The graph below shows the relationship between maternal age and the incidk4nqj8 8afy;s ence offs488ya jk ;nq non-disjunction. What relationship is suggested by the data in the graph?

  Which stage of meiosis iskc+7ulr8grz:xdphc7 t c0 j ,- represented in the diagram below?

  The diagram below sh r ;yjq(.*4yiiof-uo rows chromosomes 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 ngyhf 8c9 n*si; 1/mwnlumber of alleles of a single gene which would be present in t/*c 98glnm;1wsyfhin he nucleus of a cell as a result of each process?

  Which keyword is matched to the correct definitioetc/2: p, ickjn?

  Which statement(s) about mitosis is/aretmg./f4bnr6 d 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 +tv ufw,gv:iax38ek 4 a cell in anaphase?

  During which stage of mitosis does the nuclea32v 1 d- dejfy abx(pv.5sxtd:b9/ rnar envelope break down?

  Which one of the following transport proteins only carries out active t.:zcm5q;oz dbsrx 6z/ransport?dm6zq;zzbc: so .x5r/

  Which process does not happen in ,,dmbf, 8exazgx5 q d4the shoot apex?

  Which type/s of membrane transport do/does rl5/,pwv byx0jiz;yuwe-hk3 v/ o*r5 not require energy expenditure?
I. Facilitated diffusion
II. Active transport
III. Osmosis

  The diagram below represents a c1xtaoce29 n2,v ztem*1 ;mkr8 vrc rv4ell with a diploid number of 4. Which stage of cell division is the cell currently undeov2cx; r,4kzn tee8 tvm1vcr1am*r92 rgoing?

  The photomicrograph below shows a r re7n.nkes,v+0 ,pimz/v h,exoot tip meristem. Which of the following sent.7 ,v, +,nkzh /svmne0pxireeences correctly defines a meristem?

  When does the random oritkwi .(kvzwp nh)av( i:*v97ientation of homologous chromosome pairs occur?

  Which process does not occu8 cxk,w7o mws9es,a/lr during meiosis?

  If a cell with a diploid number lv (l:z)i *uwkof 36 undergoes mitosis, how many chromosomes wi(v ulk:*iw)lzll be present in each daughter cell after cytokinesis?

  The image shows a micror0apxm v0e1 46 vvt.bzgraph of a cell.


What explains the appearance of the cell in the micrograph?

  Which statement(s) about hs rsc)ay *yx.5omologous chromosomes 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 fomw(f4-i 4(yspsi-o znr an individual with Down syndrome.

Which statement is not correct?

  In the cells of a horss0t cp v79y-tarwk1 9q2k8knie (E. caballus) during prophase I of meiosis I there are 64 chromosomes. Whan9vr pk8t y2is1-qctak9 7wk0t is the haploid number of chromosomes?

  Which arrow is pointing to ecv3gjx*).w) ) vvoon a chiasma?

  The diagram below represents the structure of a shoot apicalhz)86,fduu g3pxpq*vex*rq / meristem. Which row in the table correctly identifies the d,vhuzer**6)3up qgpfx x q8/ processes occuring in the structures labeled in the diagram?

  How does meiosis promote varwpa 10 *o9xxuqiation?

  Which of the following statements is/are cj0kq5*f;xk( sdpj;s nshh sr 0v(m/qi6-1l dnorrect 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 h; lzh2(oc2tr hm7ymn1omologous 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 ofrieoy+ j4t(4s secondary tumours from primary tumours as a result ofjiyst4 e4 or+( the movement of cells?

  How many chiasmata arz1ii dr chr79kud ae)8,h r5+se present in the diagram?

  Which statement is a similarity between cytokinesis in animal ande-azgds l1-9 hiq kz4. plant cells?

  Which stage of meiosis is match 5u*tf hjroy6ggc5:j 0ed to the correct description?

  Which statement(s) are true of meiosis I but9 q7+qnz)r8yg lkpl g1tw87 t- mqe:hx not 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 di* +o pvix ycx6m-v9cefdcy h(//2d- jivision. This results in the formation of one large cell and one small cell. What is the fate of the large cvdhy2do+(-e xf*mciy6ci9x j// p-c vell?

  Which row correctly describes diploid and haploid c)3 va(anei 6o+lkqlv0v8+jtnells in humans?

  The following table shows the diploid chromoq7 z2)5gfct 4u2gyt ve 7j5r0lz6tltosome number of a range of species.


Which of these statements is correct?

  What conclusion can be drawn from the karyogrualsj) sr:0 2wam below?

  Which of the following procesx/km zpbzo-55ses is characteristic of the meiotic and not the mitotic p5 k-zbz mo5x/cell cycle?

  The diagram represent li1(iiwhc /w.s a bud with 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 troglodytes) is 48. Which row sbuv(;zlll, u +t rc:k(:x/tk fhows the correct chu;(lz:c,t/r+ft( ukv l kb:lxromosome number for different cell types and cell division stages?.

