The graph below shows the relationship bkodx zbg;u) zx9k9)c4z1fdhsv 45+lj etween maternal age and the incidence of non-disjunction. What relationship is suggested by the data in t 9 1dl) z 4;bgdc)sjhzovk+ kx4fx95uzhe graph?

  Which stage of meiosis is represented in the diagra-jc9g8v q 9 dx:w2xljsm below?

  The diagram below shows chromosome;teo7x+ fc mw(s 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 statkk1qis +*y77jinzzwy -c/ sb +qw m*x/es the number of alleles of a single gene which would be present in the nucleus bn+ z qy/scii17k+j*/-yw wzsqx *mk7of a cell as a result of each process?

  Which keyword is matched5 f ukav7;+xbk r:,jed to the correct definition?

  Which statement(s) ab3qvw pjg )f-q+de6 q2wout mitosis 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, which letter p gmiacs8ls(qh *,3wsu w* y0t+oints to a cell in anaphase?

  During which stage of mitosis does the nuclear envel3hjhn 4mkzhi8v0c6dy/ q.)y d5 zg9n e6eyb-uope break down?

  Which one of the following transport proteins only carries*tp at/7euukacy3:c0 out active transport?u/*7k:eya 0 ac3pctt u

  Which process does not happen in the shoot;6i lml)yl+)pvk -vg n apex?

  Which type/s of membrane tranr 4((ljn8 ;pmf a3p0g *pesglksport do/does not require energy expenditure?
I. Facilitated diffusion
II. Active transport
III. Osmosis

  The diagram below represents a cell with a diploid numbe*r5n( o8ccxsj .0cbh bcoacpd 6/h8.qr of 4. Which stage of cell division is the cell currently undergoingda*cp occ0sh q.hx( 8 8r5bnc.j/bo6c ?

  The photomicrograph below shows a root trqi d4l85tz :uog)l9 sip meristem. Which of the following sentences correctly defines a metld5 :rzgl)i98o uq4sristem?

  When does the randombbu d8:x8d :bt orientation of homologous chromosome pairs occur?

  Which process does not occur during meiosis?zer s-5:qcy- a

  If a cell with a diploid number of 3b obxe,gwmm9r;c f)phf d41 .36 undergoes mitosis, how many chromosomes will1c.dwh rb4 ,bff gx9o3 epm);m be present in each daughter cell after cytokinesis?

  The image shows a micrograph of a cell. q ;/jvgl3a t*kt kkg6;s:dpf;


What explains the appearance of the cell in the micrograph?

  Which statement(s) about homologous chromk(sgp.g. jqgfg :( )wvosomes 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 individual with Dobn55m *1rlye x;6*q wvcaocy2 wn syndrome.

Which statement is not correct?

  In the cells of a horse (E. caballus 1 todoip cdv(udy+1;.) during prophase I of meiosis I there are 64 chromoso vuco yd(+d1tp i.d1;omes. What is the haploid number of chromosomes?

  Which arrow is pointing to a chiasmry3w if43zi.: /gyrxzl;kz*n a?

  The diagram below represents the structure of a shoot apic,l z k-a0bo-fwjr4(hkal meristem. Which row in the table correctly identifies the process4k(o-r,h lfzk0a jwb-es occuring in the structures labeled in the diagram?

  How does meiosis promote variation?)i1wo7,w rys r

  Which of the following statements is/are correct for meiosis? n2pr 1sop2n :t
I. It is a reduction division
II. It involves random orientation
III. It produces genetically identical cells

  The diagram shows gametes produc/slv0 i.dy+ wc08 cowaed 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 the formation of edj 8z:v a0ob4/btxg6 (( u;hxn s1uedsecondary tumours from primary tumours as a result of; 1udd /h eb6juatoe:4 bz0xvns 8(gx( the movement of cells?

  How many chiasmata are present in the diagrad 2d5ds n d2oirw33pfv3ok5 g(m?

  Which statement is a similarity between cytokinesip -fmuo 3/n2jpbt+)nws in animal and plant cells?

  Which stage of meiosis is matched to the 62ytxg ; qppiar4y/t*correct description?

  Which statement(s) are true of meiosis I but not mq)jgpm*3 xh. teiosis 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 divisionextn(opty a (x1/pdvds;4h4 , . This results in the4py (ap,/1(s xdttdno exv; 4h formation of one large cell and one small cell. What is the fate of the large cell?

  Which row correctly describes diploid and haploid cells in huma1 9(l+)vdpyte qc)gzsxuvszg ; r)00ins?

  The following table shows the dko0a+)kfo j6th uko-8iploid chromosome number of a range of species.


Which of these statements is correct?

  What conclusion can be drawn from the karyogrxbe7g wn26 ziad 3/:zzam below?

