The graph below shows the relatw5+:e9b shoze ionship between maternal age and the incidence of non-disjunction. Web o: h5z+9weshat relationship is suggested by the data in the graph?

  Which stage of meiosis is replu 9-k xk5z;/, xhumrnresented in the diagram below?

  The diagram below shows chromosomes during meiosisk.bm jma,d 9*y s(d(mq.


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 ofg31wy2xcrpx2 n wkxl4/ i)2id alleles of a single gene which would be pre2432 nw lcix/p )x2ky1grxidwsent in the nucleus of a cell as a result of each process?

  Which keyword is match 2qddlh 0c6zp9ed to the correct definition?

  Which statement(s) about mitosis jve46 ag for(bhk779z-puqa 4is/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 i8ms(7yu1gtvspk m- l. n anaphase?

  During which stage of mitosis does the nuclear pst omy,3)5v aenvelope break down?

  Which one of the following transport proteins only carries out activ18 xvlw78cs-ls1dhx x ln8 mk o::*wbne transport?x sl81s-vn*xl :o8wk c7d1 xwnm:l8bh

  Which process does not happen in thel viy4k em 6a yo.ojmt:0sb4z*m (g12o shoot apex?

  Which type/s of membrane transport do/does not require ener/mvb07bk6 g9j dhi3u cgy expenditure?
I. Facilitated diffusion
II. Active transport
III. Osmosis

  The diagram below represents b;fb6h2,z )f8wlzso n a cell with a diploid number of 4. Which stage of cell division is the c86)w2s ofh fblzz ,;nbell currently undergoing?

  The photomicrograph below shows a root tip meristem. Which + vd1)93jk of.zjiuutdl2:o c of the following sentel to.o2)c1iz+ vdfuud39j k: jnces correctly defines a meristem?

  When does the random orientation of homon 5kyazz sn02*logous chromosome pairs occur?

  Which process does not o(p9ti8;kilss ;g- j j2qqx)e ypg(*vy ccur during meiosis?

  If a cell with a diploid number of 36 undergoes mitosis, how many nvi/cjc 3o vb+x - ,srzd*w0n50nj )gachromosomes will be present in each daughter cell av-bc i* wj3cozvg0nj 0 dns),5 r/n+axfter cytokinesis?

  The image shows a micro:7lb xpw,hm+4oa(iqq r;i c-ugraph of a cell.


What explains the appearance of the cell in the micrograph?

  Which statement(s) abouf20, nweqrog 6t 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 in,p7 p )0tbxii qc/sf* 9hp 4 7nu+h;dpfwmwn5bdividual with Down syndrome.

Which statement is not correct?

  In the cells of a horse (E. caballus) during prophase I of meiosis :effl2 ub f3/;zsr- jiI there are 64 c suf rl/;2ezfb:j -i3fhromosomes. What is the haploid number of chromosomes?

  Which arrow is pointing to ai;ioi+uf++2nkycl 5 pqgth* 6s ;p5 kk chiasma?

  The diagram below represents the structure of a shoot apical meristem. Which 96;gvtzmx; h- yzlc u0row in the table correctly identifie0utx cz9yzgmv -;;6lhs the processes occuring in the structures labeled in the diagram?

  How does meiosis promote variati7+fi(n: )w5vbuw qygq7 qsg .hon?

  Which of the following statements is/are correct fokswym;x qf0 d r.6il3.r 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 ch t/gh3;i 6melqromosomes.


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 secondary tumours from primary /y kevuh/ne-f. xvj( 1lqsh;+ tumours as a resxl/e+ ;f e(n1/ vkh q.uy-vjhsult of the movement of cells?

  How many chiasmata are prhy d/5uil ;4jb f5q0yliej;q7yv-z r )esent in the diagram?

  Which statement is a simila 2alxr 3qpxovtj8xd;2p1 du*8 rity between cytokinesis in animal and plant cells?

  Which stage of meiosis is matched to the correct descriptiml)q 182 dmn hs.ljja*5p*kudon?

  Which statement(s) are true of meiosisc 7m jc62f4u-aogi/ lk 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 showsn6x:7d3h hs,2d1yv79 7f i9uun dwsjlwo w9 of an oocyte after the first meiotic division. This results in the formation u,ino f9ds7 fw3 w so99ud2lnhw 7y1:7 6vdhxjof one large cell and one small cell. What is the fate of the large cell?

  Which row correctly describes diploid and haploid cells i wsuf ih2qdl2 t8o3qs/7jm-i5n humans?

  The following table shows the diploid chromos1(e- 5jw4x6tlzb dpo come number of a range of species.


Which of these statements is correct?

  What conclusion can be dracrzaq8t 4.1r:yxc 6 uixt*idz85m ff(wn from the karyogram below?

  Which of the following processes is characteristic of the meiotic and not thm np1ya: o/8 vtj/1gzwe mitotic cell cv o maz:g//y1tw18jnp ycle?

