The graph below shows the relationship between maigm;r6qt-c6 5 pb y4s- t,zkegternal age and the incidence of n4i-rq6e5s -kgtc6m z;p,btg yon-disjunction. What relationship is suggested by the data in the graph?

  Which stage of meios 4tvf(7s zb- go,x.opsis is represented in the diagram below?

  The diagram below shows chromosomes dur cuqx,*0z eic1 pi3t5ring 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 states6.it8f g1y b5xrq s fppo((m6j the number of alleles of a single gene which would be present in the nucleus of a cerpf6(t(s qj 5f6iy 8bo1g. xmpll as a result of each process?

  Which keyword is matched to the correct def,eu4b zi2olt3dqz 0q,inition?

  Which statement(s) about mitosis is/a9rsly c0mnp/8 pg; l8cre 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 otkcn+. -ot 2sgxz6r y:2rsl3points to a cell in anaphase?

  During which stage of mitosis does the nuclear envelope br a0ski2uns6v05xqt*x eak down?

  Which one of the following transport proteins oy0o-,7jicb finly carries out active transport? ,yiof7ci j0-b

  Which process does not hapu a4mpmi7.,pj pen in the shoot apex?

  Which type/s of membrane tra nza8emf/z zo ,jk-35dnsport do/does not require energy expenditure?
I. Facilitated diffusion
II. Active transport
III. Osmosis

  The diagram below represents a cell with a di+ 7s1qtyo 5t4yh 04krle1ff zqploid number of 4. Which stage of cell divisi10 ke 1 4tfyzofr54qy7lsq h+ton is the cell currently undergoing?

  The photomicrograph belowuqu ssyek13(j:3qqzr s )m4t2 shows a root tip meristem. Which of the following sentenceskuus:j334qz q (1eyr) sm tsq2 correctly defines a meristem?

  When does the random orientat 2xq +gp9fdt+id+tr; h0)gnopion of homologous chromosome pairs occur?

  Which process does not occur durinmd(lb;6 b*xn9nad6p njgv 1 zb7p2f2yg meiosis?

  If a cell with a diploid nuh48l /wiy:ia imber of 36 undergoes mitosis, how many chromosomes will be present in each daughter cell after cytokinesisi4: 8iayhl/ wi?

  The image shows a micrograph of a cv+ bjg961gh:4sf1im dkgw 8xt ell.


What explains the appearance of the cell in the micrograph?

  Which statement(s) about homologousjtbqrutsi7n0w : 4o ;;i9n.jg 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 indivf;b2 wi:i:vg3s / 4p*awtyf6csh xa9kidual with Down syndrome.

Which statement is not correct?

  In the cells of a horse (E. ca3f c92jktjsa 9ballus) during prophase I of meiosis I there are 64 chromscj9f 3tj29ak osomes. What is the haploid number of chromosomes?

  Which arrow is pointing to v8ejt ar7o)po(5tpj ;a chiasma?

  The diagram below represents the structure of a shoot apical meristem. Which r*q z:q(m cj m6l*mjs(qow in the table correctly identifies the processes occuring i:(* jmc(qmls* q mqzj6n the structures labeled in the diagram?

  How does meiosis promote variatii4a1zb nz(rz h:x q1g)on?

  Which of the following statements is/a*humm izdmm :/mu;3:vre correct for meiosis?
I. It is a reduction division
II. It involves random orientation
III. It produces genetically identical cells

  The diagram shows gametes produj*14 pe1 j x0j6xbvjjc-af.b rwb;)ticed 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 form6 2(n 6knc4sy s lbdvzfho*.18c7fsyyde /xv8ation of secondary tumours from primary tumours as a result of the movement y6vxd.y 6bceok /87 l1cvd( 2ssf4hnyz8 *snf of cells?

  How many chiasmata are present in the diprwd5)k6- hg qvp i(. tn6s-fuagram?

  Which statement is a similarity betw ,i r ocxsnj2m8v+o(;yeen cytokinesis in animal and plant cells?

  Which stage of meiosis is matched to pbb hz/ xm6bamk ,8e,0e/5uz: n o.qsq+xq(xethe correct description?

  Which statement(s) are true ofa7mrfm 6wmj(4 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 the first meiotic divi.xg*fs5qyq (r sion. This results in the formation of one large cell and one small cell. What is the fxq s5*rgq y(f.ate of the large cell?

  Which row correctly describes diploid and hae)+ j;pf-totmsgu fs zoo6;9*ploid cells in humans?

  The following table shows the diploid chromosome number of a range of speciesi p,pz:r:+qn g2ecdwzeq782i.


Which of these statements is correct?

  What conclusion can be drawn from the kar8nr;)zpwl( w (n i,gh6okvywz16vwg;yogram below?

  Which of the following processes is characteristic of the meiotic and not tt,6/g.orw-k4jcvj qu vd 1la8tzz*c6 he mitotic cell cycl 8z1-w6/k *v cg6,jcljarqz 4t.duvote?

