The graph below shows the relationship between maternal age and the incixjo5.)5rti c fdence of non-disjunction. What relationship is suggested cij. fr5)x5toby the data in the graph?

  Which stage of meiosis is representdg- 2ja.tj;4k taf xu)a6l1hsed in the diagram below?

  The diagram below shows chromosomes during meios 2gbujfo zeh+a.ap;81is.


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 single gen9x5phv:elh b*e which would be present in the nucleusx l:v9*ebhph 5 of a cell as a result of each process?

  Which keyword is matched to the correcbv d4az8xr9 ;yt definition?

  Which statement(s) about mitosis is/ +zgcw;7edw r6are 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 lexbq-p7p 2h5 qhtter points to a cell in anaphase?

  During which stage of mitosis does the nuclear envelope break downu l0 pzff*d;d uo:n2zlj9b8,i?

  Which one of the following transport e1ok jca4d+o7ai,wpu n -.j3oproteins only carries out active transport?ad.uoeooj4 p -3jk,7 1 n+ciwa

  Which process does not happen in b7 8pv ft m;6wtj))raalp8 g1lthe shoot apex?

  Which type/s of membrane transport do/does not require energy : rqv a9h1;x9upawj)eexpenditure?
I. Facilitated diffusion
II. Active transport
III. Osmosis

  The diagram below represents a cell with a diploid number of 4. Whichx.oh9f6 yn1ha oc-kk5 stage of cell division is the cell currently undergoingh- kx9oyofan56h .k1c?

  The photomicrograph below shows ajqsvcd9* zk1d c-wtmtf ,. ,be4:u-owjf cr+( root tip meristem. Which of the following sentofw:* 4d jt9zbvkrd+,. qcfws1,(u-cme c-j tences correctly defines a meristem?

  When does the random orientation of homologous chromosome paijvqg b ,smgs*yd0) 3hb 9c6co8rs occur?

  Which process does not (juh9 ebz.me4yn: 1ke7 g:zrboccur during meiosis?

  If a cell with a diploid number of 36 undergoes mitosis, how m3 a hyqb2c zv:h9l+o cj;,v4hlany chromosomes will be present in each daughter cell afte yqb32 vo4z+l :h;, cvla9hjhcr cytokinesis?

  The image shows a microg 0xnze-vwi s:u,fevy/l:k )5 mraph of a cell.


What explains the appearance of the cell in the micrograph?

  Which statement(s) about homologous chromosomes is- sgeiy.) a brgse).tiua )*z2/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 Do/+o 1 mkinup3joknd1:wn syndrome.

Which statement is not correct?

  In the cells of a horse (E2+ uww5vw8+) vymjh hu. caballus) during prophase I of meiosis I there are 64 chromosomesm wh5+8vw)yvu2h+u jw. What is the haploid number of chromosomes?

  Which arrow is pointing to a chias1m1wxjt vinb.q-mpico5cs ,) 77 2odd ma?

  The diagram below represents the structure of a shoot apical meristem.o8( kif3lo i:s Which row in the table correctly identifies the processes occuring in tol8( ioikf 3:she structures labeled in the diagram?

  How does meiosis promote vxf)3p x0azfd 2ariation?

  Which of the followi t6 19-m jnk3+yyjlwuyng 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 gametes produced from two homologous chr ,zi0w0/ sonxj8hef.ggn0)b j0qbto7omosomes.


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 oqpzu. c9uw xa3w(dc6*;nj- y pf secondary tumours from primary tumours as a result of the movement of c x6-(zn; cpuup.3*wwyqa9 j dcells?

  How many chiasmata are present in thqn2/u iaaij.jr3 o(w;e diagram?

  Which statement is a similarity betweez/gx m3;7ryehc 0i3k /wmkp ;in cytokinesis in animal and plant cells?

  Which stage of meiosis is matched to the correct descriptionjpph5v+y8 upbh( kp( +?

  Which statement(s) are true of meiosis I but not meiosis7 4zczw. wa,fx:lj.9n+ izamj2ed60w dpagj0 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 f-pifc*ht g d4;irst meiotic division. This results in the formation of one large cell and one small cell. What is the ph- *4 cf;gtidfate of the large cell?

  Which row correctly desczara+f5ws 3*fi:a y1o/ fyw)wribes diploid and haploid cells in humans?

  The following table shows the diploid chr*.mvpi m 4f7qpomosome number of a range of species.


Which of these statements is correct?

  What conclusion can be drawn from thelp9of w d5a8*;6z xkdm karyogram below?

  Which of the followin 61iuk502ssdcsbl- vag processes is characteristic of the meiotic and not the mitotic cell db0v ki65a c-ss2lsu1cycle?

