The graph below shows the relationship between maternal age and the inciden gd;qyt.hbzw8(z 2, dcce of non-disjutd8 .d2qbwcg(, ;hzz ynction. What relationship is suggested by the data in the graph?

  Which stage of meiosis is rep7 ve(:ymbhqd5 g8wxp;resented in the diagram below?

  The diagram below shows chromosomes during mbhqj rg:gp-r vwy,d0c3)y w5;b0.s xfeiosis.


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 allel8w*w*vld zqu vu*23qk es of a single gene which would be present *u* wv3dl*v2 uz8wqqkin the nucleus of a cell as a result of each process?

  Which keyword is matched tyj;3-q gieqj-o the correct definition?

  Which statement(s) about mitosis is/are trcfs x+d)j.+mbue?
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 nm1r8f.7;m.wvq1(ccflzo x nd +wz-zpoints to a cell in anaphase?

  During which stage of mitosis does the nhv+l7 )wplmicv ,(i y0uclear envelope break down?

  Which one of the following transport proteins only carries out active trans/dnluy(gbz ) n73w.e hport?z/.g )(n hweunbydl73

  Which process does no6t qkbtk9d-wpfir36 *t happen in the shoot apex?

  Which type/s of membrane transport do/does not repz1pbp )j x*p9quire energy expenditure?
I. Facilitated diffusion
II. Active transport
III. Osmosis

  The diagram below represents a cell with a diploid number of 4. Which stage of c:2 xzb q);b0qc9, mn0njvmznvell division is the cell currentl znq00;vmqz)nb2:m 9c,jxn bvy undergoing?

  The photomicrograph below shows a root tip fc 8k *hiqj58axv+c mjp8s.6dmeristem. Which of the following sentences correctly defines a meristem86pcv8m5k.q* j f i8axcdsh+j?

  When does the random orientatid); zqeh /pc:bon of homologous chromosome pairs occur?

  Which process does not occur during meiosi3d issjg3- ct9s?

  If a cell with a diploid number of 36 undergoes mitosis, how many ch-6xr f yuu(w en,dj(7s)a jj3rromosomes will be present in eacj(6 3nju rue7-w,djs) frayx (h daughter cell after cytokinesis?

  The image shows a microg -obo 55,/strmz4nw1sa(qqcs raph of a cell.


What explains the appearance of the cell in the micrograph?

  Which statement(s) about homologous chromosoeqf lx v6pf-16mes 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 syndb,e v 3z;qavh8rome.

Which statement is not correct?

  In the cells of a horse (E.,1xw1 y s,gpazis s(4q caballus) during prophase I of meiosis I there are 64 chromosomes. What is the hapl zy,s xqw pgsi(411a,soid number of chromosomes?

  Which arrow is pointing to a chi ldy0b*tf /2 ro5 rh-mr;6ldwfasma?

  The diagram below represents the structure of a shoot apical meriso ,uvs+qdtym. /1.rcqtem. Which row in the table correctly identifies the processes ou,rmdv.sqc/+1y qo t.ccuring in the structures labeled in the diagram?

  How does meiosis promote variat. ;2 cbo6nkzsyk43gw gion?

  Which of the following sta.g , rhr5twekaa47 ,fwtements 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 chromosoc (me1b o7gxjiktg 6m4+,tj*ymes.


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 froiczq57e-br:6r rnbik4. z6oz) ery r *m primary tumours as a reeqz -e rr)nzb 5 6r.ikyr*:6b 74zicrosult of the movement of cells?

  How many chiasmata are presen 3le m( 5gzl6ov(f(dvzt in the diagram?

  Which statement is a similarity betweaf9vhk*4dj o)( 2bk nken cytokinesis in animal and plant cells?

  Which stage of meiosis is matched;h +mu v/wp2l(+ k4ek8ztsuaa to the correct description?

  Which statement(s) are true of meio*;s+njv xd(u2ei(lvlg6 zt a4sis 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. .s6ytu3+c zy zx;qxqfd:.ej6fn /pz 1This results in the formation oyzc.f/ z; dy:z f.j1se 6pnqtx3xu 6q+f one large cell and one small cell. What is the fate of the large cell?

  Which row correctly describes di guzfu 2-7j 4vvz3pr;hmp4x4nploid and haploid cells in humans?

  The following table shows the diploid chromosome number of a range of species. 8 22iu bbmka,(smz 3me


Which of these statements is correct?

  What conclusion can be drawn from the karyogrs1 uo50hqswh,am below?

  Which of the following procem z/-) -paw e;*kv+j xx3mulzesses is characteristic of the meiotic and not the mitotic cell m*wlv-x-; a)u+ xmezjkz /3 epcycle?

