The graph below shows the relationship between materyih9aa;r( wq an/* +.du lolp 4ahwd4.nal age and the incidence of non-disjunction. What relationship is suggested/iydanhr;.4 owu ( l.9+d h*awa4pl aq by the data in the graph?

  Which stage of meiosis is re2wmidmy v6ce1u5f z -4presented in the diagram below?

  The diagram below shows chromosomes during meiosir8r7 f* i kw*8,dd twquxxlb+;s.


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 the3e.y.sqn 0hxr number of alleles of a single gene which would be present in the nucleus of a cell as ar3 ns0hxy.e .q result of each process?

  Which keyword is matched to the corauy w(wo76jiz;w /t wjj n6sx5s-ld0:rect definition?

  Which statement(s) about mitosis isqs 8qdj :x vr6(96mwsq/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 pointkap** gt3h* jy*hm0 m4drxl:ls to a cell in anaphase?

  During which stage of mitosis does the g+tr0x9f ry4ypjw7i, nuclear envelope break down?

  Which one of the following transport proteins only carries out active transpornqh9ym 3du 9z (i56gsyt?dug9 yz q3nhim6s (95y

  Which process does not halt0y r) hbu3..kbqk0x 49qygyppen in the shoot apex?

  Which type/s of membrane transport do/does not reql iyfn5pb6 :6+o.,(yuihqjn puire energy expenditure?
I. Facilitated diffusion
II. Active transport
III. Osmosis

  The diagram below represents a cell with a diploid number of n8(+ ,qu s:,jvfi-8y7/jhi foio y4vhxfmhg04. Which stage of cell division is the cell chh: 4vm7y8 iijvg+0noouij/,-f8yh , x(sffqurrently undergoing?

  The photomicrograph below shows a root tip me7(1d e-xi bjkfg+wjq )ristem. Which of the following sentences correctly defines a (7b ej+1jfd g)wq -xkimeristem?

  When does the random orientation of homologous chromosome pairs w0v87djd 0 cqioccur?

  Which process does not ocdb,04d5 cahq 3w/n okjcur during meiosis?

  If a cell with a diploid numbrw-.jufz7xgtf py8 -4ixby ..z j2fd(er of 36 undergoes mitosis, how many chromosomes will be present in each daurfy df7g(8t2j.wz- yz-xpufji b. x .4ghter cell after cytokinesis?

  The image shows a micrograph ofa u g.n1go+r 4s8iau-k a cell.


What explains the appearance of the cell in the micrograph?

  Which statement(s) a)q pn5wrrhn+25tiim+j3/ qu gbout 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 sym 9 jjmis-/o/yndrome.

Which statement is not correct?

  In the cells of a horse (//nmrjmd97; b 8dupdhE. caballus) during prophase I of meiosis I there are 64 ch dd7 hdm/jm9u;p8/nbrromosomes. What is the haploid number of chromosomes?

  Which arrow is pointing al8(revz y00pb8yn;h4 b hka) to a chiasma?

  The diagram below represexxb f 4kb/cbw;o;5qd np, /zpi/qd:j *nts the structure of a shoot apical meristem. Which row in the table correctly identifies the pr*wxddqb; /p /x pf:,ob/i4bj;z5qkn cocesses occuring in the structures labeled in the diagram?

  How does meiosis promote variatiod935fs)d h rpnn?

  Which of the following statements is/are correc +qylti,l/6th;m* ngyt 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 hoiycz. q)+9li)t8 1dl bl1no .llg9mgjmologous 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 pn 4:zdqwdzq x8w;2 no70jlppo.7:dmlrimary tumours as a result of the movement of cpl8:jznlq 7:0 dpo2dnwdq zo; xm.4w7ells?

  How many chiasmata are presentm7o0 d)jgod hyf+,q x4 in the diagram?

  Which statement is a similarity between cytokinesis in animal and plant cel vrtbig83)ox1h cnfn6bz6 t72ls?

  Which stage of meiosis*1oqm)b s*hx15xi;r9rp thf h is matched to the correct description?

  Which statement(s) are true ofc )zjsdp(a*/ lb.tl 0r 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 prq h 7;jd2r jo.tddr, 4a( szkb:3u:loocyte after the first meiotic division. This results in the formation of one large cell and one small cell. What is the fate of the large cell? d ,rhkqp z4: r3dj jt7l(o;br.:2suad

  Which row correctly describe,ks w 1-ccwy:,vl4vtus diploid and haploid cells in humans?

  The following table shows the diploid c k(jmqf* jb lm+6:ivbbcc5- c7hromosome number of a range of species.


Which of these statements is correct?

  What conclusion can be drawn px 7gjy,oe ,)os5 xs(k*98cfh xobp,yfrom the karyogram below?

  Which of the following processes is characteristic of th3p;h3z,qr (b fzg;sw ze meiotic and not the mitotic cell cycle?3;whzqbr; (3 z,pzg fs

  The diagram represents a bud with a shoot apical meristem. uark3 y4og s, px9ws4.