  The diagram represents a bup2yes66c7 sv fjd qy63l8gz ay t1.z2sii3 ou2d 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. Whic( /a yac2tlp9o0lf o*q5wxr4e - yzrz3h row shows the correct chromosome number for different cell types and cell division stage4fe5z* z09- 2xopclqryoaw3(atrl /y s?.

  At the end of which pharrx(u(:. )yct9 fpy ssffj45gse of meiosis I does crossing over occur, and what is the outcome of crossipsj(xcgy : frt suf4(.59)r yfng over?

  Which of the following statements does not describe a step:oq:it*kb( cdq /yu v; in the sodium-potassium py:(c/:i t* q vbqok;udump cycle in the neuronal cells?

  Which row in the table below is true of .iyw8yra/+ye,rr5 j q2 df*cg meiosis?

Membrane transport is important for allowing particles to move across the 4pwi5rfl5 5ipcell membrane and respond to changes in the che5p5ifwli5 4rp mical 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 inmjasbd 6qvp;yd8089e 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 taih.7e f:f8pe he cell cycle. Which cyclin is involved in preparing for DNA replica ei8.af h7fpe:tion?

The diagram below shows chroz ed/0 flsy//eq a8pk4mosomes 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: grwt m:2beh3ubao8;2r 4zn6 ,d mfhe involves the separation of homologous chromosomes?

  The mitotic index of throat tissues taken from i-,h pucay,m 74 different patients is shown beloyp -mu,i,c7 ahw. Which patient is most likely to have cancerous throat tissue?

1.Draw a labelled diagram to represent theeov-zp+t z 8(/cp3aoz process of crossing over.

2.Compare and contrast random orientation and crossing over.

3.Outline the stages of meiosis.

  The image shows an abnormal human karyotype. *u-q zr z 5xu)2y0 :aao6jfk)d*xgnfs


What is the abnormality in this karyotype and its cause?

The graph below shows the relative amount of DNA in one cell during or ;zok.yxqe(yj-h( 1lne complete cell cycle. Each letter represents one stage of the cell cyclj.e(1z;xo(rh-yk qly e.


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 sd4 )qw2o:hyymozygous for brown, long hair and a female cat th:hyw)d 2qy4osat has black, short hair.


Which of the offspring has a recombinant genotype?

1.Outline how polygenic traits can show a normal distributiulfghj,fc8i /c)r)1cyna 8ok(/tmr osj(/ 3ton.

2.Outline the differences and similarities between homologous chromosomes.

3.Explain why expected and observed Mendelian ratios may differ.

  Which gamete can result from t*5wq ad5ji )lh:ayh(qe/1ojs he crossing over of non-sister chromatids shown in the diagram below? sw5lo)aa*1q ie/yj5h:dj h(q

  The photomicrograph shows a pollen grain from L. c36w jefx c6bbo mq)56kandidum (Lily). Which stage of meiosis is s jbe5mfqx3k6wo )66 bchown?

1.Outline the events which would lead to an individual being born with Down b./sa h4e(0i.s czunosyndrome, which i4isu .bc.0s za(enh/os 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; v1wkz8 3xndd r,a(fi way of measuring plant growth. A study was conducted on white onions (Allium cepa), under controlled conditions in a lab, to ivdk w1ixdr ;a 8f3z,n(nvestigate 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 wn ,x,6 fea/yms5,n mscays in which cells can divide. The diagrams below show two cell ss,/emam56n,,yx nfcs 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 gene exicam+c/gsmy 9hvqu8 + 4wv 94wpression 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 differenl)rrk7*9t xebb7xat3 xk sj 6-t stages of meiosis rxrklak9b76bx37* s)xttj -e. Which row correctly names each stage?

  The micrographs show four phases of meiok ke lrl +mvsssxyom-xxv5;/k3f ))68sis I in a plant. In what order do these phases occur?;lolv es/+ 8fs-xv)y3k) xks6rm5mkx

Mitochondria are responsible for supplying metabolic energy in eukaryotza,y:rfevd 2 /ic cells. In most eukaryotes, which reproduce by sexual reproduction, mitochf e2azvry, /:dondrial 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 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 cdm /h ;2l6yf cp+b9ugiells in different stages of the cell cycle in four samples of lung tissue from four patif b26m9u +; icdlgy/hpents. Which tissue has the lowest mitotic index?

  The diagram shows the dominant cyclin/CDK complw2hbe*rth o a4g568jlexes at different time points in the cell cycle. Which cyclin/CDK complex activat h wo45lt*rjh6g8be2a es DNA replication machinery?

  Studies have shown that genes such as Cyclin Dependv ( 1zgmd17vfk0qz6udc kak ): 4 9d8oktnqwd7ent Kinase 3 (CDKN3) are highly overexpresd :tovdzaq)81 ( k647 7nzgcqmfw d1v0kdku9ksed 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 2 w vc595 k5sqyhadhun+5jz 7rcyclin E the highest during the cell cycle ?