The graph below shows the relationship between maternal age ands 9ik6u 5rkb;g),foe e the incidence of nr,io9guse 5efb k6;k)on-disjunction. What relationship is suggested by the data in the graph?

  Which stage of meiosis is represengc m8 9vgcdgd4i /nv9xp6(up:ted in the diagram below?

  The diagram below shows chromosomes during meiosis. zr89i yt v9 a :kol1l-z8nk(zu


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 numb-5g8 d5vnx ov6+skj jter of alleles of a single gene which would be present in the nucleus of a cell as a resu 6 +5td5k8- gxonvsjjvlt of each process?

  Which keyword is matched to the correct definiti+r g/2(fdyi7nia9a nmurjt 1 +on?

  Which statement(s) about mm+w,m6vul68mt:p2m uct6 ra zitosis 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 below5 m/dp*w)orp; jtute*d *sj(j, which letter points to a cell in anaphase?

  During which stage of mitosis does the nuclear envelope eb:v dbs2 /)muy 4:dsgbreak down?

  Which one of the following trhzj7v zgt+ys2d r; g51ansport proteins only carries out active transport?gz1svr5dhy+;7 z2 jg t

  Which process does not huo1yh)ibh2 w ./xhb-nappen in the shoot apex?

  Which type/s of membrane transport do/does not require 1uku.gdwvdip2mp.2a)at6 yhw( k) q) energy expenditure?
I. Facilitated diffusion
II. Active transport
III. Osmosis

  The diagram below represents a cell with a dipl/jz7 k we+9*wo0srfuz oid number of 4. Which stage of cell d/f* + jo0rwze9wk7uszivision is the cell currently undergoing?

  The photomicrograph below shows a root tipvt,3l olwjv* .uq9gh3 meristem. Which of the following sentences correctly defines a meris33gvu 9 j.wv,q*tolhltem?

  When does the random orientation of homol pzev9;f h5zy9-pdow73im(ln ogous chromosome pairs occur?

  Which process does not occur dslzs )t sc50sj*:hfi0uring meiosis?

  If a cell with a diploid number1hkn kx2 (-b6w)xh/k gnn5btz of 36 undergoes mitosis, how many chromosomes will be present in each daughter cell after cytok6b 2b/ -gk1 )(nxwhzxtkhk nn5inesis?

  The image shows a micr0nn2sp sk:re1ograph of a cell.


What explains the appearance of the cell in the micrograph?

  Which statement(s) about homyhm(; 3l gxtk orp:t4(ologous 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 individual with Down syndrome. o9icv)n,tqwjwj+u l /euzk* ;1n4. fm

Which statement is not correct?

  In the cells of a horse (E. cabn:if 0vvak-( hallus) during prophase I of meiosis I there are 64 chromohifk: v-v(0a nsomes. What is the haploid number of chromosomes?

  Which arrow is pointnbtb;tu in(z jl .fvdz3 .47 16hwoc/ping to a chiasma?

  The diagram below represents the structfin 1dm1uzusp;g 2ay7;u o (c,6h*dvnure of a shoot apical meristem. Which row in the table corremgi(u7f;s p1 y2 ,1ncd ;uon hadu*vz6ctly identifies the processes occuring in the structures labeled in the diagram?

  How does meiosis promote va (1tls9yv (d8kp81ii z l7 6pk;jgq 0dgbr5vryriation?

  Which of the followinw qm(h .1aob8li6ai/f g statements 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 gametesni )) 8vcyd4ch produced 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 of secondary tumours f 7v+h9y 8p fkap0plfr4rom primary tumours as a result of the movement of 9pf7+v a 0fp4kp hly8rcells?

  How many chiasmata are present in the diagram?e6joj;xkj :m9

  Which statement is a similarity between cytokinesis in anima m*qy6t bpy6bf5/8kx pq.cui3l and plant cells?

  Which stage of meiosis is matched to the c ;yoj;c-s)uci orrect description?

  Which statement(s) aryx. i)r8)utkg e true 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 the first meiotic d)vxv:j0: ge6)7yim0njgh2 b o(j lbunivision. This results in the formation of one large cell and one small cell. What il:jj bgxjnv0hy7im( nv62:gb)eu0 )o s the fate of the large cell?

  Which row correctly describes diploid and haploid cells in hut2f jc2; l0/,tf;a4 xdp -ktk55rjkdw ijyj p:mans?

  The following table shows the diploid chromosome number of a rangaqqz kl5--jt3g; dmou-., 1x b kk,yyae of species.


Which of these statements is correct?

  What conclusion can be drawn from the ik9 oq,q0ki1x /e(jhkkaryogram below?

  Which of the following processes is characteristic of the meiotic and not theiajh4y2q u5uka22p;v pj so +4 mitotic cell c2j 2okyvs244 5 aqiaph;+uujpycle?

