The graph below shows the reln irp+gv6 g9mobne6 k.v )b5dl* lxm-3pc, .eoationship between maternal age and the incidence of non-disjunction. What relationship is suggested by the data in the grapkb m rlc .vn*o)ml5npb g v.3+6,p6oeg-xdi9 eh?

  Which stage of meiosis 1q;f k -h4xe2fb 9bxmmis represented in the diagram below?

  The diagram below shows chromosooxetc)0rei 1( mes during 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 alleles ofr(kc m.yq m /we(mda-8xya7- q a single gene which would be present in the nd8crwaq x y/-7-m .keyq a(mm(ucleus of a cell as a result of each process?

  Which keyword is matched to the correct definition?ttx0 akc/s:p;ixgd x :ar: 13q

  Which statement(s) about mio6ebk* d. ksz+tosis 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 8+,dx6kqjnt jcell in anaphase?

  During which stage of mitosis does the nuclear envelope bwlnsv2 :q7r*o reak down?

  Which one of the following transport proteins only carries out active trans4otnz( r1i p*e0oq e dvv0pa,/port?,r( o t0dozp*0/eni1pe4qvav

  Which process does not happen in the shoot akiup;k+bhl.nzm-rc v 4xz(- xkv/b) 8 pex?

  Which type/s of membrane transport do/does not require energy e:z)h qjql1 2htxpenditure?
I. Facilitated diffusion
II. Active transport
III. Osmosis

  The diagram below represents a cell with a diploid number stcb kf 24;8tjof 4. Which stage of cell division is the cell currently undergobt cs;kj82f4 ting?

  The photomicrograph below shows a rob8w1(r:.le2t8v q rzx yw)wegot tip meristem. Which of the following sentencesxbtv )ry wz elwgeq.182rw(:8 correctly defines a meristem?

  When does the random orientation of homologous chromosome pairs6am aj3pw1m: f*s gzd+ occur?

  Which process does not o gwq*ci0c. s7bh upj:4ccur during meiosis?

  If a cell with a diploid numberx c,x :s(ya8tf9eqc lli1v;0 i of 36 undergoes mitosis, how many chromosomes will bel le i:(vf 9stxcai10cx;y,q8 present in each daughter cell after cytokinesis?

  The image shows a micrograph of a cell0fr 1.tdun ts0:a7o dxop-1a ,-paumn.


What explains the appearance of the cell in the micrograph?

  Which statement(s) about homologous chromosomnxg- 3js54 aises 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/q32bu;tss+ek q7ijd individual with Down syndrome.

Which statement is not correct?

  In the cells of a horse (E. ca) mkuyh*jas;z5v-s w2 skl7kn9 ljn 7.ballus) during prophase I of meiosis I there are 64 chromosomes. What i jnka*nyzm j5v7s w h-l)u.7l9;ks 2kss the haploid number of chromosomes?

  Which arrow is pointg*0ka yk27sb9pbg.ouzv-i f,x4 rn (jing to a chiasma?

  The diagram below represents the structure of a5j; .6gfd ,t )jyfhbk,u,wd5 r/vamap shoot apical meristem. Which row in the table correctly identifies the processes occuring in the s,mb)a/5vtfyk 6d,fhgjd.; a purj ,5wtructures labeled in the diagram?

  How does meiosis promotec7+es.4rex uk3nutmm/ *8-zhq /feuz variation?

  Which of the followingvxr -s9v /npa btga1kv;d68+eq pv4:v statements 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 produk)j lu*5u ga+ s8axgf;ced from 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 describes the t4gj,k0(z mhn +vpt j5formation of secondary tumours from primary tumours as a result of the mov, tm jvk+5(npgt0 hj4zement of cells?

  How many chiasmata are present in the d 4q)-t;2izfcc1xg9fhfl evxjc)l 4+diagram?

  Which statement is a similarity between chc 4h-)7rta6f6lq d bhytokinesis in animal and plant cells?

  Which stage of meiosis is matched to the co ogo 1olieu5e4;fq- v+rrect description?

  Which statement(s) are tru *xe+o6m/hru re 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 firs/o d:*e d.mpx9soq8 zwt meiotic division. This results in th*.d: pmxo/e9d8os qzwe formation 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 human y(i4r p7uhf8ls?

  The following table svs7zb)tai h,2 jh ewlu;1x3,nhows the diploid chromosome number of a range of species.


Which of these statements is correct?

  What conclusion can be drawn from the18biloh)duw (g2wg7vqkc4uk ct 2e *3 karyogram below?

  Which of the following processes is characteristic of the meiotic t3ai2 in75zjcand not the mitotic cell cycz 3a7i c2itnj5le?

