The graph below shows the relatioudcz+ s9: wj5qgag s.,nship between maternal age and the incidence of non-disjunction. What relationship is suggested by thez.djwu 5ag9cs, sg:+q data in the graph?

  Which stage of meiosis is reezq12 n ;hasc1presented in the diagram below?

  The diagram below shows chromosomw c85q wfxybo 5)*n)iees 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 alk9bjegmt9ur: x2q zd.62k.n80 a uw fyleles of a single gene which would be present in the nucleus of a ceg b20md 2nj u9.txw.k:qe86uzyr 9ak fll as a result of each process?

  Which keyword is matched *kv5 xbj yr(w(gyhm2 bja-j/o)n-(lzto the correct definition?

  Which statement(s) about mitosis ispi8b n6a2*byc/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 cell in ana7,3eq 7dx iuni cjwwr t f;1bz0+;z,lwphase?

  During which stage of mitosis does the nuclear envelope break6i v2d uzf+h2-gmzz/ n down?

  Which one of the follow kfx5+a.imxf9b.sa y (ing transport proteins only carries out active transport?i am skx5f.a fb.9(+yx

  Which process does not happen in thd314wcs m8erykvhtm 6q(;n 4w s v-b6ye shoot apex?

  Which type/s of membrane transport do/does p2cm6p;. 3syp6-yxtbgv m-8/ mru il fnot require 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 cx*jj *0-kx *j 9 .rzbix3goeurell division is the cell currently undergoing? 9.gx0 zrji*ueb-3*jxoj x*rk

  The photomicrograph below shows a root tip meristem. Which of the followin)o)a3 zaa.m a(ei.ru ;nf:se jg sentences correctly defines a meru. o(jsaz.;i a r m)aane:f)e3istem?

  When does the random orientation of homologous chromosome paihcq*:oz gjkt qv4bshsr ( -l+p6;tyx 2)u* yw1rs occur?

  Which process does not occur during+m3 x*e8vglemf m, 4ml meiosis?

  If a cell with a diploid n:o;n 7p w a)ipvgg3lq:umber of 36 undergoes mitosis, how many chromosomes will be present in each dwgi7a ::p q3vpl;on )gaughter cell after cytokinesis?

  The image shows a micrograph of awws bvj)pl8n2 ; 3w7ta cell.


What explains the appearance of the cell in the micrograph?

  Which statement(s) about homologo 5(i 6j3oy1 qftjc8 1woathkj+us 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 indivint oh*5q/asr7+ we j ap kal9y,ja031pdual with Down syndrome.

Which statement is not correct?

  In the cells of a horse (E. caballus) during prophase I ofa m xw9szdc+8re79lm. meiosis I there are 64 chr d m7cxa rl9.+ze9swm8omosomes. What is the haploid number of chromosomes?

  Which arrow is pointing to a chiasma?lrf(klof(* 1 l

  The diagram below represents the structure of a shoot apical meristem. 1g.p+e 6llmu zWhich row in the table correctly identifies the processes occuring in the structures labele +zlmg6pl1. ued in the diagram?

  How does meiosis promotec0 r2pxx3cy2gbid yy) v(7fo * variation?

  Which of the following sta/;gt)dq :9hex lp0jpplua,; v tements 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 c1a 3qb 6tv9z;pskqt9 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 formation of secondary tumours from primary tumours w;*- 9laire,7nwucru as a result of the mov7uwnlir9u *-rc a,e;w ement of cells?

  How many chiasmata are present in the 4:7)t* :jt-hqjatw he av: rbzdiagram?

  Which statement is a similarity between cytokinesis in animal and giozu-0 z/ :nt j6; (t(aka)i uox-rmaplant cells?

  Which stage of meiosis is matched to the correct ;ibv wq:*8n)9qral9kb +sb lndescription?

  Which statement(s) are true of meiosis I butf,1mi tw+wq (;8u bcmg 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 meiotry58c 8kwrnw. of;o n0l tw*p(ic division. This results in the for5;wcy8o wp or.kn(r*fn80tw l mation of one large cell and one small cell. What is the fate of the large cell?

  Which row correctly describ lgfd-up 8e5v,5i0ntues diploid and haploid cells in humans?

  The following table shows the diploid chromosome number of a rangea(f9*e 5czac9hj j.pz of species.


Which of these statements is correct?

  What conclusion can be 7xn;i *e ldmup//:ygzdrawn from the karyogram below?

  Which of the following processes is characteristic of the meioti:y)er 2 n1b q8 acrm/pod/fvb6c and not the mito:m/r d26/qcybn8obfp 1 v) reatic cell cycle?

  The diagram represents a bud w8 8d0z1ji5wjvxnx -cyith 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 c87zxxu ebd.f z(it)br/z6sh +himpanzee (Pan troglodytes) is 48. Which row shows the correct chromosome number for different cell types and cell division stages?zd( 6bz isxbfx/ueht87 .r) z+.

