The graph below shows the relationship between maternal age and the incidence82p1fmzokkqa b ;t+c/c *n5ww of non-disjunction. What relationship is suggested by the data in the graph?/pw 8t*o5 +znbqc;2 w1kafcm k

  Which stage of meiosis i; rpxj434jx)w tt dzr46wwrj3s represented in the diagram below?

  The diagram below showx3,md nnta(n0lxz3,zs chromosomes 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 tku 1pacg 562mvhe number of alleles of a single gene which would be present in the nucleus of a6g ca5pv u1m2k cell as a result of each process?

  Which keyword is matched to the correct def bxc )p) f:wjlm3.ibovq2((kginition?

  Which statement(s) about mitosis +p+ gp t zv1 )lrea*f)5q6mkycis/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 below, which let.:ipl( +ejnt mter points to a cell in anaphase?

  During which stage of mitosis does the 1wfjj5v4 k 1v22qj)v c(zdrkwnuclear envelope break down?

  Which one of the following transport proteins onlj 8m uo cxw)0s(5x6hfwy carries out active transport?jm u wf(c5x0o 68h)wxs

  Which process does not happen in the shoot afz2: q celsmk+ .f)c;epex?

  Which type/s of membrane transport do/does not requirehj5rhw89 fgqtdec4t)z7hj wp f8o f9 (zj8*9w energy expenditure?
I. Facilitated diffusion
II. Active transport
III. Osmosis

  The diagram below represents a cell with a diploid number of 4. Which slildi 3og n+(0tage of cell division is the cell curr3ii(0o+ngl ldently undergoing?

  The photomicrograph below showld(d2slqa,s ( s a root tip meristem. Which of the following sentences (l d,ssa(dl2qcorrectly defines a meristem?

  When does the random orientation of homologous chromosome pp1 ;mp dd0.9yanw-j vhhv8 v,vairs occur?

  Which process does not occur during mex-e6sbs m776wrfh5owf p u .9xiosis?

  If a cell with a diploid number of 36 undergoes mitosis, how many chromp j8pk9ljf ucqr7,gl5nz a-nn )yt-4/ osomes will be present in each daughter cell after cytoki ay94nl-5qp njcpf g)zk-8,/rnlj7 utnesis?

  The image shows a micrograph of a cellex.jh sv;k*rt4 *ex/s.


What explains the appearance of the cell in the micrograph?

  Which statement(s) about homologous chromosomes is/are not true /j etrj/fe-+l?
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 individualdkv lln9,f9 m (lo4o,liy-) jz with Down syndrome.

Which statement is not correct?

  In the cells of a horse (E. caballus) during prophase I of r .f kr9up.;,eyh nnt:meiosis I there are 64 chromosomes. What is the haploid number of chromos9krtr.y., ef; npnu: homes?

  Which arrow is pointing to a chi je,,w-ifc:ejrv ;ie6rti;3gzh2e j2asma?

  The diagram below represents the s2 .u9lm/xnya, ah.hwbtructure of a shoot apical meristem. Which row in the table correctly identifies the process.2b,ymxlhwa / u hn9.aes occuring in the structures labeled in the diagram?

  How does meiosis promote vunr8c la+y0s(ariation?

  Which of the following statementkj: o w-npq(l rbyv;*:s 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 chromosom onut tao0 bb9y;5y ;a 1ncswtc;oao(*m.-bh+es.


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 tumx;xkq7lr0x4v;-qc .;zjg jzydlm 6y6ours as a result of the movement o.4y;xk;z ql6 d706mzrv gj- lxcqxyj;f cells?

  How many chiasmata are present in the diagranoy *o(bz2r)0p 4 )6lmwgpsffm?

  Which statement is a similarity beyohvol07js 6gvai2 : +tween cytokinesis in animal and plant cells?

  Which stage of meiosis gzh g q(p3j+c.is matched to the correct description?

  Which statement(s) are true of meiosis I but not meiosisgg18 ) tg +zgqvdi3u.m 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 fir0i+mu 5ojef skkhu;;j )ey+(kst meiotic division. This results in the formation of one large cell a) h5(s+kmj yu; ki +ee0jufo;knd one small cell. What is the fate of the large cell?

  Which row correctly describes diploid and haploz;mj.6z v ya 1-k3rsocid cells in humans?

  The following table shows the diploid chromosome number of a r 6c76ak bfu+y; yzw.jnange of species.


Which of these statements is correct?

  What conclusion can be drawn from the karyogram o+u9b:*a/ijr gf. lm bbelow?

  Which of the following processes is characteristic of the meiotic and unq)v gzy z f(2acdk6.l/:z0vnot the mitot0kzf/gau v2)zy z:ncl 6dvq(.ic cell cycle?

