The graph below shows the relationship b 58l+j fnszr34sumzu50upib (etween maternal age and the incidence of non-disjuncti5n 3+ 5zuf0spzrlms(iu8j 4ubon. What relationship is suggested by the data in the graph?

  Which stage of meiosis is represented h diy0 .gfx.zylj:f6-e4zjun e f/p97 in the diagram below?

  The diagram below shows chromose 1 qq(7haw4i48 miqztomes 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 which woulmv t o3xy4r8 ..*wxodu, kqf4qd be present in the nucleus of a cell as a y , moxtx.4q*rvdk. wof3uq 84result of each process?

  Which keyword is matched to the co g(ji)sm-b2 w qsj5dn;rrect definition?

  Which statement(s) about mitosis il+92 t1hbstp3 jifbk *s/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 below3,ryq ispw71p4 t m;t.p9xdm m, which letter points to a cell in anaphase?

  During which stage of mitosis does the nuclear en qkvap,byf++1 velope break down?

  Which one of the following transporg* wfbt qk7*si;a q(e;t proteins only carries out active transport? fsbeit(ag*;w7qkq ;*

  Which process does no m7b+3ohu 2+n8d5f +v xjvlinst happen in the shoot apex?

  Which type/s of membrane t38k/k v g)w34 erdcwvxransport do/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. W- 9wc,n ,ttw(v;bxn e h6m5qvlhich stage of cell division is the ceenw, 6tqhwvlmxn,59 (bct-;vll currently undergoing?

  The photomicrograph below shows a root tip meristem. Which7(ja 9mt-bbht of the following sentences correba9-b7tt hjm(ctly defines a meristem?

  When does the random orientation dw w3;pxw)cx1.nv ;lv of homologous chromosome pairs occur?

  Which process does not occur during mei9-;lsj2o ttd dvt;f+tosis?

  If a cell with a diploid number of 36 un xkx8xw a7gy1l.y .1jk+3 htkgdergoes mitosis, how many chromosomes will be pxa1x j3.kygky. w t1kh+l87gx resent in each daughter cell after cytokinesis?

  The image shows a micrograph of a .wtd9j*q 9qiw:gtf-- sf lrkfx )k0h( cell.


What explains the appearance of the cell in the micrograph?

  Which statement(s) about homologous chromosomes is/ar qu fz)2hc8gp;e 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 wit.l)mes0 jc7(49s ae 6dibgseh h Down syndrome.

Which statement is not correct?

  In the cells of a horse (E. caballus) during prophas42bl)ci bo- 9vigh d7de I of meiosis I there are 64 chromosomes. Whatcgi 47libhv -d)2o9 bd is the haploid number of chromosomes?

  Which arrow is pointing to a n8tinr qdy;;3chiasma?

  The diagram below represents the structure of a shoot apical meristem. Which q p6jv-)wzci1row in the table correctly identifies the processev-6c zpi)1wj qs occuring in the structures labeled in the diagram?

  How does meiosis promote variationk rl7j 7hpy0 fu5n9tz)-,apmwsv khc;3+ ;dqz?

  Which of the following statements is/are correckm6+ tl0 zfr1zt 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 chromosomes. 1,mfpty 0oj9ty.a j.i


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 formatfd8j3i yx-h3 u1b4i pfy4m*k uion of secondary tumours from primary tumours as a result of the movement of cells y8 *hiu3ju3dy4-fif1p bmk 4x?

  How many chiasmata are present inv(oe4qiz6np 9 the diagram?

  Which statement is a similarity between cytokinesis in animal and plant cet/e *h k4;zx9 0a rkel quda-gsy:wk81lls?

  Which stage of meiosis i4x 3unjur i*co(0-i bis matched to the correct description?

  Which statement(s) are true of meiosis psopmm+e 5*c xq8okcn dp/nl*4w-51 q 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 ,(u6 :j itgy0j ar8jldan oocyte after the first meiotic division. This results in the formation of one large cell and one small cell. What is the fate of the large cell?lt,a :8 rg (dijj6yju0

  Which row correctly describes diploid and haploid cells in humansos,m)3w ywxu2 ?

  The following table shows the diploid chromosome number of a range y;51 pm;sq6tskrx / tsof species.


Which of these statements is correct?

  What conclusion can be drawn from the karyogram below? ib6:3 gx8bnks

  Which of the following processes is chara zt rvi* v0sm(na+ku8i/)m- mfcteristic of the meiotic and not the mitotic cell cyclef muv* zm ki( i/)tavn-0+ms8r?

