The graph below shows the relationship between malk6wan h.xe4 bj7+* 2 x2bsvieternal age and the incidence of non-disjunction. What relationship is suggested by the i42abj*.kb6nlexv 2 7e hsxw+data in the graph?

  Which stage of meiosis is representedxc/3(iz 9:r0yz:cd y p .repcy in the diagram below?

  The diagram below shows chromosomes during meiosis.9c 9a wr1uj7ba, wg;bu


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 be i:,ihb68guwj present in the nucleus of a cell as a resbighj:i8, 6w uult of each process?

  Which keyword is matched xfz4lr50 dl7oto the correct definition?

  Which statement(s) about mitosis is9/)2gt u:jqoqp :( hncxsz 1e i;cfdz(/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 belom* 83liyz jid-w, which letter points to a cell in anaphase?

  During which stage of mitosis does.p9,zl5c8irlh )dxd ),dmlw(omo p( ph( o (ht the nuclear envelope break down?

  Which one of the following transport proteins y:gjwc 313ozm/h6 x8) yhqlxzonly carries out active transport?q o:c3zzh/l1x3j x g)my6 wy8h

  Which process does not happen in the sh:6 cl 6f,lyb)h ocjai*oot apex?

  Which type/s of membrane transport do/does tat0,y*nk)d +tz/ze -1xb prus hh0w/not require energy expenditure?
I. Facilitated diffusion
II. Active transport
III. Osmosis

  The diagram below repres0u 3bod od42brents a cell with a diploid number of 4. Which stage of cell division is the cell currentrd0 34uo2bbod ly undergoing?

  The photomicrograph below shows a root tip meristem. Whichju2r6t rspv1 :yynky05: 9bu y of the following sentences correctly defines a mer:yjv5pryb269k0 nu1 yuy :t rsistem?

  When does the random orientation t1 goirzw)kny.)yh u :4jps -;e4lry +of homologous chromosome pairs occur?

  Which process does not occur duril ;uzch-+:elazde ;1 fng meiosis?

  If a cell with a diploid+pigvq )6+5gpkpgj+uib g +2i number of 36 undergoes mitosis, how many chromosomes will be present in each daughter c+ vpk bi igpuq+p2g++g6g)5j iell after cytokinesis?

  The image shows a mirw 3z6h lzd-6bjw*c 2acrograph of a cell.


What explains the appearance of the cell in the micrograph?

  Which statement(s) about homologous chromosomes is/are not trum/ykf 28f jke+e?
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 sy 2l2by ci evzsl:d63y3ndrome.

Which statement is not correct?

  In the cells of a horse (E. caballus) during prophase I ofc-+)x5cth4bsyf d1vf *d q.b r meiosis I there are 64 chromosomes. What is the haploid numbe 4cxc.q bd-1d sv )hf+t*frby5r of chromosomes?

  Which arrow is pointing to a chiasmwzaf;c)bdv+m jn7/ r(a?

  The diagram below representq5 p.zjih sbe.i (5iqap9j+q;s the structure of a shoot apical meristem. Which row in the table correctly identifies the processes occuring in the structures labeled in the diagj;i 9 je.q5qisa.bq+pph(i5 zram?

  How does meiosis promote va uc1xkbd1*(tn riation?

  Which of the following statements is/a 48hzf,8ealw79bel vi3:44s jfw fgcsre 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 homologous chromosomes.brw ) vi4i,;kz


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-d.tq guf0v*h .gil7expt ;g,ndary tumours from primary tumours as a rghpte7ugg.x qd* .l fv0it-;,esult of the movement of cells?

  How many chiasmata are pryioq-0j- kc 1wesent in the diagram?

  Which statement is a similarity between cytoki1ytw*m .xi bs6nesis in animal and plant cells?

  Which stage of meiosis ;ilgiu h-;6 ifis matched to the correct description?

  Which statement(s) are true of meiosis I but notey//ef5l pvydh3y : gdh;9;ug ky+6 am 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 divisg nnf 6bgpuj6 4 w u1-)2lsuf-ya0uw-qa41fa zion. This results in the formation of one large cell and one small cell. What is the fate of fguw6 1u-jfa 0pa-wn4u-1ba n y s6l2f )gqu4zthe large cell?

  Which row correctly describes diploid and haploid cells in humansr8kvj 6f qiz.(9hl1kc?

  The following table shows the diploid chromosome number of a range of specif9gwzk+t0i e o/ a41wcn-yq9ttd07oxes.


Which of these statements is correct?

  What conclusion can be /r vvz4u: vbeqb(20c2miiv3w drawn from the karyogram below?

  Which of the following processes is characteris75idb/ u zvcp;tic of the meiotic and not the mitotic 5;dvp ui7bc/z cell cycle?

  The diagram represents a bud with a shoot apical merseox8nc+;szv9p lc :f; 7 bux7istem.

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 thetq52ns tg8 vf2 chimpanzee (Pan troglodytes) is 48. Which row shows the correct chromosome number for different cell types 2n fstg28vqt5and cell division stages?.

