The graph below shows the relationship between maternal age a 4 j)xcc*ql.jw j)kj7nnd the incidence of non-disjunction. What relationship is suggested by the data inj jc)j xj .l)q4*wn7ck the graph?

  Which stage of meiosis is representb o(cxdukdbfi.j3;:0 7mdaa5ed in the diagram below?

  The diagram below shows chromosomes durinluu 8lx4 bun79g 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 whichf3uk.6(ggg6 8y eixlb would be present in the nucleus of a cell as a result of eaf 6 uby 8l6i.(gekgg3xch process?

  Which keyword is matched to t:0a vljm5y9, vtah vrov:q1h(he correct definition?

  Which statement(s) about mitosis is/a(lahq+ (hbvg6 re 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 anaph-i+3-j qp0a v0+h ujf p xcjin+8xla h-qy7yn4ase?

  During which stage of mpzns;9xp (bk. itosis does the nuclear envelope break down?

  Which one of the following transpoz wsm9;ee jz8rg x5 m.xx3r7:edqj.*x rt proteins only carries out active transport?s5dwr gx*3m:qm;z9rj ..jeex 7exzx8

  Which process does nzb ts;q7j:c9r vx;yz4ot happen in the shoot apex?

  Which type/s of membrane transport do/does not require eneh ( kwmcjb hmhs7.6qf*/u/c -brgy expenditure?
I. Facilitated diffusion
II. Active transport
III. Osmosis

  The diagram below represents a cell with a diploid number of 4. Whis+,r,cn1s* pnkp1dmxd2,damch stage of cell division is the cell currently undergxp ,,n dd sps m11mr,*cdka2n+oing?

  The photomicrograph belowo7zxbh: j xb96 shows a root tip meristem. Which of the following sentences correctly defines a mer jox hb796b:zxistem?

  When does the random orientation of homologous) cq: hmvxg f9z*:j-zm chromosome pairs occur?

  Which process does not occu:krwd5fa n u kyz(83-6h(2wb9ssqebor during meiosis?

  If a cell with a diploid number of 36 undergoes mitosis, how many cd6w qg 5o f5gys--n9byhromosomes will be present in each daughter cell after cytokine bfgy-6gwosn dy5q-95 sis?

  The image shows a micrograph of a cel9,vadu4 l1cr,ulp r7c xen;e8l.


What explains the appearance of the cell in the micrograph?

  Which statement(s) about homologous chromosomes isnz i ymsv7225e/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 with6ss3awjru( g9 Down syndrome.

Which statement is not correct?

  In the cells of a horse (E. caballus) during prophase I of meiosid;3gv 1 fcf, m8,y9evctvl 4dis I there are 64 chromos l vvv4 c,d;tf d,398e1icmyfgomes. What is the haploid number of chromosomes?

  Which arrow is pointing to ;69mk5rfz1quy)-6 jbi z /wz deden7qa chiasma?

  The diagram below represents the8u npu*6y(03 k ubag3-wkab zy structure of a shoot apical meristem. Which row in the table correctly identifies the procekbua03ynw(bzk*a 3g-u8 yup 6 sses occuring in the structures labeled in the diagram?

  How does meiosis promot o/k6 (p vnwl7hy9 sb,utwd-i0e variation?

  Which of the following statements is/are correkyf 2a; ec q)*ypt*wm(ct for meiosis?
I. It is a reduction division
II. It involves random orientation
III. It produces genetically identical cells

  The diagram shows gametes produced llh9 +hk w(9snfrom 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 formatiorn:xxvw n3wta/)y-4j 7 fz-0in*od gq n of secondary tumours from primary tumours as a result of the mod ro nx*-yfzav0 n :jg-4n3qtxiw/w7 )vement of cells?

  How many chiasmata are present in 2 j, j)g6hmgnrvtp4:pthe diagram?

  Which statement is a similarity y)+kv8uon8)dpe)htruy6 hw2e q6w3 l between cytokinesis in animal and plant cells?

  Which stage of meiosis is matched to nqx:(nz sac06 the correct description?

  Which statement(s) are true of meiosis I but not me 37+lf s)x(0ncwynzo de zf cj3yp480eiosis 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 8ky ffl36jc1 abu9d2hmeiotic division. This results in the formation of one large cell and one small cell. What isf3jl 291a6fk8 uhb dcy the fate of the large cell?

  Which row correctly describes diploc9ttnj *2szkk*d; 5y;6lwrmkid and haploid cells in humans?

  The following table shows the diploid chromosome number of a range of specio+qst7 0k:s .fcb5obwes.


Which of these statements is correct?

  What conclusion can be drawn frmktq- 3;p:p2 78 t e6hbcz cwpdo-tp0kom the karyogram below?

  Which of the following processava:49 n04z kyb0wf o0pf kb*tes is characteristic of the meiotic and not the mitoti: kz04w4bn 00ay9 *pftovak fbc cell cycle?

