non-sister chromatids shown in the s/phb 9ya/v8ediagram below?

  The photomicrograph shows a pollen grain from L. candidum (Lily). Which st,ooxeeyo7s9 s .+p 4sgage of meiosis se49ooeos+p 7 ,.yxg sis shown?

1.Outline the events which would lead to an individua jqi,v :qmd*z5b3y)wy l being born with Down syndrome, which is characterised by the presence oyi3 5w dvzq)jm:* ,yqbf 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 study was contkqlf*il5zqc: lve ) ck1 6mwjw;570c ducted on white onions (Allium cepa), under controlled conditions in a lab, to investigate the effect of soil pH on the mitotic index of the roots. ) iw7vlm5lc1q5k cw:kft; *e czqjl60


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 cell ;wqcq.q5)qsl s can divide. The diagrams below show two cells from an organism with a diploi;lq)cq. 5wqs qd 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 growth. pp9(j2y ,yrwqy km)5v

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, wi0c :k+nhtcg5649 v/hk (qccoo f4gjjuth a diploid number of 8, in different stages of meiosis. Which row corr/g(c4ch 0 o4tnjkcc h:5 fj6vog+ku 9qectly names each stage?

  The micrographs show four phases of meiosis I in a plant. In what ordern+1:jvedegm9ovkw e;/ ,k1 n/ c n2ble6ev rn; do these phases or1 9 g;;mk: njevn/ vl d216+eo ,vewkb/necneccur?

Mitochondria are responsible for supplying metabolic energy in eu/9nga7enq a5xn pzk*noz 0*:hkaryotic 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 theknzn5 7* hpo9a0 *:a/nzxegqn 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 cel 77n(d127uivwe avvdhl cycle in four samples of lung tissue from four patients. Which tissue has t vd wv7u(72ad7vhein1he lowest mitotic index?

  The diagram shows the dominant cyclin/CDK c1 vdt7 -o y lv(ge.x3hyi1n9nzll9mh9omplexes at different time points in the cell cycle. Which c v9dn(1oymn1 x lhzihlet9 7lg3 v9.-yyclin/CDK complex activates DNA replication machinery?

  Studies have shown that genes such as e6fur+ ur.dv(c7kdn*2)n r zz Cyclin Dependent Kinase 3 (CDKN3) are highly overexpress)rn7rcu . 2vz d6fnk+ (urde*zed 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 the highe +ufbfkdyy 5zhg9u,)3 st during the cell cycle ?