  At the end of which phase of meiosis I does crossing over occur, and what is )80 tw,6v*i;-m2 db kro9 bih glpcushthe outcome of crossing ovek)m sirp*,g0ui dht28bwl-96o bh; cv r?

  Which of the following statements does not describe a step in the sodium-potm*ra(fl2 gjqs 2h+f.ln6 ven:assium pu*mjs. :aleqf+2l2vhnn(f6gr mp cycle in the neuronal cells?

  Which row in the table below is true *7qwr kw/o6c-9yw yid of meiosis?

Membrane transport is i 3khf r :okovp eg+m,b(ta3;h:,lyjp0mportant for allowing particles to move across the cell membrane and respond to changes in the chemical composi+:f3r,: 3yjptevh;,kl apb oh 0k (gmotion 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 cells.kcbo/yqei83c ztrh 2 6 jl*u-)

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 concentrcqko/d0 ;myl h5 1,cgxations of different cyclins during the cell cycle. Whi/5; yq l,g0kxodhccm 1ch cyclin is involved in preparing for DNA replication?

The diagram below shows chromos 7ih)vd yei 2u9w(lql(omes 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 separation of homologous chrom oimh0t,.h/e7a o2 hokosomes?

  The mitotic index of throat tissues taken fromt wca+vj,w9w ) 4 different patients is shown below. cw)9ta ,jw+vw Which patient is most likely to have cancerous throat tissue?

1.Draw a labelled diagram to represent th i74 fu.*hxvbse process of crossing over.

2.Compare and contrast random orientation and crossing over.

3.Outline the stages of meiosis.

  The image shows an ab8xpha kh9i83nng uk /gud2xpk;4p:o 4normal human karyotype.


What is the abnormality in this karyotype and its cause?

The graph below shows the relative amount of DNA inft: 3ssw f fe6 .kxz*ie1dak7a2kq. ba5uf 8p/ one cell during one complete cell cycle. Each letter represents one stage of the cell cya2f /:3 zkt8wi1e.ed7bx.q kuk saf56fsfap * cle.


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 spy22 --uhwm.;pa n(1 qjq*:b+wnrxuuv ox/ithat is homozygous for brown, long hair and*u jw (avyq r.i+x-pn/:2m-uxp q2n; uhb1ows a female cat that has black, short hair.


Which of the offspring has a recombinant genotype?

1.Outline how polygeniokszr)qsqu/ ;o 1 *s4kc 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 fr r2wkra- :-xya;igsoz 3b+0 grom the crossing over of non-sister chromatids shown in the dibrrargx-z2kys;3i+g -:0oa w agram below?

  The photomicrograph shows a pollen g7( 27ys*k qfh vxafks4rain from L. candidum (Lily). Which stage of meisfykq*(2747 k xashfvosis is shown?

1.Outline the events which wouldl8(-ski f0h ft lead to an individual being born with Down syndrome, which is characterised by the presence of three copies of chromosomeflsi-8k fh(t0 21.

2.Explain how meiosis increases variation.

3.Outline the stages of meiosis.

The mitotic index is an indirect w,o4qse:l z0jqv y3cb6ay of measuring plant growth. A study was conducted on white onions (Allium cepa), under controlled conditions in a lab, :qovy4jb6zc 3q l 0,esto 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 be oe1vvf4h6r-o low show two cells vo ore-6vf41h 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 growth.:wek iaw b jys5)h83 ep5 ;7kb7ult4rg

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, w9i f-px-oo(aert 3hcm5cx(. with a diploid number of 8, in different stages of meiosis. Which row correctly names each stage?p xrmioxc 9o-eh(a5(ct3w - .f

  The micrographs show four phases of meiosis I in a plant. In what order do lxkehb69+z2kj2;l+q 5at mb+v kls 6ythese phaseebzlbvjyll+thx +22 ;makk6q+59 k6 s s occur?

Mitochondria are responsib re;0jxp0 j 6iq 1emx.wrtrt29le 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 ;jx tqrm2 p. 1wr 0j9i6x0reetnuclear 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 of cells in differ9j t/i id:u(/xuw stmi4 h0 /cau7bnr0ent stages of the cell cycle in four s(dhui/m:9ji u 7ixtwt /0b 04 /acnrsuamples of lung tissue from four patients. Which tissue has the lowest mitotic index?

  The diagram shows the dominant cyclin/CDK complexes at ( dol4zxt8 e;adifferent time points in the cell cycle. Which cyclin/CDK complex acti;l4 dx8tzoe( avates DNA replication machinery?

  Studies have shown that genes such as Cyclin Dependent Kinasezhnjt n1vfrsato:0,9 scx 23/ 3 (CDKN3) are highly overexpressed in cervical 1nrfo:sj3 9cs,/x 0na 2 htztvtumours.


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 cyclila5;v(m, bqq-vu 0w ubn E the highest during the cell cycle ?