  At the end of which phase of meiosis I does crossing ove2wp:l4uex.y xu )e pxz,cr8v.r occur, and what is the outcome yupelx2vxu.xp4,: w.e) z8 rcof crossing over?

  Which of the following statements does not describe a step o*hcsibl7ech2 h37u pqp -fdpi): n ;ez+d 8r1in the sodium-potassium pump cycle in the nebcuhz 7*e 82)p3:i-pqihcr;pd n+e1f ls7o dh uronal cells?

  Which row in the table beloy8hp1p7 nquptq+.u9 .z, s io46pwhlew is true of meiosis?

Membrane transport is important for allowing particles to mov.8/r spohi-bh e across the cell membrane and respond to changes in the chemical composition of the e./h b8hs io-rpxtracellular 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 regu ad tksu75l3fsy um(;8lated 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 duy6 k,- iws4p5swlz:ig ring the cell cycle. Which g6psi-syz5 :,wwl ik4 cyclin is involved in preparing for DNA replication?

The diagram below shows chromosolb4vsp.l rpc:d54o9w mes 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 involves the separaty;h .e 0 ,kz2ppmjw(viion of homologous chromosomes?

  The mitotic index of throat tissues taken from 4 differrqqe8q8z3kxda ,94 mq f;ng .sent patients is shown below. Which patient is most li 8;kqd8r,ma.fqz3g94qs ex nq kely to have cancerous throat tissue?

1.Draw a labelled diagram to represent the process tr95tj h:r3yy of crossing over.

2.Compare and contrast random orientation and crossing over.

3.Outline the stages of meiosis.

  The image shows an are;1vt4e: t1.f(dkb(t zvgo qbnormal human 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 coj6w9hcj - 2.hb4w orl arp/xa)mplete cell cycle. Each letter reprpwhl-6j2c/b4j.9 wox )aarh resents 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 buy)3lv5 x07sfj ch w+erown, long hair and a female cat that has5yj) lwe3sxv hc+f7u0 black, short hair.


Which of the offspring has a recombinant genotype?

1.Outline how polygenic traits can show a normalu6 usa7ezc+eb9j t*,p 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 c)uz n.n7jmd 3d;q omj7rossing over of non-sister chromatids shown in the diagrammm;jj3dq). n d7zuo7n below?

  The photomicrograph shows a pollen grain from L. candidum (Lilxsiuiv;+-8: sc *fz gy7pmosa1lih 0fmb0 8p6y). Which stage of meiosi-sz +6:8y* lvsgi;poi pa 018fh mi0xmfu s7bcs is shown?

1.Outline the events which would lead to an individual being born with Down syn) qnpimm i* ) .zoc)mf1y5rhs5drome, which is characterised b*5)m)z 1ir5mn mhf oqpsc. iy)y 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 fam0,p 2a t dyh;ejp05t d-e5 ybaa:*pwas conducted on white onions (Allium cepa), under controlled conditions in a lab, to investigate the effect of soil pH on the mitotic index of t py5bem;t 5 a,y2:a*fa0tp0d-dephajhe 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 wahw oc(1):9et 7uvw asjys in which cells can divide. The diagrams below show two cells from an organism with a diploid number)e u wahco7sj9 1(wt:v (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 gen6os84y9m2tih0skvypd( c ft4 e expression 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 diploid numb*i ;e 1vd nh)mpao/jh2k 3fjx4er of 8, in different stages kxn1ih h/3vo;)j *md4jfp2aeof meiosis. Which row correctly names each stage?

  The micrographs show four phases of meiosis I in a plan+ pv2,htu awwvzp4x2 dm/ u19st. In what order do these phaxt hd+m uap2 uz9wv,/ps2vw41ses occur?

Mitochondria are responsible for a 5ew,hplslzw(,;rhfo. fdxlko 0... supplying metabolic energy in eukaryotic cells. Ino ff aklw(s.50 .,; .hphel.rlodzw ,x 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’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 numbe95( 8-lhik6imb+ sbyv kylyv1r of cells in different stages of the cell cycle in four samples of lung+6 98y-5h( yimilb1sv ykkl vb tissue from four patients. Which tissue has the lowest mitotic index?

  The diagram shows the do9 g9dfu1 uc-eiminant cyclin/CDK complexes at different time points in the cell cycle. Which cyclin/CDK complex activate9 9ieu g1fcdu-s DNA replication machinery?

  Studies have shown that genes such as Cyclin Dependent Kinase 3 (CDKN3) arv)af65 mtk0w k v(mti c6.e6pxe highly overexk (tfv)vp6xk6t e0.maw5m ic6pressed 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 qoc u4o0y:n8 pduring the cell cycle ?