The graph below shows the relationship between maternal age ) j;ltznj4 k,vand the incidence of non-disjunction. What relationship is suggeste tzkj )4,vj;lnd by the data in the graph?

  Which stage of meiosis is represented i9qnu)hk+w f l-h fn9,mn the diagram below?

  The diagram below shows chrojfpi)6p6/q 2tab0 pgi 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 thexkc9(. . mr7 *bmehdkj number of alleles of a single gene which would be p.crmkd x jh7e(*b9km.resent in the nucleus of a cell as a result of each process?

  Which keyword is matc dr+(vv8s ky,f omed9fx4v9 .,kf znn1hed to the correct definition?

  Which statement(s) about mitosis i 2k8r;hmtbx/3yz z.rbs/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 cu wmocy7i/k )*ynu65xell in anaphase?

  During which stage of mitosis does the nuclear envelope breakn w1bxt-whg7 t3 zk(e/vrw0m2 down?

  Which one of the following transport proteii jt io+p,dqiq5*ok *4ns only carries out active transport? d5qpqji,k*i4ooi*t+

  Which process does not happen in thez+8gdfa q2v+h 9 g,mhl shoot apex?

  Which type/s of membrane transport do/does not require energ pfealtk,hk5 e9t ggnr9 -*w;;y expenditure?
I. Facilitated diffusion
II. Active transport
III. Osmosis

  The diagram below represents a cell with a diploid number of 4. Which stage offv g4wg: e; i(5 *0 fvtdce9mq,*euwjii 1,cxf cell division is the cellvw01 ijdi(i9x;ut* ge5 c4f,fgeecv:* ,mw qf currently undergoing?

  The photomicrograph below shows a root tip meristem. W2nozokt4f00 smc2db7hich of the following sentences correctly definesc mto 0b2n4f70zs2 odk a meristem?

  When does the random orientaua(g(vh gr /k5tion of homologous chromosome pairs occur?

  Which process does no8wmn9-0biktn lpyye.779b34segh8d n kh.l rt occur during meiosis?

  If a cell with a diploid number of 36 undei v)o3.gm wqmpqm8 zo q9/-l6qrgoes mitosis, how many chromosomes will be presq9 m-qw /ipmomzlo8qg q6.) v3ent in each daughter cell after cytokinesis?

  The image shows a micrograph of a c; daf -zrhy2ng3t v5k0ell.


What explains the appearance of the cell in the micrograph?

  Which statement(s) about homologous chromosohj b7uav* 3ki9mes 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 wiknb*h8 +kza u0th Down syndrome.

Which statement is not correct?

  In the cells of a horse (E. caballus) during prop.qu- :;nft/e kiw87spxmw 1kbm1xd;d hase I of meiosis I there are 64 chromosomes. What is th kw/xfe-1q;unt18 m ;7i d:x.wdpksbm e haploid number of chromosomes?

  Which arrow is pointing to a ch+ 02p y(slmocxiasma?

  The diagram below re;fc b )rbv.aaxt 5b7q:presents the structure of a shoot apical meristem. Which row in the table correctly identifies tht bx7ab.b:a qv) ;fc5re processes occuring in the structures labeled in the diagram?

  How does meiosis promote variationm1sx 81 hzduj+?

  Which of the following statements is/are correct for lr,hhae8/ ;n;fy djj: meiosis?
I. It is a reduction division
II. It involves random orientation
III. It produces genetically identical cells

  The diagram shows gametes produced(dylr66(wy 1g g ufkcyt7v/a( from two homologous 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 ofqzy u72deft4b0p t,:c secondary tumours from primary tumours as a result of the movement ou2yqe b0tz4tc d,:7p ff cells?

  How many chiasmata aoq/3t.id) k4u*vfxz0g f+nqf re present in the diagram?

  Which statement is a similarity between cytokinesis in animal and plant cells x3vsx8roxfu 045wc0p?

  Which stage of meiosiswwtt+wu 5*lb f5-,i hr is matched to the correct description?

  Which statement(s) are true of qtwj6ik(e.d +2 zn0 aip/cwp,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 y3 tybg 2+-y,ah lxhhr,xo:0j g8iqk7an oocyte after the first meiotic division. This results in the formation of one largeo:a7qjbki g+,, -yht gh0y2xl3 8xhry cell and one small cell. What is the fate of the large cell?

  Which row correctly describes diploid anb 2; q:t*;9tn xzahtksd haploid cells in humans?

  The following table shows the diploid chromosome number of+wmut 4uak4u zd)qo f8m 3j6:h a range of species.


Which of these statements is correct?

  What conclusion can be drawn from tvvf+nu(s uj9 s: +km-che karyogram below?

  Which of the following processes is characteristic of the meiotic and not r*1t0 y: w.cagw kt,i)xc3sxjthe mitotiw:wck)x,cs x*tj01 i.r3ytg ac cell cycle?