  Which of the following processes is characteristic of the meiotic and not th2) qtrk8ix x*xe mitotic cell cycle?q rxtx)k*82ix

  The diagram represents a bud wi a.sn:8t y -3dk:gpphyth a 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 (Pan trogvl27urnvh r,awb . /-blodytes) is 48. Which row shows the correct chromosome number for different cell types and celllbn/ aw7 ,h.-b2uvrv r division stages?.

  At the end of which phase of meiosis I does crossing ovelgp;sehb e( 0-r occur, and what is the outcome of crob ;e-e0lg(shp ssing over?

  Which of the following statements does nog,)hbcpgf)wj44q si*wlt*( qt describe a step in the sodium-potassium pump cycle in the ne,h p4lwg4 jc))qwstb*iq( *fguronal cells?

  Which row in the table below is true of mei9(o5 t 8mesknc s)hq9tosis?

Membrane transport is important for allowing particles to move across thewe/u, syx ,xr46gojt+ cell membrane and respond to chaswgt jo+/xe, 64yu,rxnges in the chemical 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 regulated in k7fye. u k r;orjyv+98cells.

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 during the sybiq(v4uc22kwe3*o cell cycle. Which cyclin is involve2eu2w4y(*oqk 3bc sivd in preparing for DNA replication?

The diagram below shows chromosomes + u 34ijhr9kiaduring 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 ch ke(4e g bvhawt854 10*twqqjbromosomes?

  The mitotic index of throat tissues taken from 4 differentig6+7jrdefj: 8m2 ffssd)2rpc7q hk1 patients is shown below. Which s1hm+6 jc:ff2q)dfk 7er28 s7gripdjpatient is most likely to have cancerous throat tissue?

1.Draw a labelled diagram to represent the process of crossing ovqyhg 1.j ies+):e 7xzjer.

2.Compare and contrast random orientation and crossing over.

3.Outline the stages of meiosis.

  The image shows an abnormal humap / x e*p4cbm(y0sf8x :m8yxsan karyotype.


What is the abnormality in this karyotype and its cause?

The graph below shows the relative amount of DNA in one cell during one completedaz6b7/6yl ovf+ r1fzobi+o;/p9bo o cell cycle. Eaco+bp6fyzbo;iv l9zd7/6b 1ro +ao /ofh 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 hoyysn0::nolb r;-7ax l gah( r7mozygous for brown, long hair and a female cat that has black, short :h0;rnl:gla x7(bnayys7-o r hair.


Which of the offspring has a recombinant genotype?

1.Outline how polygeni vwit 6qjxk6,/c 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 chroma9k lw4s2 p*cyftids shown inp *lc94fwsk2 y the diagram below?

  The photomicrograph showc-mnujcal9 00 ah 9f0q24l djws a pollen grain from L. candidum (Lily). Which stage of meiosi l9 f d-w0ah0qcjau02 mcl9jn4s is shown?

1.Outline the events which would lead to an individual being born with Down 9o2jid 2tx3tq syndrome, which is characjt d9qxt2 i32oterised 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 i i)6msa3co vc55npa0 indirect way of measuring plant growth. A study was conducted on white onions (Allium cepa), under controlled conditions in a lab, to investigate the esi5c6imoav 05a3c np) ffect 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 diagvj5l96 9. ffb5sx j7gh6e w/ugp2vzodrams below show two cells from an organism with a diploid number (2n) 7/jvsvebjl9f . z5po695 gd62 uxfhgw 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 inc;, (8tg;cqo,g re wnd 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 differentrej 3gzz hdh+6r(uc i:vp ri16ehx2( 2 stages of meiosis. Which row correctly names each stagc6( z3e6 h1ug+pr hxrz:rje i2d(vih 2e?

  The micrographs show four phases of meiosis I in a plant. In what order do t;kf/+qzy o*+6jdiuja hese j+ y*di; qakujo+/z6fphases occur?

Mitochondria are responsible for supplying metabolic energy in eukaryotic cellsg1c(er84t c:s dl wb)p. 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 organisms, inheritance patterns of mtDNA found in hybrid cells, which are the result of sexual reproduction between twpcct) w rd(4slg1:e8 bo 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 differentdl)z)agf7;bn 7z f7 hy stages of the cell cycle in four samples of lung tissue from four patients. Which tissue has the lowest mitotic index? ;d hnfg) bfl zazy)777

  The diagram shows the domhd(ebj6-;u p --ga ec u0hc,okinant cyclin/CDK complexes at different time points in the cell cycchk(eced o-0- , ;aug6-hupbjle. Which cyclin/CDK complex activates DNA replication machinery?

  Studies have shown that genes such as Cyclin Dependent Keidmidj q1l1 v8b01n,inase 3 (CDKN3) are highly overexpq1in1id b8md l,e1 v0jressed 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 of cyclinl 2*rv8.3v7nvbfm u 0u p8dgko E the highest during the cell cycle ?