  The diagram represents a bud r2 mj1n*2 ))s4qcw8/ rcomoksqnr:nafeg) 9dwith 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. Which row sh*(83+addg:j sdsnth hows the correct chromosome number for different cell types and cell division stag d(ssnd *dga:j38ht+hes?.

  At the end of which phase of meiosis I does crofu nkb +:4k6osssing over occur, and what is thekobu6s:kfn + 4 outcome of crossing over?

  Which of the following statemen)li rqwj; ;cfy -h/oy66jzq*a ts does not describe a step in the sodium-potassi/ hf;qr*cl joaiy6y;w6 - q)zjum pump cycle in the neuronal cells?

  Which row in the table below is true of meixijre*m7.5 eol.-fp dosis?

Membrane transport is important for allowing par ziz o,2t9-veiticles to move across the cell membrane and respond to changes in the chemical composition of the zi2t9o- zvei ,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.b2) a1 axp0 iu krn5-e:a gvgn,)k wym/k-;ncs

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 dfx f), ukpfk3 : vc(sqwx9l4-pifferent cyclins during the cell cycle. Which cyclin is involved in preparing kf-fpqw:3 uf) k9clv 4s(pxx, for DNA replication?

The diagram below showc ,gb6 ,voqw4gs chromosomes 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 z6n ; e2 oex5ub3ozfbo cq1fle15s/x pa.(k(lhomologous chromosomes?

  The mitotic index of throat tissues taken from 4 difm2tx b4wf 6m;sferent patients is shown below. Wf mm4xtbws26 ;hich patient is most likely to have cancerous throat tissue?

1.Draw a labelled diagram to represent the process of croxje-s)tpe /ky 32blu7 ssing over.

2.Compare and contrast random orientation and crossing over.

3.Outline the stages of meiosis.

  The image shows an abnp h c9r; w.krlhd6;gvyw0q/f).tq1 iiormal human karyotype.


What is the abnormality in this karyotype and its cause?

The graph below shows the relative amount of:psi 2pdq */cm+iot *u DNA in one cell during one complete cell cycle. Each letter represents one stageo qsim:p t+p2uc*i/ d* 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 ca0 s 1bz-(a s0iaiufx /,xqryy9t that is homozygous for brown, long hair and a female cat that has bl0qbi9(,sxa sxy 01r aifuyz/-ack, short hair.


Which of the offspring has a recombinant genotype?

1.Outline how polygenic traits can show a normal3po+ 0unw+bi l distribution.

2.Outline the differences and similarities between homologous chromosomes.

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

  Which gamete can result frozxz1a+ j-n4 v; qz4aze5z v)gbm the crossing over of non-sister chromatids shown in th4zaz1b 4 )aqgvex;-j+zzv zn 5e diagram below?

  The photomicrograph shows a pollen grain from L. candidum (q9dpi i9v qjf3+s 6 na*nd*tn8Lily). Which stage of meiosis is shown8sii3qtn*d9df*+v6a n9jqnp ?

1.Outline the events which would lead to an individual being born with Down6 ; du2kbn(m3;fljla w syndrome, which is characterised by thea f nu;m(23j l6b;dlwk 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 grqonj7 hm1 7v+ l;+zmwpowth. A study was conducted on white onions (Allium cepa), under controlled conditions in a lab, to investigate the effect of qz+n+ vm7 h7 ojwlm1;psoil 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 cells can divide. The dq:aj9 cw ey g7q22om- i 38l3g+wndu9b ejrx+qiagrams below show two cells from an organism with a diploid number (2q:7yjngj ucb9- 3 ex+qli2edaqwo 23gw9r8m+ n) 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 grox7gdhh*f/- kpf5w8o jwth.

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, im y. 8vv9ncnv7n different stages of meiosis. 9cv8ymnn v7. vWhich row correctly names each stage?

  The micrographs show four phases of meiosis I in a9v5huh s 1gh5 8o7 qgcq8jfc4f plant. In what order do these phasesgh5q85hfvg1qhsc9c4 f8o j7u occur?

Mitochondria are responsible for supplying metabolic energy inq5cxc- d4) ktl eukaryotic cells. In most eukaryotes, which rc4c tql- 5d)kxeproduce 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 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 xrp ) ze7gw*h-;3 cctvnumber of cells in different stages of the cell cycle in four c ;g*x)vt37w-phcerzsamples of lung tissue from four patients. Which tissue has the lowest mitotic index?

  The diagram shows the dominant cyclin/CDK complexes -:s,li-r c4sn*kk1 wai ca+j7fsm*gcat different time points in the cell cycle. Which cyclin/CDK complex activates DNA replication mac cr+7 a:lwsk*m1nj s4fkg aii c-s-,*chinery?

  Studies have shown that genes such as Cyclin Dependent Kinase 3 (CDKNsyb)q, yb9qp +3) are highly overexpressed i ,sqpyby 9b)+qn 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 h6e ;l f)puyfd-.oa gc;ighest during the cell cycle ?