The graph below shows the relationship between maternal age and the a6 hqa4 p1no:lwat;y8incidence ofy l1 top:;ah864wa anq non-disjunction. What relationship is suggested by the data in the graph?

  Which stage of meiosis u;.7-l 31 m ok ops)c;b zdmgdhc*w7igis represented in the diagram below?

  The diagram below shows chroz1yvrx97m.3p b0 bx5duobawk (p gn:5mosomes 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 nuoz9p) 8aw7cf6yhhjv9 +e jxh6mber of alleles of a single gene which would be present in the nucleus of a cell as a result of each proce)h6+9opvh f6c9a z8wy7 xhje jss?

  Which keyword is matched to t3s qgaloyzj6h6 wc/:2he correct definition?

  Which statement(s) about mii6t n-y7( (yk,vmkr bstosis 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 hkdrhopylg*+ l7-d wz1 3c*r) in anaphase?

  During which stage of mitosis does t 2freahkq 5/+che nuclear envelope break down?

  Which one of the following transport proteins only z bazviq x+q.g*l703a carries out active transport?.lxa*qab 0 g7+qzi3 zv

  Which process does not happ7+c;gf b s+.kxpa/v ki/o6 inlen in the shoot apex?

  Which type/s of membrag6;q0s ;lohmm ne transport do/does not require energy expenditure?
I. Facilitated diffusion
II. Active transport
III. Osmosis

  The diagram below represents a celbvgo/8i;ov+5lcg5 j ol with a diploid number of 4. Which stage of cell division is th58g ;o cov/gl+vi j5obe cell currently undergoing?

  The photomicrograph belo6sv2eg :hq **e(yljvcw shows a root tip meristem. Which of the following sentencehvcl*:y qse (*2jevg 6s correctly defines a meristem?

  When does the random orientation of homologous chromosome pairs zuiq5v dib/tj6cq8a bk)(bl tv75;5 moccur?

  Which process does not0 n:xeyszg.* q occur during meiosis?

  If a cell with a diploid number of 36 undergoes mq8 txj;j -n )u1mire2aitosis, how many chromosomes will be present in each daug1 rqm)t-x2n;i auej8j hter cell after cytokinesis?

  The image shows a micrograph of 5iabnom93o y(ot17p j a cell.


What explains the appearance of the cell in the micrograph?

  Which statement(s) about homolog,ngnclkq40 i 7tfo5,ra9uk3wan t7 : gous 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 individu kq*:gk(n2w zt4 evm4ck*p4pwal with Down syndrome.

Which statement is not correct?

  In the cells of a horse (E. caballus) during prophase I ) -1f8v()vqygj gnhtuof meiosis I there are 64 chromoso n)u1-jvg8g y)vh tf(qmes. What is the haploid number of chromosomes?

  Which arrow is pointu9 hfceskvx0 j679n rkm9dq94 ing to a chiasma?

  The diagram below represents the stru)tctty: mjh;u jr4(5h cture of a shoot apical meristem. Which row in the table correctly identifies the processes occuring in the structures lab4rhy5thmu j) t:ct(j;eled in the diagram?

  How does meiosis prom3 vznk+p5kalfk)+z: a ote variation?

  Which of the following statementl3cipiv,ho nfas9b31 / ft4 og-g4e0ks 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 homologouse;t9 xk7yiteuhl i*+ (5vf/m t 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 seco z y.0imy+8mmw*)epnandary tumours from primary tumours as a resul )+ *ap8y0mnm emyzw.it of the movement of cells?

  How many chiasmata are present in the4g3,* nzggzx z diagram?

  Which statement is a simil+3jqf sr b)oy6p7t1j )9cxxes arity between cytokinesis in animal and plant cells?

  Which stage of meiosis is matc8hqrb a-7l pg*p4)zje 1 reun)hed to the correct description?

  Which statement(s) are true of meiosis I but not meiosis II0 v1 nt2wmnrov3+j ga.8iw6fy ?
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 /vgg,ayzso,pxh5y. f:by)i3o+ x( lg meiotic division. This results in the formation of one largeayyys5gb pox/.lf (i, +zo3x g,gv)h: cell and one small cell. What is the fate of the large cell?

  Which row correctly describes diploid and haploid cnbv(((s5tu wh ells in humans?

  The following table shows the diploid chromg1gql as6 x bb7*dk,(dosome number of a range of species.


Which of these statements is correct?

  What conclusion can be drawn frh( w7*2l lplsdom the karyogram below?

  Which of the following processes is ch hn/a, rqb-(jcz s,pm(aracteristic of the meiotic and not the mitotic cell(/(mj, hnp q, r-cbsaz cycle?

  The diagram represents a bud with a shoot apical ml p0r+m. p5beqeristem.

