The graph below shows the relationship between maternal age and the inciden50uqi4xb;fdqlf6 b t/ ce of non-disjunction. What relationship is suggested by the data in the gqbdl;u4 qx0 5fi /tfb6raph?

  Which stage of meiosis is2:9*oc;rkionw y3 opg represented in the diagram below?

  The diagram below shows chromosomes)sl56 ri2u cwgy -ar0s 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 a ;1nr)yr l szka3t:*yclleles of a single gene which would be present in the nucleus of a cell as a result of ezac r :ky *s;r)t3ln1yach process?

  Which keyword is matched toj)y h kw5*zi,a the correct definition?

  Which statement(s) about mitosis8v b3a(-nol gc 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 x ;(yok .yzm i+4zfh2rto a cell in anaphase?

  During which stage of mitosis does the nucl gu:qqdm/(w b2ear envelope break down?

  Which one of the following transportfmr26gz - bxekmo(r xr0b72 l1 proteins only carries out active transport?20z7 kog2 ( xr rrmxel1-fmb6b

  Which process does not happen in the shffg a ,6a)(vakoot apex?

  Which type/s of membrane transport do/;qwhh5y tm v xhwi8+tvhi)j+nd6:) 1zdoes not require energy expenditure?
I. Facilitated diffusion
II. Active transport
III. Osmosis

  The diagram below represents a cell with a diploid number oh4m m/ rgg- f9/prfqoam/3y1hf 4. Which stage of cell division is the cell currently undergohr1 /pyfmq9mr3 fgoha/m/g -4 ing?

  The photomicrograph below shows a ro-i(sh/g8h c-1iuls2r fnp,t8o * p arqot tip meristem. Which of the following sentences correctly defines a plh2 ouc/srn (gi ap fiq1- s-t8h*,8rmeristem?

  When does the random orientation ov ;3 iu)x 4 jela-wmcv2rkm-k2f homologous chromosome pairs occur?

  Which process does not occur dkyztc.9 z*hf ; g5d1eluring meiosis?

  If a cell with a diploid nu6pgp;r,nmb v6 +ervg:mber of 36 undergoes mitosis, how many chromosomes will be present in each daughter ce;gpvrb,gev6p:6 +m nr ll after cytokinesis?

  The image shows a micrograph of a cef0vo7q hq13 ;dewwuv*ll.


What explains the appearance of the cell in the micrograph?

  Which statement(s) about homologous chromosomes is/are not tru/o2ulvb-d+1b3q2 v kf dz7 s(piv0yzpe?
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 sya c); /n)u bstn2zgav/ndrome.

Which statement is not correct?

  In the cells of a horse (E. caballus) during prophase I of meiosis I therq mb, b4r *aowbdex6wlv54/ 4ae are 64 clwrb*dvoxw 454,a4a b b6qme/hromosomes. What is the haploid number of chromosomes?

  Which arrow is pointihzxpnh+ w ;dlr56r4zdb+ + y(yng to a chiasma?

  The diagram below represents the structure of a shoot apical meristem. ywcqtqb/;3* mWhich row wby*;qcm/3qtin the table correctly identifies the processes occuring in the structures labeled in the diagram?

  How does meiosis promote v7zx(h7s2pbi3ti;q7dayi - m aariation?

  Which of the following statements is/are correct for meioth co)tn9tom r81z f2*sis?
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 chro x-v rc.ald ut;fxo;8k4qe.k( mosomes.


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 tumours as ;3sf5p)qebqg a result o;3bgq 5q)s peff the movement of cells?

  How many chiasmata are present in the dn*i*ci-vpe,1 poiq 7 kiagram?

  Which statement is a similarity betwe j6to3pve.oi/ 84ovpxen cytokinesis in animal and plant cells?

  Which stage of meiosis is matched to the corh 9lje-h; -g o;p9dkv; r8uim sfb 5b+7ejvk(grect description?

  Which statement(s) are true of meiosis I but not meiosis IItnr8(z 8e3nlv ?
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 meiotf8u w(*f/xnzsg,gemn7hf ) r3ic division. This results in the formation of ogn gfzm(u3/ffx ,w*e r8) shn7ne large cell and one small cell. What is the fate of the large cell?

  Which row correctly descrz,luqben(:k5 pqgc8o8kp 2)h b ddk22ibes diploid and haploid cells in humans?

  The following table shows the diploid chromosome number of a range of species u* 4v0typ7leshy3;wgzp,o*y.


Which of these statements is correct?

  What conclusion can be drawn f;u:lbu9 5 gz*u4xd 2ujqw-o ktrom the karyogram below?

  Which of the following processes is rz/9st c8(a/u yiou 8gcharacteristic of the meiotic and not the mitotoi 9rt u /88yugszc(a/ic cell cycle?

