The graph below shows the relation 3z f1iqk x.xsqk9)bwtz37sl5ship between maternal age and the incidence of non-disjunction. What relationship is suggested by the fs zt .ix5xwb71k9q )s3lz q3kdata in the graph?

  Which stage of meiosis is represented in the divg5 b ds2oes*1agram below?

  The diagram below shows chromosompsaz3 :ib+),ue y 4mfles 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 sn7a sz5fd f8t9bxd++g tates the number of alleles of a single gene which would be present in the nucleus of a cell as a result of each process8z5d 7+nfs+t xaf9dbg?

  Which keyword is mat+9zr5ya)qb o8 slb fs/ched to the correct definition?

  Which statement(s) about mitosis is/are8wnnt*:mmm f fof )80z 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 tobkt;:gkz /rp ; gsg.t) a cell in anaphase?

  During which stage of mitosis does the nuclear enveap*ttv h3: s0nlope break down?

  Which one of the following transport protw1; r csoqcv10lhc 3v vhjf3 -mi4:b6jeins only carries out active transport?f6j1 1r3h;cb vso3 cwj vi-m: 0lcv4hq

  Which process does not happen in hgv3pkk66e d,m 9r0) bu merb; gfu8k-the shoot apex?

  Which type/s of membrane transport do/does not require energy exp /8paqam4f6 sh.jj.pg w/du4u enditure?
I. Facilitated diffusion
II. Active transport
III. Osmosis

  The diagram below represents a cell with a dipwg b8 qb1nxy/9loid number of 4. Which stage of cell division is the cell currently undergoiny 1xw8b/gbq 9ng?

  The photomicrograph below shows a root tip wu:k*d rn1;mzx gi kgkf-0*8(mw+ aqk meristem. Which of the following sentencea gdrnww; zm+- m :8kxu*q0 kg(*i1kfks correctly defines a meristem?

  When does the random orientation of homologous cn akm,mm8-,ra hromosome pairs occur?

  Which process does not-o,c-msk trvjbgkkm1 y/h5 f- 1f2kl2 occur during meiosis?

  If a cell with a diploid number of 36 undergoes mitosis, how many cl n5s ar3xiglai2-2/q hromosomes will be present in each daughter cell after cytokinesis alrla-s2x5qi2n/i3 g?

  The image shows a micrograph of a ; ;bpt.( kaurtfaa5vfm ; ,nvfty37t- cell.


What explains the appearance of the cell in the micrograph?

  Which statement(s) about homologoud+yx 9 spi t) ioe55gv7t:tji1s 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 mky)s65vg u.f an individual with Down syndrome.

Which statement is not correct?

  In the cells of a horse (E. caballus) during pro z )z;hoq*ifrhulz 8:9gzo( i6phase I of meiosis I there are 64 chromosomes. What is z;689izzr)hqogl*z (oi uf:hthe haploid number of chromosomes?

  Which arrow is pointi vv j5cggf/8o6sf9lb;ng to a chiasma?

  The diagram below reqa-q(. ony5 s3a) tvcepresents the structure of a shoot apical meristem. Which row in the table correctly identifies the processoy .)-van eq3sc(aq 5tes occuring in the structures labeled in the diagram?

  How does meiosis promote varia l r,wjm0ry 5a)jap2fc3m c).rtion?

  Which of the following statements is/are correct for mei:0-6o hp ink8: qlhoqnosis?
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 :ux4re 09txfqromosomes.


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 formationrxx8d 1( o-kpz of secondary tumours from primary tumours as a result of the movement of -x o8xkdr( zp1cells?

  How many chiasmata are present in the diasu 5fi3zczv qtv4 .7x*gram?

  Which statement is a similarikgo(l;cw :4xuoz *o3 b.what3ty between cytokinesis in animal and plant cells?

  Which stage of meiosis is matched to the cot+x-ps *jddk3nd4gya4/ sx -5 lzyfa/rrect description?

  Which statement(s) are true of meulh6bks:,yk )t*t:knr sli 4(iosis 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 o26ary+0qrb v xocyte after the first meiotic division. This results in the formation of one large cell and one small cell. What is the 0 x26ay vbrqr+fate of the large cell?

  Which row correctly describes diploid and;o5i u r0ve+cq haploid cells in humans?

  The following table shows the diploid chromosome ni n6i bnc7,;a4dy)s1j5sb 8krq9 bx(bc-nxfnumber of a range of species.


Which of these statements is correct?

  What conclusion can be drawn from the karp : qx)0nndrge2.e0cm yogram below?

  Which of the following processes is cha ii;w ho000m vey9tcl6racteristic of the meiotic and not the mit09ych ;v0 im6wei ol0totic cell cycle?

  The diagram represents a bud with ab(oqri +bgn5gya;(1.u (n igi 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 chimpanzecd;ub:/boyz s/xz h(x5bp b99e (Pan troglodytes) is 48. Which row shows the correct chromosome number for different cell typeh9bdb( sx;5zob x:/pu /ybzc9s and cell division stages?.

