The graph below shows q5pm ux7p*wrz .vms4lc6 nq+8the relationship between maternal age and the incidence of non-disjunction. What relationshi4 s7mqxpzwl6q+.rm* 58cpv un p is suggested by the data in the graph?

  Which stage of meiosi,adnqy(c)e u th/:;yj s is represented in the diagram below?

  The diagram below shows chromosomes during meio80+o lk7nrnn10jgi.p5 .yo; tfdanv y sis.


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 ox 2 b.gsdbi*p)r.gim qui3t7 33eod1 ef a single gene which would be present in the nucleus of a cell as a resulr*timd3 31q3s.p)2b7eeid . o buxiggt of each process?

  Which keyword is matched to the cor2;qi .vpund* grect definition?

  Which statement(s) about mitosis is/ 15gsl vx)cwv6cm8jg/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 points to a cell in jx z m e7xw,6r0hz4w/d,vk.ivbh0+ uvanaphase?

  During which stage of mitosis does the n vd )izf2z9sa3bd 5ih*uclear envelope break down?

  Which one of the following transport proteins only carries out active transpo7lmmog k* 4qec.; *f,0fcvvzurt?vfczv0mc.4lm o ufg7qe, ;**k

  Which process does not happenaqz:ab ,yg v37 in the shoot apex?

  Which type/s of membrane trap1pdg8g ot : ;c8s tgv.0d03mdpt5atjnsport do/does not require energy expenditure?
I. Facilitated diffusion
II. Active transport
III. Osmosis

  The diagram below represenn b* b7; jumoai.s1d6mts a cell with a diploid number of 4. Which stage of cell division is *;1 immuj 7and6ob.sb the cell currently undergoing?

  The photomicrograph below shows a rh*78on fnq5y4foggy /nil :;woot tip meristem. Which of the following sentences corre7fyqg*ol o;wn5/fyh8 ngn4: ictly defines a meristem?

  When does the random orientation of homologous chromosome*cmlbl+ 3w( gb pairs occur?

  Which process does not occur during mei59vtja k f2xe9tezy9 ;m-; dhhlh zggej2.d*9osis?

  If a cell with a diploid number of 36 undergoes mitosis, how m p5hjea sp6:3gany chromosomes will bea35ep6hs p :jg present in each daughter cell after cytokinesis?

  The image shows a micrograph of *7ivgnxd)a 7f a cell.


What explains the appearance of the cell in the micrograph?

  Which statement(s) about homologous chromosomes if 3:juk7qcx+o5f 0qi hs/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 Dod c wou:9wf x9f6jg8z)wn syndrome.

Which statement is not correct?

  In the cells of a horse (E. caballus) during prophase I of meiosis I there ayf,3- cdtc0hnmhz g4h18 fmg( re 64 chromosomes. Whathzh m,gm84(-t3dc g yhf1nc 0f is the haploid number of chromosomes?

  Which arrow is pointing to a y99j1vkslt0 kchiasma?

  The diagram below repydey6s2mwz9:x +pyc/ resents the structure of a shoot apical meristem. Which row in the table correctly identifies the processes occuring in the structures lz2pc+wm:6 9yyy/dx se abeled in the diagram?

  How does meiosis promu9s9f1 tz9sk4ehnmj.u a j5h ;ote variation?

  Which of the following stb(zevqd3*18sct x9gmatements 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 homologous chrortwwh958 bz6bmosomes.


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/ q w ,i h6ybpawl:q.3xfb6(dr tumours from primary tumours as a result opx,/iqh6(yf:q6rwwd3a b .lb f the movement of cells?

  How many chiasmata are present 0kh-(+u.qrjvo3lgkb yb gg) ,in the diagram?

  Which statement is a similarity between cytokinesis in ani a*b1 dow(e,eb /o5dhnmal and plant cells?

  Which stage of meiosis is matched to the,kj819ryqoa9bt j1zwp6h eu , correct description?

  Which statement(s) are true of meiosis I but not mez7 xqc7, gshp3iosis 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 afte6)*fkudq60 xe6if+ vohbusu+ r the first meiotic division. This results in the formation of one larg+e6uq0o*bu+d6u h vf )fs6kixe cell and one small cell. What is the fate of the large cell?

  Which row correctly descrism4q :)e0aqyj, vyr58 8 g +npijmt yg+7ksm/sbes diploid and haploid cells in humans?

  The following table shows the diploid chromosome number of a range of species0v931qho hw dbkiuq7 u8 y5pg7.


Which of these statements is correct?

  What conclusion can be drawn from the g rlz05ttv6di3,y dk,karyogram below?

  Which of the following processes is characteristic of the meiotic and no*bzf p+x1*v pekwv4 3jt the mitotic cv*v+ *p4 xjewfbz1pk3ell cycle?

  The diagram represents a bud with a shoot apical meriohn 8, p9weweuis7/ 48jolq8ostem.