  The diagram represents a bud with a sh2 ;5vclpzq0hp oot 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 (x zre0fo9ti(e-q+a h48. Which row shows the correct 0h9 ex+f(toe(-ia qrzchromosome number for different cell types and cell division stages?.

  At the end of which phase of4 j48 qspg06or*tm hzy meiosis I does crossing over occur, and what is the outcome of sg4rtj moz864p *hq 0ycrossing over?

  Which of the following statements does not describe a step in the sodium-potassi785psa2owfsb m6thy k/l 0kq: um pump cycle ino lbtkq/hp28s7kmwa 6 y0f: 5s the neuronal cells?

  Which row in the table below is trkzvl8dcts 2meg,c/ (.ue of meiosis?

Membrane transport is important for allowiz0pdb oztlkf h89* 16mng particles to move across the cell mem0thkf8 bp *z1ld m69ozbrane and respond to changes 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 cellroc v1-tkr(s.s.

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 durk*q2 ihelp6zlfqvwy 93)k +a/ing the cell cycle. Which cyclin is zvapqiy/l9f6)l e+q *hkw3k2 involved in preparing for DNA replication?

The diagram below shows chromosoc:j n1(- qtlsames 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 homologous chromospbrz. qp58f,vomes?

  The mitotic index of throat tissues taken from 4 differentbtl)8 1s(ysb t patients is shown below. Which patient is most li 1bt)s( tslyb8kely to have cancerous throat tissue?

1.Draw a labelled diagram to represent the process /ok) waafsgpvy8:8 sv3c ) m2gof crossing over.

2.Compare and contrast random orientation and crossing over.

3.Outline the stages of meiosis.

  The image shows an abnormal human kary)8( zxu p3dqq4c-zlpa3ni5 j botype.


What is the abnormality in this karyotype and its cause?

The graph below shows the relative amount of DNA in one cell kif 6.2uh9mgcss ej1 :during one complete cell cycle. Each letter ufegh. m9j1 6kcsi2s: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 ho. ec. h 2u-hn4dw 5l7sbvzso:o)ay2k mmozygous for brown, long hair and a female cat that has blac- 2 nyb72svh5 .c ez wsudoh)lo.ak:m4k, short hair.


Which of the offspring has a recombinant genotype?

1.Outline how polygenic traits can show a normal distre xrfkapckrd f1 *r4l7:h60;cibution.

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((m8n 77 zxv msag5ktm shown in7 tvm8 gk(za(nsm xm57 the diagram below?

  The photomicrograph shows a pollen grain from L. cand /yivpz:g2 d 9/qn2ntcidum (Lily). Which stage of meiosis is vngi/c pdn/:y9z2t q2 shown?

1.Outline the events which would lead to an individual being *t/xfkq 2q92wg:oziyborn with Down syndrome, which is characterised by the presence of threiqz *f k9wyg2toq/2:xe copies of chromosome 21.

2.Explain how meiosis increases variation.

3.Outline the stages of meiosis.

The mitotic index is an indirect way of mea pz;4fe12qp9,ujmyox /q.: dmrrue 7 xsuring plant growth. A study was conducted on white onions (Allium cepa), under qeu1e,4 ;/mrxdf p7: q p9r2ojuzymx .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. The diagra jlfv95+yp1mu,ucaot: i1 ,w*wwh;sbms below show two cells from an organism1w;w ah:wt9 pumf,*, 5ciyu+vjlb1so 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 grjpdt 8)cjf:gm 4 ld-,iowth.

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 4kell uqj4+ dj;i uk74a diploid number of 8, in different stages of meiosis. Which row correctly names e74e4d ;ukiq4kllu+jjach stage?

  The micrographs show four phases of meiosis I in a plant. In what ordt vfzi .sjs0kalbe xymy/: 6 zn/722/ner do these ph jyy7esf6bn0ln z2t /vm.i2s //z:axkases occur?

Mitochondria are responsible for supplying metabolic ene 7wb 6karm7w1ergy 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 77bw k16mwraebeen 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 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 nu i gbmws8pag,o(rp2 ((mber of cells in different stages of the cell cycle in four samples of lung tissue from four patients. p b,som a p8rgg(2w((iWhich tissue has the lowest mitotic index?

  The diagram shows the dominant cyclin/CDK complexes at different time points uns- d4baasem 9,*l r;in the cell cycle. Which cyclin/CDK complex activates DNA replication machsab ;ar 9ed*,s-nlum4 inery?

  Studies have shown that g;k.dbst/j 6 yjm nx;r9enes such as Cyclin Dependent Kinase 3 (CDKN3) are highly ovs . ;/jb6x;yj9krd nmterexpressed 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 highest during the cell cyclek)mfy:t;b1a 1 pt2awd,pvo+h ?