  The diagram represents a bud with 7 xnuq,.a m4 qjq)e.qba 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 (Pai.ny ,8t1fxazdj5r.s 5l2og oic3o 1cn troglodytes) is 48. Which row shows the correct chromosome number for diff.l cd8o ji2nac g 1.s1rxytofz5o35i ,erent cell types and cell division stages?.

  At the end of which phase of meiosi++ik1i-mcf w ms I does crossing over occur, and what is the oui-ifc++ kmw1mtcome of crossing over?

  Which of the following statemscs;fac pyh cxbqd+: 58qd86j v/+3heents does not describe a step in the sodium-potassium pump c yd+a3d8e;cjx b hs6pq vq5/c+fcs:h8ycle in the neuronal cells?

  Which row in the tablepa+hq,lqbec5ue ( 61f below is true of meiosis?

Membrane transport is important for allowing particles to move acros:srn 0vy5 3 5i(eku iha)(ulnns the cell membrane and respond to changes in the chemicalen lnaurvi) :k s((ny5h5 u0i3 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 reg qw l9oi*f41j2 xl4fvkulated 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 k+yb+*tw rl)/xiz d m7d4zo c8cyclins during the cell cycle. Which cyclin is involved in +o zmcd 8yw)k +7/ l*id4zrxbtpreparing for DNA replication?

The diagram below shows chromosom 4k+eg **lvmzzhjf( 6xes 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 chromosomes2a/)fp yby33e,yf ml n?

  The mitotic index of throat tissues taken from 4 different patients is shown bydmvr38 1ipq0elow. Which patient is most likely to have cancerous th80q vim31dyprroat tissue?

1.Draw a labelled diagram u,ssq: ob-wc0to represent the 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. is4bjbg78eo 1


What is the abnormality in this karyotype and its cause?

The graph below shows the relative amount of DNA in one cell during,.o4;j4h kq +ciegtet )xhq/q kng u(0 one complete cell cycle. Each letter rehkc e/k 0i;n t )oqthq(g.4gx u+,eqj4presents 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 betwu5jm,+ng mn * +s qjy4 kaf(/c0fb)3z9edq hideen a male cat that is homozygous for brown,f4 df5u g ac*e snqy9dnm)z/+03 hjj(km,b+qi long hair and a female cat that has black, short hair.


Which of the offspring has a recombinant genotype?

1.Outline how polygen * bxq yz.s9mle:68eyifh s,p.ic traits 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 of non-sister chromatids shown i hw,tfa5)*; +tnlk+uyw ;xxkf n the diagrakl xw ;ht)fk+* yan5+ xu,;fwtm below?

  The photomicrograph shows a pollen grain from L. cn 4qst,3xth s6andidum (Lily). Which stage of msx46h,t3 ntsq eiosis is shown?

1.Outline the events which would lead to an individual being bornxws022jdk 2zv with Down syndrome, which is characterised by the presence of three copies of chrkx0v2d z2j2 wsomosome 21.

2.Explain how meiosis increases variation.

3.Outline the stages of meiosis.

The mitotic index is an indirect way hjsxt+7w uc0j0oh,l3of measuring plant growth. A study was conducted on white onions (Allium cepa), under controlled conditions in a lab, to investigate the eflus3x0 j7tc 0jh+ ,howfect 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 cells can divide. The diag (jt30htpuk/b/d j(nc rams below show two cellj/k((jh/t ptun0b3c ds 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 express nj9. wq.o/ee2(jzynnl j3z;bion 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 differ1n.- )iydlilv/q0f d qsgi *n+ent stages of meiosis. Whqfvy+l1s0 /d gl.*-ini)idq nich row correctly names each stage?

  The micrographs show four phases of meiosis I in a plant.q/yja27dbg0zj w qy ). In what order do these ad7 qz2b w qjyy.j/g0)phases occur?

Mitochondria are responsible for supplying metabolic energy in :sllu1 k( ;kev4vju8veukaryotic 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 o(8;u v klsj:u4ev1kvl rganisms, 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 3zz e9dq0il0e number of cells in different stages of the cell cycle in four samples of lung tissue from four patients. Which tissue has the lowest mitotici lzez09 qde30 index?

  The diagram shows the dominant cyclin/CDK complexes at differentxh;3ygb1or .q 0s3 cun time points in the cell cycle. Which cyclin/CDK complex activa31qbgrny.osxc03 ;u htes DNA replication machinery?

  Studies have shown that genes such as Cy q+k l6s+m ypj )*:b0jtbeyrg+clin Dependent Kinase 3 (CDKN3) are highly overexpressed in cervicalpbj+:s+r k+yj)y0ml*gt e qb 6 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 hi0; 5x h/xiqqafghest during the cell cycle ?