  The diagram represents a buoazq2: qew,wd+ s;3qp1 2 ez rj;-mtpdd 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 ir bfnz,*g m+p9 e05metroglodytes) is 48. Which row shows the correct chromosomng zi5f*p+emme90 ,rbe number for different cell types and cell division stages?.

  At the end of which phase of meiosis I does; o.br: xp*rf7plxu;s(8npg w crossing over occur, and what is the outco; pu.;8wg*r xpfps bon(l 7r:xme of crossing over?

  Which of the following statexd c/ lu:fmah04bt.1lments does not describe a step in the sodium-potassium phu clmtda:b.0/lx4 f1 ump cycle in the neuronal cells?

  Which row in the table bkd6mgq2 7q;m.o xj/pja xo8qe,;y,n nelow is true of meiosis?

Membrane transport isvyx6rpbxnx kw4-3s+ 9 important for allowing particles to move across the cell membrane and respox 4y +wb-n3xrpxkv s96nd to changes 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 mitosis5 orgglz 4 q2:uune-;f is regulated 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 cycj32vb. pn6ct wlins during the cell cycle. Which cyclin is invw6ctj.n32bpv olved in preparing for DNA replication?

The diagram below shzbq* kmil 277hq b,j;aows 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 homologous wj4; nd xcske11pq8t(m;mgj qy 2:v9jchromosomes?

  The mitotic index of throat tissues taken from 4 different patients isjk5 o 2hsc8 xv/oacru;f705iu shown below. cxcj/ vorus0f7258i5;ah ouk Which patient is most likely to have cancerous throat tissue?

1.Draw a labelled diagram to represent thea3*.ggba jd5e( a)yb; c 71 ke:v3dqmz4mt tfi 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 kar/vaij l7p 3qjlkk:zlv3wku/k 4n2*(eyotype.


What is the abnormality in this karyotype and its cause?

The graph below shows the relative amount of DNA in one cell during one f t-myxm2/gl+ complete cell cycle. Each letter represents one sgy mf -mx+2tl/tage 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 showd2f1 * nu5w jj:nxdzc2s a cross between a male cat that is homozygous for brown, long hair dznj:52x u1 c*2wfndj and a female cat that has black, short hair.


Which of the offspring has a recombinant genotype?

1.Outline how polygenic traits can show a normal distributio acnvm u((gle01)zk3yq*3v 3rb k e*lon.

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 overhp p(sd /bwszj*kkc87c (9th. of non-sister chromatids shown in /k7c z 8pds*pb9ht. ((wskchjthe diagram below?

  The photomicrograph shows a pollen grain from L. candidum (mpcfgbb q0;y 3 ;s5qr.zdy(n8 Lily). Which stage of meiosis is sh850zf (y p;g;dc3rbnmqqsy. bown?

1.Outline the events which would lead to an individuwzy30cd7d2h c qu;s 2cw8,rb xal being born with Down syndrome, which is characterised by the presence of three copies of chromosome 2hyx ,87s32zwrb0;2udc c wq dc1.

2.Explain how meiosis increases variation.

3.Outline the stages of meiosis.

The mitotic index is an inrzv+q)p8 f8kn gs8ht2direct way of measuring plant growth. A study was conducted on white onions (Alli8qtp+kzn8 shv8g2)f rum 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 tw3k ,vtk d5/0ay22eu zlozv0wkn*wn s4o ways in which cells can divide. The diagrams below show two cells frovno,kwke 0usld z4nvk2y0*w2a3z /5 tm 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 expression in sti:fyiims c 1kz5k*7s 3em 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 83vg hi+jbsybc2 :w5oo ,lzw*diploid number of 8, in different stages of meiosis. Which row correctlo2 w5: z8cbj hw3lgvi+*bso,yy names each stage?

  The micrographs show four phases of meiosis I in a ud c.by k9e13ee ,9jd9rpw3nnplant. In what order do these phases occ,kd9cneub pn.w93d jy 91e3reur?

Mitochondria are responsible for supplying metabolic energy in eukaryoticfbs)rezb (xx2oq8 qw6 k392r q 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 wqk92q ox2bqr83bz(x)fsre6 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 of the cell cycle in foniqay -7a5d i(ur samples of lung tissue from four patients.-i7 iy5nq da(a Which tissue has the lowest mitotic index?

  The diagram shows the dominant c34evm14jbr1 wj n9k+a 0utwbuyclin/CDK complexes at different time points in the cell cycle. Whichjkr bwmnwj +10tu91eu3 bv a44 cyclin/CDK complex activates DNA replication machinery?

  Studies have shown that genes such as Cyclin Dependent Kij i4 kd86 ac pqd)abr1(qt2jx3nase 3 (CDKN3) are highly over ktxa()4cd 1r8 qbd6 jqa2pj3iexpressed 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 hitra,t d5ffn.*q5 6wrnghest during the cell cycle ?