  The diagram represents ak*r:y i2 ob4tu bud with a shoot 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. Which row shows t:oaur/(wl(r j h (*(ttet6lui he correc(uj(rt t*l6 ih(e:/(rlaut wot chromosome number for different cell types and cell division stages?.

  At the end of which phase of meio7qrso9:y zn6l0tz , hrsis I does crossing over occur, and what is the outcome of crossing :yqr 6z o,9nr lz07shtover?

  Which of the following statements does nn r7cherlynxcbl8zc)gd,64: axnb9zlu; - 9+ot describe a step in the sodium-potassium pump cycled- creyhzc)c;9xran 69 74:g8ll n,nl zu +xbb in the neuronal cells?

  Which row in the table s90abhcs)p7-g s :gmabelow is true of meiosis?

Membrane transport is important for allo i,o0vf4wbzaamv(- l. wing particles to move across the cell membrane and respond to changes in the chemical compozb-o am.w,f 4l a(i0vvsition 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 mitosi3afkji1olhg/6w-l d m, h6 pi+s is regulated 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 the concentrations of different cyclins during the cellgqd. wxbx2 k*, .7uwjh-w (zbd3qy5p s cycle. Which cyclin is involved in preparing for DNA replic, qb7 *y25.- d xxb(dj3kzghwqw.swpuation?

The diagram below shows chromosomes duri vf--6 jdyw,gvng 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 homologouik4b-f2; nrb4 yy6swzs chromosomes?

  The mitotic index of throat tissues taken from 4 different patients is showntla3fcu -w 0qog3./zx below. Which patient is most licqt w.ag0/f- 3ozx l3ukely to have cancerous throat tissue?

1.Draw a labelled diagram to represmj3me6 s-h dk w,8,pzh)qt c1 g2we;juent 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 human kariq4l9f tb(;lnh9f hzt(gs0 o-yotype.


What is the abnormality in this karyotype and its cause?

The graph below shows the relative amouna:. v39u smxggt of DNA in one cell during one complete cell cycle. Each letter : xuam3.9gvs grepresents 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 cro3j low1p3o+- h hsgy*dss between a male cat that is homozygous for brown, long hair and a female cat that ha-g 1hhypo o3l+dj w*s3s black, short hair.


Which of the offspring has a recombinant genotype?

1.Outline how polygenic traits can show a normal distribution.p r1 y*7kwls*r

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 crosmm9h2; 5/jbs0 trfjyvsing over of non-sister chromatids shown in the diagram beloms9myj 5 jfrh2/tb;0 vw?

  The photomicrograph shows a pollen grain from L. candidum (Lily). Which sta lkfeqvrqisw+67. +4bge of 7kqwse i+.rfb+6q 4vl meiosis is shown?

1.Outline the events which would lead to an individur7d7s-v9i-g0tu r0 ij 5 iocbd baw2z6al being born with Down syndrome, which is characterised by the presence of three copies of chromosome9v- 0b6gz cwdordus-2iiab775rj t0 i 21.

2.Explain how meiosis increases variation.

3.Outline the stages of meiosis.

The mitotic index is an indirect way of measurqv09k*lo c 9u;i 9mdpying plant growth. A study was conducted on white onions (Allium cepa), under controlled conditions in a lab, to investigate the effect of soil pH on the mitotic index of the rooc m;uipylo0d*9qk 9v9 ts.


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 whic( hw8h1*b /c(1ha qgcdh zs il(he:re7h cells can divide. The diagrams below show two lh z1*( c s/h(crq1bg:ihe7hdaew( 8hcells 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 gene expresf9 ns0u96 x(hmiic92yc wl wb*sion 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 nu2j*ug le4n pa6b4na,hmber of 8, in different stages of meiosis. Which row correctly names each6gnnp l4 * bje24,haua stage?

  The micrographs show four phases of meiosis I in g 6lgvr 2 q)v1t)jii)ca plant. In what order do these phases occucl6v 1jg 2grqi) tvi))r?

Mitochondria are responsible for supplying metabolic ene cek hz+sbwbj5*zz.,, rgy in eukaryotic cells. In most eukaryotes, which reproduce by sexual reproduction, mitochondrial DNA (mthe,js cb 5zw.zk bz,*+DNA) 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 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 cell cycle in fo+qj9 3 * urwueuhfk2a4ur samples of lung tj* e fq3urh+u92awku4issue from four patients. Which tissue has the lowest mitotic index?

  The diagram shows the dominany71x p7 d5l iqchibv8em 2*(yjt cyclin/CDK complexes at different time points in the cell cycle. Which cyclin/CDK complex activates DNA replication m7 1c7 xylvjd(hbqm*ei2p5i y8achinery?

  Studies have shown that genes such as Cyclin Dependent 248*k;jldzc tic8;h1j fyv) 9iuytd f Kinase 3 (CDKN3) are high41j89 ;;i y*cft)jf8d2z hktyluic dvly overexpressed 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 during2/kt3y4wcmqvqn v w0d5 6d7nm the cell cycle ?