The graph below shows thetgs3,e ac w.d6v4n4qw relationship between maternal age and the incidence of non-disjunction. What relationship is suggested by the d w.6at,e4 qwsng3c4dvata in the graph?

  Which stage of meiosis is repre n tsw0. l;n,0sjnau+m5l68h3f lyqccsented in the diagram below?

  The diagram below shows chromosomes during meiosis. niore-( v7zqf* fs7 gl-w2f2 u36dsol


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 si 3uftiu:gvvj*l;a9 eb/j e75r ngle gene which would be present i5 ;ujt/a3ei 9guvfv7rl:e*b jn the nucleus of a cell as a result of each process?

  Which keyword is matched to the cormqmq7 w t-49n1n pna p+p+kvj,rect definition?

  Which statement(s) abo6(ae2vmrn/g n ut 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, which lettf6c*zc+)nq4 c u4dyn-ejmny6 er points to a cell in anaphase?

  During which stage of mitosis does the nuclear enve/d 3(d(:obpdch. qe9fbpfon 2lope break down?

  Which one of the following transpe d3sg7 ksvxd((p;l 7aort proteins only carries out active transport?ssgv 3(7;( 7 pdxedalk

  Which process does not happen in the shxg-mz )/h+nz;yp c(m db:oao1oot apex?

  Which type/s of membrane transport do/does not require energy gjkm ol;: hzyify l+k*:n*; ,yexpenditure?
I. Facilitated diffusion
II. Active transport
III. Osmosis

  The diagram below represents a cell with a diploid number of 0.m wx2aj6qy h5m7psp4. Which stage of cell dhy 6q5ms7w j20pp axm.ivision is the cell currently undergoing?

  The photomicrograph below shows a root tip mw*:0iwwg 1)c wd5kp eeeristem. Which of the following sentences correctly defines : wge5d )c*wk e1w0pwia meristem?

  When does the random 85*lv*q.tph*xsp iqk, )zc2f fm t(tjorientation of homologous chromosome pairs occur?

  Which process does not occur du) qo/-5tjj(e8w fduxyring meiosis?

  If a cell with a diploid number of 36 undergoes mitosis, how many chromosomes p an)cq11ji9:x9phc pwillpnxpp9)9 c:1qa hicj1 be present in each daughter cell after cytokinesis?

  The image shows a micrograpfgfs 1. v .5b:jos)wsxh of a cell.


What explains the appearance of the cell in the micrograph?

  Which statement(s) about dd ;w4f49gdg aplr b65homologous 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 an individual with Down tqymb s 5d r30bbr*xm7pe7ii:-w /+fa syndrome.

Which statement is not correct?

  In the cells of a horse (E. caballus) during prophase I of meioo6f mqd97r9 mesis I there are 64 chromosomes.o9 mq9f d7m6er What is the haploid number of chromosomes?

  Which arrow is pointing to a ch q; .8dgvk/qd c sjaz,v,-c6aciasma?

  The diagram below represents the structure of a shoot apical meric iec./cmn vc;rkonz49(c o8oo00ub 4 stem. Which row in the table correctly identifies the processes occuring i90cbr8 oumc.z44o(nn/ cko ccov; i0en the structures labeled in the diagram?

  How does meiosis pro1 kgjpldwz5:yxa*8 y/42tfm m mote variation?

  Which of the following sta;b2 x:qqfzam *h3aqs 9tements 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 from two homologous : o*hex 6bv20,nkio fochromosomes.


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 the0unkp cy)m,1hd 6u yz2 formation of secondary tumours from primary tumours as a result of the moveme0u z uk1d mp6cyh)2n,ynt of cells?

  How many chiasmata are p d33 bg03um11xnawuj o9og2aeresent in the diagram?

  Which statement is a similarit:(op1n3zqpx whu y cj4rk)p54y between cytokinesis in animal and plant cells?

  Which stage of meiosis is matched to the correct descrir(4 j0d bmsizn2 c)f0iption?

  Which statement(s) are tr*rsnmuz ;0 cj9cq7 e*iue 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 ddi.rj,a e*alcay: 7t)+ ;zdqn ivision. This results in the formation of one large cell and one small cell. What is the fate of thyad.*i+q,ad;z7nj r: el ca )te large cell?

  Which row correctly describes diploi9fbnn,wwizylvz5at* a ,4 3a,v4s0lyd and haploid cells in humans?

  The following table shows the diploid chromosome number*2oa6) a zalh:za ng)vq*fcs * of a range of species.


Which of these statements is correct?

  What conclusion can be drawn from the karyogram besm 2zbff9 dv z(np6jv 8+q2(ivlow?

  Which of the following processes is cha 9ti l4elfisbf63 t-a1racteristic of the meiotic and not the mitotic ca 3if1 -9etsi6 lbftl4ell cycle?

