The graph below shows the relationship betweentaj3(jj6f mw 3 maternal age and the incidence of non-disjunction. What relationship is suggested by the datjwj ja tm(3f36a in the graph?

  Which stage of meiosis is represented in the diagram belo1a -9 8m rc5rvtgtaq0uw?

  The diagram below shows chr eydh/-4mjh s5d: a.7hmh5zaromosomes 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 number of alleles of a single gene which would bek-um z,jitg:t 7f.z;r present in the nucleus of a cell ;tzut zr.:,k-gmf7 ji as a result of each process?

  Which keyword is matched to 1 b1w0.jxp twc 4hnr0 4xe8ditthe correct definition?

  Which statement(s) about mitosip bk,ziy h2afiu,::3s s 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 letteq d30ayud(p: gr points to a cell in anaphase?

  During which stage of bx, i* yavnq*qc.zy1b 4;vs+l mitosis does the nuclear envelope break down?

  Which one of the following hj2t35i hywl s,05xtotransport proteins only carries out active transport?o23,5x ij yw5t 0hstlh

  Which process does not happen in the shoot1rdgi9pi.2z.8cn5dff e pc6 t apex?

  Which type/s of membrane transport do/does not require energy exp5z* cgpdq /f.hr+fw ed 7d1ep,enditure?
I. Facilitated diffusion
II. Active transport
III. Osmosis

  The diagram below represejhn 7ua2lnm79kw m+ s8nts a cell with a diploid number of 4. Which stage of cell divi8m27l7nkhan uw j 9ms+sion is the cell currently undergoing?

  The photomicrograph below shows a root tip meristem. Which of the fo3 5yse7 u(9o )jk* zdzyotpu)kllowing sentencesoupykzu5)j3 d y7zo (etks9*) correctly defines a meristem?

  When does the random orientatp4. i(vg)j,/ytm)3fa nj mois ion of homologous chromosome pairs occur?

  Which process does not occur k i/pce :b)potih7++a during meiosis?

  If a cell with a diploid numbe /u1l -/nqhpnk )qd3igr of 36 undergoes mitosis, how many chromosomes will be present inq 1n-d)ghpu/lk/ 3i nq each daughter cell after cytokinesis?

  The image shows a micrograph ogeb5ozu weq64 5 d/iw+f a cell.


What explains the appearance of the cell in the micrograph?

  Which statement(s) about homologous chromosomes is/arek+)kn, l vmlf, 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 indivsto pvd; nqz4(5u7tmx3. o(q uidual with Down syndrome.

Which statement is not correct?

  In the cells of a horse (E. caballus) during prophase I of meiosis I there al jpl5xc* 52w ztv-vm8re 64 chrom 55t2xplcv -zm*w v8jlosomes. What is the haploid number of chromosomes?

  Which arrow is pointing to a chiasmzd vv8sr z3bojh1 l;,2a?

  The diagram below represents the structure of a shoot apical meriste5jh zog1wsyakr1rn5 8rp2vuy5, 77zhm. Which row in the table correctly identifies the processes occuring in the structurea,p g zwr1rzk15hy 52rv8ouh7y7ns 5js labeled in the diagram?

  How does meiosis promote vaa);f8 j6eus(uj kai.criation?

  Which of the following statements is/aregy4jgh o. r.t3 6k +ttmp mzc312sln vcnk;s-+ 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 homolo9v2p yjj :w u9k *lwfmt.,ppo3,*nw magous 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 secondary tumours from primary tumours ahxmucr4ua i.qx1* u8q70 6uvss a result of the movement r4cv8 uu* uax hq167ux.0mqi sof cells?

  How many chiasmata af 0p7 0gnf hkckw0h.4mv bev:.re present in the diagram?

  Which statement is a similarity between cytokinesis in+ohjvz3(cgh* kl*ihzcrk 6 8+iq0c7b animal and plant cells?

  Which stage of meiosis is matched tommtaa: 2kxv-)v; (azq the correct description?

  Which statement(s) ar*p;*s s .xfcazce9mz 7e true of meiosis I 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 af9wjqu xk0o p5mxi (+z(ter the first meiotic division. This results in the formation of one large cell and one small cell. What is the fat(omw0 ( xi9p kquj+z5xe of the large cell?

  Which row correctly describxk *v0qie o2t3es diploid and haploid cells in humans?

  The following table shows the diploid chromosome number of a range of specie8(:dju)sgp r jvo,l+ ss.


Which of these statements is correct?

  What conclusion can be drawn from tnwl8iu z,g:ndz 4im93 he karyogram below?

  Which of the following processes is .vi 3z6e esqevag*e* 3characteristic of the meiotic and not the mitotic cell cycleeeez 3.qv*v 3*a6sige ?

  The diagram represents a bud with a shoot apical merip.a4jnz (onmvn77; lastem.

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)+3 pn;8)nh,y pvu(sx;(fc kd qyny/r u is 48. Which row shows the correct chr uup8nhy;/yvk(d)xn( f+;q y snp,cr3omosome number for different cell types and cell division stages?.

