The graph below shows the relationship between :wggd)m xqxc3)s:k(/f 7ne1 xqo aq3vmaternal age and the incidence of non-disjunction. What relationship is suwfnk:q: qgeqs13x 37g / ax()vcxdom )ggested by the data in the graph?

  Which stage of meiosis is represented int hsf02n2ka t3 the diagram below?

  The diagram below shows chromosomes mh0h fv(9hzy3 tj b*0fi,2tf5tj4lf kduring 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 all .th itxo,na fw06k9i )xm;7xseles of a single gene which would bek9nxxm xa0t;.his,6 fow)7i t present in the nucleus of a cell as a result of each process?

  Which keyword is matched to the correct defnnp* yits 32:wh l6/fsinition?

  Which statement(s) about l obvsy8rl9l ,6j tf;5mitosis 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 below;*2he,tmh yho , which letter points to a cell in anaphase?

  During which stage of mitosis does r 5tri9a*evvn/syip3w*u,4 uthe nuclear envelope break down?

  Which one of the following:9w / nhrr94k,gaw d.mg8 s9/tf; zhymvn5oxx transport proteins only carries out active transport?rk/hm gmxwn;49o: ta5g8 n,9y9drsxzh. f w/v

  Which process does not happen in the shoot ;i 15gwu5nccc glj o(4apex?

  Which type/s of membrane transport do/does not require energyg4n.jthb ie 8e il,91y expenditure?
I. Facilitated diffusion
II. Active transport
III. Osmosis

  The diagram below repres3uu r6.a9zhl fents a cell with a diploid number of 4. Which stage of cell division is the cell currently unf9l .z3uh6 arudergoing?

  The photomicrograph below shows a root tip meristem. adbmlm*(n 9ehfmz)g 1 y1o,k- Which of the following sentences correctly defines a m9)lf h1 o1dgmynz,b km(ea-*meristem?

  When does the random orientation of homologous chrnaws( 6d1 qzbifle(2: 1d 4emk e5ql5tomosome pairs occur?

  Which process does n : x4 py6kq,,qgy2y q6gza; .m*wizqkzot occur during meiosis?

  If a cell with a diploid number of 36 undergoes, o,sn sank v5oaj71d4 mitosis, how many chromosomes will be present in each daughter cell after cytokinesis?1n, 4nkdjos7va5 a,so

  The image shows a micrograph of a ceo5h;/de xc o:xll.


What explains the appearance of the cell in the micrograph?

  Which statement(s) about homologous chromosomes )q5kqse c5pb0 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 individ;goo: h*k 76mf) fnm xl2feeejyg0 /l4ual with Down syndrome.

Which statement is not correct?

  In the cells of a horse (Edar3i ;(fq4p d. caballus) during prophase I of meiosis I there are 64 chq 4(pda 3fr;diromosomes. What is the haploid number of chromosomes?

  Which arrow is point.fd+ p09ew(-,i8wnyaz1ctjl-gfg cd ing to a chiasma?

  The diagram below represents the structure of a shoot apical merist;tbwx d u2h 3g*ts6kmxc-r;6 mem. Which row in the table correctly identifies the processes occuring in the structures labe sm* -; 2tg r66cu;dxb3xwtkmhled in the diagram?

  How does meiosis promote variat.db6 lcti,i) dion?

  Which of the following statements is/are correct for mepw+0 , nqkbit9iosis?
I. It is a reduction division
II. It involves random orientation
III. It produces genetically identical cells

  The diagram shows gametes produced from two homologoiirvvc4bm 9*0us 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 prima+ki0/5v 05lt+m ebtff5m6 (m tgixtjzry tumours as a resut ftj5fmbi0+v5(+6g 0tmx/zm5letk ilt of the movement of cells?

  How many chiasmata a9m +kgkfmhz8eg8up( 0re present in the diagram?

  Which statement is a similarity between cytokinesis in aw3;/rfv y q:bonimal and plant cells?

  Which stage of meiosis is matched to the correct xanp;4tgpw41 1pn )pndescription?

  Which statement(s) are true of meiosis I but not meiosis II?ja:fs8uy,i,f 3q:ek, pxdbf ir6 )*ksz.ha5i
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 result(v2m3 jk+lw eus in the formation of one large cell and one small cell. What is the fate of t l+k32(jumwv ehe large cell?

  Which row correctly describes diploid andoh:3;l ntyg ,v haploid cells in humans?

  The following table shows t 0tnx zs riw3w1*e: l.(gw1deche diploid chromosome number of a range of species.


Which of these statements is correct?

  What conclusion can be drawn from thh2 9y v6lvmp;7rd 7no3b9zff ae karyogram below?

  Which of the following processes iy.ns7-e hz-n8i:b0 tr klka)ds characteristic of the meiotic and not the mitotic celt-i.kbs8en - 7:d 0ykrha)lnzl cycle?