  The diagram represents a bud w7uixfyusx 3+;n 6o nx8ith 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. Whianbp:b34 w ,r ydsnrz3;*:wz gch row shows the correct chromosome number for different cell types and c pa; :nr*bnwz,3ys r 4:wdz3bgell division stages?.

  At the end of which phase of meiose e:*dzqto.4 (i7z z*h j8kyldis I does crossing over occur, and what is the outcoedjz*l4hkdq*zo t 7(yi: .ez8 me of crossing over?

  Which of the following statements does not describe aoej drg95/yy 0 step in the sodium-potassium pump cycle in the neuronal cells?jd/ye9or y05g

  Which row in the table ; fecx66oh0acjq(a / ebelow is true of meiosis?

Membrane transport is important for allowing particles to move across ocq 4f 3ge)/qethe cell membrane and respond to 4qg3o ec)q/fechanges 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 regulate0cfhj ul 1*yz4d 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 during themcn ni*er 6z/ :7 h 8ed;uouzzq./kvd6 cell cycle. Which cyclin is involved in preparing ezc vki7 /8/zrou*66qm;d.:ehndzu n for DNA replication?

The diagram below shows chromoso(3z (z8,zkojtxr roc: mes 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 invol ossfbb e+5,g7b1tfehq-./ wkves the separation of homologous chromosomes?

  The mitotic index of throat tissues zl-kf (m nwcye3t.ku( y17r4s taken from 4 different patients is shown below. Wh yw.7ukfem3 4 kcrstz(nl-(1yich patient is most likely to have cancerous throat tissue?

1.Draw a labelled diagram to represent the process of crossis 1 d0)s.tx8ozd7jr utng over.

2.Compare and contrast random orientation and crossing over.

3.Outline the stages of meiosis.

  The image shows an abnormal h zk(c8s3i9ebc (ikg*ywzd -f,uman 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 com ) )2 1*kyrpj27iszu yqfulvhyaxp/07il9,s yplete cell cycle. Each letlra, ziy71fuy syxks9 2v *j)u72qph p0lyi/)ter 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 shows a cross between a male cat that is ho wz3p,*rnm/6ejhlhf+ rm/cyv i 4 3vv7mozygous for brown, long hair and a female cat that has b 3*niwmv r/7m+zv , rj/pchhf34lv 6eylack, short hair.


Which of the offspring has a recombinant genotype?

1.Outline how polygenic traits can show a nxct0ndjeu8t/ 53cvjp 13 f/ sjormal 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 chromatidv5 rvgi*5(0ol a8jd wzs shown in the diagram b ivaz5*jd(wov085 lg relow?

  The photomicrograph shows a pollen grain from L. candm-jn*t xbi s4;rvc1 s5c2y+b xidum (Lily). Which stage of meiosis cxcmi+ 4r5 jsb1tv*s2xn;y- b is shown?

1.Outline the events which would lead to an indu+qu 4h bb)uet,cd.)iividual being born with Down syndrome, which is characterised by the presence of three copies of chromos,e)) c+uuqhbtdu 4i b.ome 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 wsqp m-q,(i4)ok hg6k ras condukk4( )s p6qo-h,irq gmcted 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 whic48+;z pmrl:yvj0ij/ :vycwez qg+v*ph cells can divide. The diagrams below show two cells from anv 4/z:p8r j jilc:e wqv*yyzv+m;g+0p 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 , wo5z bs8hm0wgene 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, in diffe1a-- 6cnp ;3h9xm*oy vgi*o9zcxd+oia, blxrrent stages of meiosiso-o* an3adcmixhc yxr o-1lbp9vg9 6*,i+; xz. Which row correctly names each stage?

  The micrographs show qdz lp )rb1jp+9+u,wpks1 qg,four phases of meiosis I in a plant. In what order do these phasw,r lqk+u z1bp19gp+d) , sjqpes occur?

Mitochondria are responsible fo)bqefqz+ w d+-x n,y0)jcylp 2r 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 between two different yeast species, could be influenced by the parent’s +-0f)j, ze w2qxnpb)lyq+d yc 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 ,tnl y( 7z.3eidtt.-ye slw6aof the cell cycle in four samples of lung tissue from four patients. Which t6s ti7lzea.t yeyn.-,dt3w (l issue has the lowest mitotic index?

  The diagram shows the dominant cyclin/CDK complexes at dif;bivo,f.7 s uxv2e +rfferent time points in the cell cycle. Which cyclin/CD rfev.fuso; 27i,xbv+ K complex activates DNA replication machinery?

  Studies have shown that genes such as Cyccz1s6 qs l(wr4eh4tczu .k/4vlin Dependent Kinase 3 (CDKN3) are highly overexpressew.eks4(c s46czql r14z tuhv/d 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 cyclin E the highjg.o7h rpc+g-jb 2y z:est during the cell cycle ?