The graph below shows the relationship between maternal age p+.oztxf58(sk0 (rtcp(e )hkoqkc o8 and the incidence of non-disjunhkp0kkex8 totf (q8zoc5rs.(oc+p )( ction. What relationship is suggested by the data in the graph?

  Which stage of meiosis is represengkfx*dt w/+ qqe; ;uz7x/e o1rted in the diagram below?

  The diagram below shows c- izxw7w,kubhea vs7 ;w0 61gthromosomes 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 nuc n6qhult4 n.in/ 8oq:4-brkmmber of alleles of a single gene which would be present in the nucleus of a cell as a result of each pqbqn t4l-.oui n6hm8/r4n: kcrocess?

  Which keyword is matchedrv8djyq1.0fyj)/14zfey5c np yac m4 to the correct definition?

  Which statement(s) about mo (hm5u9s784crnwaxgt e(c wy *da r**itosis 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 p3rrys-8 5 w1tvx9z cgroints to a cell in anaphase?

  During which stage of mitosis does the nuclear7f fh.5zep3n lyl 3a+l envelope break down?

  Which one of the following transport proteins onl hryxrh+n/tnh r.k3 lh- t(-4my carries out active transport?(3rx rhh .mttnl -r /hyk4nh+-

  Which process does not happe:p2cci)gt k/hneq ;s*n in the shoot apex?

  Which type/s of membrane transport do/does not require energ c xy,qa 27jr3t8,zgfby expenditure?
I. Facilitated diffusion
II. Active transport
III. Osmosis

  The diagram below represents a cell witqxjuget4kdy.( a 04m:h a diploid number of 4. Which stage of cell division is the cell(jd:y u 40ekqmg .4axt currently undergoing?

  The photomicrograph below stwb ghu43 fl(0hows a root tip meristem. Which of the following sentences correctly defines a meristehltu(3b0 gfw4 m?

  When does the random orientation of homolo)nsgs- t3 1igigous chromosome pairs occur?

  Which process does not occur p)u 6 sdz(x74shh- z6pgqw1 vhduring meiosis?

  If a cell with a diploid number of 36 und*q b4ncrcq- u t9 ),ki 7yygo:3ls5ihiergoes mitosis, how many chromosomes will be preb huo5-csrl* 4cigq q3y:it)nky97i, sent in each daughter cell after cytokinesis?

  The image shows a microg*vkih uidyz24uq5tp/ 30 e .mzraph of a cell.


What explains the appearance of the cell in the micrograph?

  Which statement(s) about homologous chromosomes is/are qlkez :e(7em 0uy 2n(xnot 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 4 cvkgeay98 +alzip(+dpv m 1be)i aq0o+ta7+ individual with Down syndrome.

Which statement is not correct?

  In the cells of a horse (E. caballus ur+dh3b1jghsa71,gkbaj/ g 9) during prophase I of meiosis I there are 64 chromosomes. What is thrd jkbhasb19+u/a7 1 ghjg,3ge haploid number of chromosomes?

  Which arrow is pointi pcbdx-n u1*xm ta2+4qng to a chiasma?

  The diagram below represents the structure of a shoot apical meri)6r p mkm10n tidw53vestem. Which row in the table correctly identifies the processes occuring in the structures labeled inm t31 5)mvi0rne6wd pk the diagram?

  How does meiosis promote r3 o)3ay y/f u)t9fghwvariation?

  Which of the following statements is/are correct ln6 c3lxt( ;,ab-dytw for meiosis?
I. It is a reduction division
II. It involves random orientation
III. It produces genetically identical cells

  The diagram shows gametes produced from crd oty+y(1d *8 *u8iulqesf7two 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 secondary tumours from primary tumours4n:gmo ccyj9 zn3g, k8+zc:pd as a result of the movement of ce9z gk3n:pdj n+ yo4m8,gzc:cc lls?

  How many chiasmata are present in the dia,lt8viv,+o p+ z*dpt;(a85cfpiwhp 0drq+ f agram?

  Which statement is a sg s1 q4msn 3e/adhd;c0imilarity between cytokinesis in animal and plant cells?

  Which stage of meiosis is matched to the pp 7bnvya6m0s qf76b4mbe.p r0wy1:s correct description?

  Which statement(s) are true of meiosis I butgv2n wz gtl9,x469tkeycn0t 9 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 first meiotic divisionf6o:cb:zds77nl ( cek. This results in the formation of one large cell and one small cell. lz sb:nk:7fce (d7oc6What is the fate of the large cell?

  Which row correctly describes diploid and haploid cells in h) j b,r+s0gmi)ip(txr* yfoo *umans?

  The following table shows the diploid chromosome number of a ds 26kg0v m:a..hbwoprange of species.


Which of these statements is correct?

  What conclusion can be drawn )pr g9ulb+x/o f zxncv4akdym6f8)4np;u3w8 from the karyogram below?

