The graph below shows the relationship between maternal age and the incidencyoc+yzph: o3i* 30zgo ,lj6a) e d*sgse of non-disjunction. ih,3c soap zo*g+3 zyg*6se:ldy)0joWhat relationship is suggested by the data in the graph?

  Which stage of meiosis is represented qi/nrwh f( vw/ui;4t-in the diagram below?

  The diagram below shows chromosomes during/ k,zgv7hb z6k 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 number of a.au 2 wobyr4b;5:wtst lleles of a single gene which would be present in the nucleus of a cell as a result of each proceob srut5w;ay wb.t2:4ss?

  Which keyword is matched to the correct , s 6nv nr*bsac iec12s3+sl9fdefinition?

  Which statement(s) about mitosis is/aguv 7v az4rjfzq e zp:+/us58)re 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 ijwd cq;6)ne ;bn anaphase?

  During which stage of mitosy q-q ft*10jrris does the nuclear envelope break down?

  Which one of the followms wm9b3t 1dbkx;p7 s7ing transport proteins only carries out active transport?71 w;bdp s9xsbt 37mmk

  Which process does not happen in the shojnm2h b8nykm9-nqp7bhjc: 5.ot apex?

  Which type/s of membran 3 aal2caj6hhx:5t*s ll8cou3e transport do/does not require energy expenditure?
I. Facilitated diffusion
II. Active transport
III. Osmosis

  The diagram below representz. a:r z2avveue3ys( 1s a cell with a diploid number of 4. Which stage of cell division is the cell currently u3e1zesa :z(.avvur2 yndergoing?

  The photomicrograph below shows a root tip meristem. Which of the fol;t/wlkn* .v 50u ghyztlowing sentences correctly defines a me0vw*tt .5lukz g nyh;/ristem?

  When does the random orientation of homologous chromosome pairs occur/i 5y6at rub.z?

  Which process does not occur duri1tmw v (zz3:vr1c2q jmng meiosis?

  If a cell with a diploid number of 36 undergoes mitosisq jg ytjd,w:0knq44brs+)n6t , how many chromosomes will be present in each daughter j qb+kqs0gydn,)r4jwt4 : t6ncell after cytokinesis?

  The image shows a mic 29cr3qba fu+qrograph of a cell.


What explains the appearance of the cell in the micrograph?

  Which statement(s) about homologous cr7o33y1qjr z rhromosomes 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 individua f2y/h rufo4.v5bud)f l with Down syndrome.

Which statement is not correct?

  In the cells of a horse (E. caballus) during prophase I of meiosis I t5-rj9rae1dcpd a9) f qhere are 64-drcf a j9qp)5de91 ar chromosomes. What is the haploid number of chromosomes?

  Which arrow is pointing /sv*1z. l 6n4)hoyc 8xqcace tto a chiasma?

  The diagram below represents the structure of am,;i5 vly;5 vbbupdn 6d:,wia shoot apical meristem. Which row in the table correctly identifies the processbyi: 5b,; dplnv;wam5 ,vi6u des occuring in the structures labeled in the diagram?

  How does meiosis promote variate0sky41 rndtcew06e 7ion?

  Which of the following statements is/are correct6)3mx9yp aw uh 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 chr hfiwapd9(u ciph11mw -..g os*qg;0n omosomes.


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 *clkt+m z.z k nc;/un.of secondary tumours from primary tumours as a result of the /nnz.k tul;zkm+*c c.movement of cells?

  How many chiasmata are present in the wo,+7zfp q 2x1dup1 /3rpvlhzdiagram?

  Which statement is a sin1,p wir m p4irto4k+2o*h s(ymilarity between cytokinesis in animal and plant cells?

  Which stage of meiosis is matched to the correct descript xdu*kr: j;j1bion?

  Which statement(s) are true of meiosis I but not meios .wtr1yoo +m(s1i wfeq* y,w+qis 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 af;3hmxgpdrj7 9ter the first meiotic division. This results in the formation of one large cell and one small cell. What is the fate of t9g;rx md37hjphe large cell?

  Which row correctly describes diploid and hapr,y iuoz m(p;5loid cells in humans?

  The following table shows the diploid chromosome number of a range o8i1:-udstd umf species.


Which of these statements is correct?

  What conclusion can be drawn from the nf zww*lzgg wxk(/. 5(d,;uxskaryogram below?

  Which of the following procjdy()rwr-e h 9esses is characteristic of the meiotic and not the mitotic cell cyclerdrew( yh j-)9?

