The graph below shows the relationship betwe00t9n5vteq)ot)ui u ten maternal age and the incidence of non-disjunction. What relatqte ut)u9o0n5 it) 0tvionship is suggested by the data in the graph?

  Which stage of meiosis is represented in the diagram bel wfn ).v6) hg0wi6a d4 /jhsknp/ri5ntow?

  The diagram below shows chro;dik;mk8+l npmu fofn 96e,m0h,lco,;fq - iomosomes 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 si5 r k54x:7 qhni+7cyllmvf1dc ngle gene which would be present in the nucleus of a cell as afm y:l5dqcl+nxkch 7ri5 4v71 result of each process?

  Which keyword is matched to t4cjgm*dm5di488 jo6vpbs p) jhe correct definition?

  Which statement(s) abouudf*f(2; r djg3r7djet 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 belowz bx.8v7-jwd ).wgcz4d xn,ji, which letter points to a cell in anaphase?

  During which stage of mikuipys)-ydi* . cc1.kww2-t rtosis does the nuclear envelope break down?

  Which one of the following transport proteins only carries out activ0rky;m x2j l46(zh yzje transport?jyhz mk0(4;z6l2 jxry

  Which process does not happen in the shoot ii 5ttt 021e 6n;xph:nv f.pcyapex?

  Which type/s of membrane transport do/does n/zcvn,;kr g*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 stage ofq 1b2-ymt4tgcb7sp3a cell division is the cell currently underta3ym pc7b12tbq-4 gsgoing?

  The photomicrograph below shows a root tip meristem. Whichd6x e 0s0,f6h sj9i xy;v50vi) mrgjkb of the following sentences cor;jg0b i0vskjf,em h9x d 6siyv650rx)rectly defines a meristem?

  When does the randomy-h(;ks; dly8 ( ;itkgr +pbfq orientation of homologous chromosome pairs occur?

  Which process does not occur du9gor1a; vk,1svz n.x cring meiosis?

  If a cell with a diploid number of 36 undergoes mitosis, how yo xrm :o(lg qffqrspfy6y rq,21-0i;/mf,-c many chromosomes will be present in each daughter cell qfmryp-6 fy(s r yf,g;coxq lrq,2i / f:-10moafter cytokinesis?

  The image shows a micrograpfzj,eeyj (fw)7z5 .b/-dprr k h of a cell.


What explains the appearance of the cell in the micrograph?

  Which statement(s) a tjec)eybte 7bnu 5nbl .cm)/j6 u301qbout 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 -(b4nz 9d mlea2ix1 k kf(r6vbm x)xq9individual with Down syndrome.

Which statement is not correct?

  In the cells of a horse (E. caballus) during prophase I of meiosis Io*m9af(qf(r).j db6:n:fc1r t rpx i l there are 64 chromosomes. What is the hq:6 c rim().t1borf:da (*9j flxnrfpaploid number of chromosomes?

  Which arrow is pointingh,;zm4(yd s g+aoxz, u to a chiasma?

  The diagram below represents the structure of a shoot api .aw)p48c( 0(kj jwg5cjxk bkhcal meristem. Which row in the table correctly identifies the processes occuring iw5k k )p(xkb0.jjca gcw84h(jn the structures labeled in the diagram?

  How does meiosis promote varia yps -ol*y3:z+t0bprge0 t r1rtion?

  Which of the following statements is/ae1w lt+sw :ywri105l 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 hom tpm -dnyo-ws3;9l11 dtxac 3bologous 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 primary tumours astqc8v+xuqb:c 9 6im+o a result of the movementqx 89cvom6qbuic+t+ : of cells?

  How many chiasmata are present in the diagramrjiel+-w dfq1if: , 6w?

  Which statement is a similarity between cyxpc3t 7+wvpp9 tokinesis in animal and plant cells?

  Which stage of meiosis is or53x2+vf;c5xsc)cbm:hrgs e;gv n .matched to the correct description?

  Which statement(s) are trueg1a k jf1/en2w 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 an oocyte after theu+*zsq6 oxadwsejd ): 2.z z3c first meiotic division. This results in the for zo )cds j.as3z6z:w+d2x*eu qmation of one large cell and one small cell. What is the fate of the large cell?

  Which row correctly dekwnc p65gjx3bw9svuru d/)lyz/;( 3pscribes diploid and haploid cells in humans?

  The following table shows bx8hkw)drju/ w -oc + y5i)qo7the diploid chromosome number of a range of species.


Which of these statements is correct?

  What conclusion can be drawn yl6 2s3 h3e ngwt5)bwfy6)ujrfrom the karyogram below?

  Which of the following processes is characteristic of the meku0r g8pvyz02 iotic and not the mitotic cell cyp 2v8zu00k grycle?