  The diagram represents a bud with a shoot apical meristem. t :2 pqi(ixh(9koz/d02v fzey

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 chic/z 6w8mtcuf) mpanzee (Pan troglodytes) is 48. Which row shows the correct chromosome number for differ6 cmc/wf8 zu)tent cell types and cell division stages?.

  At the end of which phase of meiosis I does crossing over occur, a;,v/(4gii d 8 jr9 oxktlasps4nd what is the outcojadvprt8 /ii(94k slxo4g;,s me of crossing over?

  Which of the following statements doiu hx,/p,y0m v6wj9ae+ zpyzgmi7 , 4pes not describe a step in the sodium-potassium p m7 ,0ji 6y,ypmzwpgex+4av/ z,uip9hump cycle in the neuronal cells?

  Which row in the tabqj55vfeol ndv4e75-fy0 *d mm le below is true of meiosis?

Membrane transport iscxi9xr;n w:9u iey9prs+sf ( io3l 9t)46opea important for allowing particles to move across the cell membrane and respond to changes in the chemical composition ou99;reip9xsi43o poxye a+ilft(s: 9c6w n ) rf 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 mitosi d-mw1y1-gr pws 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 cyclins d06vl b,grbv:luring the cell cycle.:l rvl0b v,gb6 Which cyclin is involved in preparing for DNA replication?

The diagram below shows chromosomej4*4ewgjp .ktnb2 9 wo70tq, k9kahqys 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 involves5j -46cfugq*8 k 1gd2ncn dent the separation of homologous chromosomes?

  The mitotic index of throat tissues taken from 4 di87lszcbyp z9z+c,s vz00 w8iofferent patients is shown below. Which patient is most likely to have cancerous throat tislc07by9 izz,8oz 0zw spc+8 vssue?

1.Draw a labelled diagram to represent the process of crossing over. dw,-cstak3 p;

2.Compare and contrast random orientation and crossing over.

3.Outline the stages of meiosis.

  The image shows an abnormal human karyotyejd .jy c,2p9dpe.


What is the abnormality in this karyotype and its cause?

The graph below shows tnxutwpc/ r5uqs;4 b 27c x v8,rpxd+)ohe relative amount of DNA in one cell during one complete cell cycle. Each letter represents one stage of the cell cycle.dcr ;+bx/8tsqcp 5247nwpu) o x,urxv


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 cat fvhv3-/c/ 4dcihkc90 ip7 bsn6*;j hb fj.ktrthat is homozygous for brown, long hair and a female cat that hascb6iff j3/c h/k4kdhtnvvci7 rbp 9-0*h;.s j black, short hair.


Which of the offspring has a recombinant genotype?

1.Outline how polygenic traits can show a normal dist*anovn5 edp v 42.n:9fv,hvlaribution.

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 cnn.mi6y6 fpr xrp;:y2rossing over of non-sister chromatids shown in tnry:;2 f 6ni6.mxy rpphe diagram below?

  The photomicrograph shows a pollen grain from L9 .+)inaojui -b c.ac jxl)g1v. candidum (Lily). Which stage of meiov.a1j .+ jc gxoaib-)9uli)ncsis is shown?

1.Outline the events which would lead to an indiv x2hlrrom : z87nqyp,5idual being born with Down syndrome, which is characterised by the premnq l,z 782xpoh5rry :sence 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 measu chbjutocd1* 6:i ob,(ring plant growth. A study was conducted on white onions (Allium cepa), under controlled conditions in a l hc:c,1ubotb6oj* id(ab, 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 i7zm v,3e*wgnz n which cells can divide. The diagrams below show two cells from an organism with a diploid vzemw,n*3zg7 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 lr5d7aav0zq 2 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 number7 .c4:cyczdb o of 8, in different stages of meiosis. Which c:dcz.4o7bcy row correctly names each stage?

  The micrographs show four phases of meiosis I iaks3yby ;k -y.d8e)q zbcey,* nqi p2:n a plant. In what order do these phases occus2de3akzknq ). p-cqyb y*:e b,;yy8 ir?

Mitochondria are responsible for supplying mq3(rsun2 t hra3lr7 iw5rf.0setabolic energy in eukaryotic cells. In most eukaryotes, which reproduce by sexula(0 3ns.3ru7s rrtqr5 2i wfhal 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 number of cells in 8)c o+emmhyiq0l p-o(different stages of the cell cycle in four samples of lung tissue from four patients. Which tissue has the lowest - o(yemp m+0c8ol)ihqmitotic index?

  The diagram shows the dominanth / g(dcp ;j ropk5sypdb2lj0hx/;u5- cyclin/CDK complexes at different time points in the cell cycle. Which cyclin/pb l5hpj0o;yr(cjh g 5-/sd;/pdkxu2CDK complex activates DNA replication machinery?

  Studies have shown that genes suzbjah (l437kwch as Cyclin Dependent Kinase 3 (CDKN3) are highly overexpressed inj 4hzwa3 l7kb( 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 (f fk1 yjt0iz:j:gq6zE the highest during the cell cycle ?