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 chimpa+ guru.-,m-:c xn k)irc9gsvj nzee (Pan troglodytes) is 48. Which row shows the correct chromosome number for different cell types and cell divisiok uj-)ggr:ixuvn9 -.ms+cc, rn stages?.

  At the end of which phase of meiosis I does crossing over occur, and whaty-;zfkpkvl+em8vy 0u/2w n//gtj+ q/byp d 8z is the outcome y8+kwb8 jv/t2nf/pqkp+ /zgzudy y-/vm ;l e0of crossing over?

  Which of the following statements does not describe a steclzz 0 58akf:p0oy qon ecgh4(m,5q*fp in the sodium-potassium pu5hq z zepg48:,*f0 ofaclockm(50n yqmp cycle in the neuronal cells?

  Which row in the table below isid;/esgyv ig2 w *:)hc true of meiosis?

Membrane transport is important for allowingl 5kz)77w)c /de4 zcsm 7smdppc5bvz7 particles to move across the cell membrane and respond to changes in the chemical composition oc)7pzc5/7s4b w c5z7 dvedmml p)7szkf 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 mitosiuo j2h0s *kp/nhjq;hq- lg iesb h,,.9s 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 y2 ng1p:nqg)cthe concentrations of different cyclins during the cell cycle. Which cyclin is involved in preparing for DNA rep)n:2n qygg c1plication?

The diagram below shows chromosv5o t )j/6 fzxe:80oq.jcdksdl5nw c 8omes 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 involve2b,gzzii:xh 9 s the separation of homologous chromosomes?

  The mitotic index of throat tissues taken from 4 different patients is shown aivume w1 o59k5utz;:4).j x l d6nb,tzsat-wbelow. Which patient is most likely to have cancerous throat tissuez5w5 9:tkmi,-o zw4au1jd ba .)xevt6nls; ut?

1.Draw a labelled diagram to represent the process hx ;tdnj5ap( /of crossing over.

2.Compare and contrast random orientation and crossing over.

3.Outline the stages of meiosis.

  The image shows an abnormal humz-h.kdg;f*3zp 3-s bn mmij* lan karyotype.


What is the abnormality in this karyotype and its cause?

The graph below shows the relative amount of DNA in one cell during s;+yualnu3 jo 73ze1done complete cell cycle. Each letter reprenszo37l uy+edu;1 3 jasents 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 homozygous for bros8:azqy(a n9zwn, long hair and a female zasza89n (: yqcat that has black, short hair.


Which of the offspring has a recombinant genotype?

1.Outline how polygenic traits can seid-)bbs s u*7how 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 8h96 fziy.; uw 1tfcxlof non-sister chromatids shown in the diagu9fzxl f;tci hy6 w1.8ram below?

  The photomicrograph shows a pollen grain from L. candidum (Lily)ut(xp9d 6 a14gwj// wittic5s. Which stage of meiosx4 wcjidu s/6(5w19ig/tp ta tis is shown?

1.Outline the events which would lead to an individual beiu j+r 5b+c* 8kig+ffubng born with Down syndrome, which ribff++ ju*85g u cbk+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 :ov 7*jj95s84r xtpgkrutkecfl * t(-measuring plant growth. A study was conducted on white onions (Allium cepa), under controlled conditions in a lab, to investigate the effect of sotkeskrtcuo( 7**gjrt fl8p 5xjv:9 4 -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 wayy-s+ wikxc(ov.;g ;s fs in which cells can divide. The diagrams below show two cells from an organism withsy+fok(-; wgsx;i c.v 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 expresuyu /st11i 9ni yt;i(ssion 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 sh f zs9al17:pe,j8nh kvow a cell, with a diploid number of 8, in different stages of meiosis. Which row coz hs 7 9n:kvel,18jafprrectly names each stage?

  The micrographs showq:adr yr8t53hdy, q l*mn:3 gn four phases of meiosis I in a plant. In what order do these phase qhn 8 3gayrd3 rdml:,q5nyt*:s occur?

Mitochondria are responsiv w/ch.*yo l0v5kjh3ible 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 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’swco .5l jkyv0/3h*ivh 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 hrn ljh4 sv5rot*.ue 10:-pmxdifferent stages of the cell cycle in four samples of lung tissue from four patients. Which tis*m prjusrh 1:0x.-v5 nlto eh4sue has the lowest mitotic index?

  The diagram shows the dominant cyclin/CDK complexes at different timeb- (dj q4pyo/e9f po2l:2hoqu points in the cell cycle. Which cyclin/CDK complex aqlphqo oojudf-2e/p(b 9 4y:2ctivates DNA replication machinery?

  Studies have shown that genes such as Cyclin Depe zslv80yc(m 1pndent Kinase 3 (CDKN3) are highly overexpressev1 ys08m(lcz pd 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 duringnfk 2c4spwr(c:) dowpn 6 sv3: the cell cycle ?