  At the end of which phase of meiosis I does crossing over occur, and wh.8ws ;9 hgek54luwucc at is the outcome of crossing over?lu 89c.csw4ue5k g;wh

  Which of the following statements doe ezy(h88sm* oq10vt ifs not describe a step in the sodium-potassium pump cycle in the smyoze8(*v1q8tfhi 0 neuronal cells?

  Which row in the table 9 amxu(of(a;wqx,2vz below is true of meiosis?

Membrane transport is important for allowing particles to move acrossbr;) jj32.7el3uogx8kq/hhhf+uto n the cell membrane and respond to changes in the chemical composition of the extracellular. uroh3g;/fboj2q n+7 )x3hth keju8l 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 regulatedko4 qdmepqjjetm;yw6j31641 02u n hm 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 dur:(,qqli c1,f j;bvh- nnetre8fp 54tring the cell cycq t e(crf:n8-i54 ,,qvrfhpj 1letnb;le. Which cyclin is involved in preparing for DNA replication?

The diagram below shows chromosou3 ,- hrfmf.ucmes 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 hom)hzx2)rwgoq 5z zc 6o0ologous chromosomes?

  The mitotic index of thr1li ox ,yfdy f*7om/m7tudo18oat tissues taken from 4 different patients is shown below. Which patient is most likely to have cancerous thi1of*oudy, 871f mlo mtx7d/y roat tissue?

1.Draw a labelled diagram to represent the process of crossing 4(l/f v47xta)jmoz n zsm( z(wxpl-4u1kqvc2 over.

2.Compare and contrast random orientation and crossing over.

3.Outline the stages of meiosis.

  The image shows an abnormal human : 1qtokbgoi/8 az9m 5nkaryotype.


What is the abnormality in this karyotype and its cause?

The graph below shows the relative amount of DNA in oneme,h81efs7z6vs kec.)pn lvqy8g(* w cell during one complete cell cycle. Each letter represents one stage of the cell cyc hel(v*k6f 7 8sq 8.ny1)cegzpesv,mwle.


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 homozygouo3kh:jl z;x1zi)kd,z s for brown, long hair a):izjzlkz3hd,;ok x 1nd a female cat that has black, short hair.


Which of the offspring has a recombinant genotype?

1.Outline how polygenic traits can showvv u5m,au9./z4zo cbd 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-sz8yu3t/hv2ngh/n4vd j z5q l7tvu ;*rister chromatids shown in the diagram btgvnv8/ nr u2*4j;lzq3udyz v/7ht5 helow?

  The photomicrograph shows a pollen grain from L. candidum (Lily). Which stagel.y/nykp:cz( )lq-oe+8 ygpc ofz.(yp+yoc)8 l c-l n/ekgyp:q meiosis is shown?

1.Outline the events which would lead to an individual being born with D59l6yl 3sv.etaq3a qpzx:n3 a own syndrome, whil6:95sy a t3 vpq3.qxznal3 aech 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 wo;nya *,xf 0 hg:l2vmoay of measuring plant growth. A study was conducted on white onions (Allium cepa), unlv,n *0yao;:h2xo g mfder 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 ruzubk+k q1k s6i1r: ;in which cells can divide. The diagrams below show two cells fr ikk :ru+ 611uqkb;zsrom 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 growth. ksp*(x .hy k::6 bpf;vi tfdm8

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 diffazti 7xs; 1s; f dq)lmt/moh86.*aceeerent stages of meiosis. Which row correctly names each . za1et/)l ;f;oh6exmc 8 q it*7ssmadstage?

  The micrographs show four phases of meiosis I in a plant. In what order do7ipo(8l6hw 2s a- ecmz these p 7hac8s( 2plwzo6 e-mihases occur?

Mitochondria are responsible for supplying metabolic s3rktf2w*q w7s,1e92bqwy qv 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 w9*t e12yk2 vf w7rs bq,qs3wqof 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)x16nay +hxqm in different stages of the cell cycle in four samples of lung tissue from four patients. Whixyx6m1 +)aqnhch tissue has the lowest mitotic index?

  The diagram shows the dominant cycliwl6l4mb0tl *1 gsib wg g p1o8o(/x3pcn/CDK complexes at different time points in the cell cycle. Which cyclin/s3lpow1b6*pgb/ l g 1xomi(gl8t0c 4wCDK complex activates DNA replication machinery?

  Studies have shown that genes such as Cyclin Dependent Kinase 3 (CDKN3) are oghn;a: tj 52t-,j qfihighly overexpressed in cervical tumnfaioh qt,g5 :j ;j2-tours.


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 thi;h .9hupvr-y/ k.nbbvnd h, /e highest during the cell cycle ?