  At the end of which phasqsm8o ,yt pgp7hp*fs0i v- +v-e of meiosis I does crossing over occur, and what is thevif7v0h8p ,-q-tp*sygmp s+ o outcome of crossing over?

  Which of the following statements does not describe a sld8 kqi47jbb 9tep in the sodium-potassiumdi47bkb98 lqj pump cycle in the neuronal cells?

  Which row in the table below is trk ;z:h l rvb7we5trh9n,ro2tmyz di+8m3,8 mtue of meiosis?

Membrane transport is important for allowing particle:yktskg 0bpxqs3psv*7 ,(ms4s to move across the cell membrane and respond s s:(xy0 tp*q4 gvp7,kskm3sb 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 ,+cizt(p r x;zc9as; e6xfv+.;zhukpis 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 concentra,8 uyb-oz* sltpc6 ba,tions of different cyclins during the cell cyclec 8tb*,abl,-suypzo 6. Which cyclin is involved in preparing for DNA replication?

The diagram below shows chromosomes during meiosiscimhje8x/t*3w4q oih.il 3n 8 .

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 klfp.cb::r cxivlaf /0+s; ,echromosomes?

  The mitotic index of throat tissues taken from 4 different patients is d hyn xtc2d rm./ge3;(shown below. Which patient is m/yxt2;ce3 dgn rm.dh( ost likely to have cancerous throat tissue?

1.Draw a labelled diaxxh9edbq1k :*z i3ezg1:qt. w gram 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 abe zom,fj */qxtf.ol53 normal human karyotype.


What is the abnormality in this karyotype and its cause?

The graph below shows the relative a)ex37/j(f jd5yg /guxk4m oxmmount of DNA in one cell during one complete c43gu/fg7j5m odym) xjkx x/e (ell cycle. Each letter 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 homozygous fv j o- e c;/bvqzg+5,2,zibvxvor brown, long hair and a female cat that,- bviv g2oz qbv;cez5jx, /+v has black, short hair.


Which of the offspring has a recombinant genotype?

1.Outline how polygenic traits can show a no gkh2/5 (n4an4ln2rvqo u pgv;rmal 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 crossinpbjwj ()mh3w (8c qh: tli9ej:g over of non-sister chromatids shown in the dmwj3(8(pt:ljhib 9w:jh qec)iagram below?

  The photomicrograph shows a pollen grain from L. candih -jju vyt 7jzses :r99(rjevfj4-/yj 2*p,vu dum (Lily). Which stage of mejvzjs 7-* :shu94j9e,/ yfrr j-yje(v jpt2uviosis is shown?

1.Outline the events which would lead to an in13n h:md ;3 5)moedb qrqvr3+ b p3tayk*(kncbdividual being born with Down syndrome, which is cmbc: (+ r3 13)ndymptkhnoevqq dak3*b;3b5rharacterised by the presence 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 measurtn4 l3 zwk;b,3 hnqxo.ing plant growth. A study was conducted on white onions (Allium cepa), under controlled conditions in a lab,;.lk,hz 3txonb4n q3w 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 whw.mdp4v 23 -urln:jy hich cells can divide. The diagrams below show two cells from an organism with a diploid number:hw4ryj np-v.lm ud32 (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 inmp6+dh) vte kgi2+8y0t76 r ap2ceg af 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 number of 8, in different h-6w) p ; f1bvb tbayjwnsgiu ;1,y7r)stages 1tvijhw u7-1)b,p;brgyf6 ;ab wyns)of meiosis. Which row correctly names each stage?

  The micrographs show four phases of meiosis I in a plantf/0ezs cnk 0v hx/,a*s. In what order do these phas0f 0s kx/,c vznh/a*sees occur?

Mitochondria are responsiblen t8jqr*wt r+aw*a 13o for supplying metabolic energy in eukaryotic cells. In most eukaryotes, which reproduce by sexual reproduction, mitochondrial DNA (mtDNA) is inher*a+* n1oat trwq jrw38ited 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 ce f83yym8xa50r 8 db(yu*(qfc;pak fqkll cycle in four samp acydm yb 8kff( 0qxr( yu8fa8p5*kq;3les of lung tissue from four patients. Which tissue has the lowest mitotic index?

  The diagram shows the dominant cyclin/CDK complen.6es 3oi +vevxes at different time points in the cell cycle. Which .on6+ve si3v ecyclin/CDK complex activates DNA replication machinery?

  Studies have shown that genes such as q3+sdsr r8 ov4kudos/qak f02;md+2f Cyclin Dependent Kinase 3 (CDKN3) are highly overexpressed in cervical tumoursdoskd4+aq2k3frsud + /; mfq0r82s ov.


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 high d7mwagk b +pmva7w4 vnm946k3est during the cell cycle ?