  The diagram represents a bud with af ykh*w.k.o d r6aw53q 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 6 +j/ erk/kh1janmx(jt7.a d0s jlm4 ;wcisv*the chimpanzee (Pan troglodytes) is 48. Which row shows the correct chromosome number for differr; mt1a(kvs*iks+a. /l4 xd67jjjj0mhc/ newent cell types and cell division stages?.

  At the end of which phase of meiosis-k pht)- 8cbi.xu q4fs I does crossing over occur, and what is the outcome of crossing ov- hkx4qfst .-c)u8pb ier?

  Which of the following statementsc t(pji*7fs*bo*dk de,ev:+q does not describe a step in the sodium-potassium pump cycle in the neudfej7okbv dcp** ,* qtei(:+sronal cells?

  Which row in the table below is true of meioi*zr j c;u g(/eyzray(vq,0c:sis?

Membrane transport is importan e2u. w/3/c8qjt/sh9sktjkxh t for allowing particles to move across the cell membrane and respond to chant.q3t c9/2xhsujkkj 8/es h/wges 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 regulatedc;ku1lwe *u1 p 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 different cyclins during dyde /r cn7awdh95b/1the cell cycle. Which cyclin is involved in preparing for DNA replicace5 rybd9dd/7h/wn1 a tion?

The diagram below shows chromoos,yn, r e,,pa;;gh(xingc p7somes 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 oc:b 0so8 q7,i d)w3l zwhxxc2pf homologous chromosomes?

  The mitotic index of throat tissue 7hwhq34 +3bnjeuqju9j o l;p23qed +ys taken from 4 different patients is shown below. Which patiuoh u+;y3pje 3newjl927 qj4qq3 hbd+ent is most likely to have cancerous throat tissue?

1.Draw a labelled diagc *y;9b8rp:n1 itn z6tvl)sdwram 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 abnor f6*6c ia3rkn bf8ibb0mal human karyotype.


What is the abnormality in this karyotype and its cause?

The graph below shows the .kx4 x.jkdkt. relative amount of DNA in one cell during one complete cell cycle. Each letter represent d..xt k4jkx.ks 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 h*:hvsx 0.gzp yomozygous for brown, long hair and a female cat that has black, sho:v.*x shzgpy 0rt hair.


Which of the offspring has a recombinant genotype?

1.Outline how polygenic traits can show a n6-zox vag z5d5 ty) f,df2ngj/ormal 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 th zamqj0hsdbxu ),5u s 4958+qc)d cixqe crossing over of non-sister chromatids shown in the diag5 c,9czsi)x mhq x58 as04qu+bddqu)jram below?

  The photomicrograph shows a pollen grain frowgm a2z3llfk3/*n v-wm L. candidum (Lily). Which stage of vl/2zlm ngkaw*f3-w 3meiosis is shown?

1.Outline the events which would /t fp.;+ukzjelead to an individual being born with Down syndrome, which is characterised by the presence of three copies of chromosome +p;/eu fkjz .t21.

2.Explain how meiosis increases variation.

3.Outline the stages of meiosis.

The mitotic index is an indirect way of measuring plant growth. A study was cofs+ r,q/jsa-cq j;.ys nducted on white onions (Aj ;+cs ar,f-ysq/qs.j llium 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. The diagrmx 2+mtz it9;t ok)b*dams below show two cells from an organizot t)kidt;m*bx2+m9 sm 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 express/47an z hcc;mz0qu44-moq xkb ion 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 diploid number of 8, in different stages )fb*n-tg)fl ytr+r 5k of meiosis. Which row correctly names each stage?)flbf) -+yntg*kr r5t

  The micrographs show four phases of meiosis I in a plant. In what order do therov :ga,5suta(a-s m5se phg( ao5at:s,sv5mar-u ases occur?

Mitochondria are responsible for supplying metabolic energy io sw22dl:euh.n 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 organi :hosdu.ew2l2 sms, 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 n t 1haui710bfcells in different stages of the cell cycle in four samples of lung ti0anh utf171i bssue from four patients. Which tissue has the lowest mitotic index?

  The diagram shows the dominahdfwkfq80 lf9r 10h*gnt cyclin/CDK complexes at different time points in the cell cycle. Which cyclin/CDK cdlfh 08g*qf09hr k1fwomplex activates DNA replication machinery?

  Studies have shown that genes such as Cyclin Dependeq3q6ccn;u6g ukw 36ymnt Kinase 3 (CDKN3) are highly overexpressed in cervical tum;nuguc6q 3 6cw36q kymours.


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 o3nflajpd9 :4cf cyclin E the highest during the cell cycle ?