  At the end of which ppyq o+(6hnrvm9f6s6-e fv i-a hase of meiosis I does crossing over occur, and what is the outcome of 6mfhvsnqy66+vea- o9fip(r - crossing over?

  Which of the following statements does not describe a step in the so;sn:(0 k aerdqg 4y/drdium-potassiu0qn (:srg/eka4 d; yrdm pump cycle in the neuronal cells?

  Which row in the table beh 0ym5dyyznjk-3zamy8 52gv ) low is true of meiosis?

Membrane transport iy7 l( n tdlu7hd63iy)ds important for allowing particles to move across the cell membrane and respond to changes in the chemical compositiondinuyh(y t l7l )d36d7 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 regulatedcud i4t+a*mfd b;u*;f4 (lpwp-j4 esgaco)1 m 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 cyclinsu,1 ochn gq.0q during the cell cycle. Which cyclin is involved in.cq1hgn,0qo u preparing for DNA replication?

The diagram below shows chromosomes during m+ni : stn(0 5xz/juyem-*br pveiosis.

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 lc c97j en-iv3homologous chromosomes?

  The mitotic index of throat tissuetmgh 8az-y 4b2aetj8s l.3qt9 s taken from 4 different patients is shown below. Which patient is most likely to have cancerous throat tissu4st9 he jtgmqa38 t-8bazy .2le?

1.Draw a labelled diagram to represent the process of crossing ove25ej d enpqt8.hd/y 8y+yx3fh r.

2.Compare and contrast random orientation and crossing over.

3.Outline the stages of meiosis.

  The image shows an abnor6x0qz ct5+z9di 6 sljy,g; dybmal human karyotype.


What is the abnormality in this karyotype and its cause?

The graph below shows theoib sg*s2 bh2czs keo+7,l g47 relative amount of DNA in one cell during one complete cell cycle. Each letter represents one stag 4oc, glbkeb7gisosz+2h*7 2 se 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 s5hg58t heou(ted kcl1b l)26for brown, long hair and a female cat that has black, short h5g(u2 oth) ebt56dh el8s1 klcair.


Which of the offspring has a recombinant genotype?

1.Outline how polygenic trqh1t2d+j i e-m7z1hhru 28qrjaits can show a normal distribution.

2.Outline the differences and similarities between homologous chromosomes.

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

  Which gamete can resul/ wn j74 aok c9)oht1*kmpc0ndt from the crossing over of non-sister chromatids shown in th onkk4/m jw)1n9t0chco7 pd*ae diagram below?

  The photomicrograph shows a pollen grain frw .7k)huupgcmt ps 016om L. candidum (Lily). Which stage of meiosis is shop61u s)p7 h kwc.gum0twn?

1.Outline the events which would lead to an individlu8h7+n 2 gn pb7ljms-ual being born with Down syndrome, which is characterised by the presence ofn8jubh 7gm2+-l l7spn three copies of chromosome 21.

2.Explain how meiosis increases variation.

3.Outline the stages of meiosis.

The mitotic index is a7.k, hrrlka3 + rylc n+bx le,/l8jy;cn indirect way of measuring plant growth. A study was conducted on white onions (Allium cepa), uy y 7rn kr,lblkl+ajh8c x+ e;,/r3c.lnder controlled 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 which cells can divide. The diagrams b 32t kurkp: w0um).tzvelow show :vt u32kuzkr.)mw0pt two cells 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 inbqlb dy4iz a88 )we-18tfs -sr 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 cell9 q l/0q)zadod, with a diploid number of 8, in different stages of meiosis. Which row correctly n/9)dqz0a dolq ames each stage?

  The micrographs show four phases of meiosis I in a plant. t.u 65*bf uyz c me67ndptkh:9In what order do these phaybpz6etd h fkt.:6u9m*5cu 7nses occur?

Mitochondria are responsxx,s p)4g(xmpji-. xd ible for supplying metabolic 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, inheritance patterns of mtDNA found in hybrid cells, which are the result of sexual reproduction between two different yeast species, could be influenced by d.xixxg() -j4pxp, smthe 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 stages of thb02f+s x3o fdie cell cycle in four samples of lung tissue from four patients. Which tissue fx3oi f2+db0shas the lowest mitotic index?

  The diagram shows the dominant cyclin/CDK complexe1gbxwg2*g.r 54sz 1zb )rbfgrs at different time points in the cell cycle. Which cyclin/CDK complex activates DN x1rrs .bg 2wzf r)zbgg*4gb15A replication machinery?

  Studies have shown that genes such as Cyclinxj3b0:) t)ffj ad wwpi(j ni95 Dependent Kinase 3 (CDKN3) are highly overexp9(jxj0w:w f3id) pbta)5jnif ressed 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 the ce). ,-+ 2h i3rakyw ksu5hzauf4vtv -dnll cycle ?