The graph below shows the relationrl7),xna fyz -ship between maternal age and the incidence of non-disjunction. What relationship is suggested by the data in the )f-z ,rnay x7lgraph?

  Which stage of meiosis is represented in the diagram be7pc0)c4him gelow?

  The diagram below shows chromos2 x h)z*isym,gomes 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 all/edggnu2-i c/t/ qn)cv) *mj geles of a single gene which would be present in the nucleus of a cell as a g* /tguqj/neig)d2cv -/ )cnmresult of each process?

  Which keyword is matched to the correct definitis )as*rv 1lt +f98yapgon?

  Which statement(s) about /xjez0aoif:td /06ywubv o( (t(m r z3mitosis 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 poi/mxb jq,bwuj8cpa40 2nts to a cell in anaphase?

  During which stage of mitosis does the nuclear (0h;rq /ohxnmdx 5,t3o k1y 17dmaro 3 9wbgcbenvelope break down?

  Which one of the followin0+s/9e8yxll qm0vl bvg transport proteins only carries out active transport?0mqe+/ 0lv9vsl8bxyl

  Which process does not happen in the z8k q/1u5xw pqshoot apex?

  Which type/s of memb( d n+l*up6(0*fyd m3errrbnlrane transport do/does not require energy expenditure?
I. Facilitated diffusion
II. Active transport
III. Osmosis

  The diagram below represents,t lu*l4e oif57vbtpivt h+m0v3vy9 * a cell with a diploid number of 4. Which stage of cell division is the cell uevi ,ibphl7*9 ml+0v3y*4t5v to t vfcurrently undergoing?

  The photomicrograph below sh8syod qf/c*au(ov t 7+ows a root tip meristem. Which of the following sentences correy q8ovfs+*c o/(7utda ctly defines a meristem?

  When does the random9 i0vv,ncwn * q9z3 fjw y9+rj*wdiwk,mx/r-v orientation of homologous chromosome pairs occur?

  Which process does not occur during( ig h:3dat.xhnw2jx9 meiosis?

  If a cell with a diploid number of 36 undergoes mitosis, how many chromog 0;e0to h /bf uu7o:ns8hck;ssomes will be present in each daughter cell afh cutesf 70oo/ 0uk8:b;nsg;h ter cytokinesis?

  The image shows a micrograph of ggz1m9 84velba cell.


What explains the appearance of the cell in the micrograph?

  Which statement(s) about homologous chromosomedit192x, 9 8 uy*hf85a dpn;yqyltg fms 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 ind38ic9 izbd q1goa+7 ucividual with Down syndrome.

Which statement is not correct?

  In the cells of a horse (E. caballus) during prophase I of meiosis I the9u2+z :.w1zfci m i+uo q2ynj;d0go qkqqj7e/re are 64 chromosomes. What is the haplju1q/ yz22ijif.m+7nw:k +d0c o 9;qqo zgequoid number of chromosomes?

  Which arrow is pointing to a chia2 a6+ gbupyiq3sma?

  The diagram below represents the structure of a shoot apical meristem. Whil6kagzi4 5+2s 1h2 otv;(wwzglno ve6ch row in the table correctly identifies the processes occ2t 5k41gwg lleowvvn2+z6 h(z6 ;o isauring in the structures labeled in the diagram?

  How does meiosis prom34 u7smgs0kyxote variation?

  Which of the following statements is/are correct for meh,b s9lu5rkqr 35 zyfo977fm yiosis?
I. It is a reduction division
II. It involves random orientation
III. It produces genetically identical cells

  The diagram shows gametes produced from two homologous chromosomes.pml.4 c/j 9yk9rvv q)p


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 th-pdt b: aff(w6e formation of secondary tumours from primary tumours as a re6wfpat(b: f -dsult of the movement of cells?

  How many chiasmata are present in the dia4:l vtrc4.x2cs*ptw5-xquh p gram?

  Which statement is a similarity between cytokinesis in a6bio5h8 kbi ,wnimal and plant cells?

  Which stage of meiosis is matched to the correct descriptnvr*7;d qpl v-ion?

  Which statement(s) are true of meiosis I but not meea ie).w:(k+jdndg-+u u(: ogp9xu cuiosis 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 divgzj 69xe5vj; zision. This results in the formation of one large9z;vg 6j xzj5e cell and one small cell. What is the fate of the large cell?

  Which row correctly describes diploidy*wz g bk7z v1 hss39i3da);wd and haploid cells in humans?

  The following table shows the diploid chromoso85w5 z*nj aelbme number of a range of species.


Which of these statements is correct?

  What conclusion can be drawn from tgsh z69+ 1af-gblyxr*own:g 0d*ypm :he karyogram below?

  Which of the following processes is characteristic of thgkksss h auo4+mzvc0(w2v d 3y4kg-94e meiotic and not the mitotic cell cycleus920 3 ss 4c44do+gwm gkzk v(vy-hka?