  The diagram represents a bud wia1ph ,d. .vxuath 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 shoct6v gi i/2;p u(p9w8 o;.eq mkzz7otxws the correct chromosome number for d(o7tv; ;pk6/zz i8 2oiugtxmecw.q9p ifferent cell types and cell division stages?.

  At the end of which phase of meiosis I does crossing ov6b7tu-kmxg 4z 2 omfl ..5o.zcc fol+xer occur, and what is the outcome of crossing ov c m bt zf.x+5-ool2m74x.kug 6zcl.ofer?

  Which of the following statements does not 8hjrc16)h m.zn* yln elz x*0ddescribe a step in the sodium-potassi eh dc6nzyrlz*8l)0jx*mh1.num pump cycle in the neuronal cells?

  Which row in the table 2khjk9eb1i4 bbelow is true of meiosis?

Membrane transport is important for allowing pylo1h5xnc i ujpo e(m-.p8e3/ articles to move across the cell membry8(o j5ien m3phxlucpe / o-.1ane and respond 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 is regulab 9kwsl-caz7d3m 13 hhbs9tug ;ur( (pted 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 shmt pm/vbzye6i: k(qt+(4+strows the concentrations of different cyclins during the cell cycle. Which cyclin is involved in preparing for DNA 6(t4/itpbr+: zmtv+ms e qk(yreplication?

The diagram below shows chromosomepn -jq:qu:it:nugfz*zla2z .l z:1 p.s 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 chromov6r(r ;r kgcg6somes?

  The mitotic index of throat tissues taken from 4 diffkz8 2dyes(. pjerent patients is shown below. Which kyjs (zp8 .2depatient is most likely to have cancerous throat tissue?

1.Draw a labelled diagram to represent the process of cro k7u3ycwg d+7ossing over.

2.Compare and contrast random orientation and crossing over.

3.Outline the stages of meiosis.

  The image shows an abntiwy- 4knb ;r xv v:dl) 8ge;es9e-9tbormal human karyotype.


What is the abnormality in this karyotype and its cause?

The graph below shows the relative amount of DNxvny,; -c- zwcA in one cell during one complete cell cycle. Each letter represents one stage of the cec;-, cx nwvzy-ll 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 hgekdae -c),s8 m(k+di0;qbe is homozygous for brown, g(0akd+h;-sd) iee eb 8 mqkc,long 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 norm9*x (2hgwu qmqzmd6,fal 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 chromatids showduevpt:()d h,ovvs; 2n in t;us, :hvdtd )e(ovv p2he diagram below?

  The photomicrograph shows a pollen grain from L:u x.x 2*pnh: acgqht/. candidum (Lily). Which stage of mhq.p 2hxax/nctu :* :geiosis is shown?

1.Outline the events which would lead to an individual being born with Down synd/e )-delxdb: wrome, which is characterised by the presence of three c)/-le de:db xwopies of chromosome 21.

2.Explain how meiosis increases variation.

3.Outline the stages of meiosis.

The mitotic index is an indirect way of measur .2q qbu80s8;bwf 1si synjg5ding plant growth. A study was conducted on white ouw 8b5sfynssi0 1 gqb;.82qjdnions (Allium 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 whichwqore;+./ xy9 beckqw+5; 1mpznu,sf9nw mc: cells can divide. The diagrams below show two wnq+5s 99;yz cuo q/me kepbxr:;c1w. mw,n +fcells 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 expression in stem growo 7wjts+ fqu3:xlx3b5th.

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 diplork9vpfn.c91wz7p j 4/t)dljwca(iv;qn4 tg1 id number of 8, in different stages of meiosis. Which row corr. /vpw a t9z41;qi1cfwn p (r4lcjjv9)7dkgtnectly names each stage?

  The micrographs show four pf nipq5m-r7ydx 5/g *mo) 9dhehases of meiosis I in a plant. In what order do these phases occuy 59e5ohp7n i)gm-*d /f mrqdxr?

Mitochondria are responsible fof9 gb 3h(v5eyl-e1lsnr supplying 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 eukaryotic organv3e gl1(nlh9-5 f sbyeisms, 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 cellss/:l* rjhxq(s in different stages of the cell cycle in four j:sr/s*( q hxlsamples of lung tissue from four patients. Which tissue has the lowest mitotic index?

  The diagram shows the dominant cyclin/CDK complexes at different time points if9d 1co /ic0ftn the cell cycle. Which cycli fd ot1ic0/fc9n/CDK complex activates DNA replication machinery?

  Studies have shown that genes such as Cyclin Dependent Kinase 3 (CDKN b*6b8 z,aia5w(xl3io51au ag tw5vkl3) are highly overexpressed in cervical tumours.5,83 5ka6ai15u*o via wbgl l wz(bxat


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) xn2zmh) exq,0xrp6t the highest during the cell cycle ?