The graph below shows the relationship between rx;/hk rp**fa+kq phr+9sb3 ip1lj+k maternal age and the incidence of non-disjunction. What rqkx +hpj;fs +*pa3 k/+hi lrb 9krp1*relationship is suggested by the data in the graph?

  Which stage of meiosis is represented in tnfb.)i5h*r j the diagram below?

  The diagram below shows chromosomes dua+r:3jf 2+t cdljxoz vcgm+ )+ring 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 statel u/qzd .5pojgi+0 )ma;2w+n1tkxsuc s the number of alleles of a single gene which would be present in the nucleus of a cell uca1u.m0k z+ joq)pxl5sdn/;2 wi+ t gas a result of each process?

  Which keyword is matched to the correct definition? qo b:v2.a0r7vbxj3 hi

  Which statement(s) abour*j s-4 ++-7k.uxzppmnbf gm wt 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, whq pt6 i+e/6wapich letter points to a cell in anaphase?

  During which stage of mitosis does the nuclear envelope break dp(n 5qwa9 vnyfs,83rgd4kj7 cown?

  Which one of the following transport proteins onlrrsu07r (0tm5ijo, x i,m0vxp y carries out active transport? ,irj to0,mmpxv0x 5r0ur( s7i

  Which process does not happen in the shootxt4a8r62ox xbo i/9xm apex?

  Which type/s of membrane transport do/does not require energy e0t,oo+kk cnp2 xpenditure?
I. Facilitated diffusion
II. Active transport
III. Osmosis

  The diagram below represents a 7pvr 66co5 og4j .sgs0hh/ r0kj(hsbk cell with a diploid number of 4. Which stage of cell division is the cell currently underghgb/s o 0cr hvp0s7h6 .r 4j6ok(ksjg5oing?

  The photomicrograph below shows a root tip meristem. Which of the follo gxcv8ytbx 06tplnh dluzz1m:6v-*: (wing sentences correctxtphdulv:cbz*z0 -8m:1xgt6 vl6 ( nyly defines a meristem?

  When does the random orientation of homologous chromosome pairs k q smytkun+ ;eywfz+n*4f5,b e0 f,4boccur?

  Which process does not occur during meiosis?1,zra+9 +,q)ky ove(nzy .x w)rxvigq

  If a cell with a diploid number of 36 undergoes mitosis, )a 0 vyvzbog-,how many chromosomes will be present in each daught bzyva)0-o ,gver cell after cytokinesis?

  The image shows a micro9wgy2pps+ iqq i(0ci, graph of a cell.


What explains the appearance of the cell in the micrograph?

  Which statement(s) about homologous chromosomes icl qh e(djvn,b t78s w+lq-;6gjie80ts/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 syndrome. w m+zs:e4/n yp 6 puvljel)n61

Which statement is not correct?

  In the cells of a horse (E. caballus) during prod4nf* h 7x2t.g i4obbkphase I of meiosis I there are 64 chromosomes. What is the haploid numoi f*t4k.7xh bdn 2bg4ber of chromosomes?

  Which arrow is pointing to a chiasma?+hba7v(-wh yzl 4f8yf

  The diagram below represents the structure of a shoot apical meristem. Whichcr0)mmqt.6cvm coj2) row in the table correctly identifies the processes occuring in the structures0 coq.mc6v)mj) mctr2 labeled in the diagram?

  How does meiosis promote variation( x4.v6hvlx b-ppmik; ?

  Which of the following e2iqgi 0i,ay144 bktn)0ionqstatements is/are correct for meiosis?
I. It is a reduction division
II. It involves random orientation
III. It produces genetically identical cells

  The diagram shows gametes produced yg;gw )qt(tz5l gpcc(i,g0 nps747fx 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 : cx ij5.t9apyh+sr+ gformation of secondary tumours from primary tumours as a result of the movement of cellg+p sr9 5t+ja: ixh.cys?

  How many chiasmata are present in the/ host+s.)wgb j8*s 4q7ie ymt diagram?

  Which statement is a similarity between cytokinesis in animal and 1 ao lbsm:3qj)rk5 ipf6a wi*(plant cells?

  Which stage of meiosis is matched to the correct desca wx ww ypwb(),*dpo :i9q3.dyription?

  Which statement(s) are true of meiosis pq+.j oyt u35ctzk.,w4enfq7I 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 the h+wv; d er0f5rfirst meiotic division. This results in the formation of one large celle5 f;0rrwvd+h and one small cell. What is the fate of the large cell?

  Which row correctly describes dipll3g.kkk vp 0k;pi c4y.oid and haploid cells in humans?

  The following table sho8hwl.; e nywsgz/ p75ows the diploid chromosome number of a range of species.


Which of these statements is correct?

  What conclusion can be drawn 1hpy2mc o8(e2w-jv ktfrom the karyogram below?