  Which of the following processes is characteri.o p* k9qywy 2vgq,odoy-p2q3stic of the meiotic and not the mitotic cqqkw* d2-oo9,.o2 v ypyypq3gell cycle?

  The diagram represents a bud with a shoot apie97kisvb x(ni t,6o t0cal 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 0u.jp0 6/veby/a wxip m7e8-j n ty(ki(Pan troglodytes) is 48. Which row shows the correct chromosome number for different cell types and cell division syii (ku/y0n6e . w-j08ajpmx 7e tb/vptages?.

  At the end of which phase of e(n71h6f 0*r ytimb3 pwvc2(gjp o6je meiosis I does crossing over occur, and what is the outcome of crossing over? nyb1( mcet g670 jr36pjpwh o2efv*i(

  Which of the following statements dond/ nn7h,:/rjdwy v(a es not describe a step in the sodium-potassium pump cycle in ther,d/h :/ dny njv(a7nw neuronal cells?

  Which row in the table below is true of meio cvuvv,7w (.xvea +qn6sis?

Membrane transport is important for allowing particles t0f v6j49ej ao g1ag;puo move across the cell membrane and respond to jfe apu46a ;g0 1jgvo9changes 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 cel9 )w1q7 ; 4zu/xmlzdzg9fj ddebxa;.wls.

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 conce1com9l 2o9ec bntrations of different cyclins during the cell cycle. Which cyclin is involved in preparing focc2 lb9m e9o1or DNA replication?

The diagram below shows chromosomes duringkgow 1 sdcsnp+p ,(,z.0+zfms 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 chromosomeqr3b c; zb6jbvah8 uqr(7gr.1s?

  The mitotic index of throat tissues taken from 4 different patients 6dido 1zc)d4mu4i(oy is shown below. Which patient is most likely to have cancerous throat y dz4u1 (iio)6dm 4dcotissue?

1.Draw a labelled diagram r/v:d: vq5a tjjq+x;yto 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 abnorm- h nn w3)g.lu5x4uhezal human karyotype.


What is the abnormality in this karyotype and its cause?

The graph below shows the3u1bu chz,rf bpmr**+ relative amount of DNA in one cell during one complete cell cycle. Each le3rbu +b1 ,*urmz cfph*tter 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 betwe;o mp3 4mbhiiq*1 r5apen a male cat that is homozygous for brown, long hair and a female paq5 b 1i4;pihm*orm3 cat that has black, short hair.


Which of the offspring has a recombinant genotype?

1.Outline how polygenic traits can show a normal distribution. n, byxu0umf0 8r1ld-gzfm( 8x *vht :c

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 w6:dm zusl- xt;gl(kjmt+4;xvy 5*bbof non-sister chromatids shown in the diagra;u yjt- lxt; gm(+dsx:wbv z64l*kmb5m below?

  The photomicrograph shows a pollen grain from L. candidum (Lily). Which stage y9xks,ydo(+mov e9 rn6ff0 drofr1 :/of meiosis is fky,xe90dfyr r (f+ 6:sn 1ovmr9oo/dshown?

1.Outline the events which would lead to an individual being bo j2j9( z+efsnm 9ygde-rn with Down syndrome, which is c2 d9ymegsfzej -n+ 9(jharacterised 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 indirectr9a 2snnr f6q- way of measuring 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 roo9s6rn fanq2-r 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 a7. m6hq 4ebmhbbn-u r4g4l- hspvt /4in which cells can divide. The diagrams below show two cells fbph4e4 butmr gb4 sh/hqm6a--lv.7n4rom 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 expressio*0bj7jb wy9r )i.mzkp8sm+r2 jd 9 xhrn 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 diploi6xk c*oz b-gq rdy)7 +bykk,u5,ezpa*d number of 8, in different stages of meiosis. Which row correctly ox b-aekz,+ k)y*pu57crqg dy,k*z6bnames each stage?

  The micrographs show four phases of meiyg :rkq9inmtjn6 jw:j9 u2)0mosis I in a plant. In what order do these phases ocr:q:nj2 guj9w9j) 0knimm 6ytcur?

Mitochondria are responsible for suz6mtlc+t3 /1bwh .c lkpplying 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. This is in contrast to nuclear DNA which is inherited from both parents. It has been suggested that, in some 36lhkb zlc1+tm .cwt/ 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 ja5q)qzbm.s 9in different stages of the cell cycle in four samples of lung tissue from four patients. Which tissue has the lowe)5. jqqa9mzbs st mitotic index?

  The diagram shows the dominant cyclin/CDK complexes at diffeb9f qz2/ zkvj jpd;,-frent time points in the cell cycle. Which cyclin/CDK complex activates DNA replication mac/j fb zd9v,jp2z-kq;f hinery?

  Studies have shown that genesy txaqj)/qj7p2ye7,w such as Cyclin Dependent Kinase 3 (CDKN3) are highly overexpressed in cervical tumour7/q)y x2p ae qwj,y7tjs.


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 the42* z mb+wb9jh; vsgwy cell cycle ?