The graph below shows zz3 k9 i/ls*h5)2mgk q .v8fua nzff4cthe relationship between maternal age and the incidence of non-disjunction. What relation8ufg nkz9i5sc2z) 4 z.hqfl3k vmaf/*ship is suggested by the data in the graph?

  Which stage of meiosis is revi4q) md(hgcrcz.f 5)presented in the diagram below?

  The diagram below shows chro t 8at ajs.ow3ubt.o6wt b:,r-mosomes 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 of a single gene whicl t:m7a;wu4n ph would be present in the nuclt ;alp4:uw m7neus of a cell as a result of each process?

  Which keyword is matched to the correct mtix,nb:7b3e h2v*c zdefinition?

  Which statement(s) ancr ;nl6q h*22-sanjkbout mitosis 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 vmcwo9)xmu*4;ic r gonrr -6ct:t/i0 to a cell in anaphase?

  During which stage of mitosis does the nuclear envelope b*gv05im s2 llvreak down?

  Which one of the following traqdxa if;)a 0+i-wq- scnsport proteins only carries out active transport?w; qxada+-0i)qic -sf

  Which process does not happen in the shootv57as(u9msnjo 7x 2 md apex?

  Which type/s of membrane transpg/lan */x y03citbetp;s7: a oort do/does not require energy expenditure?
I. Facilitated diffusion
II. Active transport
III. Osmosis

  The diagram below represents a cell with a diploid number of 4. Which stag8v; :,y-2hl7 l:rv impvenxpoe of cell division is the cell currently uoy2-xr: i8l;nv:lp,7vve mhp ndergoing?

  The photomicrograph below shows a rooda s3 fa39y1yrt tip meristem. Which of the following sentences correctl3fad1ysyr 3 a9y defines a meristem?

  When does the random orientation of homolmyzv9/ ir1afh 13ic5e ogous chromosome pairs occur?

  Which process does not occur during meiosive is:x4op 5o-kwl:*c s?

  If a cell with a diploid number of 36 undergoes mitosis, how many chromosomes win1q v sz.oebkks/ qj,q2eo 4()ll be present in each qk4zvqo,e./1) jes (s oqbn2k daughter cell after cytokinesis?

  The image shows a micrograph of a cell. gmyquy u hd,juc 12a-/,w.6n b


What explains the appearance of the cell in the micrograph?

  Which statement(s) about homologous chromosomes is/are not tz*g0bd- s ibxq* qu5/ f95lhmyrue?
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 sk)h0bk.*kmyvkq lm/e a*s g5s 0)s8wkyndrome.

Which statement is not correct?

  In the cells of a horse (E. caballus) during prophase I of meiosis I there are kh i09m p)iz,a 2swu7p64 chromosomes. What is the hka m2 shppi7z)u w0i,9aploid number of chromosomes?

  Which arrow is pointing to a ru(7 g.i. 5b:id rcvvrvndcc04/fd3 x chiasma?

  The diagram below represents the structure of a shoot apical mer h4 tog5)bcm/vistem. Which row in the table correctly identifies the processes occuring h) b5c tm/4ovgin the structures labeled in the diagram?

  How does meiosis promote variatin 2c65aer1c-/lt (s g qv ug3vgb/s;qlon?

  Which of the following statements is/are correct for meiosis9p9 fd tp b )77xh6pat2o8tnvk?
I. It is a reduction division
II. It involves random orientation
III. It produces genetically identical cells

  The diagram shows gametes produced from two .9xd4c ybu)7u d, rjt -d) jnjrx8nu6fhomologous 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 secondarywz 3jxvuqdu2(xv0 slc d257 q8 tumours from primary tumours as a result of the movjx l5d720w qcz8dusq v32 xu(vement of cells?

  How many chiasmata are present in6pqlj, w/6 5 jd+wtvqf5lu5ei the diagram?

  Which statement is a similarity between cytokinesis in animal and8,arcsq vgjle8i*h3 / plant cells?

  Which stage of meiosis is matched to the cosg*95 :a8jaca rnbu7a rrect description?

  Which statement(s) are true of ; ii vwnejzyd-s, :u21xhvw9/ 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 thf)em n ,l5xi9le first meiotic division. This results in the formation of one large cell and one small cell. W5n l,e )xiflm9hat is the fate of the large cell?

  Which row correctly des6 6qvlptcl )gihmo u va6;gcy-p;0*u3 cribes diploid and haploid cells in humans?

  The following table shows the diploid chromosome nuf msfka8ji;c:4.sq oa 0 q0vc+mber of a range of species.


Which of these statements is correct?

  What conclusion can be drawn fromhktb s:*x (p6 c9njan+ the karyogram below?

  Which of the following processes is characteristic ofhqy-e;liaq4qd84 ifx e.y2 g 3 the meiotic and not the mif;2hyxee lga8 i44 q.y i3qqd-totic cell cycle?

