The graph below shows the relationship between maternal6.awk; tmy l:d age and the incidence of no ly; .t:dw6akmn-disjunction. What relationship is suggested by the data in the graph?

  Which stage of meiosis is represenbhq3 krw;wu6sr-fo:1q: 7tys ted in the diagram below?

  The diagram below shows chromosomes dur-yx)9ktutgyn) 4 ruh otbja)j+/ ,6il ing 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 allejna6i59ez pjs*z h/3eles of a single gene which would be presjz6z5*pjis/ 9e eah n3ent in the nucleus of a cell as a result of each process?

  Which keyword is matched to the xze 1:p5ia5vhcorrect definition?

  Which statement(s) about mitosis idvp(+- wcald/s/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 cely w i,-9vs0fdtl in anaphase?

  During which stage of mitosis does the nuclear envelope break down?(pqud8ju by*q44h242vzw ggr

  Which one of the following transport prothq+a l :zj :2 vm4kict+,-zgngeins only carries out active transport?mlaz+ck:t:-zhn j4giq2g, +v

  Which process does not happen in the shoott8u t e/*n mavszqjj+qvp1 s)c-6,o* x apex?

  Which type/s of membrane transport do/does4v mi0 f r1vyiql+pw j,z*50y.jkef-o not require energy expenditure?
I. Facilitated diffusion
II. Active transport
III. Osmosis

  The diagram below represents a cell with a diploid number of 4tw ymheg 2fx.n-m(w5/g; ihf 6. Which stage of ce/gt .w xfmny6-g(fe 2hw h;i5mll division is the cell currently undergoing?

  The photomicrograph below showm:b0pi,.fk* )9 o1jzkrlyiz8svc um6of (fa+ s a root tip meristem. Which of the following sentences correctrly *j.(9+a bfuvzk0)zi16f8,ocsp k fm io:mly defines a meristem?

  When does the random or +(m:g6q2o/.fjjfefw gi,q ptientation of homologous chromosome pairs occur?

  Which process does not occur du mtggqjp sujww zd2+(5l-)10 uy7 ir,ering meiosis?

  If a cell with a diploid number of 36 undergoes mitosis, he wjq x tae)tz+o 0lu024x4jrzgyz7+ 2ow many chromosomes will be pres jeu )044 y+ze 02a2+zglw oxrztq7jtxent in each daughter cell after cytokinesis?

  The image shows a micrograph of a cell. b+kk:6lu*v b(l0m 1-vobsf zf6j avs6


What explains the appearance of the cell in the micrograph?

  Which statement(s) aboutsqu 9zhs;lgv7-pp t8nq+jh3. homologous 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 s/x3 swrdhq g;.4q- rx5oqsxe7yndrome.

Which statement is not correct?

  In the cells of a horse (E. caballus) during prophase I of meiosis I therer6jap c6owue3 tv5* ;p wjukb0+m:,pc are 64 chromosometkr;w:a v 0p*3j c,6u6mobcj +upwep5s. What is the haploid number of chromosomes?

  Which arrow is pointing to a clk1(weil8hz.s/d) vcg c ,.behiasma?

  The diagram below re4x +kn r* 1j qygi7fehzym+6z4presents the structure of a shoot apical meristem. Which row in the table correctly identifies the processes occuring in the structures labeled in the diagram?14m *4xe+j hrq7znyi6yfgz+ k

  How does meiosis promote variowqs+h d 7+c ;e7xlem/ation?

  Which of the following statements is/are corrdx))2zsxkwo;-wu 5j1q- hu x oect for meiosis?
I. It is a reduction division
II. It involves random orientation
III. It produces genetically identical cells

  The diagram shows gametes produced )/tdbb 82fzcrfrom two 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 describes9gdx)ey a r2/vsv* t:ev4q7os the formation of secondary tumours from primary tumours as a result of t2 oysers/ax4:vgdv7 tqve*)9he movement of cells?

  How many chiasmata are present in the diagramd,f4dxfu4 x 6* xd(apl?

  Which statement is a similare4 p 7bqjc3.gmity between cytokinesis in animal and plant cells?

  Which stage of meiosis is matched to the correct description h, )tv0- qid+56b9q2 tlfv,sv2gmycruhs7 mt?

  Which statement(s) are true of meiosis I bupdxe,7u o2kr* t 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.5(bnxo*khyp* *xf o*g This results in the formatiyk p n5x*o x(fh*g**boon of one large cell and one small cell. What is the fate of the large cell?

  Which row correctly describes diploid and haploid cells in )b5pn9g k: zta*jrs z)humans?

  The following table shows the diploid chromosome number of a range of sp(k sl kpst02 1(evwt,t-n yz(becies.


Which of these statements is correct?

  What conclusion can be droapgd,c3xbwr7m 4g r )a 3tmbg6q09t7 awn from the karyogram below?

  Which of the following processes is characteristic of the meiotic and not the mx+gny*lt95vu itotit*5 nxyvug9l+c cell cycle?

  The diagram represents a buu jocz14p7r *id with 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 chimpanze :k7svztl0pd /e (Pan troglodytes) is 48. Which row shows the correct chromosome number for different c/s0 vld p7kt:zell types and cell division stages?.

