The graph below shows the relationship between maternfdy9 p:8 .pagfal age and the incidence of no:.payd9f 8fpg n-disjunction. What relationship is suggested by the data in the graph?

  Which stage of meiosis ;w;qo)ixdqyhgsn9 d a2k( o..is represented in the diagram below?

  The diagram below shows chromosometi+gea*of: 8t6l6q wbs 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 alleles99m0scy5 fnc i of a single gene which would be present in the nucleus of a cell as a result ofif5 ycc9mns90 each process?

  Which keyword is mato1ck,dc xm, m8ched to the correct definition?

  Which statement(s) about mitosis is/are4ljz*gc1-tw f 6eqldk:hs 8o3 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 5g 0at3 y/w1mai7 ah 1ubg+k8c u4hmugto a cell in anaphase?

  During which stage of mitosis does the nuclear envelope breay 35q64amsiotdsex .sge(9(nk down?

  Which one of the following transport j*8/ d mp w:dlby)qrt*2i2w niproteins only carries out active transport?ii q rw d/)b*8*2jdt:y 2wplnm

  Which process does not happx jk825(abyd: 0l*ktvux2 67sbbsebden in the shoot apex?

  Which type/s of membrane transport dftu; 3q5th qpnjxl p.-al.f02d;0kle o/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. Which stage of cyh-/b+ uh5iu well division is t-hb/5u+ uhyi whe cell currently undergoing?

  The photomicrograph below),mji7r z aur10cls0y shows a root tip meristem. Which of the following sentences correctly defi1z,l jc0i70mys )urr anes a meristem?

  When does the random orientation of homologous chromosome pairxa(oa)s,e)nx cfdh2 q(,logp, 1)ryrs occur?

  Which process does nomjq6q6pmj3 f:3iaf/oi s+0hot occur during meiosis?

  If a cell with a diploidb-75euu2aa21g iuctz number of 36 undergoes mitosis, how many chromosomes will be pr7 c z-1uuea2u5iat2g besent in each daughter cell after cytokinesis?

  The image shows a microgry2/pyr nu rlgj p698w3aph of a cell.


What explains the appearance of the cell in the micrograph?

  Which statement(s) about homologous chromosomes is/are not trkjl8 v36vy.gbue?
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 wiiddan*n+5ii7. 0+wo+ cu att tth Down syndrome.

Which statement is not correct?

  In the cells of a horse (E. caballus) during prophase I of meiosis I there am+0ke2fvt ghy.)h4xvb.sy y*d9 dbye16 ot -ore 64 chromosomes. What is the haploid number b)1g 2fyv6ys9beh+yo. -mvo hd t.4x0* tyekdof chromosomes?

  Which arrow is pointing to a s2 pm bn9i z1/a53q xklo7;jgfchiasma?

  The diagram below represents the structure o6 pin1n;*fz6b+0jz sdrh twy*z hq5k(f a shoot apical meristem. Which row in the table correctly identifies the processeszqi*+ y1 pr; n w0jkzhzsh6(fb5tn6* d occuring in the structures labeled in the diagram?

  How does meiosis promote variationsr z85ff85 ifu?

  Which of the following statements is/are correct foev6(wt ul)*4satnf i9r 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 homol*q jmbawb( ,-zl(6djp gep3z5ogous 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 3m3vr eiouw2b* 4f la8of secondary tumours from primary tumours as a result of the movem a3u e2b3wifv*lorm48 ent of cells?

  How many chiasmata are present nn.k zmvbu)n5uc 4t .q4t fo*4in the diagram?

  Which statement is a similarity cjw 3au;vb 9f.between cytokinesis in animal and plant cells?

  Which stage of meiosis is matched to the correct descme5ko1i++ (dftxdz- j ription?

  Which statement(s) are true of meiosis I bubn7e4b w5:nolue:m 3qi i/ v*rt 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 division. This res2jpg n7cv0tk/c *c 5owults in the formation of one large cell and one small cell. What is the fate of tc2/cw*5 vknjtg 0op c7he large cell?

  Which row correctly describes diploid and haploid cells in humane 6olnty9i (.ehu9u4 ts?

  The following table shows the dipofq vw+j:2-e rr88ubp .xnif 0loid chromosome number of a range of species.


Which of these statements is correct?

  What conclusion can be drawn from the karyogral -* jo6jsz+yd, itq/vm below?

  Which of the following processes is characteristic of trbx7xw:m /)p 0jnqn6 hhe meiotic and not the mitot06)7hrnp: jxw /bn xqmic cell cycle?

  The diagram represents a bud with a shoot apical meristx*qlib5 .gik x+4vlx4em.