  Which of the following processes is chara2s fbz9qrj 5;irq;op+cteristic of the meiotic and not the mitotic i;;5p9oqsjqb zrr +2fcell cycle?

  The diagram represents a bud with a shoot api p.h5x4fc pok(cal 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 ofmvu3x z( a6 p5 sp9o;0fyrto8r the chimpanzee (Pan troglodytes) is 48. Which row shows the correct chromosome53prs( ox6r;mfuav z8p0 9yto number for different cell types and cell division stages?.

  At the end of which phase of meiosis I does crossing over occur, mt )vhzcm516 ;4m+ogguq 3 cofwyj8y9and what is the outcou48+1 mhgc;y5 zvo9m6f m yj3)cqwgtome of crossing over?

  Which of the following statements does dtt:,c se6e4yt(aa 1.txc v 7onot describe a step in the sodium-potassium pump cyclacc46eet .,v1oy(7: xtdtats e in the neuronal cells?

  Which row in the tablsuk3**h/e6x:wl jdzd e below is true of meiosis?

Membrane transport is important for allowing particles to move across the cryd8 yj6k(9ji ell membrane and respond to changes in the chemical composition of thej6y iyr dj(9k8 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 cellj v)9 zusf*fbeb7.v9qs.

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 concentjgv3-0je 28bwonvt ( flw; v3vrations of different cyclins during the cell cycle. Which cyclin is involved in preparing for DNA28 33g;vw l-bfvn vj(tevo0 wj replication?

The diagram below shows chromoso2bvyhzvd , 2 y6iof (4vp8x4rpmes 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 chs*lci vi**utw z1jtz 1-lo,/gromosomes?

  The mitotic index of throat tissues tak ,tmwzx0 +-tayen from 4 different patients is shown below. Which patient is most likel0zt tyaw,+-x my to have cancerous throat tissue?

1.Draw a labelled diagram to represent the procteceoqg(k,idzo:4/ .he -k k8 n6v*mx ess of crossing over.

2.Compare and contrast random orientation and crossing over.

3.Outline the stages of meiosis.

  The image shows an abnormal human karyoty tl60 1)(gcl;zfwuwye pe.


What is the abnormality in this karyotype and its cause?

The graph below shows the relatijj wycooo /o2;- d,8.q-3 reqhtqde1ive amount of DNA in one cell during one complete cell cycle. Each letter represents oc h1o8rdq.q2,do;wqjoo -/3 - tiyeejne 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 j0 u4-hn.lc axmale cat that is homozygous for brown, long hair and a fema04c-jx.a hnu lle cat that has black, short hair.


Which of the offspring has a recombinant genotype?

1.Outline how polygenic traits can show a 0qlvml r-wq.p1d*/gxnormal 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 chro9k6b+/y 50 mdail (hrunsvk hoc x(0z5matids shown in the dibd(c00sv nrxhomk+ ( haku/5 9 zl6i5yagram below?

  The photomicrograph shows a pollen grain from L. candidum (Lil3uo lbpe()v 2by). Which stage of meiosis is shouvobe23blp( ) wn?

1.Outline the events which would lead to an individual being born with Doh)09z h9 ctbfajp3tn)wn syndrome, which is characterised by the pb3 th0) an)hp9z9tjf cresence of 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 pl5kbx tc6n: t*wcu63 34 fsrffxant 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 roots. x w3cf*:xtb6ffurn6 ts4 kc 35


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 (yx7dt 81so u,ost)8yjqgd 7ss can divide. The diagrams below show two cells from an organism witog (7 q1u ysx )8d8jtysd7ts,oh 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 growth./wmu :kb(wt*l

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 numbe*l5p1fyf ybtnja.i9 d2pazf5u92a .or of 8, in different stages of meiosis. Which row corri9 yal.jpfa 2 9fp52.z5a *o1ftuy bdnectly names each stage?

  The micrographs show four phases of meivms wa:jn 1g2+osis I in a plant. In what order do these phases ocmn:wvg+ sj2a1cur?

Mitochondria are responsible for bjocvu7)e,u v +68t /fgx.d nhsupplying metabolic energy 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. uc/v f8g ub+xn.j7t6) vodh,eThis 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 cellmw;-ijmazmf,p : rf/- cycle in four sample; r mmj-ff/-,im:zwp as of lung tissue from four patients. Which tissue has the lowest mitotic index?

  The diagram shows the dominant cyclin/q.na,hp+o8u nkbzde -im (;p.CDK complexes at different time points in the cell cycle. Whie+n8,a - mub ipqnkho(pz.;.d ch cyclin/CDK complex activates DNA replication machinery?

  Studies have shown that genes such as Cyclin D co5. k/c u*on*0wcoqvependent Kinase 3 (CDKN3) are highly overexpressed in cervical tumo w5cnc*o*/.ocokq v0uurs.


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 cycl h:ei5qhn:6gmxmax 1/in E the highest during the cell cycle ?