  The diagram represents a n/dow*2 ,v;8l 2rdo+km ke ant 2y+ubxbud 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 chimpanzee (Pan troglodytes) is 48.s c cd/4:rkbl uzp*m;( Which row shows the correct chromosome number for dif m r4u:c*p dl/zc;bks(ferent cell types and cell division stages?.

  At the end of which phase91y7t,nses7x b(b- 4zw cqags of meiosis I does crossing over occur, and what is the outcome of crossintsa 7z,c9 7yx4 1bwseqnsgb-(g over?

  Which of the following statements does not describe a step in the sodium-potasx( m 6* kgiskfq/t7:0cf5v uf+gxmq2ysium pump cyclvq6muk gf7fg0ci+k ftx:(m2s 5/qy *xe in the neuronal cells?

  Which row in the table bog,ljq70 bi)g elow is true of meiosis?

Membrane transport is important for allowing part ,izstt2;idvjq ynuzuu n5ug )5/))0picles to move across the cell membrane and respond to changes in the chemical composition of thqj)2u)dz t5yii 5u/,zngut);np u v s0e 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 ce*k hn7a-ub fb-lls.

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 cyclh-p vop ,oddm7ar/m2: ins during the cell cycle. Which cyclin is involved in preparing formm2pr- op:,v7od dh/a DNA replication?

The diagram below shows chromoso (jsb+ arpp7( xrp8k4kmes 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 sepa, q jv +v,dei,ueg77blration of homologous chromosomes?

  The mitotic index of throat tissues taken from 4 different patients ,yomjmpv7- 3v is shown below. Which patient is mostvvpj3-y7m o, m likely to have cancerous throat tissue?

1.Draw a labelled diagram to represent the process of crossi8g p 03rj/bz rsyin(hx8.fn7eng over.

2.Compare and contrast random orientation and crossing over.

3.Outline the stages of meiosis.

  The image shows an abnormal humail(oe; b 9xbe.n karyotype.


What is the abnormality in this karyotype and its cause?

The graph below shows the relative amount of DNA in one cell during one complet*fp s xa(uf1e3*mx4na zkv(1b jxs)r9 e cell cyclejra1s( e*9*(xb) skffx 3zaxu v4p1mn . Each letter represents 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 showspgv4:e3kg af rq72 w+p a cross between a male cat that is homozygous for brown, longew pgkpg7:a +32fv4q r hair and a female cat that has black, short hair.


Which of the offspring has a recombinant genotype?

1.Outline how polygenic tra1 5wn0p:q 2)rrpmhb puits 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 overg9ed (z; 0qdjkz98)t mgnbbk/jr yg;. of non-sister chromatids shown in the diagram be.gr 9mqb;;zd9/8ejgzkk)(bn dygtj 0low?

  The photomicrograph shows a pollen grain from L. candidum (Lily).-x0q (6hs zvb jmeo2 r/)gl-lt Which stage of meiosis is shown?s0jh- r/ gq bztllo26v)(-xem

1.Outline the events which w,kv,z:qq5f- it ;yxnj8: wqxes,gw(would lead to an individual being born with Down syndrome, which is characterised by the pre gz,qqv-y x ,8n:,skji(5w;tqw: wf xesence 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 condl6scqp c)p m9ami88o3 ucted on white onions (Allium cepa), under controlled conditions in a lab, to investigate the effect of soil pH on a 68cm)9o3pipl 8smqc 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 d*us1g 5j5 b8ytwf +cwziagrams below show two cfy5*wwb+uj1g5 s 8ztc ells 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 g k+eha- tvn-, k:dkmv.ene expression 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 + (if,vlcu fs.9fvha y1uea ;;a diploid number of 8, in different stages of meiosis. (v +faf9u sech1l ,u;ai;yv.f Which row correctly names each stage?

  The micrographs show four phases of meiosis I in a plant. In what order do thescbm6g4t tr64j a ,k7vge phases occur?t c6vjmr ggt6 7bk4a4,

Mitochondria are responsible fomt u 0.kgy,jq1mqd7, zr 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 nuck d7y0q1 m.,u,q mzgjtlear 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 nu-4 -blb3e q-wnrpuhp)mber of cells in different stages of the cell cycle in four samples uq pb)ler-wh -bp n-34of lung tissue from four patients. Which tissue has the lowest mitotic index?

  The diagram shows the dominant cyclin/CDK complexes at different tn4nh6,ez9ix bje bc7 .ime points in the cell cycle.,x z4ehjn7 e.n6 bcbi9 Which cyclin/CDK complex activates DNA replication machinery?

  Studies have shown that genes such as Cyclin De xblo8ex6y7 p,c3-yjs8yqt d5pendent Kinase 3 (CDKN3) are highly overexpressed in cervical tumou 7jx6peycs88oyb tx3qy-l , d5rs.


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 concentra 6xw9te)wsb8bhe 5h q;tion of cyclin E the highest during the cell cycle ?