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 trd( o7v.q cdqz10j 6e4plxr(proglodytes) is 48. Which row shows the correct chromosome number for differocj ( 60z1rdqpl(ed.xr qv 74pent cell types and cell division stages?.

  At the end of which phase of meiosis I does crossing over occu,hx: n0 sez9ao0iaga9r, and what is the outcome of crossing az9n a: 0goexs,09 aihover?

  Which of the following statements does not describe a step in the sodiud i : -7i8wxlyy;3ktsdm-potassium pump cycle in the neuronal dtyi-x 3;8 lsik7dy: wcells?

  Which row in the table below is true -)0r t8*y(atfdxbd*,+q asi*pqla j5ybk -jhof meiosis?

Membrane transport i7qr0s2++m 7 gzqq5s9ogdf ibtgc )6xg s important for allowing particles to move across the cell membrane and respond to changes in the chemical compodc7mg9 fqr2qib+o qz 6s+5 7 ggs0xt)gsition 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 cellyumw2p -4q bb4+vzw k(s.

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 cyclinsz odg okf6w68) during the cell cycle. Which cyclin is involved in preparing for DNA kd o)fw86 zog6replication?

The diagram below shows chrq zs) nxe,c1c:omosomes 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 t ayu 0zd*ub; -ez x7bj4i:gx,khe separation of homologous chromosomes?

  The mitotic index of throat tissues taken from 4 different patients is shown b+yp +d5e- snhbelow. Which patient is most likely to have canc y be+dp-n+5sherous throat tissue?

1.Draw a labelled diagram to represent the proces0po0i4c97:qxfcag,zx9jf 9v7rtxp 8rjb *lrs of crossing over.

2.Compare and contrast random orientation and crossing over.

3.Outline the stages of meiosis.

  The image shows an abnormal human karyotypej bv0.,ldbjr bl8nu/; .


What is the abnormality in this karyotype and its cause?

The graph below shows the bhy+g7sw8p9 (s:c7w xg+espzrelative amount of DNA in one cell during one complete cell cycle. Each letter representss8sz7:7 wg +e(9gshcybp+wxp 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 homozygous fk jhz5 /p06 4l j;k zfuz3a*fmosy+gc*or brown, lonk* o*/ujpzsym45ag3f;k+ j0zl zhf c 6g hair and a female cat that has black, short hair.


Which of the offspring has a recombinant genotype?

1.Outline how polygenic tr y)j*:by,8 cj ;gqbrnq1 x/x+jknbi.raits 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 chromagdgx); w/ab x3tids shown in the diagram be/wxg3;bdgx) alow?

  The photomicrograph shows a polc4s fge.lx d5nq.m2*blen grain from L. candidum (Lily). Which stage of mei2qns 4.d5 bxgle.m *fcosis is shown?

1.Outline the events wbp+;z;5wz+ o 0npfia lhich would lead to an individual being born with Down syndrome, which is characterised by the presence of three copies of chromosom ap++b;o ziflw5z; n0pe 21.

2.Explain how meiosis increases variation.

3.Outline the stages of meiosis.

The mitotic index is an indi;7fwl(ky08;uy su xoerect way of measuring plant growth. A study was condue;;y wufu 7ok8xy0s(l cted 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 are two ways in which cells can divide. The diagrams be f -mnru68(hjqlow show two cells from an organism with a diploid number (2n) of 8. mhq(j -6uf n8r


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 expge te 2a7 oa3l vv2uqk6y:pq: 2m91gzdression 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 numbkmu(y2 jx5tn .+5bmgqp*3t6 u udew-ser of 8, in different stages of meiosis. Which row correctly names mq.btmpsu2*5k-6ynx5 e tugwu( 3 j+deach stage?

  The micrographs show four phases of meiosis I in a plant. In e.. gua im2/pbl8q5 zsn xal24what order do these phases o5e4x2.m.bila2z nl /p8sgua qccur?

Mitochondria are responsible fhqe+h6t iq 4x7or supplying metabolic 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 betwee 4q+hi 6xhtqe7n 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 different stages of the cell cycle in5 n3ehpoqc+ t+dj0 7frio4)wk.6gr oahq:u/j four samples of lung tissue from four patients. Which tissue has the lowest mitotic /kw. gq) 7u oq5r:3j0 4ho hojn6ic pe+df+traindex?

  The diagram shows the dominant cyclin/CDK complexes at din6a g3voaes./fferent time points in the cell cycle.e.a vgn3s/a 6o Which cyclin/CDK complex activates DNA replication machinery?

  Studies have shown that genes such as Cyclin Dependent Kinase 3;hrvwgg9q oc-1 k)js:ym 1y4x (CDKN3) are highly overexph:j1g ;)m4g w -cy1 sr9qxoykvressed 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 cyclin8u 8n*b2aspr l E the highest during the cell cycle ?