  At the end of which phase of mei50y 2cod,fd t+jqtl h-w; lm9fosis I does crossing over occur, and what is the out md-, tcqlwh;d+0f lo52j9yftcome of crossing over?

  Which of the following statem4o 2obmcmex 4slmm; mdl/ (/u,ents does not describe a step in the sodium-potassium pu dbc/(smx m /l;m4 o4olm2meu,mp cycle in the neuronal cells?

  Which row in the table below is true of meioslvj; -1 h lug-swq2)sdis?

Membrane transport is important for allowing particles to move across the mhl ci2w k8+yqm jp,k)5,omrs1 x0so(cell membrane and respond to changes in the chemical composition of the o,5hx20l8 o k 1y sk+r,scwijqm(mm )pextracellular 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 cs h 7qtxqbdxvol5:mlb +)/:,oells.

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 differentoqh604b1 /nh(b jin.q jg+xtb cyclins during the cell cycle. Which cyclin ishibbt0 qq4+n/ (.bnho1 6jjxg involved in preparing for DNA replication?

The diagram below shows chromosooi)gt-,+,u3 m;q lmk9h oykn:kf,n tsmes 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 meiosisy dyc9xjd7nkf0; 4ombcq )n2t 2c:md6 involves the separation of homologous chromosomes?

  The mitotic index of throat tissues taken from 4 different patients is shown bv;wm9 p /jyqf)vlv +i:elow. Which patient is most likely to have cancerous throat tis wj)v v9p+i;/vqm:yflsue?

1.Draw a labelled diagram to represent the process of crossing over ru* lu 2o7jt**yz.yiy.

2.Compare and contrast random orientation and crossing over.

3.Outline the stages of meiosis.

  The image shows an abnormal human kav- x*qr+bzyz (.eoq sq);z *fcc2shl2ryotype.


What is the abnormality in this karyotype and its cause?

The graph below shows the relative amount of 5agg0xj6:,oe j jjsz/DNA in one cell during one complete cell cycle. Each letter represents one stage o:sj jo/j6x5ga gz0e, jf 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 h+22;ku 4kycq*ecwy 1nwmqh4 a cross between a male cat that is homozygous for brown, long hair and a female cat that has blahnqwmk4u+; *h1c22 yew yqc4k ck, short hair.


Which of the offspring has a recombinant genotype?

1.Outline how polygenic traite:eehy+ .* zoys can show a normal 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 t2it-cr z(z54pex + qts lb-+kthe crossing over of non-sister chromatids shown in the diagram below z4ktt2leq-pzxb rt 5( c+s-+i?

  The photomicrograph shows a pollen grain from L. candidum (Liezhsp. qq h4p 6ab7:h9ly). Which stage of meiosis is showhp6qp e 7sha4 zb.:9qhn?

1.Outline the events which would lead to an individual being born with Dow2qwpyikt;1x dm7n nc-p;u. t /n syndrome, whickdn;/ip tmycn-; p.w 7q 2tx1uh is characterised 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 measuring plant growth. A study was 7cz+4jybtjrh ( *oms(conducteczt m( 4yrb7*(jo+hjs d on white onions (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 arevf25 e6i8jef0-/1vf wfae lk;ewetn: two ways in which cells can divide. The diagrams below show two cells from an organism with a diploid number (2n) of 8.f 0ejflv5ita2f;/wwe-e8e v fk6n: 1e


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 q i(4dirih )of;/ +w2zqfysr9n 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 / (dc7 -5lke(ljhogb3b m(qj+u dj(yy diploid number of 8, in different stages d(l(yk 7 dhyqel/ b(+( 35gbjj-j cuomof meiosis. Which row correctly names each stage?

  The micrographs show fobi/,qv*r/.j) ,t/gs jydg vc5 +vucrwaeo1g )ur phases of meiosis I in a plant. In what order do these phases so/e +w ug)vvg*bqytc,,5acvj)i d.r/g /jr1occur?

Mitochondria are responsible for supplying metabolic energd1aujmpy ,zr 3ia 3.w)y in eukaryotic cells. In most eukaryotes, which reproduce by sexual reproduction, mitochondrial DNA (mtDNA) is inherited from only one of the puwyad,jam1i r)33. pz arents: 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 cel.s p(2cprd/n76 k ekau nz26kce tsai2:h. y5lls in different stages of the cell cycle in four samples of lung tissue from four patientp 2er6n2 lia7u2paykdn6 tckzh:s c(/e s.5 .ks. Which tissue has the lowest mitotic index?

  The diagram shows the dominant cyclin/CDK complexes at different time points in 1-p + de0lszx mltq5.vthe cell cycle. Which cyclin/CDK 5. qd+1- z0ltmxlsepvcomplex activates DNA replication machinery?

  Studies have shown that genes such as Cyclin Dependent Kin1nik2(m;tiwxyr5+qwp 9/ ea xase 3 (CDKN3) are highly overexprii+9p;2k1wt5m w ery nq/x(xa essed in cervical tumours.


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,prol+qh/ -cu cyclin E the highest during the cell cycle ?