The graph below shows the relationship between maternal age ymt 9b3j2q d4)iccislft54n8;pe th *and the incidence of non-disjunction. What relationship is suggested 8j25c f * t4cy3 ihdqt)ibmpstln9;4eby the data in the graph?

  Which stage of meiosis iswh oc2. h-lgdnjv.dkb,t1(up,: xfg8 represented in the diagram below?

  The diagram below shows chromosomes during mv 9 t8y.0t8kpjkxo7c feiosis.


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 prtyuffj:1clq* 84, 2mucy+d gene which would be present in the nucleus of a cell lm*4yqdpuc2cu +jy,ft1r8:f as a result of each process?

  Which keyword is matched to the correct0:traqp49af w definition?

  Which statement(s) about mitosis is/(8kvkw 1t 8yey3bbxt( 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 letjp x 3;iq*wo4bter points to a cell in anaphase?

  During which stage of mitosis doesxwc.x 63nex w( the nuclear envelope break down?

  Which one of the following transport proteins only carries out active transp ave;47of x-:b tonvx0ort? nbvv04 eft;xo- oa:7x

  Which process does not happen in thepc4wh2(x 8 5i9 nmsamw shoot apex?

  Which type/s of membrane transport do/does not requir3 mm:epe mbg,.3ci;gre energy expenditure?
I. Facilitated diffusion
II. Active transport
III. Osmosis

  The diagram below represents a cell with a diploid n8gl, w6e 9frx5 xoa9ypumber of 4. Which stage of cell division is the cell currently undergoe56foxax 9w p,y r8l9ging?

  The photomicrograph below shows a roo6 t*vhwj+m 1v llu*,r/ lh.o1n(h rjjet tip meristem. Which of the following sentences correctly define*h1 ,orlhemvr.(/1unw*jh 6j lv+j lts a meristem?

  When does the random orientation of homologous chromosome pair;;6 fwhs ym.zil.sku1*cvv .ks occur?

  Which process does not occur dur,hyadt *x;ttu;0k +ghicxp6 3df4 4pfing meiosis?

  If a cell with a diploid number of e0ov.ir dio z826 h;f8y f7bcm36 undergoes mitosis, how many chromosomes will be present in each daughter cell after7vzobihrf6ey 8 d8 2icom;f .0 cytokinesis?

  The image shows a micrograph of /ufe;qp mjr blj5r ).)a cell.


What explains the appearance of the cell in the micrograph?

  Which statement(s) about homologous chromm 5st(ot mf::.rco h2posomes 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 individual69yzysva brz .mjs,3a)tz h .9p nn06f with Down syndrome.

Which statement is not correct?

  In the cells of a horse (E. caballus) during prophase I of m1,4wow bo,mc ypk +(smeiosis I there are 64 chromosomes. What is the haploid number of chp owobmm4 w, (,kcs+y1romosomes?

  Which arrow is pointing to a t2bt 7 .rtsa7hchiasma?

  The diagram below represents the s35- ;os -py+4fogoaacsyc 53 qhyup4utructure of a shoot apical meristem. Which row in the table correctly iy;5a4 fahoos5y43gu 3-c po- ps+ucyqdentifies the processes occuring in the structures labeled in the diagram?

  How does meiosis promote variation?8d/em.;co72gs*d e zvw9k w tt

  Which of the following statements i8z313naxr :(rmxil qas/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 fromu80u q, vzg9nk 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 from primary+5l(ek08 lo,piirhtt tumours as a result of thkp5 ht0oi8r tl (+i,ele movement of cells?

  How many chiasmata are present in the diagramrp hi+m/hbt j;v72n7a ?

  Which statement is a similarity between cytokinesis in animal a)lo.a x ysi qtmd8u7 ctg8(/1jnd plant cells?

  Which stage of meiosis is matched to the correct ;vwh1cn-;uo h 0c( trcdescription?

  Which statement(s) are true of meiosis0zp ;gp/ kyw zmz2(emn z)+b5u 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 division. This resul-+ff2gb a zn+.7wy gc8prhh0in vy. r+ts in the formation of one larc 7+nf0gh..i+ynr pavwybgfhz8 +r 2-ge cell and one small cell. What is the fate of the large cell?

  Which row correctly describeof)lq 2hj5mk 6s diploid and haploid cells in humans?

  The following table shows the diploid chromo/*n*vmk c:wfz95 ldn qsome number of a range of species.


Which of these statements is correct?

  What conclusion can be drawn from the karyogram by: . b- l4f9fp-*d kdo+hd4pbhdhbzf0 elow?

  Which of the following processes is characteristic of yt/:al b p/ww(the meiotic and not the mitatlwpyw :/(/b otic cell cycle?

  The diagram represents a bud with a shoot apical meriou0bpp9. kwzc5or 1w j0)hb7 eff; h(c(bjq 4qstem.

