The graph below shows the relationship between maternal ageyl 01ynt/x9jz and the incidence of non-disjunction. What relationship is suggested by thtyjz x/l1y90n e data in the graph?

  Which stage of meiosis is re ig ktnb2s shfj +wu/eu44c32-presented in the diagram below?

  The diagram below shows chromosom7ojnw)8jaw)g8 rpeixn:b d+xo1 n l(6es 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 the number of alleles of a single gene 0bm/auvx c5,*n kt. d/d/vthsdvo5b- which would be prest/tv.bd,uk vd*x-bsn5m /ac /vo5h d0ent in the nucleus of a cell as a result of each process?

  Which keyword is matched to the b6dc p k zk6+ 2+pie 3v(h0e8tlrcmb9mcorrect definition?

  Which statement(s) about mitosis is/are tr+:8gx :tm(cj7erwg(cez4o z aue?
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 letthk10ib*mzp 2v er points to a cell in anaphase?

  During which stage of mitosis does ,) zmmik6 ue51ce:vx styf m51the nuclear envelope break down?

  Which one of the following transport proteins oj l8gw (3viia:++d txr:geg8 only carries out active transport?:i g8 or(xei adj8w:tvlg 3g++

  Which process does not happen in the shoot apex?9 * rh 6,p)m;gz a8p4ggk-dls pd6fvph

  Which type/s of membrane transport d0i f-mvvwv5p* o/does not require energy expenditure?
I. Facilitated diffusion
II. Active transport
III. Osmosis

  The diagram below represents a cell with a diploid number of 4. o0x/6lq kpo+ xWhich stage of cell division is the cell current q+/6po0k loxxly undergoing?

  The photomicrograph below sh/23ri3vdcnus51ac rf ep 4gh1ows a root tip meristem. Which of the following sentences correctly defines a meristeh 1a/4gfru 1seciv3 d 3pn5r2cm?

  When does the random orientation of 1k; dd.0 fuxpl8ncs*r homologous chromosome pairs occur?

  Which process does notkh8 vhsd *g0w* occur during meiosis?

  If a cell with a diploid number of 36 undergoes mitosis, how many chromosomesndxgs,e-gax5 eu( x )cw0ns +) will be present in each daughterc-)0+xsx asxgd ee )(,g wu5nn cell after cytokinesis?

  The image shows a microgr,cw;pc*cp4ddbv uwv3i ff+6, aph of a cell.


What explains the appearance of the cell in the micrograph?

  Which statement(s) about homologous chromosomes is;s x;lf 63-e)rul gsrd/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 892 u qxv*qrjrDown syndrome.

Which statement is not correct?

  In the cells of a horse (E. caballus) during prophase I of meiosis I there arvq:oo igf0 w-)e 64 chromosomf- oo wi:)vqg0es. What is the haploid number of chromosomes?

  Which arrow is pointinif,0vdps ngd f.:;f e8g to a chiasma?

  The diagram below represents the structure of a shoot apiu1 lu6z;*x eepr cpx58cal meristem. Which row in the table correctly identifies the processes occuring x plue*1z;5c rpuex68in the structures labeled in the diagram?

  How does meiosis promote i11 zfv mlwcd 9p6tg;ah b:yrd78ui*8variation?

  Which of the following statements is/are correct for meioc6i2 7tld f2bio8 fly0m-p.fisis?
I. It is a reduction division
II. It involves random orientation
III. It produces genetically identical cells

  The diagram shows gametes producediu8 u er .7st-s2w j1nh+s*igx 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 t1dg,himo4f p1 7z5yjg he formation of secondary tumours from primary tumours as a result of the movement op1d,7mfgg oi4yz 5h1 jf cells?

  How many chiasmata are present in ther) 5q lb:cz4rm diagram?

  Which statement is a similarity between cytokinesis in animal and plant cnno . q+oxhs:+eg)h.dells?

  Which stage of meiosis is matched ttqsj h12)i aj :)o ttcu6*jf3co the correct description?

  Which statement(s) are true of meiosis I bu;*nlm77eva3tk 0hm (g xnb718kwxhzx t 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 oocyt an,f9ix 0fk ,t;8xolte after the first meiotic division. This results in the formation of one large cell and one sma8x nkttaf;9lfo,x0, i ll cell. What is the fate of the large cell?

  Which row correctly describes diplod3 c0b8 vtt6haid and haploid cells in humans?

  The following table shows the diploid chromosome wl *y4mu9zfr8idz ,w;x/ a 9gjnumber of a range of species.


Which of these statements is correct?

  What conclusion can be drawn from the karyogramd+z;pq)x gyf 6/;g vlb below?

  Which of the following processes is characteristic of the meiotic and not t s;tx/yh/r 4-yi0 saadhe mitotic ces0y;/hd ya4s iat-xr/ll cycle?

  The diagram represents a bud with a shoot apical 3y :jf, cm-sycmeristem.

