The graph below shows the relationship between mm0pp bi, -ti4pk .ny(saternal age and the incidence of non-disjunction. What relationshi4its,(bm pp0nk .y i-pp is suggested by the data in the graph?

  Which stage of meiosis is representb j;d ,1p(1tgij3 vpjded in the diagram below?

  The diagram below shows chro,ga*px*s2sv-* yflopl:a rz2gygs1 . mosomes 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 numbe3 - +5r0 yfbpgh 9rh1ndx8xb:d*qme rqr of alleles of a single gene which would be predq:y1b8x -0 xdfh*hr b9e+pr3 qn5rmgsent in the nucleus of a cell as a result of each process?

  Which keyword is matched tgbsk+m/ gc16ei6 i)kgo the correct definition?

  Which statement(s) about mitosis is/are true? .i d:yc4:bwlxt/ jc+xbugvlw - w08e.
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 points to a ce.1q.q flzh:m rll in anaphase?

  During which stage of mitosis does the nuclear envelope 3mka wm:3w;+1+p tvwbzbmhe;break down?

  Which one of the follow.nl8tvc8 1ji ying transport proteins only carries out active transport?8tny1v l 8ci.j

  Which process does not ha s* p+hpmtx:( jx;vkw n+ t1t0lt2gyg-ppen in the shoot apex?

  Which type/s of membrane transport do/does not requiybb0f7-7b q udre energy expenditure?
I. Facilitated diffusion
II. Active transport
III. Osmosis

  The diagram below represents a codv0 lreycgnz4h mq 9e6:) b94ell with a diploid number of 4. Which stage of cell division is the bq9l49n6m de r: z)04chovg eycell currently undergoing?

  The photomicrograph below shows a root tip meristem. Which of + 9 y(k4o1owxps9 1wgh,espjr the following sentences correctly defines a meristem9o,o r(pp1sj gw9kw+1sx e4 yh?

  When does the random orien:ve l3:9v;b bh xtc)qqtation of homologous chromosome pairs occur?

  Which process does not occur durin.7ie0wjz*tycawzn . f19c0 oyg meiosis?

  If a cell with a diploid number of 36 undergoes mitosis, how many chroma lz ml54c/jw4osomes will be ll44ca w/zjm5present in each daughter cell after cytokinesis?

  The image shows a micrograph of a cell.e2f a gr36xpy:


What explains the appearance of the cell in the micrograph?

  Which statement(s) about homologous chromo7j5mhfkfm-,7ig*iolp. n7 me somes 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 witradi9m, 8(tmg )5qfajh Down syndrome.

Which statement is not correct?

  In the cells of a horse (E. caballus) duringaf3l; *g:mqiesz1 p2c prophase I of meiosis I there are 64 chromos1qi3: m;a*lpfe2 zgs comes. What is the haploid number of chromosomes?

  Which arrow is pointing tb 4ikdzn;5re(u: j wn4o a chiasma?

  The diagram below represents the structure of a shoot apical meristem. Whichgf e/hx+e;d h7+cp(.klrbd k5 row in the table correctly identifies the processes occuring in the structuh(d 5hep7+/; lxgr.e dfcbk +kres labeled in the diagram?

  How does meiosis promo:w/o i)i+s lktte variation?

  Which of the followi-)cf v/p b ;m pk6ylvf+r:.dkwng statements is/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 from two homolbtsbgq 8pi/o3e;52qj ogous 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 tumoursd k-yst(7;hmbbu6i tvo2 8i s( from primary tumours as a result of the movement of cell - k(i(oss y tm;vdti287hbb6us?

  How many chiasmata are present in the dun9 2uz xjnjgsr;0:3bh - c5xdiagram?

  Which statement is a similarity between cytokinesis in aghog5 -s h +5pwk x87tkgv)0/ ertyoykod7/(onimal and plant cells?

  Which stage of meiosis is matched to the corrdwviu-4t1xawl)y bh 9xf 8 :8lect description?

  Which statement(s) are true of meiosis I but not meiosis II? z 5:sc ve,bwqvmd1: :l
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 a xdl.c ))jdpz9 :lda jvbot137fter the first meiotic division. This results in the formation of one large cell and one small cell. What is thd1v)p ajt7)b l9:xz lo cdj3d.e fate of the large cell?

  Which row correctly describesn9a fv- 1o.bhkxku 7w. diploid and haploid cells in humans?

  The following table shows the dipldf-3- e yxelf4f 3h twa.xjm0*oid chromosome number of a range of species.


Which of these statements is correct?

  What conclusion can be drawn from 6cgcdy1lff )f743dfzm9wht, nb p)8 athe karyogram below?