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. Whiz1m q3- rkk/wvc3 iev/ )a1k5o i5pppuch row shows the correct chromosome number for different cell types and cell division stages?kq3pr1k5vv-zi 51/cowa) p/ku3pi me .

  At the end of which phase of meiosi *urf7xhb(ml4s I does crossing over occur, and what is the outcome of crossing oxfm u r*(74blhver?

  Which of the following statements doer4f 06)jtsnni q ut vn0*80niss not describe a step in the sodium-potassium pump c8 u40qij 6t*ivns)0nftrnsn0 ycle in the neuronal cells?

  Which row in the table belowg j 6wblibx93rz9 o0q f,lj35w is true of meiosis?

Membrane transport is important ;oxwq0 b r-ia:for allowing particles to move across the cell membrane and respond to changes in the chemicar w0ba- xoq;:il 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 reguls.9 bxt:opvrn ta*4a8y 4woz :ated 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 show1fhd-m ee;uyco zpn718 pzl98s the concentrations of different cyclins during the cell cycle. Which cyclin is involvzf1 p pohn7um9e- c8dz8e;1 yled in preparing for DNA replication?

The diagram below shows chromosomes during meios,g c5jhexb)8nqu+.inbls 1r 4is.

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 chromosom.myugf6j3f . l4h fk:yes?

  The mitotic index of throat tissues taken froms tn6u bfd d:u/8qkgvvw o(+)c5)5ng w 4 different patients is shown below. Whicw)+qwb8us5dk5 6con gvvu td:g)f ( n/h patient is most likely to have cancerous throat tissue?

1.Draw a labelled diagramngxu r6y sf:,f2yi:5s,,ga xq to 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 karyoty1; 8bp383ogi 6h akqgfzan4jx pe.


What is the abnormality in this karyotype and its cause?

The graph below shows the r dt45qee5c w,kelative amount of DNA in one cell during one complete cell dt5qw ece 5k,4cycle. Each letter represents 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 shows82g x1 a cr,qo,iyw0mlkp4ii9 a cross between a male cat that is homozygous for brown, long hair and a female cat that has bla0lqpyi ,m o9i i,ax8cwk 4rg12ck, short hair.


Which of the offspring has a recombinant genotype?

1.Outline how polygenic traits can shsk8itw( uff t3,cfx74 ow 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 f4dnft/8ero8 4aqip oh mne*7bc ,c28shown in the8fq b8h4oditn* 2 ca7fmr4n/o8 pe e,c diagram below?

  The photomicrograph shows a pollen grain from L. candidum (Lily). Whicxiysx+ 0b hbu t55gw5o/n5dt(h stage of meiosd y5(hn05x5oit 5+b gts wubx/is is shown?

1.Outline the events which would lead to azac ydzr;/xnk+;cz 7)n individual being born with Down syndrome, which is characterised by the presence of three 7 / xzzn;dkzr)yc a;+ccopies 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 growth. A study was cond82vq/;pv)tgu s8y bnlse+2*qc* l jbeucted on white onions (Allium cepa), under controlled condi)cegp / 2buq;* 8lsjyn2+s8leqvt b*vtions 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 cells can divide. The diagrams (0 :u tsw.m,j )8nsmtqxop5 vcbelow show two cells from an organism with a d5t0 cx:ts. vs(pmu jw,moq8 )niploid 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 60bi- .usim2cfdjq7w expression 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 numbea5hf:fu-s b i4r of 8, in different stages of meiosis. Which row correctly nhbai5fsu- 4f:ames each stage?

  The micrographs show four phases of meiosis I in a pgvr1 oqhe;d2 ro7 w:vh3jml).lant. In what order do these phao .17hgjv l:o;hwv 2r)qe rdm3ses occur?

Mitochondria are responsible for sl0rsyf6hl r -(om0gw*ye6rf w ,d gf44upplying 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 nuclealr0 4s*lmf,-wyhf f(errwogd4y6 60g r 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 cells in different stages of thex ;pi2j ) b/q5,xdvkou cell cycle in four samples of lung tissue from four patients. Which tissue has the lowest iuxp; 2q), bv5jkxo/ dmitotic index?

  The diagram shows the dominant cyclin/CDK complexes at diffe) a7x5e6qtqvb+pf1p+drrz *h rent time points in the cell cycle. Which cyclin/1ex7rpqtrv b+d *6fqh) 5zp a+CDK complex activates DNA replication machinery?

  Studies have shown that genes such as Cyclin Dependent Kikv* u8x.9rzm 6ab hkj1h )*ncbnase 3 (CDKN3) are highly overe1bznj8*x ha) h96cm.kku *bvrxpressed 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 oe qv)k7(l5vi uf cyclin E the highest during the cell cycle ?