The graph below shows the relations*y5sg63bjt +eqyn6x mhip between maternal age and the incidence of non-y*jsgyb 5q mt63 en+6xdisjunction. What relationship is suggested by the data in the graph?

  Which stage of meiosis is represented in the diagram belm1q twth x/v 87wt3.sfow?

  The diagram below shows chromosomes during meiosis. tf *l5/m4mzroa 73xlm


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 which would b*v t3lyx3pej:rtzbp,q8om ; 0e present in the nucleus of a cell as a jo* qpvl: pm,8t0;txbye3z3rresult of each process?

  Which keyword is matched to thexp:r.z(t ld fc 84.ify correct definition?

  Which statement(s) about mitn ry8md5s- ty4*cv2 lnosis 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 oc3yb3i.)/vnm qllft;+wt m+, which letter points to a cell in anaphase?

  During which stage of mitosis does the nuc lh rww:1;ckzq18*duflear envelope break down?

  Which one of the following transport proteins only carries out active tra;zldf mvdj4du39:n gi+9,n d tnsport?m,9;glduv :in 43fn9zd +ddtj

  Which process does not happen in3ur pb(n1og *o:c/kit rz4e+ w the shoot apex?

  Which type/s of membrane transportdpaw3f .xjfw3rx),t2toe . 2 i do/does not require energy expenditure?
I. Facilitated diffusion
II. Active transport
III. Osmosis

  The diagram below represents a cell with aej mp 3 sz*t.- ktt7pan+bi5*a diploid number of 4. Which stage of cell division is the cell currentpkpj*t3z* i+.st ma7a 5e-bntly undergoing?

  The photomicrograph below shows a root tigcup9 d,w1ki1p meristem. Which of the following sentences correctlp,9ukcwi d1g1 y defines a meristem?

  When does the random orientation of homologous chromosome pairs occuw-+q 2 7x1gcujaoxie3 r?

  Which process does not occujuhpsedc5 px* :kf29fm1 h x3/r during meiosis?

  If a cell with a diploid number of 3fpa h0*(+;ukxz tqyc3 ,3qcyejl71dz/;fp oo6 undergoes mitosis, how many chromosomes will be prt7x+poc*,q zy3op1 ;eflhcku( y0/ zfqd;a3jesent in each daughter cell after cytokinesis?

  The image shows a micrograph of a ceupb w,* iq+wf*ll.


What explains the appearance of the cell in the micrograph?

  Which statement(s) about homo.aav:b2ue4s pg ykpwfb3+9e-n+ wa. llogous 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 ind ku)ra03ng 3x*bb o a)mptip7 s,p-4gxividual with Down syndrome.

Which statement is not correct?

  In the cells of a horse (E. cab xrb8wsw+w65s allus) during prophase I of meiosis I there are 64 chromosomes. What is the haploid number o8 +w6bsw5xr wsf chromosomes?

  Which arrow is pointing to a chiasma?l q.w;wz5x(k egk2/bi m;mke 9xuo +ib40 vin+

  The diagram below represents tfr: f4pt -nez6he structure of a shoot apical meristem. Which row in the table correctly identifies the processes occuring in the structures la6n:zpf-e4t fr beled in the diagram?

  How does meiosis promk.h o fs-q.r( o)fxhecio g.x.( u4r8bote variation?

  Which of the following statements is/are correct for meiosis? + o-hev qahj(8
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 chid;xsyv6 k89x 8y*y qaromosomes.


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 tumou9 jc (sy+n+lvrxmvn 9*rs as a result of thy(xv nr l9+9cn sv*m+je movement of cells?

  How many chiasmata are prere swm,f 9.6nusent in the diagram?

  Which statement is a similarityrgx,k 8m/h2r7wa n8ykysj,8v between cytokinesis in animal and plant cells?

  Which stage of meiosis is matched to the correct dex:fl4xw ,oz ,vwrz0h1b ot3t: scription?

  Which statement(s) are truee sir kz)-1myz ja6.n8 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 anllo:h1z 1opq,f4 gh m( oocyte after the first meiotic division. This results in the formation of one large cell and one small cell. ph4 :q11,fg lzo(hmlo What is the fate of the large cell?

  Which row correctly dv)8*46 s t)/h*ny ooo nwhxu*fwitd0yescribes diploid and haploid cells in humans?

  The following table shydplblr b; 8 /mb*4gs7ows the diploid chromosome number of a range of species.


Which of these statements is correct?

  What conclusion can be drawn from the karyograc 1 pyt k,fb-gmkza+3-m below?

  Which of the following processes is chaxavdm,y / y;1hracteristic of the meiotic and not the mitotic cell ;d/h m1vayx,y cycle?

