The graph below shows the rela im*ube0 i4f7ktionship between maternal age and the incidence of non-disjunction. What relationship is suggested by tm 4ikif7 *ube0he data in the graph?

  Which stage of meiosis is repr-w; yk d;onu8oesented in the diagram below?

  The diagram below shows chromosomes duri(* jl(n1jtde- ;e :jgii kth2ih8vg5 ing 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 s vva2s 4n2e5l--cvnklgu.cz2ingle gene which would be present in the nucleus of a cell as a result of each pr2n-en2szla 2vg-5v c .clk4uv ocess?

  Which keyword is matchej-h5w o,fjtq.2ar(bw d to the correct definition?

  Which statement(s) about -s/ta(ywz54*ij 4s24 va o sog x,bytemitosis 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 points to a cell in anapn9cv3yuh,3ir rj zu/(l )g,xq 5si 5xbhase?

  During which stage of mitosis does the nuclear envelopes)tpu 9 v. -vmhxr9 xt(/7d:fav0seoa break down?

  Which one of the following transport proteins only carriem5 .mpy/t eow5lsl.3js out active transport?lowts j p3..mel/ ym55

  Which process does not happen in th mv,5uyemk ) + g1fiz:ko2cig)e shoot apex?

  Which type/s of membrane transport do/does not require eno0;x 9tv g:csmwd uc.1ergy expenditure?
I. Facilitated diffusion
II. Active transport
III. Osmosis

  The diagram below represents a cell with a diploid number of 4.-ai-aj :+o(/8fgpbc u1wi8midqf*mg Which stage of cell division is the8w c a(pim +offaiq /i1j-8u-b*d g:mg cell currently undergoing?

  The photomicrograph below shows a root tip merisvbxpuy 4 yigsij. **w( 3sp57utem. Which of the following sentences corrwbis s7.iyy jx( u v**pgu4p53ectly defines a meristem?

  When does the random 1+xh+9 gg8 :utmcmz*kwe rml : +gb4jworientation of homologous chromosome pairs occur?

  Which process does not /*hp*gbq t/hd1zp ci2occur during meiosis?

  If a cell with a diploid number )x49vgyqb*br f / d1brof 36 undergoes mitosis, how many chromosomes willf r/x1*d) brbvy49q bg be present in each daughter cell after cytokinesis?

  The image shows a micrograph o ljy d9(*tj8j vq.p+nqf a cell.


What explains the appearance of the cell in the micrograph?

  Which statement(s) about homologous chromosomes isx 9gbf ;8t:lmc u/coe*m8bd s7/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 k (xjo9wcv3g2 an individual with Down syndrome.

Which statement is not correct?

  In the cells of a horse (E. caballus) during prophase I w ymc3. xqfi3;of meiosis I there are 64 chromosomes. What is the haploid number of chromosomes?. ;iyq 3c3mwxf

  Which arrow is pointing to amueb:n06m o vk)q0km5 chiasma?

  The diagram below represents the structure of a shoot api9zyslkeu2tsb : jm42kw8*p rcv( 5 vf3cal meristem. Which row in the table correctly identifies the processes occuring in the structeu 92 zr3 2my*wfk spk5c8vv(:4jt sblures labeled in the diagram?

  How does meiosis promomca-trv ;y *k 5t;6 c22ro.nlkf72hflxiyze . te variation?

  Which of the following statements is/areivy3ozgz(2syx d+ k)7 vpqh,8 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 yk/ hr *z(aecoz+5 xefj.0fwoqzy.55two 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 sec nbcw hf 7-d*v)w6( j+mqh f(s;d)hpysondary tumours from primary tumours as a resnv hh (p6 s b m)wj7;)cfhyd(+ds*fq-wult of the movement of cells?

  How many chiasmata are present in the diagram?a ng35hxk5l-t(0 yrsj

  Which statement is a similarity between cytokinesis in animal and plaqe1jenyuu qzjog/zg3d z*6 y65) *4o9gys:dsnt cells?

  Which stage of meiosis is matched e dnhel-d9z qyb: 9+y-to the correct description?

  Which statement(s) are true of meiosis I but not zaq svyh( ;ru.4cx6v* 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 oocyte after the first meiotic d2 lj x;45khs/o-tg(fzifl0tfivision. This results in gz5ik;- 4xft(0lo ftl hfs2 j/the 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 humansokr58k z)--j(con rp+.qecj f ?

  The following table shows t ncmamri+;s; )he diploid chromosome number of a range of species.


Which of these statements is correct?

  What conclusion can be drawn from the kar6l2vcw+)zh jck c*usf5h77v eyogram below?

  Which of the following processesl4wjl03 veq 6b is characteristic of the meiotic and not the mitotic c3j v6lbelw04 qell cycle?

