The graph below shows the relationship betweeegr n5 9qs;k).c*tkr 0xxiki +n maternal age and the incidence of non-disjunction. What relationship is suggested by the data in thekn5x rik9 q cits;.0k +e*)rgx graph?

  Which stage of meiosis is represented 4(0vt)w l, a cv bzt:3kntua(qin the diagram below?

  The diagram below shows chromosome r2a( ft*uxwe0 l6e2xes 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 twbzk sr k11.*uhe number of alleles of a single gene which would be present in k*1krwbz .su1the nucleus of a cell as a result of each process?

  Which keyword is matched to the correct17ff4m1wn b plk1sx6t definition?

  Which statement(s) about mitosis is/ mbslo*ufd*j)t nj- l;34ils +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, whih 028tx v4v2vdebcr-p0m mdt5i qyy,;ch letter points to a cell in anaphase?

  During which stage of mitosis does the nuclear envelope break. ylcd61m/jij e.33 xnpuapj+ x8u 4xn down?

  Which one of the following trajkyf7ut9tk a p kki g6,;8;b:ynsport proteins only carries out active transport?uaiy;ktj: kbkt78k; 6,9gf yp

  Which process does not happen in the shoot ap 3nm+,lta +rggex?

  Which type/s of memb /4uigln,pw f+rane transport 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. Wo:i ah2 3i(sjmhich stage of cell division is the cell j aihmsi (2:o3currently undergoing?

  The photomicrograph below sho658jaml cuu hrh*yzg,rxxrb ,/u k-4) ws a root tip meristem. Which of the following sentences correctlkr a -jy4,ub6g /luhu xm*5zhr8c, x)ry defines a meristem?

  When does the random orientation of homs:pqub/ h 2rrai v:0l-ologous chromosome pairs occur?

  Which process does not occur during me/r 0yh:jkcn+1 i2kaf0tb 7oe liosis?

  If a cell with a diploid number of 36 undergoes mitosis, how zezp.7eo.be2q : k5fx many chromosomes will be pkep7qe zo.f x:e2.b5z resent in each daughter cell after cytokinesis?

  The image shows a mic1ysz3 z;du:n ts )3pzhrograph of a cell.


What explains the appearance of the cell in the micrograph?

  Which statement(s) about homologous chromosomes is/arqie 0w pv1 nk2:hd ,d2k1sw.oj4ehu+ne 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 wwb s7::5cmy tvith Down syndrome.

Which statement is not correct?

  In the cells of a horse (E. cajn(* b8hqbcx;qo8dx1of8ij madr3s -/ f7bp 3ballus) during prophase I of meiosis I there are 64 chromosomes. What is the- 3( /f 8b o spocd;nf*8h13qqiadxrbm bj87jx haploid number of chromosomes?

  Which arrow is pointing to a ch 8 uza)e4*t+tds9uyb kiasma?

  The diagram below represents the structure of a shoot apical merishy *e/gh6uac7pkfy(.ro(6/m 7qz ey mtem. Which row in the table correctly identifies the processes occuring in the structures labeledz /rpy/m(y7ye uf.6hge(hcoq a76*km in the diagram?

  How does meiosis promote variationd7cuufy8rygr,n /:;f4l yei6(wi;tia * 9ryt ?

  Which of the following statem:;7,dpjn*p b gcgij+a ents 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 homologous6a ;xc r,p.1 eoplox8g 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 thqtbf-6 5 vx;ahe formation of secondary tumours from primary tumours as a result of the movement of cel v -x;tfba6qh5ls?

  How many chiasmata are present in the diagram1r( ln ;:dr.mid 7+ozrviu(cr ?

  Which statement is a similaw 5o,w6nyeuc.gktp0/dg t5(srity between cytokinesis in animal and plant cells?

  Which stage of meiosis is matched to the correct descp +p4+7, jcd *juppyipription?

  Which statement(s) are true of meiosisekq+ *7lk j4xlsta5ijt3b; +r 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 ann(q3f9)qier hbc 6tirr 2 /i9t oocyte after the first meiotic division. This results in the formation of one large cell and one small cell. What3th(bn i/f t 92r)qr iie69rcq is the fate of the large cell?

  Which row correctly describes diploid and haploid cells in hum9d-ea5 z +r w2f8tvigxans?

  The following table shows the diploid chr)jff o.nn t,9 lt*m,rkomosome number of a range of species.


Which of these statements is correct?

  What conclusion can be drawn from the karyogram puzza-;; 0r dmbelow?

  Which of the following processes isx.o 9 qu;jseaw*x)wecdm1z1srkt65, characteristic of the meiotic and not the mitotic cell cycle?wsj6,e ;)5 xseq9k czorwd11mx*at u.

  The diagram represents a bud with a shoot apical meristem xi3gb58w k 7dj*eaipylib26 e0.fir 4.