  Which of the following processes is charac kq;qj7z+.)pfd0pgx f teristic of the meiotic and not the mitotic cell ;d 7q0zp)fxkjf+qg.p cycle?

  The diagram represents a bud 8gkso-f8ifk q z:7krww 3t,0 qwith 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 chimpai9:ir ytk( w,lnzee (Pan troglodytes) is 48. Which row shows the correct chromosome number f:iy( rl,9kti wor different cell types and cell division stages?.

  At the end of which p r 9p,a9 gjcr9hn.b(qphase of meiosis I does crossing over occur, and what is the outrbph99pnc a(rq9,g j.come of crossing over?

  Which of the following statements does not describe a step in the sodiumwdtox.y5cp +idda6 muu *-e0 /-potassium pump cyclox6m d+p*e0tw udc 5yi/.d-ua e in the neuronal cells?

  Which row in the table below is true of me7ddx ncs -(ks h07b/mkiosis?

Membrane transport is important for allowing particles tof nb2*9 . sdapaah*7es lu*8q2zqc 8nl move across the cell membrane and respond to changes in the chemicalp8 .fql2sbnuqs* 9a 8 h*czal2 a7d*ne 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 4+j ew-ok7aed 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 during the cell+ gk1tl uxs+hth,n.(c cycle. Which cyclin is involved in preparing for DN+.1tlgs hhkc ,(tnxu+A replication?

The diagram below shows chromosomes +zr m)oy+ ov2pt :8g8-kcqqttxs12b vduring 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 chr9 w; z8d.rhbmx+c0vrnomosomes?

  The mitotic index of throcy2zay3jn o+ -em kswf6(5a+ve 0r6fhat tissues taken from 4 different patients is shown below. Which patient v2 m3-e6+(56af+yzwkce rfs njohy a0is most likely to have cancerous throat tissue?

1.Draw a labelled diagram to represent the process of crossing over p,5 /gphw/y2 * vwo*rv3bwwhxt8kg +r.

2.Compare and contrast random orientation and crossing over.

3.Outline the stages of meiosis.

  The image shows an abnormal human /6.at9pkyuza karyotype.


What is the abnormality in this karyotype and its cause?

The graph below show+)- a (osdce7z 7tbtsgs the relative amount of DNA in one cell during one complete cell cycle. Each letsgct7z ) (-os btad+7eter 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 thaax 92mlwzu+ud0 c-u8rt is homozygous for brown, long hair and a female cat that has black, short hai 2wcd x+-rul9u0 zu8amr.


Which of the offspring has a recombinant genotype?

1.Outline how polygenic traits can show a normal dinjzk5n pkm j..)2k* g2p:w tusstribution.

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 chromatidd3 pc,9-f cnphrgjv46s shown in the diagram belop6,9p vcrj 43cdnfh-g w?

  The photomicrograph shows a polqys .ikrlfp8 wm:mc kt )./r))len grain from L. candidum (Lily). Which stage of meiosis is shoskpr qm lyk .wc)m)/t:.8) ifrwn?

1.Outline the events which would lead to an individual being born w6b dlq+6nwg 2jx8 o7faith Down syndrome, whico7 dwxb+6ngqj2fa 86l h is 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 indirect way of measuring ;1gklv4j pq-/ ay a6ytplant growth. A study was conducted on white onions (Allium cepa), under controlled conditions in a lab, to investi-t/ya1; j6lqpyg k4v agate 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 below szj olq- d+-6f/pnr vz(ho+fl(-q jn/p rzzd6-o vw two cells from an organism with a 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 of gene expression in stem tl)2.3 5ycxxcp/ eka k*( cesygrowth.

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 different stkfc mv9vk:zcgs;3s) 6 ages of meiosis. Which row coskc:sm3c6vz g ;kfv9) rrectly names each stage?

  The micrographs show four phases of meiosis I in a plant. In what order do thkm1hyi;4g4 thpri *.dese pi*ip1r dg.h4m4; thky hases occur?

Mitochondria are responsible for supplying metabolic energy i3. 2kdtpatsum i.n6:rn 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 inheria62str. im:n ku3p.tdted 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 ni uz+r-ndp r/( ;cn,ndifferent stages of the cell cycle in four samples of lung tissue from four patients. Which tissue has the lowest mit(rci+ n, -zn;n/drp nuotic index?

  The diagram shows the dominant cyclin/CDK compyr,4i( ts+e 6(da lhallexes at different time points in the cell cycle. Which cyclin/CDK comhry,la d6e l+ ai(t4s(plex activates DNA replication machinery?

  Studies have shown that genes such asp:8kwyl k4 t9w Cyclin Dependent Kinase 3 (CDKN3) are highly overexprw489 : wtykkplessed 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 cyclin E the highest during the cell cycle ?)xlayz0(f tpk zz8 9v1