  The diagram represents a bud with a shoa cr+ )rq3 ev92jpiuk;ge t+;wot 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 thesl,ajj 6 3j ak td,+zb7z)x*kp chimpanzee (Pan troglodytes) is 48. Which row shows the corz j)zab*ps,ldk,x37 jajkt+ 6rect chromosome number for different cell types and cell division stages?.

  At the end of which phase of meiosis I does crossing over occur, and what is the0/ tdfib1 asq 43o(fglzjtk * qr9fuj/- gv:c. outcvgo 9ft *qcrl:fzdf i/ g3(ku.s-0/ jat14bqjome of crossing over?

  Which of the following statements does not 5rb6(a/g mjmrpx m jh4(c-t ,hdescribe a step in the sodium-potassium pump cycle in the neurt 4ajb5jr(gr p -m/m,h(c6hxmonal cells?

  Which row in the table below is true of meiosis3-qypilr,m; c ?

Membrane transport is important for allowing pad o4g k6b:w/sn:agqe 2gl,cb+rticles to move across the cell membrane and respond to changes in the chemical composition of the e4gl bbkgqn 6d,o+ea :/2gwsc:xtracellular 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 celawet:,lg u:b7 0cai jv,ru5x:ls.

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 cyclind,ylsy07ea6b 6r5 y rgs during the cell cycle. Which cyclin is involved in preparing for DNA replicatio y0gr,y5sdb67 y6arel n?

The diagram below shows veg-;; :b wlayd/s-5s m1oxaj. pjxh9chromosomes 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 separ.e/ jr;e ld(f p50uaypsor+(ration of homologous chromosomes?

  The mitotic index of throat tissues taken fromwk4s u h*:v6atta7ud6 4 different patients is shown below. Which p* 6 udu4t hv67atsa:wkatient is most likely to have cancerous throat tissue?

1.Draw a labelled diagramk93 0 si3tftzx0(qh ot- (neeq to 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 humc).5-q zzvugiuzc *o 7an karyotype.


What is the abnormality in this karyotype and its cause?

The graph below shows the relatf4 lvlbp(;h 5u4k)fdtive amount of DNA in one cell during one complete cell cycle. Each letter represents o4l5fp klf;b(h4 utvd)ne 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 homoomgt7n7p7,b 13hqgh.im: -)chj rdcnzygous for brown, long hair and a female cat thatcnmgi)-7ro3dbcm n:hth. q ph77j1, g has black, short hair.


Which of the offspring has a recombinant genotype?

1.Outline how polygenic traits can showeb yr86xhhr-c798 dz a 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 b:l * 4baohe712hcnbh of non-sister chromatids shown in the d7bo4ha1e h *lb:2 hbcniagram below?

  The photomicrograph shows a pollen grai 6z sas o12ftdzs+5l:in from L. candidum (Lily). Which stage of me 2sfds516la: t izz+soiosis is shown?

1.Outline the events which would lead to an individual being borgofx:49 *3/ zoajf kck+j,oky n with Down syndfz ox*k4 ,aoyj/j3okgkc 9: f+rome, which 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 way of measuring plant growth. A study was con*.a6k1ka4 4tvjxf2ec thb- qxducted on white onions (Allium cep6ka f2a.htqvbc kj x4t*1x e4-a), 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 diagramyv5 eoyac+yg76qfz d;q9q+8kl,u 5 hrs below show two cells from an orgy,q85dfy57 ++gyr ;a hvlo 6zuke9qcqanism 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 genebpc8.tx.(l a u s*1c89ujjqbk 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 a diploid number of 8, ilzo9;haa5 g v(+ivjop189i oiw y5t: in different stages of meiosis. z:yo9ii+( pw5i;1voa59il8gvajhot Which row correctly names each stage?

  The micrographs show four phases of meiosis I in a plant. In what t/wt v,of +7cxddkcx)7xb. x7z5.f w jorder do these phases oc+,7c f7fw )t.kbd/x7x jx xzvw5o.dtccur?

Mitochondria are responsible for supplyingk0q:wr 0oz(ssbi:m)f g ((mgx 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 in(s(mmx) kq frgigs w(o0z 0b::herited 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 number of cells in different stages of thee)i r (0h)ltr(lcf(le ccl8g 5 cell cycle in four samples of lung tissue from four patients. Which tisse(el8rhr li) ( clt5gl() c0cfue has the lowest mitotic index?

  The diagram shows the dominant cyclin/CDK complexes at difokw pg 1g,jhk4m4fd63 ferent time points in the cell cycle. Which cyclin/CDK cojhwk44 kd1 g gofp,6m3mplex activates DNA replication machinery?

  Studies have shown tha st x)z(ywta3zh5p q,0 ukr0*bt genes such as Cyclin Dependent Kinase 3 (CDKN3) are highly overexpressed in cervical tumours. a,5 b*zwx(k03yttr s0zqphu)


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 concentratio * 8jj.f hkwojimy86-fn of cyclin E the highest during the cell cycle ?