  The diagram represents a bud with a s2l-txx /8h y*egztx6 dhoot 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. Which r;0/ul1s gwhaycy/o.x3b q q; sow shows the correct chromosome number for different / lcos uyqw3gx ;a.sqb;/1yh0 cell types and cell division stages?.

  At the end of which phase of meiosis I does cro0rew0w:ci9wnj ( pax 0ssing over occur, and what is the outcome of crj iw p90e0r n(0cwaw:xossing over?

  Which of the following statx-whrfgu+ 0:l43 c jtf 6j1zzvf., xdnements does not describe a step in the sodium-potassium pump cycle r hv z.6f1dux lftn,w4x f+g03cjj z:-in the neuronal cells?

  Which row in the table belowof4qge(fv m/ hy/ q/b+ is true of meiosis?

Membrane transport is important for allowing particles t t7p7p+nr g1g/-k (3wo gpncopo move across the cell membrane and respond to changes in the chemical7kntp g p/1o 3gpcn-7o+gwpr ( 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 regul.w;rv h ()b;cvdj-p sou +5fhuated 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 conchy8 9v. 2,mvbv )qhre2e*kzck0azs9c entrations of different cyclins during the cell cycle. Which cycli scm h99a8,*.ekhqb2zkzyv2 0ve)r vc n is involved in preparing for DNA replication?

The diagram below shows c 8o7nh wxww6-mdhq7 .*pe,r mkhromosomes 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 separation of homologous chromm5k d+ dixzwbw wr jni1 ,3u7o85q,0qsosomes?

  The mitotic index of throat tissues taken from 4 diffec)l/klw:s-zo cuha p26-.um bxw* 2 ss;1bw zqrent patients is shown below. Which patient is 6wkb1ususaxm/o2z*-;)2 -:lqcz b wh . csplwmost likely to have cancerous throat tissue?

1.Draw a labelled diagram to represent the process ocx-qb2+jlx ciozh9 ; 7f crossing over.

2.Compare and contrast random orientation and crossing over.

3.Outline the stages of meiosis.

  The image shows an abn n5ugtsr3 ww+ rzp:+l7ormal human karyotype.


What is the abnormality in this karyotype and its cause?

The graph below shows the relative amount of DNA ir7em ;:mvenq;5n+m gyn one cell during one complete cell cycle. Each letter repres g7yme +emnmq5v :n;r;ents 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 for u +znmzg7vk nn2ma(-5s0u ba+brown, long hair and a fb2v5(auk0 +7mnusz +-nman gzemale cat that has black, short hair.


Which of the offspring has a recombinant genotype?

1.Outline how polygenic traits can shot)l fcgr d8gjp2o/(4kw 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 crosu e+3a7sqknz 6sing over of non-sister chromatids shown in the di+3sk67 neqaz uagram below?

  The photomicrograph shows a pollen grain from L. caqa(, by+uo fsr e36n3j fkd1g2ndidum (Lily). Which stage of meiosis ,3f ek6o qu+j s3fg(darby21nis shown?

1.Outline the events which would lead to an individual b3s npy/ta1t xi+m*m:g eing born with Down syndrome, which is cha3sag mpn:+ m1yxti *t/racterised 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 growtjni1nmpyw mr2mi-+ )rzj 5) k2h. A study was conducted on white onions (Allium cepa), under controlled co)jrm+ywpk-15i)jmi2 2m znrnnditions 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 whieb+him 7,j0fgwk-gfv q+7u4ich cells can divide. The diagrams below show two cells from an organism with a diploid numbb,+70fk7 ih -g ivmqjwu4+efger (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 i;/9s ,1b9ag ,baeqs c,ietl qexpression 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 different st(ky ;,d+v m+p oxnguv5q s3io0ages ofkoxvdvi ymu0 ++3(qso gnp5; , meiosis. Which row correctly names each stage?

  The micrographs show four phases of meiosis I in a plant. In what order do thesey jjrh vk,w)*. phasej, .wyh*kjv )rs occur?

Mitochondria are responsible for supplying metabolic energy x qz4ked2 67quf,xi+qin 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 q,xqx 7qie2fd6uk+ z4 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 o+6felm i) ws:(gde;u zf the cell cycle in four samples of lung tissue from four patients. Which tissue has the loweszume+6 ) g:if( lw;edst mitotic index?

  The diagram shows the dominant cyclin/CDK complexl/8 dk stsbi(2es at different time points in the cell cycle. Which cyclin/CDK complex activates DNA replication machineri tdks8( bls2/y?

  Studies have shown that genes such as Cyclin Dey9 mjz e1lq42fl rj6/k0tzl r,pendent Kinase 3 (CDKN3) are highly overexpressed in cervical y,k qj1z /l4j9 efz6rt2m ll0rtumours.


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 highest 03n*cb0tr z jhduring the cell cycle ?