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 shp gf(+a715 eca;rmz5uaa (whyows the correct chromosome number for different cell types and cell division stages?p(;g a557( ha1cryue wzafa+ m.

  At the end of which phase of meiosis I does cros esku*u-:gll:.jxu t) sing over occur, and what is the outcome of )u jgu kl.-ls *ue::txcrossing over?

  Which of the following statements does not describe a shqi3.knckfni9( : pb3 tep in the sodium-potassium pui 3kf ki9n3b.qn( hcp:mp cycle in the neuronal cells?

  Which row in the table below is true pv9q:er7.i4o;vcz)9a zme sefae l v+j8q:; bof meiosis?

Membrane transport is important f *-0nce(+mm +fe8hezrdrv6v sor allowing particles to move across the cell membrane afsv60 dhn-erc8+mvr*+( eemz nd respond to changes in the 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 ijv z;tav:3cu3bz:sf4 n 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 differenta3* fui s3hjr: cyclins during the cell c3rfausji3*h: ycle. Which cyclin is involved in preparing for DNA replication?

The diagram below shows chromosomes during meiosis. r t fmr*h64s:+dcypk f/pj81t

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 meios uzq,myagghk a g4nd3hh2mu:1b 9.6/tis involves the separation of homologous chromosomes?

  The mitotic index of throat tissues taken from 4 different patients is si x125qj6wwtty7s(mzl4n7f;o ) mdckhown below. Which patient is most likely tjlt o(w w6mk4;52 xqf)si7czdny t7m1o have cancerous throat tissue?

1.Draw a labelled diagram to represent the pr7 * 4bnl ui3fwstfs.v;ocess of crossing over.

2.Compare and contrast random orientation and crossing over.

3.Outline the stages of meiosis.

  The image shows an abnormal human karyotypewl ro *h:2ssd6.


What is the abnormality in this karyotype and its cause?

The graph below shows ki.gx/ fb-k8rba t/7fthe relative amount of DNA in one cell during one complete cell cycle. Each l/8f -bak/t. 7fixkgrbetter 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 bh4mdy/h mr2:oa/1(qs )e kohcross between a male cat that is homozygous for brown, long hair and a female cat that has black, short hair.4bq: ohyerh)h asmo/1/2 k(d m


Which of the offspring has a recombinant genotype?

1.Outline how polygenic traits can show a normal dis4 (0m o;qjnipwrrq*:qtribution.

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 of non-sister cho59lqnh3pd 2 lromatids shown in the didhp 3 5nl9qlo2agram below?

  The photomicrograph shows a pollen grain from L. candidum (Lily). Which st9p+mi0a p yryi s29l (y:/gqybage of meiosisi0y ylbsy2gp+:/qyarm9 9p( i is shown?

1.Outline the events which would lead to an individual bect87r*npyb g a)rk6j-ing born with Down syndrome, which is charactry-*kng c rbjpt7)a86erised 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 stud qpowuo jc3+hy: 9+(ygy was conducted on white onions (Allium cepa), under controlled c+g+o (3pqwjhy9o :cyu onditions 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 which cells can divide. The diagra7,i uwn48iopg4 *pzhh h1:ernms below show two cells from an organism with a diploid nuenzgn u*i1 hhh7,4p4p:r 8 oiwmber (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 expressctj uvd6xs5iy 81q) 0sion 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,grb31k.(b:o n :bfz ur fu6b:v with a diploid number of 8, in different stages of meiosis. Which row correctly names each ngb :1 k.z3fb 6:urr( bvfuob:stage?

  The micrographs show four phases of meiosis I5a3(sjxnlm 8 r6en f s8ppo-x4 in a plant. In what order do these phases occur? 8x( 3lpansos mfxe48-n5pj6 r

Mitochondria are responsible for supplying met tu9du. hs.i;p.;0unlv1mvwtabolic 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, inherita;h tu..uwsi np ;t90vmul.dv1nce 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 olj -sg -r9bz.gf cells in different stages of the cell cycle in four samples of lung tissue from four patients. Which tissue has the lowest mitotic ind.sr -zbgg l9j-ex?

  The diagram shows the dominant cyclin/CDK complexes at different (dauhew7 : q)h0h8qtos8se +-kc def8time points in the cell cycle. Which cyclin/CDK complex activates DNA replicatdus: 88hdkqew)-oe s0hf q t+87ah(ceion machinery?

  Studies have shown that genes such as Cyclin Dependent Kinase 3 (CDKN3) kj9 i+8d.fdq 7ddx r(.zxju. mare highly overexpressed in cedfjx7.x(qu9d.d+i.8 k zr jmdrvical 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 concentratioo7hsqzf m u ,he.6v0k0n of cyclin E the highest during the cell cycle ?