  The diagram represents a bud wit )m cb3xpm-yt1fj x7c.mp 3ksz+t 9fx q.:)fnmh 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 troglodytx9vjq7:*rux3 w* khbyy )j+hp f jqd32es) is 48. Which row shows the correct chromosome number for different cell types and cell )f px3vdqwy9kx* 2jj3qhry : *ju7bh+ division stages?.

  At the end of which phase of meiosis I does crossing over occur,1 httmm+ukmc8s1 je;oc/ l x63*uxnl+ and what is the outcomeexjx1n lmct m1lsucth *+6 m/3+;uok 8 of crossing over?

  Which of the following statements does not describe a step in the sgv sm)-84 vhbkodium-potassium pump cyclb)vmgs 84 khv-e in the neuronal cells?

  Which row in the table below is true of3) dobue6k5 sr ;iy.vf meiosis?

Membrane transport is impo;sj7j8x4ba;bc5. h 7sy vnx tprtant for allowing particles to move across the cell membrane and respond to changes in the chemical composition o 4xtc7 y;n bjb57s.axjsv8h;pf 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 cellr2r9rz6v qm-fe zh4 j)s.

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 differx-um sq+,eurbyy)0 )qfzf1 j*ent cyclins during the cell cycle. Which *fyjexzq)rmb yu)+q1s f-0u, cyclin is involved in preparing for DNA replication?

The diagram below shows chromosomes during meiosio: 3p xmd m.oru:e2n r37slz/ws.

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 cs 3 vwtqfxi.;7/tp1fghromosomes?

  The mitotic index of throat tissues taken from 4 difflvb8zjklj. 7 /6b2tmmerent patients is shown below. Which patient is most likely tzbl/v6jk.jm b 8mtl27 o have cancerous throat tissue?

1.Draw a labelled diagram x -ifj6 8 w (ncihf871sbkbyx2.)dbec 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 abnok8mi/(7h 9ehic,dgoarfc; y6:c/z dvrmal human karyotype.


What is the abnormality in this karyotype and its cause?

The graph below shows the relative amount of DNA p.1 :ky; buifjin one cell during one complete cell cycle. Each lei;fj b:kup1y.tter 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 thaeq9f y t.kf8o0t is homozygous for brown, long hair and a fema 8oq0fy9etf. kle cat that has black, short hair.


Which of the offspring has a recombinant genotype?

1.Outline how polygenic traits can show a normal distribution. u-la581zku p *a3gxds

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 crosnc;c je5g) *v*gnrrc ;sing over of non-sister chromatids shown in the diagra *rc; n)*grgj c;vcne5m below?

  The photomicrograph shows a pollen grain from L. candidum (Lily). Whir6(.gta6rxr rch stage of meiosis is r6(arxr.gr 6tshown?

1.Outline the events which would lead to an individual being born wii+fjnw1jxkfo 6p,r1cv ,l 0smi 0od83th Down syndrome, which is characte xm w1ndvi, pscjfif1k0r+ol6o0j8,3rised 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( xnlabg06am z69qhdnv:gk6vk+ y. 3f measuring plant growth. A study was conducted on white onions (Allium cepa), under controlled conditions in a lab, to investigate the effect of soil pH on the mitotic in (3am06+: nxl9 .dkqgyhbkzv 6af v6gndex 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 di ocp5rdl +h9ql :h73xfvide. The diagrams below show two cells from an organism with a diploid number (2n) of h qhfl9rl7 cp:+d 5o3x8.


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 ex eu1*jmv8piz v7on. ;yj+kkj 3pression 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 dipd/d 9nyfxg6r2 v2v;uf)- qgw zloid number of 8, in different stages of meiosis. Which row correctly names each stage?u6/- fgrg92y)f q d2z wxvvdn;

  The micrographs show four phases of meiosis I in a plant. In what orde 907)k h8xzywso0z kper do these phasesyekks0) 8zo7 xph9w z0 occur?

Mitochondria are responsible for supplying metabolic energy in eukaryotic cells 9q4iy3g7uwdv4bc2s a . 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 from4vcubw sg394dq7ya2i 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 stage oeej51+3hj5 rkhga3hs of the cell cycle in four samples ofeajjh53h+g 3ko r eh51 lung tissue from four patients. Which tissue has the lowest mitotic index?

  The diagram shows the dominant cyclin/CDK c/ t;1r,fjkii nomplexes at different time points in the cell cycle. Which cyclin/CDK complex activates DNA replication machfr 1;inkj i,/tinery?

  Studies have shown that genes such as Cyclin Depet1 2+hiddftbaetepf/3 ned8- i ha8(1 ndent Kinase 3 (CDKN3) are highly overexpresse/1hnptb3dei2ad ia8- t+ef he8(ftd1 d 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 thhp0p yxa1 c(m1e cell cycle ?