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 + qyb0v4 ,zobq48. Which row shows the correct chromosome number for different cell tzbv yobq+4q0 ,ypes and cell division stages?.

  At the end of which p y, ef;e(up3jc+s) orz+x7it whase of meiosis I does crossing over occur, and what is the outcome of crocow rtp7++ysju)x;iz3fee( , ssing over?

  Which of the following statements does not describe a*udq bg/s0-is,sw mj/ step in the sodium-potassium pump cycle in the neudsqsi0/sg- /b *wjmu,ronal cells?

  Which row in the tables 3l1 2wc2vln8y6jjk7q- m aui below is true of meiosis?

Membrane transport is important for allowing particles to move acros*c* yztp9 *zebs the cell membrane and respond t zzebt* **9pcyo changes in the chemical composition 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 cells.1j;bg. bhdhh4i+fg47dbkm2,9khg da s y 9j.w

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 diffb* f+mvuxc2 e/erent cyclins during the cell cycle. Which cyclin is involved in p+c 2xvb *ufe/mreparing for DNA replication?

The diagram below shows chromosopm7+4 g 7kmeiml7c + hgfqhx3z+46fismes 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 meiosz q)jqbb.48sm is involves the separation of homologous chromosomes?

  The mitotic index of throat tiwbf 7)q d6b:tttc4le;ssues taken from 4 different patients is shown belqbwc4el7f:dt ; )6 bttow. Which patient is most likely to have cancerous throat tissue?

1.Draw a labelled diagram to*zfe t/y;:x2*so gqq w 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 abn8ye g0zg7 x gvpj2z;-formal human karyotype.


What is the abnormality in this karyotype and its cause?

The graph below shows the relative amount of DNA in one cell during cqz5vld* pzst-x8va ul2 )n)7one complete cell cycle. Each letter represents one stage of the cell2*5dqz7 - 8pv)ls tlu cvza)nx 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 croo3j(2p/g (r7h gi/gias4c(oahqhvu- fq q o2(ss between a male cat that is homozygous for brown, long hair and a female cat that has 4p hicq2(2go fogah (j 3gq(sh/auqro(v7/ i-black, short hair.


Which of the offspring has a recombinant genotype?

1.Outline how polygenic traiulti/l:+7 lokts 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 nouj r s1*wrw/:cn-sister chromatids shown in the wws:rcr1*ju/ diagram below?

  The photomicrograph shows a pollen grain from L. candidum (Lily). Which stage e,hijle6qv/-b vn: k o9/3dzt of vv/h:toqk l/ bj3z9-ni e ,ed6meiosis is shown?

1.Outline the events which would lead to an individual being boronul/uh6j2l/8-u0 7 o sonb-tfk 4emen with Down syndrome, which is m6tufohl- j2kn 7-40bl /8en/ uuoeoscharacterised 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 mepyzs36/0 2ta swwowx51hn+v+bq l 2lnasuring plant growth. A study was conducted on white onions (Allium cepa), under controlled conditions in a lab, to investigate the effect of soil pH on the mi2sqnot wy3 + pl+0w 5bh z/w2l1vna6sxtotic 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 diagr vssm-tnas. 2u6.nv-b ams below show two cells from an organism with a diploid numnamsb.unvt .6 --s vs2ber (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 ;.khx7/c4s9 iv btmqfgrowth.

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 uarkx/2 )qne.be7*je g(d8bq stages of meiosis. Which row correctly nameu2ken br/j *b) qag7.e8 dxq(es each stage?

  The micrographs show four phases ccs g+ p.w9mo(aa2qa( of meiosis I in a plant. In what order do these phases occurs(p cog( 2qa9mw+ .aca?

Mitochondria are responsible for supplying metabol8) wqskhquzpq3u. d(3ic energy in eukaryotic cells. In most eukaryotes, which reproduce by sexual reproduction, mitochondrial DNA (mthz3p).8(3uduqsq wk qDNA) 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 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 diff5b5kd(e3 8rsrktg e3l ;gs; zserent stages of the cell cycle in four samples of lung tissue from four p k3zlregr d(gsbk5 se83ts5;; atients. Which tissue has the lowest mitotic index?

  The diagram shows thbvc hjrt89,ol v7*,jrpj72 ev e dominant cyclin/CDK complexes at different time points in the cell cycle. Which cyclin/CDK complex activates De,l8 bvo vv72r7j9jpt,c*j hrNA replication machinery?

  Studies have shown that genes such as Cyclin Di83gx t m ei63jw+ nn.c5jtzk(ependent Kinase 3 (CDKN3) are highly overexpressed in k(cw5.n jjetg+8tz3xi6 i 3mncervical 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 concentratio tjeug vs+e8 o;xnd9*,n of cyclin E the highest during the cell cycle ?