The graph below shows the relationship between maternal age and i7f7v- z 8c/ :twylblzthe incidence of non-disjunction. What relationship is suggested by the l-li tv:cz 8z77bfyw/data in the graph?

  Which stage of meiosis is represented *jxrhc/ ;mu.wmzew 1*in the diagram below?

  The diagram below shows chromosoim,o;yhzb k2-y9eko /mes 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 thkuryn r17s;z2l ysx3i ;0i n:ae number of alleles of a single gene which would be present in the nucleunyzri :071 auln ;2s3r;kysxis of a cell as a result of each process?

  Which keyword is matched to the correct defini13nt pb) h-f zcu+9utbtion?

  Which statement(s) about mir a( a7h 26 lf72fvsam5jm;ykptosis 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 a0 w bwpuxpuwsn 7-e/u-d6 t/brr7x i6-naphase?

  During which stage of mitosi ;z5.n60uskwto pckmk.u(- j wwb*wb)s does the nuclear envelope break down?

  Which one of the following transport proteins only carriesi.cis7:etwmt*kf u l3+o4x y0ksnyph3 5+ tb. out active transport?uktb pysi+h. s+ 7o 3ckwet.y f3:n i0t5lx*m4

  Which process does not happdb anm -9k)szk2m9 *cnen in the shoot apex?

  Which type/s of membrane transport do/do/6l zxxqu/ 8eres not require energy expenditure?
I. Facilitated diffusion
II. Active transport
III. Osmosis

  The diagram below represents a cell with a diploid numbvj1jh1ms*a 7 cer of 4. Which stage of cell divisiosajc71v *mj1h n is the cell currently undergoing?

  The photomicrograph b :y wm5su256etc/ ccepfu-y9below shows a root tip meristem. Which of the following sentences correctly definese 2 /5mfbcy -w 5yuctupe96:cs a meristem?

  When does the random orientation of homopek 5j e9udf(+logous chromosome pairs occur?

  Which process does not ocgb cu0 u64adv7cur during meiosis?

  If a cell with a diploid number of 36 undergoes mitosis, how ma)ca ,*fmzv5 mqny chromosomes will be present in each daughter celm a) zcv*,f5mql after cytokinesis?

  The image shows a mi9uk(,h fmha -ncrograph of a cell.


What explains the appearance of the cell in the micrograph?

  Which statement(s) about homologom+ 1 c/xgt2tlqus 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 for an individual with Down syndroz5 q sl8y am4kesoa)h;94m0lxme.

Which statement is not correct?

  In the cells of a horse (E. caballus) during 9:0k4sokupvo prophase I of meiosis I there are 64 chromosomes. What is s 09k:ok 4ouvpthe haploid number of chromosomes?

  Which arrow is pointing to a chiasma? h;:jq.2zyuno5m vo) o

  The diagram below represents tydw (mr 56xi;o0ykuq .he structure of a shoot apical meristem. Which row in the table correctly identifies t d;yki0ouyq5w.6 (mxrhe processes occuring in the structures labeled in the diagram?

  How does meiosis promob87bnf rmj4g;mj kv)3te variation?

  Which of the following stateme 0 g6wft09 lunbj3flia jt21z1nts 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 homolosj5 h ss(zx.2mz(vc,:o*kgde l*rda) gous 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 9rvh* yl/ hpc.the formation of secondary tumours from primary tumours as a re9cl*rvp/yh. h sult of the movement of cells?

  How many chiasmata are prgm(( sl 9x5d.,aczup+cm q*ihesent in the diagram?

  Which statement is a similaricwcv0i*n+:kx ty between cytokinesis in animal and plant cells?

  Which stage of meiosis .chc iz z2fb13is matched to the correct description?

  Which statement(s) are true of meiosis Ie6 xf)dwj +c 1 9f+3rge cur:s1zaip2j but 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 afte+zg3u ;gyt s7cr the first meiotic division. This results in the formation of one large cell and one small cell. What is the fayu ;c+ tg7zsg3te of the large cell?

  Which row correctly describes diploid and haploid cells -hrhgsfvwq/h*9s 9 .c a. x+) bfwgmk1in humans?

  The following table shows the diploid chromosome nuvynex((0u: i3wv.n g vmber of a range of species.


Which of these statements is correct?

  What conclusion can be drawn from the karyogram below? ) /p qgp+i9e +7 5evdnb 9 1bsftoxx1fhc5+ajb

  Which of the following processes is characteristic of the meiotic and not thsys6v knjlx(6it7w 56 e mitotic kisxwt y665 nv7ljs(6 cell cycle?

  The diagram represents a bud with a shoot apical meristn7lh 930gbni ix 32fqiem.

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 ofo1b/ jcp5(ik : mmdz1p the chimpanzee (Pan troglodytes) is 48. Which row shows the correctc : (bm/op1dp5mij 1zk chromosome number for different cell types and cell division stages?.