  The diagram represents so8f8;d4trzr f + v,ava bud 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 chi+*cn yb ;a r )rzuo,)vw7zop/qmpanzee (Pan troglodytes) is 48. Which row shows the correct chromosome number for d;rnav)qz o p *y7,uzcwb)r+o/ifferent cell types and cell division stages?.

  At the end of which phase of meiosis I does crossing over ocv *)y vnzmhtdge522 v;cur, and what is the outcome of c; 2vgm*5z2hd te vnvy)rossing over?

  Which of the following sty h)jo,s* 43 s,keqweh3,l essatements does not describe a step in the sodium-potassium pump cycle in eqo4l *k)yh,s3hwe s, j e3s,sthe neuronal cells?

  Which row in the table belo sj9psqj1e4( fw is true of meiosis?

Membrane transport is bxu *vy pz*xkbz1 z4w.l,y,*aimportant for allowing particles to move across the cell membrane and respond to changes in the chemical composition of the extracellular f**.pbzlw,v kyzxaxu 4*zyb 1,luid.

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 r bd-3j :0oent5iceh -pw- 1ocqegulated 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 8w ckxvu85h( kthe concentrations of different cyclins during the cell cycle. Which cyclin is involved in preparing for DNA kw (8xuv ch5k8replication?

The diagram below shows chromosomes dugu25b3kb w:(e1t bpv 7tk*i/w r hcl,hring 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 separatiogeg zrkwx /b3k/c- v. (ouj*2un of homologous chromosomes?

  The mitotic index of throat tissues taken from 4 differ .e71 q8udqlv4dy5yhxent patients is shown below. Which patient is most likely to haeu84v7.ydqhd 1lq x5 yve cancerous throat tissue?

1.Draw a labelled diagram to qc vhm3:qnk a g4b)j)(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 karyotypevlr/:rv.ni(3e1nw *0cztxq67c usr w-q wlj7.


What is the abnormality in this karyotype and its cause?

The graph below shows the relative amount ofb+n3 :h wm5puzvv:kad6gh :/e DNA in one cell during one complete cell cycle. Each letter represents one stage of t3hdnvma:b wvek5pu:+z: g 6h/he 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 cmx(tbe1a0a.pllt +m *at that is homozygous for brown, long hair and a femlpx(mte .l mt 1a+a0b*ale cat that has black, short hair.


Which of the offspring has a recombinant genotype?

1.Outline how polygenv +if,*zwamf28 fygh0ic traits 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 the crossing over of non-sister chromatids shown iv,s japu ip1i- 5u3sg;njz09mn the diagram below? nv9gupzm3ji au50 s-spji1; ,

  The photomicrograph shows a pollen yg; /s t/crqh4 dgafp sx3:r2;grain from L. candidum (Lily). Which stage of meiosis is shsp ga4; /rxd3g;rfytq:2c/ sh own?

1.Outline the events which would lead to7n;6latfdl8 el +ma6q4f)-e+eoxxd f an individual being born with Down syndrome, which is4 qn)+fx7lme -o+;6l dalae d6fe8x tf 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 gro1be5vj/( r apa1-3 jyjl m0wnvuto- 1pwth. A study was conducted 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. v/enpr51p 3 oa11lvjwu-0jy(m jta- b


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 diaf)0d ysmcax : :,)gznhgrams below show two cells from an organinh)0s acxd) gy,::zmfsm 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 ste2cisc0zzu 21 tm 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 staen93e*yhvb; a ges of meiosis. Whice*nv9ae h3by ;h row correctly names each stage?

  The micrographs show four phases oem 48/9rka: abundn.b f meiosis I in a plant. In what order do these phases occu. mdb48an rnab9e/:kur?

Mitochondria are responsible for supplying meta7)d.* uqbrlczon+ ym)bolic 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 organisms, inheritance patterns of mtDNA found in hybrid cells, which are the result of sexual reproduction between two differen +urdm*7qy olz))bc. nt 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 diffe8w:t57,xf hxu rh(ghzcvt20m t 1ovq8 hlym;2rent stages of the cell cycle in four samples of lung tissue from four patient(2h v1yt:,hz8m5thvx h8;l7 tfqxgu0 r2owmc s. Which tissue has the lowest mitotic index?

  The diagram shows the dominant cyclin/Ci 3xgu conix v/8afvp3q6 loz-7 *(lb.DK complexes at different time points in the ( -g x /.367ua xfv8 3loviocqlzin*bpcell cycle. Which cyclin/CDK complex activates DNA replication machinery?

  Studies have shown tgx -q)jas1n4 nhat genes such as Cyclin Dependent Kinase 3 (CDKN3) are highly overexprenx -jqn1s4) gassed 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 cyclin E the highest during the cell cyclew ,1 d2swp4ckm ?