  The diagram represents a bud with a shoot apical ml9c es hnd,1 -kizo;2jo8cs.deristem.

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 troglodytayin tml 3a4p/:l(dkcmmdc./1 * ;xg ues) is 48. Which row shows the correct chromosome number for different cell l1 tdak*d/;xpml ym.4nu3g(a c/cmi:types and cell division stages?.

  At the end of which phase of mei y.3zr fl2w+6o+sziruosis I does crossing over occur, and what is the outcome of crossing over?. 3wuf zsyz +lr6ro2+i

  Which of the following statemenjt;(obp fi1 6 ;(gbwgpts does not describe a step in the sodium-potassium pump cycle in the negbw1;t6(j(;ppfi gob uronal cells?

  Which row in the table cq-fmf yy +y-y1kc;8pbelow is true of meiosis?

Membrane transport is important formpceru 8/w*7ljz8 ni ) allowing particles to move across the cell membrane and respond to changes in tnzie)wj7c8l/pm 8ur* he 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 , zekvchutp/aehg4/gi r24 :; 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 concentratirvwf:+ bijbwje.(n6 7ons of different cyclins during the cell cycle. Which cyclin jr.jbweb+n(f iw76v : is involved in preparing for DNA replication?

The diagram below shows c 8 g2yd20g zp i8v71h9ejsuzihhromosomes 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 meiosi w9cj- ajvj(s 0; /gvjocsc4(fs involves the separation of homologous chromosomes?

  The mitotic index of throat tissues taken from 4 different patients is se-ji* f nqmz 0h.ag b)u:s1n9zhown below. Which patient is most likely to have cancerous throat tis*h bf-z e :jqnaus9)mig.n1z0sue?

1.Draw a labelled diagram to reqj- x4p)/mn +by.o mo58qa 1c0bxoltapresent 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 human kvm e*c69py rvj8k4. b7j(nar* by. kjnaryotype.


What is the abnormality in this karyotype and its cause?

The graph below shows the relative amount of DNA in one cell during one complnle76) 3dcktq . -s-iqtp7qcw 1phcuky;3/ cfete cell cycle. Each letter represents one stage of the cell c pwp cic6)qf dct3nq3khscey71;t/u -lkq -7.ycle.


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 homozygomy vfz j mpy2 jf/((by-su179dx 8s+sdus for brown, long hair jm-yuxsz fmdj 9/1sy 7yp+v d(s(b2f8 and a female cat that has black, short hair.


Which of the offspring has a recombinant genotype?

1.Outline how polygenic traits can show a normal j* t .yqppxwbvqr; w4iap ,v,j/l(2b: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 ove: l.+nvji-ntk*hrgo; r of non-sister chromatids shown in the diagram below.n+onlhtjgv ; -kr i*:?

  The photomicrograph shows a pollen grain from L. candidum (Lily). Whichy +hr jvy68lq- stage ofr yh6lvj 8+y-q meiosis is shown?

1.Outline the events which would lead to an individual being bg;7k:fo) i 8hqr2 jesrorn with Down syndrome, e :fqkr;gih)27rjo8 swhich 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 plant growth. A study was cone hmh4u3*l* rbducted on white onions (Allium cepa), under controlled conditions in a lab, to investigate the effect of soil pH on the mitotic inh*mu4* hbr3el dex 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 n nc;jf:x abl ,l9y71fdiagrams below show two cellsl1; l,fy7:xfjn n9 bca 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 s9fki.yg (vr zphum8):tem 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 different stages)vih 7ct5* u d8b id6p*uhh-ds of meiosis. Which ro 6)did *pshu*7vhhbt5cd u8 -iw correctly names each stage?

  The micrographs show four phases of meiosis I in a pl cs.g5)- mzr7jc5gbupant. In what order do these phases occur?5bj5 z-ug.c7rcmsgp)

Mitochondria are responsible for supplyin4j2/hqlww u0k g metabolic energy in eukaryotic cells. In most eukaryotes, which reproducew4 kqlhj/2 0wu 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’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 n.iu h68.ngo;eon e+,ufopu (oumber of cells in different stages of the cell cycle in four samples of lung tissue from four u.(fgiopne; o,hn. o68+oe uu patients. Which tissue has the lowest mitotic index?

  The diagram shows the dominant cyclin/CDK complexes at different tixzvk9a om qi;ck+ s:nv p9::s+me points in the cell cycle. Which cyclin/CDK complex activates DNA repvxc:k 9 zns9+::s+ki o ;avmqplication machinery?

  Studies have shown that genes such as Cyclin Dependenm87v3*xli 8f1r5xnzfnk l z4 jgn4n /nt Kinase 3 (CDKN3) are highly overexpressed in cervical tumourn lx*jn fz51 lfgn4rnz 4mi8vk/xn873s.


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 c4m0kgwg: tdcms 7t+-mycle ?