The graph below shows the relationship between maternal age and the incidence j*-uwho r,)8-)m* t idcfkfnrof non-disjunction. What relationship is s) j -r-r*dwmfkf 8no *,)chtuiuggested by the data in the graph?

  Which stage of meiosis otu) g tt-tz*bd1 j(2sis represented in the diagram below?

  The diagram below shows chromosomes duringcoia)y. )0e0;ih gg:yl:42jnvxg i ek 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 wo(jz0e8js dxv+ uld be present in the nucleuvs80jzx( d+jes of a cell as a result of each process?

  Which keyword is matjjk ):c. a8,sfx0kpqom1wwax 1j zq-gs- qk( ;ched to the correct definition?

  Which statement(s) about mitosis is/arc;udu +; b .m/3yp.l(vrqzhaf e 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 czcm dqzi /89sygx+ bpzquct8l- br(p.8p //e,ell in anaphase?

  During which stage of mitosis does4x cnqvl ::v8qj *peq( the nuclear envelope break down?

  Which one of the following t 2 *-dmn )o2ug;zjxs**agmynl ransport proteins only carries out active transport? sogu-am n*)m n2 *dgzxl2;j*y

  Which process does no l,-fq7qx:c/sc nd 5fet happen in the shoot apex?

  Which type/s of membrane transport do/does not requirqn22ae+ gebe i-6e qf/e energy expenditure?
I. Facilitated diffusion
II. Active transport
III. Osmosis

  The diagram below represents a cell with a di(wh+ mzqr /u v7si2v(m/7ucqtploid number of 4. Which stage of cell division is the cell currently undergoing?v+2u q(/istz7m ruhc7 mvw q(/

  The photomicrograph below shows a root tip meristem. Which of the foln8ofbmwpw s4w 6ekz2l+ u (e31lowing sentences correctly 1 knml4e8e6wpfw 2szw+ou(3 b defines a meristem?

  When does the random orientation of homologoh5j5o-(peeeou(b)sr d lln(7 us chromosome pairs occur?

  Which process does not occur durinig ov)39svc-tg meiosis?

  If a cell with a diploid numbejuqy blioyc +x68u (ipr22f//r of 36 undergoes mitosis, how many chromosomes will bl uy8fcb( xpj//r6qo+iyu22ie present in each daughter cell after cytokinesis?

  The image shows a micrograph o*f1 +n-:tly egeiyj qgo h6)t:f a cell.


What explains the appearance of the cell in the micrograph?

  Which statement(s) about homologous chromoun- 0wem;n yz5somes 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 *5*xp) j8eulf9lhxc5xu :rab,z5hasan individual with Down syndrome.

Which statement is not correct?

  In the cells of a horse (E. ,vv5sb8o.a qscaballus) during prophase I of meiosis I there are 64 chromosomes. What vs vo.b ,a8qs5is the haploid number of chromosomes?

  Which arrow is pointing to a cnq 1*phwvkpy iip70mo)0hcy)w7 pu +5hiasma?

  The diagram below represents the structure of a shoot apical meristem. Whi,m/.biami;yq9a / +, kafq ctqch row in the table correctly identifies the processes occuring in the structures labeled in the diagraamtm / q aqyqi,b/9 +fa.i,;ckm?

  How does meiosis promoteh1/d/qql0 da7 q nmg1 vrpfl*qr3(xn 9 variation?

  Which of the following statements is/are cori tz. ri-uj19irect 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 chromosomesj)x2r1c;pnr 22 r6/k;z5gfw iqb r (vnumdq7c.


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 tumo wuqkqrp1 n19 jn6d69kurs as a result of the movemennk6pq q161k9d9 jrwnut of cells?

  How many chiasmata are :x5*rwd tfu/tpresent in the diagram?

  Which statement is a similarity between cytokinesis in anims ; +8qej(zpleal and plant cells?

  Which stage of meiosis is matched to the correct descriptioxex6 +z yy, delb4j/sx.m3 b6en?

  Which statement(s) are true of meiosis I but not 3bm6kte9ez+++j pqpt 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 after74 i1gnsee (xdcgqd 94 the first meiotic division. This results in the formation of one large cell and one small cell. Wedi(x14gdcg7 4q ns9 ehat is the fate of the large cell?

  Which row correctly describes diploid and haploakd pg+*d7 vw3:rnz f-id cells in humans?

  The following table shows a-qgk mi ,8/dzq: yu/qthe diploid chromosome number of a range of species.


Which of these statements is correct?

  What conclusion can be drawn from the karyogram belxwr7l: g2b -krw q.v/fow?

  Which of the following processes is characterx 5umg u 1x*/mbbq qt+mgbw1 c33d/(psistic of the meiotic and not the mitotic cell cyclem xd/t5x3cpbuq*gs13q 1b/gm+u( mwb?