  The diagram represents a bud with a shoot zq-w ex;8tyb rs1 yby3j61tn0 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 w7q0o cd:bln1 48. Which row shows the correct chromosome number for different cell types and celwqo d0lb:c17 nl division stages?.

  At the end of which phase of meiosis I does crossing over occur, and what i 1xo(m5,imyeuyd:8ur s the dxy8i (em:1 uoy u,m5routcome of crossing over?

  Which of the following statements does not describe a step in the sodium-pota*g1th:oh2d)fmq5hwbrj 0j 1 ussium pump cycle in the neuron jot1 1hu d0:mfhw25bhqg* )jral cells?

  Which row in the table below is truefv*.yvn.;-p4 pm2p hlrbqyw 9 of meiosis?

Membrane transport is important for allowing particles to move across the,ya.inn,nz a : cell membrane and respond n:anna zy.,i, 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 regulated in 69d vw9kyenn-i2j ks3 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 differetrnz9/8r.o d hnt cyclins during the cell cycle. Which cyclin is involved in preparing /9dn zorrt h8.for DNA replication?

The diagram below shows chromosomes during meiosis. nv/9zc :kz/c7etkxt 8

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 chro-oi5 p7bp4cp+ iq ov(a(.c1o l /re3u.wofimjmosomes?

  The mitotic index of throat tissues taken from 4 different patick /2mt(1un6nnwfaq*ents is shown below. Which pnck 6/ *q2n twn1fm(uaatient is most likely to have cancerous throat tissue?

1.Draw a labelled diagram to var1g tv*;/nz 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 abnormal human karyo9 w am;rdg0;xk:0 cxtsl) f*attype.


What is the abnormality in this karyotype and its cause?

The graph below shows the relative amount of DNA in one c 6uh0th 9 ix/nw2 vxa1iu;+odpell during one complete cell cycle. Each letter represents one stage of the cellvuhw12 n tdo xh/6;9+ auix0pi 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 between0( fd ast /cwsfg;5q,f a male cat that is homozygous for brown, long hair and a female cat that has black, short hasf, 5q;tf f agwd(/sc0ir.


Which of the offspring has a recombinant genotype?

1.Outline how polygenic traits can sh.(7qyjxuzxr0r ous 19ow 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 thgys /pwti/ a 5sx;,kq,e crossing over of non-sister chromatids shown in tasq ywxs/,k5/,g; t pihe diagram below?

  The photomicrograph shows a pollen grain from L. c7cfp,foc9 zd/ -c2 p c-fwbn:dandidum (Lily). Which stage of meiosis is shown? o:-ccbfn-9p fd /cz2 ,cpd7fw

1.Outline the events which would lead to an indiv.d4:md.j 8bnn6piz /q6:sm lkmhm0siidual being born with Down syndrome, which is characterised by thm0zdin8.: s k4hm. jm/6lp:d6nqm b sie 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 stu)38reazvrj q qj2, dj,dy was conducted on white onions (Allium cepa), under controlled conditions in a lab, to investigate the effect of s,v2qjzj8jqr)3r d, a eoil 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 ts;fne(9b -09x y w.3gjukwzr owo ways in which cells can divide. The diagrams below show two cel3fe su-z0(jok .w x9;wnr9y gbls 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 stjdnoll.cs1t8 5zfz y7 n aj.23em 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 1 6vu+l v0-csjppt r6w;vq 2sd8, in different stages of meiosis. Which row correctly namevd+s j2v;61ql wtp6c -0u svrps each stage?

  The micrographs show four phases of x( pkt05xg, ei1bm/hzmeiosis I in a plant. In what order do these phep(/zi 5t mhgxk 1bx0,ases occur?

Mitochondria are responsible for supplying metabolic enetkkfhwb iiq)ge l (.8 0vnq/09rgy 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 )i0vtnke/qi8l (h q0 kbg9.wf 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 in difp ucboa 8c8fue 9j:s)w.9*ekfferent stages of the cell cycle in four samples of lung tissue from four patients. Which tissue bfup. kc e88 9e*fua w9:cjos)has the lowest mitotic index?

  The diagram shows the do tp5a p:f q:nvhjoa252minant cyclin/CDK complexes at different time points in the cell cycle. Which cyclin/CDK complex activates DNA replicatn:2 5a:o2qfavp t5jhpion machinery?

  Studies have shown that genes such annk57damdtwh gq79l-t9 lz p 8xn24x 9s Cyclin Dependent Kinase 3 (CDKN3) are highly overexpressed in cervic9t9 l ndzn mx 7q2n5 pl7h8d4agk9-twxal 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 cyclin E thbq 8 )st*jug7ll 6;epbe highest during the cell cycle ?