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 ty hwjdb+3 .j/ /k:phpjroglodytes) is 48. Which row shows the correct chromosome num/3pwhbh jjjd :pk+y. /ber for different cell types and cell division stages?.

  At the end of which phase of meiosis I does crossing over occur, and what is t+q. ym1bc*zdbhe outcome of crossing.+byzcdqb 1m * over?

  Which of the following statements does not describe a step in the sodi7fxmcz81e d n+ 3wpjn.um-potassium pump cy1cdmzex n37.8+w j npfcle in the neuronal cells?

  Which row in the table below is true o,1,/ lrkzwn5v w 46m;; ukgn(e l*ljs8ilczz xf meiosis?

Membrane transport is important for allowing particles to move across the wx()m skir6f2 cell membrane and respond to changes in the chemical composition of thewi(k26x smr )f 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 regulatjb gl,lgpy *wnb-qx )99n,f i1h u)8gued 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 h).tbk/w nc/0ar-grbg7av.lthe cell cycle. Which cyclin is involved in preparing for DNA replicati.l t)rghb c7a ./ar-gknbv0 /won?

The diagram below shows chromosomes during *y zo w5d3cjv)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 homologouse igi pwdx zr+j0f6 h:iwor6uohe5)r(h5 5l9( chromosomes?

  The mitotic index of throat tiss2bt*kfms 1np.rjih( as7 )lk5ues taken from 4 different patients is shown below. Which patient7f . lsrsjna)m 2hp1bk (ti*k5 is most likely to have cancerous throat tissue?

1.Draw a labelled diagram to represent the process of crosse j/e1nz5 g7,sef eo1bing over.

2.Compare and contrast random orientation and crossing over.

3.Outline the stages of meiosis.

  The image shows an abnormal;k8;q kn 6sjzeel *t;ppj;gm. 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 ojy+g4hczke zed/. q0/ne complete cell cycle. Each letter represents one stage oycez 0ghk.e4 //+zq djf 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 betweekai.9mb*: cb2 *5 vom wzfpy:mn a male cat that is homozygous for brown, lo am*yc 2ip*bw:kmb o5.z9mf: vng hair and a female cat that has black, short hair.


Which of the offspring has a recombinant genotype?

1.Outline how polygenic trait e;i2 za ccdi6b32t)cc7ka.hjs 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 8k3crkj 92tpgof non-sister chromatids shown in the diagra8g 9 pc3jrkkt2m below?

  The photomicrograph shows a pollen grain from L. candidum f82y wg8mu p3:fmh/r l2.bk4j,mgaec (Lily). Which stage of meiosis is shownw j/rkum p34c.8 mf2g:8fg , lm2beyah?

1.Outline the events which would lead t *y:y5f2m.,) *suf* shus)zlmd pj ,escll8dx o an individual being born with Down syndrome, which is characterised by the presence of dx5, sf:y)l* ez,* )u*fc8susmjdh 2. lymlpsthree 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 pzx9hyv -7knt/nw0q (yjgh6a7hg5 .vilant growth. A study was conducted on white onions (Allium cg7qg.w9 5 j hv yazn0h6(7xtn-i v/hykepa), 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 celldni9 d3u-gp/n/l if+ ys can divide. The diagrams below show two cells from an organism png/+ yilf39ind/u-d 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 expression in stem growt1jqa5jez)a 5nikal6i z45pf: h.

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 stagesxk5wg 33k ep(l of meiosiw l (kkgp53ex3s. Which row correctly names each stage?

  The micrographs show four phases of meiosis I in a plant. In what order do w9tsdo./,hfn these pha/9nf.t ds w,ohses occur?

Mitochondria are responsible for sup,, f8g;wrqn:cqoe d* xji(t9rplying 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 mtDq,:;9wcio r8rd *nj qetfxg(, NA 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 in08 a2rmi jmswdu 6kk-6 different stages of the cell cycle in four samples of lung tissue fro6 i m2d0k6k-m8rwusj am four patients. Which tissue has the lowest mitotic index?

  The diagram shows the dominant cyclin/CDK c: 0kg+:pdnhd:fq /ivh n7jtl0omplexes at different time points in the cell cycle. Wh k/fh dn0p thq:l di:jng+v0:7ich cyclin/CDK complex activates DNA replication machinery?

  Studies have shown that gene nit47b9ip,;:ln dh(3 wp hhvks such as Cyclin Dependent Kinase 3 (CDKN3) are highly overexpressed in cervic, pk(dwn ;hti9il:3bnhvh74pal 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 high1 if ky20t1tm -3owlpfest during the cell cycle ?