  At the end of which phase of meiosis I does crossing over occph*k zt0pb09o ur, and what is the oub h90p0po zkt*tcome of crossing over?

  Which of the followinanhw5b/sq(i / g statements does not describe a step in the sodium-potassium pump cyclen/h/5w(s a iqb in the neuronal cells?

  Which row in the table below is trx-sn+sc k;e3xue of meiosis?

Membrane transport is important f/hh5shm-66v nes cdm*or allowing particles to move across the cell membrane and respond to changes in the chemical compmvd ns h* -6/cshme65hosition 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 nl- yxd,;jp/vgg( s6hn1 -pqgcells.

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 concentrayn29nr0n7mi i x0z9wl tions of different cyclins during the cell cycle. Which cyclin is involved in prz70wnyrlnni99 0x 2 imeparing for DNA replication?

The diagram below shows chromosomes during m: 7 vao.gawiya2xr+ b)ex:q-veiosis.

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 chrr;*) 4syr obj.r r( lbq6d+xvqomosomes?

  The mitotic index of throat tissuesi n)v- q(yyu-h taken from 4 different patients is shown below. Which patient isnq(-ui ) vhyy- most likely to have cancerous throat tissue?

1.Draw a labelled diagram to represent n2jue3sjl4 /qthe process of crossing over.

2.Compare and contrast random orientation and crossing over.

3.Outline the stages of meiosis.

  The image shows an abn7xe1 c m zefj83a7tqvj .)i4rcormal 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 completeeuze:ql:o l q)yblus+z/3o- . cell cycle. Each letter represents one stage of the cel :elze3q+/q )zolo :.byuls u-l 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 s j v2nk08.* rvkx6fi)4s xomylat,;lhomozygous for brown, long hair and a femalk8f*l, kjvy 4mvis0 2r;6sx a.xn otl)e cat that has black, short hair.


Which of the offspring has a recombinant genotype?

1.Outline how polygenic traits can show a normal distrib 9y--rwyy e*s8 kcx cqo6nxsf01k:v;kution.

2.Outline the differences and similarities between homologous chromosomes.

3.Explain why expected and observed Mendelian ratios may differ.

  Which gamete can reswc s p t0ct+z0:u8(srwult from the crossing over of non-sister chromatids shown in the diagram belowp 8wtr+z(css0u:cw0 t?

  The photomicrograph shows a pollen grain from L. candidum (Lily). Which n,cwh,l.v;(w9e s ;mdmdmw +9ggm8pguh-5k c stage of meiosis is 5m nv ;h9;uplcsm,g kg+,dmhd wgwe(c.9 8w-mshown?

1.Outline the events which woux2i;pyctl x4 0ld lead to an individual being born with Down syndrome, which is characterised by the presence of thrc;x4y2tp0il x ee 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 bcg4:e tf6zydzb ); +agrowth. A study was conducted on white onions (Allium cepa), under contro def ;)c6:ta4bgyz+ zblled conditions in a lab, to investigate 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 whic .e*d2-wqo8exq,uvlf ;+ cfueh cells can divide. The diagrams below show two cells from an organism with a diploid number (2nv8qeudf +x- . *efe,lq2 uow;c) 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 u:osvz fd:da3kb1mle2x)j4 ,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 number of 8, in different stages 49nga;cy5bi8ak1x2l +n w p yrof meiosis. Which row correctly names eangiryba+l1w4p x ak58n2yc; 9ch stage?

  The micrographs show four p( yfei;.l9cn9sv(w kahases of meiosis I in a plant. In what order do these(c.;n aks le(f9iv9y w phases occur?

Mitochondria are responsibqxu0c/,f mc2 p8let. /mpwph6le for supplying metabolic energy in eukaryotic cells. In most eukaryotes, which reproduce by sexual reproduction, mitochondrial DNA (mtDNA) is inherited from only onp echft6.cwml2q/um0 ,8 /pxpe 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 number wq1y* -upd g.s/dqm9y8v y3lhof cells in different stages of the cell cycle in four samples of lung tissue from four patients. Which tissue has dwgvy9syh .m/ -y8pqd * 3l1quthe lowest mitotic index?

  The diagram shows the .4 no+uekl* -sy6a2qctfqjf *dominant cyclin/CDK complexes at different time points in the cell cycle. Which cyclin/CDK complex activates DNA replication machinery* 4.fkyn*fusqj- qeca6+tlo2?

  Studies have shown thmy8 3osxgspu p85w dag(c/3 z ej0/k6hat genes such as Cyclin Dependent Kinase 3 (CDKN3) are highly overexpressed chsk/ 63 gz8pjpu(3x5 w d/gy0 o8smeain 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 lx) n eg)ss*v7of cyclin E the highest during the cell cycle ?