The graph below shows the relationship between matern5q/ r0mnf yi ,1 y.au:jkt0eqmp:fld( al age and the incidence of non-di :qr, 0/pmlm5dq (ytfa1f:0j i.ue yknsjunction. What relationship is suggested by the data in the graph?

  Which stage of meiosis is reziycf,rln. cyk4 p8g) fp,3a-presented in the diagram below?

  The diagram below shows chromosomes during .foec6uf(7n 2akiz( wmeiosis.


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 alleles of a single gvp-y-ig 0le 4gene which would be present in the nucleus o- lpg0vi4yg-e f a cell as a result of each process?

  Which keyword is matched to the c0gu dzjim98q1 bo-8l korrect definition?

  Which statement(s) about .i8u5any(/ m*/h iv0xn7in:lcm nnoumitosis 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 to a cell in anaphaud d- l xqmw+a+,4dbly0qs4s8se?

  During which stage of mitosis does the nuclear envelope brea3svkagf 3og0+c45vk w u:gw 0qk down?

  Which one of the following transport proteins only carries out active tqcs f7os+u,0*az -1hu5lc s6 ottypn; ransport?*cucsanq7ss u;o-f0+ lo 6zy1h, 5p tt

  Which process does not hapt8 n +odi/l0llpen in the shoot apex?

  Which type/s of membrane transport do/does pz *eb yn4 90j/zf-dminot require energy expenditure?
I. Facilitated diffusion
II. Active transport
III. Osmosis

  The diagram below represents a cell with a diploid number of-r. m+zq)y x-m -p;odzq mwlz7 4. Which stage of cell division is the cell currently um+oq-z;lx-d m p7)-z rwzm.yqndergoing?

  The photomicrograph below shows a rol;b 0 75,0rkd .eyhj olihxt:dot tip meristem. Which of the following sentences.j: ylix5ed7dt o 0;,kh0hlbr correctly defines a meristem?

  When does the random orientation of homologousb4 zq2k ;ftua2 chromosome pairs occur?

  Which process does not occur during meiog9foscb:9pg 8 qb:4mqwu :;st sis?

  If a cell with a diploid number of 36 unh4i d,sa:y ,wqdergoes mitosis, how many chromosomes will be present in each daughte,awqish d,: y4r cell after cytokinesis?

  The image shows a micrograph t3 ) 2tuvf+,yfizh f67: sn3 erzg/kxoof a cell.


What explains the appearance of the cell in the micrograph?

  Which statement(s) about homologous chromosomes is/are not true? ia5+ zl8pd q- vy;z6xe
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.ir /)nqij)j )xo(eshe l,k5 3e

Which statement is not correct?

  In the cells of a ho2yr+: upfg3 vy ll5/xirse (E. caballus) during prophase I of meiosis I there are 64 chromosomes. What is the hx2+r5lfyy:g /iul pv3aploid number of chromosomes?

  Which arrow is pointin.)mp xky)1kcvfvv *2xg to a chiasma?

  The diagram below represents the structure of a shoot apical meristem. Which izhfp )09u0nthbu1a / row in the table correctly identifies the processes occuring in the structures labeled in the dh/ t )b0pi0 91hauuzfniagram?

  How does meiosis promo6ay0cr*n:qqol 36o/wr 5q r*xh w1ethte variation?

  Which of the following statements is/are correct for meioskthx+v99fl)i5wnm 2 up :7vwm is?
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 chromosomes. x,a80wyv k) i(s 4wfef


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 t5rg458jctp za ,db*l.6gjylof secondary tumours from primary tumours as a result of the movement of t*5,apzbjl g6j.8gly 5d4ctrcells?

  How many chiasmata are pro wsx4sv3v2dd yf 7g81f d9 ymr,g(lz-esent in the diagram?

  Which statement is a similarity between cytokinesis in animal and plbqdmbyk:m do:ne;pl1 (1qa6 0o; c3h cant cells?

  Which stage of meiosis is matched to the correct descrip wrhyro4k/-,rtion?

  Which statement(s) are :nt 7urj 6ou,7(kbcv ptrue of meiosis 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 oocyte after the first meiotic division.*wjtjm/ b99sa This results in the formation of one la9 t jm/j9*wabsrge cell and one small cell. What is the fate of the large cell?

  Which row correctly describes diploid and haploid cells in humans;sr5hxr/ 8wg g?

  The following table shows the di vh4* 5kn.rrj;)wnp yvploid chromosome number of a range of species.


Which of these statements is correct?

  What conclusion can be drawn from the kar il6x0kh r k,y9;tcn*pyogram below?

  Which of the following processes is characteristic of t 0squjq5eyw+8r eenc gk9 +c1ym:tc+gw 995f fhe meiotic and not the mitotic cell y+ kw9ft8nuems5c0ejgecwg9 y +1 qq:+f59rc cycle?