  The diagram represents a byh sdgyq, /dfe a6(m/3ud with a shoot 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 (Pan troglodytes) is 48. Which rdy7w3xm aal2( ow shows the correct chromosome number aawy 2(l7dm3x for different cell types and cell division stages?.

  At the end of which phase of meiosis I does crossing over occx qj.z)r9tqs 9dnv1gw9 2pz 9ro6 h-m3)cdmosur, and what is the oo9z ngsw9z)92 rqv3.p6 drxdos c- 9mhmj1)qtutcome of crossing over?

  Which of the following statements does not describe a step in the sodium-ph; b m94hi .a+envlp1 ol-h)iqotassium pump cycle in the neuronal camq-h+ ip1n;4.vheolb )l9h i ells?

  Which row in the tab:5w)nh3r1g pj (juq +fb)cp )fi cziw/le below is true of meiosis?

Membrane transport is important forbpe.kj tsoh k:94:vc- allowing particles to move across the cell membrane and respond to changes in the chemical compositio. chej sv tb:pk9-ok4:n 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 isanmv niq*o 9;q swz+, fd(15js regulated 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 shoi (hjun bl.yr8i3/)v 2kc kyrl5:h*uyws the concentrations of different cyclins during the cell cycle. Which cyclin is involved in preparing f5h3bry j:rkyliuc(8iv2.nl yk /*h)uor DNA replication?

The diagram below shows chromosomes dur--h/,ub8ga zgeo . rrking 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 chrombya3u-) lbqc7 w; am)z gn(p9mosomes?

  The mitotic index of throat tissues taken from 4 different pati r*. uk .r90xhmxkh5xu2h .izfents is shown below. Which patient is most likelyhk2.zfk * 0uux9hh.i. 5rmxrx to have cancerous throat tissue?

1.Draw a labelled diagram to represent the process gj*iyh 6z;q3dof crossing over.

2.Compare and contrast random orientation and crossing over.

3.Outline the stages of meiosis.

  The image shows an abnormal human karyotyp)j)3onfx 9 klmwbu7::w5 5s;bskpmvxe.


What is the abnormality in this karyotype and its cause?

The graph below shows the relative amount of DNA in one e2f.nlwl /l80uu26e(bx4uyke2 i t pb cell during one complete cell cycle. Each letter represents one ( ne ulb0wk2ub.eufe t6i22 8l/yxp4 lstage 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 p8p2yg)l wb+ efor brown, long hair and a female cat t2e gy p8wp)+lbhat has black, short hair.


Which of the offspring has a recombinant genotype?

1.Outline how polygenic t5d-m-gj gj83 xtsgfh0raits 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 crossi rg-yixn qhg22l5 jk-k+g ;p;hng over of non-sister chromatids shown in the dipg;gl gi 2jy;5xnr h-+kh-qk2agram below?

  The photomicrograph shows a pollen grain from x;htsgx+wpq*,uf k3t/b5 q;bh k i4t7L. candidum (Lily). Which stage of meioi; g /ux3*h4 w+ fq;hbqpxbk7kttt5s,sis is shown?

1.Outline the events which would lead to an individual b wqveo (trr;m73qwc );eing born with Down syndrome, which 3q;qvcm7)w(r;toer w is characterised 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 measuribiu52 qniiii-v0y l51ng plant growth. A study was conducted on white onions (Allium cepa), under controlled conditions in v52 qu1 i5l yii0-niiba 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 arewnv lb ;oinum 8v7i5pq4y+ zha;ffj7f:5tt 35 two ways in which cells can divide. The diagrams below show two cells from an organism with a diploid number (2n) of874t5otva+zmyh;f : l j5uwi;i3f5qpbn nf7 v 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 * umsyeb;w*o0.

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 oh41 +6ic b1 mtiwkt(mdifferent stages of meiosk ti+otimb1w h( c61m4is. Which row correctly names each stage?

  The micrographs show four phases of meiosis I in a plant. In what order ptiiwt 3 kun9(- rer6pm 3.kxko+,wy2do these u.(ptxk oky9w2n ,er m3k+ r-6ipi tw3phases occur?

Mitochondria are responsible for supplying metabolic energy in eukaryoo.:;t dq t inpf.8du7ttic 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, which7nui;q: dtop8. tdf.t 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 different st.r rum,y03ye7z: d pviages of the cell cycle in four samples of lung tissue from four patients. Which tissmr 3.rpud:iz, 70v yyeue has the lowest mitotic index?

  The diagram shows the dominant cyclin/CDK complexes at different time points iz:ehz 66jk 4idn the cell cycle. Whic64di zhzke: j6h cyclin/CDK complex activates DNA replication machinery?

  Studies have shown that genes such as Cyclin Demb ix9 cnr2)bf2(.kympendent Kinase 3 (CDKN3) are high2n9 .) ( mkfymri2xbcbly overexpressed 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 duri:*i54wnst epeng the cell cycle ?