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 ro0:pfgbiog lt/ 2ck(b7(mb : enw shows the correct chromosomegnb(b:o/m lt70(p keg b2i cf: number for different cell types and cell division stages?.

  At the end of which phase of meiosis I does crossing over occur, ffcb(m5o 2 6c2ykum (aand what is the outcome of crosca(bc 2ko5uf y(f 2mm6sing over?

  Which of the following statements does not dejsj 7*c;o0kk(c agqq0to*xh* 8 wvmv2 scribe a step in the sodium-potassium pump cycle in the vq2vxk8kc7j 0jt*og*os(hmwc*a; 0q neuronal cells?

  Which row in the table below is9clhd.xh 99/ )tv:wjlnpf z:hxou/7h true of meiosis?

Membrane transport is important for a-(*jxf6)bzclzq e5er llowing particles to move across the cell membrane and respond to changes in the chemical composition of th6-cbzleeqz r(* )5fxje 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 re80w *sut wt:k5 uw5zrrgulated 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 differkg 94pnvebv /q;+om9mzv29 lnent cyclins during the cell cycle. Which cyclin is involved in preparin9l nvk4nv9 ebz+ omgp/2q9v ;mg for DNA replication?

The diagram below shows chromosomes during mef re8o;a45dhl lck3j1 j7p 1rviosis.

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 chgvb osahu *m 0w;.mg(d 3mh6+vromosomes?

  The mitotic index of throaax(2u a, icnzv2 5dpc6t tissues taken from 4 different patients is shown below. Which patient is mosta c 2iv2cpu56 xzda(n, likely to have cancerous throat tissue?

1.Draw a labelled diagram to represent the pe (8s9tjtlid 0ypvj 8lou .qy tf73v;.rocess of crossing over.

2.Compare and contrast random orientation and crossing over.

3.Outline the stages of meiosis.

  The image shows an abnormal humalgt.w)arkc ap+ z+,k,n karyotype.


What is the abnormality in this karyotype and its cause?

The graph below shows the relat/2f3i cjp, gyf0sim e:w)-xsj ive amount of DNA in one cell during one complete cell cycle. Each letter represents one stage of the 2jspj s),wyfixcm0-:/ g i3fecell 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 sh+nac hb6b3kk :+ silv 4opg8i.ows a cross between a male cat that is homozygous for brown, long hair and a female cat that has black, shor6onb4k+ch+8g i:v.pl bis3ka t hair.


Which of the offspring has a recombinant genotype?

1.Outline how polygenic trezg ae:ggd+*fw; pst2h:);d vaits 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 c:u(y iqe- qywv7.la:*j,ahdnrossing over of non-sister chromatids shown in the diagram below i:vj*q qaa dwly.-eun(7:,yh?

  The photomicrograph shows a pollen grain from L. 0k,x k up/r8;q5dzpricandidum (Lily). Which stage of meiosis is ipdk ru0/5x; ,r8qp kzshown?

1.Outline the events which would lead to an in1naviz p31 iq2dividual being born with Down syndrome, which i12viaq1 p i3zns characterised by the presence of three copies of chromosome 21.

2.Explain how meiosis increases variation.

3.Outline the stages of meiosis.

The mitotic index is an indi;adog 1 / *np3dg,wknarect way of measuring plant growth. A study was conducted on white onions (Allium cepa), under controlled conditions in a lab, to investigate the effect of so ,ad;npgon3k /1gdw a*il 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 cm, j6qi7akv ujfg.ma6w5r( 4pan divide. The diagrams below show two cells from an organism with armjjikwa5 7u6a 46g.(qf, vmp 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 ofiv:;u dzd.i/xov5 d:o gene 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 number of u6zph .qw5h//y5e gkv 8, in different stages of meiosis. Which row correctly names p 5y/u/v6hgqez hkw5. each stage?

  The micrographs show four egrm6+5h/ 7w soaw0 kdyc a4-rq p;fo.phases of meiosis I in a plant. In what order do these phases occ; g+0o-eahqroy7mwrfp wsa / 6d.c45 kur?

Mitochondria are responsible for supplying metabolic 3t +yk5(yhql(z9qfxlm8f 3 pnenergy 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 nuclear DNA which is inherityz9hn+3tp58 l3 q(f lk yq(xfmed 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 the cell cycle 8hq2bl/z- gftin four samples of lung tissue from four patients. Which tissue has the lzt g/ 2q8-lfhbowest mitotic index?

  The diagram shows the dominant cyclin/CDK complexes at differe;nyws 02b :g+axpkcmvsn jm1o7n; *u5 nt time points in the cell cycle. Which cyclin/CDK complex activates DNA replication mw7*ob0 amcu1;vpxgnk :jn 5ys s2mn; +achinery?

  Studies have shown that genes such as Cyclin Dependent Kinay (eqkvp9jh33se 3 (CDKN3) are highly9p y3 (ejh3kvq overexpressed 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 concentratio/2,sqiyuezo vg25h(lg5 q 8cin of cyclin E the highest during the cell cycle ?