  The diagram represents a bud with a sh tc/mu33 p-oit -kc,qtoot 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 chd. 6uyp7lzo p a+n*b0gimpanzee (Pan troglodytes) is 48. Which row shows the correct chromosome number fornlzp d.o+gy0b7 * apu6 different cell types and cell division stages?.

  At the end of which phase of meiosis I does crossing over oca +y)kac7bt l/cur, and what is the outcome of crossicy+)/lab kt 7ang over?

  Which of the following statements does not describe a stevj*- 8ov 4bfppp in the sodium-potassium pump cycle in the neu4 -*vjp8ovfb pronal cells?

  Which row in the table below is true of mcqe5z ko.n *lk0 luz1:0k/s5 ris(im ueiosis?

Membrane transport is important for allowing particles to move acrot 3kgkf0 xcs0;ss the cell membrane and respond to changes in tx0 3ktsc; gf0khe 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 regu, ay*eui +zyy7lated 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 di6pp ;ljupf kv.t9z3( r v0jzd+fferent cyclins during the cell cycle. Which cyclin is involved i pvjuzz.k(l 6fpdj; r09+ tv3pn preparing for DNA replication?

The diagram below shows ,i q(o(vl4bubw k4n0m chromosomes 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 sep1l o4gwd e6p;rqd57 ncaration of homologous chromosomes?

  The mitotic index of throat tissues taken from 4 different paybo ;bja +3kq85q 63)fifxs,/ y x4zp*e mxgtwtients is shown below. Which patient is most likely to have cancerous throat tq8 +)yt3yfax/ijg b s q zxxo*,wkb;m6e53pf4issue?

1.Draw a labelled diagram to represent the process of crossing overwi vw j.,(k,q7bai9 wd.

2.Compare and contrast random orientation and crossing over.

3.Outline the stages of meiosis.

  The image shows an abnormal human karyotype./o9 x qf7/gzec


What is the abnormality in this karyotype and its cause?

The graph below shows the relative amount of DNA in one cell during o4lq pz4cp)ks-un.f xzr567idxet ,6 fne complete cell cycle. Each letter represents one stage of the cell cycle.i-4ld,rtf4 zpzpu )x 5c6 . nfseqx76k


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 for brol6folicq i)q3 llq+9 w4 *t/ytwn, l *itq/+6)y octw l l4i9qlf3qlong hair and a female cat that has black, short hair.


Which of the offspring has a recombinant genotype?

1.Outline how polygenic traits can show a normal distg8hf;2mae mz9 ribution.

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 o*b6dsx*ph e- nn6)f d zg(0rg7rtd g/tver of non-sister chromatids shown in the diagram belor z*7dptd / *6bntgxf-sh0d)egng(r 6w?

  The photomicrograph shows a pollen grain from L. candidum ,):x u*n6v .orkrtk ow uw2eq5(Lily). Which stage of meiosis i v.kon2 :kx,)t*rw 6 uqoeuwr5s shown?

1.Outline the events w5 ujwks*2mc7oq xd+ -nhich would lead to an individual being born with Down syndrome, which is characterised by the presence of three cokc2u* s+qj-m 5x wd7onpies of chromosome 21.

2.Explain how meiosis increases variation.

3.Outline the stages of meiosis.

The mitotic index is an indirect way of meas2nlcw / b o/trj6lr)1yuring plant growth. A study was conducted on white onions (Alliu//n )t o lr1wbryj2lc6m cepa), under 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. Thep9ccms 6/g/agq a yd82 diagrams below show two cells from an organism with a diploid number (2n)y/d26 9sgpcc ag/8 amq 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 groa-7pdqc)5-kayo +*. exfl fu zx.rq- gwth.

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, wiy 4kjc1mjx /* bq4k8f7a mtdt4th a diploid number of 8, in different stages of meiosis. Which row correctly namxkm 1d7 jq4bf 4t/ymkta4jc* 8es each stage?

  The micrographs show four phases 1 3wvqkmw1,ev59k eekof meiosis I in a plant. In what order do these phasek mv511 wweq,v3e9kk es occur?

Mitochondria are responsible for supplying metabolic energy in eukary e)vhu 5p1tll+ skk8k8otic 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 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 evs k5h81tp8)kku l+ lgenetic 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 the785scc n.sh:7 w7s,mg *zmvv-cieah z cell cycle in four samples of lung tissue from four patients. Which tissue has the c7v7.zs vg5s w-i n:aszmc,h8m*ch 7elowest mitotic index?

  The diagram shows th9()7nz y. : +ba7gwfj hygs oz/r/zqqse dominant cyclin/CDK complexes at different time points in the cell cycle. Which cyclin/CDK complex activates DNA replicaz/ga ) nq+yoys79.7zsj:(fhrb /w gqztion machinery?

  Studies have shown that genes such as Cyclin Dependent Kinase 3 ( i 6t x0t tld*z7.1;kzvkerpu6CDKN3) are highly overexpressed in cervical tumours. tru1.7kz0d 6etv*t ik xz;lp6


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 cycnl.k ) bk3 o4ktbxn)o1le ?