  The diagram represents a bud with a sho9l0rovpprfwuv uz) ,ll 53+: fg8ni(not 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 );wnz 5s)em vl(Pan troglodytes) is 48. Which row shows the correct chromosome v nm ews5z)l);number for different cell types and cell division stages?.

  At the end of which phawlh91 /sdl7eytko,q t)w8oal ag) 4i 9se of meiosis I does crossing over occur, and what is the ou)ek ) sgq7w14tahi/d o9lw lo,tay8l9tcome of crossing over?

  Which of the following statements does not describe a step in the sodiumpya6amt: 9 ld(-potassium pump cycle in the neuronal ce:p6y d(aa9ltm lls?

  Which row in the table belowd 5v 5aps2(waw is true of meiosis?

Membrane transport is important for allowing particles to move across the cell m1j7ow8eza m r3embrane and respond to changes in the chemical composition of the ex 8eamwj3oz1r 7tracellular 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 s0-;gs* hhw0achd az *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 differen.pr w;kh7ot6 ct cyclins during the cell cycle. Which cyclin is involved in prec.76;tpk roh wparing for DNA replication?

The diagram below shows chromosomes during meiosi7**la1ay .wwp l7bdtjncfr:0 s.

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 y1wqy2zi/ a9n(c kk*z,5 :fb/ekqqzi the separation of homologous chromosomes?

  The mitotic index of throad-ohr 57nq/.sqoc7 3 .dl 1likn5macrt tissues taken from 4 different patients is shown below. Which patient is most5r3 5alnd7. h- im 1 ncdol.qc7qsrok/ likely to have cancerous throat tissue?

1.Draw a labelled diagram to represent the pr bzs2 nx.zrp3)6;f)ik ya6louocess of crossing over.

2.Compare and contrast random orientation and crossing over.

3.Outline the stages of meiosis.

  The image shows an abnormal human ka f:(d n.n82lg5v yu,es*vroa4 6htqqcryotype.


What is the abnormality in this karyotype and its cause?

The graph below shows th6rvclb5(g;of e relative amount of DNA in one cell during one complete cell cyclec(f65v lb o;gr. Each letter 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 /jgj*a o :+s8ucw+wwz;9aif ka cross between a male cat that is homozygous for brown, s8aoj9 :fui ja*+zww k+;/cgw long hair and a female cat that has black, short hair.


Which of the offspring has a recombinant genotype?

1.Outline how polygenicu mnc 9v(etx;(tq0x io30om3l traits 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 result from the crossing over of non-sister chromatids shown incom sm f;,1sd6c6sdfm,;1ms o the diagram below?

  The photomicrograph shows a pollen grain from L.i9*y gn7ptagf u* ,d+v candidum (Lily). Which stage of+ 7dvg9yung*tpfia *, meiosis is shown?

1.Outline the events which would lead to an individual being born with Down13 h8f;ryioyttx pg c48n wl.;cpn:8b syndrome, which is characterised by the presence of three copies of chr48c nph xcy :yni;tg lt3 88w;.b1opfromosome 21.

2.Explain how meiosis increases variation.

3.Outline the stages of meiosis.

The mitotic index is an indirect way of me g3h2zmt:k*r gasuring plant growth. A study was conducted on whh3 * rmkt2zg:gite onions (Allium cepa), under 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 6kyrp2 jydeyk51b3-mpupb) f 7w;yd( can divide. The diagrams below sh b fyk5-ddwy7)62k ;pemju1ypbp ( ry3ow 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 in stem gw4 m)7 nz6qpif3rjg k7rowth.

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 aj:+x 6+gim7s s.faucb diploid number of 8, in different stages of meiog+ 6sj7x+fs aucmb i:.sis. Which row correctly names each stage?

  The micrographs show four phases of meiosis I in a dgk 4lm olb(+4plant. In what order do these phall+dbo4 m 4g(kses occur?

Mitochondria are responsible for supplying metabolic enue;td4ltw28xd3ev , rw( p/xeergy 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 /e(v,xe uwtel8;dwx d4r2tp3which 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 of cells in d p3fvxsv 0u q9: g;f5qewli88.tv .uueifferent stages of the cell cycle in four samples of lung tissue from four patients. Which tissue has the lowest ;t59l.uvgf .e i x0uv: v 8q8pfwsqu3emitotic index?

  The diagram shows the dominant cyclin/CDxxboq ;by3.jjt x1 82jK complexes at different time points in the cell cyclejyo xb8.;x b1jx32tqj. Which cyclin/CDK complex activates DNA replication machinery?

  Studies have shown that genes such as Cyclin Dependew+dj9puj) ft+nt Kinase 3 (CDKN3) are highly overexpressed) fjptj+d wu9+ 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 celvpnx6b/0k,z:+n-r b /ebbvl ol cycle ?