  The diagram represents a bud with a shoot api3.:mlx:2g ;ogtei o hrcal 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 troglodytes) is 48. Which row sh 0ivi2 ab . r-ixkecx)m+dd18hows the correct chromosome number for different c kxx8i1+v)r0ebi -i2 mchd da.ell types and cell division stages?.

  At the end of which phase of meiosis I does crossing over ocer k (dulx472) nbn1fucur, and what is the outcome of (l 41ud)un7 fb2nxr ekcrossing over?

  Which of the followijhuwy f x3mi(9e(v6h )ng statements does not describe a step in the sodium-potassium pump cvhi xeyum3()h6w9( jfycle in the neuronal cells?

  Which row in the table below is true of 3uhat(86l1x x3dlkt bd 5*o-e/x kojz meiosis?

Membrane transport is important for allowing particgv;8irokzo 3+les to move across the cell membrane and respond to changes in the chemical composition of the exro 8ozg3iv k+;tracellular 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+w f *ttsm3)das 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 conc5(8 ojfpnwno( entrations of different cyclins during the cell cycleow8o5 fpnj(n (. Which cyclin is involved in preparing for DNA replication?

The diagram below shows chromosom; 2cz:v(/ 9*bnau5er plwwxe mes 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 invo a*w7hm)pe/d:l xeb-d,s+wr xlves the separation of homologous chromosomes?

  The mitotic index of throat tissues taken from 4 differe0b q,6/ hm-*qs0askoj bysi4s nt patients is shown below. Which patient is most likely to hhsm sqb6q*yj0ao/i4b0k-ss, ave cancerous throat tissue?

1.Draw a labelled diagralvj.;: nm7r tj,itl4m m 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 humr.8p/xu oj0a b md3*hjbf/xy (an karyotype.


What is the abnormality in this karyotype and its cause?

The graph below shows the relative amount of DNA in onei+o *k;09sysi 5xtcnt cell during one complete cell cc;ni+ yxsoi*0ks9 tt5 ycle. 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 shows a cross between a male cat that is homo7mf;njo)htgr6)s j 7wzygous for brown, lo js)w7hjo;f)rn t76g mng hair and a female cat that has black, short hair.


Which of the offspring has a recombinant genotype?

1.Outline how polygenic t ja0.1e)c)ych pgt f 2yov6d)draits 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 frj : 9k(6m8fh*e cqbxjiom the crossing over of non-sister chromatids shown in the diagram6j 9be*:kqfjx 8ihcm ( below?

  The photomicrograph shows a pollen o9)4u pfe/jrd y+.hi / xugbz,grain from L. candidum (Lily). Which stage of meiosis iupg /,rufh 9 xjz+/oiebd4) .ys shown?

1.Outline the events which would lead to an individual being boo5y gxcbj4w t( ;qco;0rn with Down syndrome, which is characterised by the presence of three copies of chromoso gjoc;5b wtc oqx(;4y0me 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 condn,srimcax; : /ucted on white onions (Allium cepai a/;:xmsn rc,), 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 two ways in whic/ 9i4 *flzm t ji2qu26akymx(ph cells can divide. The diagrams below show two cells from an organism with a diploid number (2n) of 8. kla2t*zmqipf2 9m 6u 4y /ixj(


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 stem.8ptrscn- rbe:qy8l: 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 differentkdh htt6ev 9l+c;m 0rs(+l( ww stages of meiosis. Which row correctly ns c9 ;r+h(kttdh 0e wl6+vm(lwames each stage?

  The micrographs show four phases of meiosis I in a planmv a.0qn*2ahe0 z +2flsh8 lwgt. In what order do these phases nva g a2+0fq8lz.s e2mh0*hlwoccur?

Mitochondria are responsibl8g.q:/7sr:oi4 +pj, - dwn eggjw dpmbe for supplying 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 nuclear DNA which is inherited from both parents. It has been suggested that, in some eukaryoti+dq8g7/r :n,.o ibj gge:p wpms-j4dwc 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 o 215)jigivhftf the cell cycle in four samples of lung tissue from four patients. Which tissue has the lowest mitoti hvtjf)igi125c index?

  The diagram shows the dominant cyclin/CDK complexes at different time pointsgd::zztk4urh un(0nha nz0b*( 5/tlo in the cell cycle. Which cyclin/CDK complex activates DNA replionu* z0h(tu(4a/hk nn 0g:z :zrdbl5t cation machinery?

  Studies have shown that genes such as Cyclin Dependent Kinasag8pry f 2/7tk;1 ayvae 3 (CDKN3) are highly overexpressed in cer;ga8y yrpkf av7a2/1tvical 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 jgd- im *fpp, 7y5ek-ithe highest during the cell cycle ?