The graph below shows the ree)r j:t . x1pnnku6fug,;n4jg lationship between maternal age and the incidence of non-disjunction. What relationship is suggested by then)rj6 k enn1g ujfuxg:t4;, .p data in the graph?

  Which stage of meiosis g5b8ts wby/o/2l6lulis represented in the diagram below?

  The diagram below shj/n6 elzxuv+5ows chromosomes 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 ap.5x 8gxh0ap m+ eui)y(h3 krflleles of a single gene which would be present in the nucleus of a cell as a result of each processhxge( pf 08ki3upm5h)rx+y.a?

  Which keyword is matusvwz, x1 ut4*lg,w;ql9nqi9 ched to the correct definition?

  Which statement(s) abou3a91zn; uhz 3dg3xlukt mitosis 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 x4zti /zge y2fapof-,scj4,*a cell in anaphase?

  During which stage of mitosis does the nuclear envelope brea;8e 6jxy vp osaun5f44k down?

  Which one of the following transport proteins only ca1 j 3kxvew2c+8qg3,epm f d *pjcam(2th x6ls;rries out active transport?dv+c s6ew2,lj pj82 tf;m *hk p3 13gqxexac(m

  Which process does not hap r*1x:w;yyivv g)z 5rrpen in the shoot apex?

  Which type/s of membrane transport do/does not require energf9kvl o8g)g :pd0jn/cy expenditure?
I. Facilitated diffusion
II. Active transport
III. Osmosis

  The diagram below represents a cell with a diploi04 0clacwayr m2-wm e.d number of 4. Which stage of cell division is the cell currentlw4wa 0mre.m c0ay2-c ly undergoing?

  The photomicrograph below shows a root tip meristem. Which of the followinu 994ktjkim o p5y+nu(g sentenceiy5+u nmk9 9(j4oktu ps correctly defines a meristem?

  When does the random orientatiophk z1go)rr3k;jr+7 fn of homologous chromosome pairs occur?

  Which process does not occur dur1a44/tfn wfad5*pg,,-nhm dis9pn cxing meiosis?

  If a cell with a diploid number of 36 undergoes mitosis, ho8 yuy8,1f j kgs6sf:tcw many chromosomes will be present in16u8k:s , fsc yy8ftjg each daughter cell after cytokinesis?

  The image shows a micrograph ofdcmq/uf7.z(l,n8ai + qt2imi a cell.


What explains the appearance of the cell in the micrograph?

  Which statement(s) about homologous chromosomes is/are +ej1l 5c-zeyrddt 5(uiawjr.5:pf f2not 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 individual with4*l/ekgc-dc+z 9vsi s Down syndrome.

Which statement is not correct?

  In the cells of a horse (E. caballus) during prophase blh( vbb+r4css wfwga4,g5* 4I of meiosis I there are 64 4lg*rc(w5b4 +,wahv f bbsg4schromosomes. What is the haploid number of chromosomes?

  Which arrow is pointing to etu otpx 0;if4i-/ y,zq8box.lj s;j*a chiasma?

  The diagram below represents the structure of a shoot apical meristem. Whi pkr*rn)+p xkz*:fsav qd4/3ech row in the table correctly) 4seqn 3/zvdar:k+pfx * pkr* identifies the processes occuring in the structures labeled in the diagram?

  How does meiosis promotu+6bqr3v ) 7/5 ly1gxwb ilkqrfxmx6 +e variation?

  Which of the following statements is/are correct9t e c-6i;picb 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 homologo-b 38 / ;/ 2xwqiw)mf/mk.kzzbtqjuqdus 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, 9 )enertdfa,bl r:(v of secondary tumours from primary tumours as a result of the movement of cerev )flb 9nt ,adr:(e,lls?

  How many chiasmata are u,:4x tv. sulvxjlz0.f05 ddfpresent in the diagram?

  Which statement is a similarity between cytokinek+ 2qkf8a9uwqm 7vd+iu 7)6np 9q0sveqv ib2osis in animal and plant cells?

  Which stage of meiosis is matched tz1 )i6l+ha,q cf ,acgu a3ek;xo the correct description?

  Which statement(s) are true of mwg1ee +wtqaj7dx(m e (1i)dg8e q5cy-eiosis 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 after the fg4ffq19*th3 85c.w bmqcme8tfzd7 ogirst meiotic division. This results in the formation of one large cell and one small cell. What is the fate of the gwgqt4b*3 e fmtz8.d8cc f9fm71qo5hlarge cell?

  Which row correctly describes diploid and haploid cells in humans?vo (hoz u7(,yzz5ego0cd3,s a

  The following table shows the : vf/g gvxspz:h)20 ghdiploid chromosome number of a range of species.


Which of these statements is correct?

  What conclusion can be drawn from the karyogram:vy6lb djv 03h( 4deed below?

  Which of the following processes is characteristic ofglw)m)vbbic *kx8y-3 the meiotic and not the mitotic cell cyw-kxg8m )v)byib c*3lcle?

  The diagram represents a bud8hwd jw:*sk7hy ( *vf4 squy1t 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 jqperb e+fb, g,;eq 8948. Which row shows the cor,9f8qbe grp,e;bqje +rect chromosome number for different cell types and cell division stages?.

  At the end of which phase of meiod;yhq5s: d w4qsis I does crossing over occur, and what is the ouyw5;4h d :qdsqtcome of crossing over?

  Which of the following statements does a.rq2zyw2qzh i2*6cn not describe a step in the sodium-potassium pumnzy6 2.z c2ih*r2qqwa p cycle in the neuronal cells?

  Which row in the table below is true of lkam7w et++r1-zeo k6meiosis?

Membrane transport is important for allowin:k5a vi*ledz8g particles to move across the cell membrane and respond to changes in the chemle kvzda8* 5:iical 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 irxeoy+1z9oy3g zoh11r.u m.zn 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 cyclins during theyi e gvfz79pdto j,q+f4/u3 h7wko yi cr*5..j cell cycle. Which cyclin is involved in preparing for DNA replication? f+ iy .yk 34d7cq7vu9jfg*th oezwo,/i rjp 5.

The diagram below shows chromosomnho( c iu 7j:z4udfv52es 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 h-)ik/x yuxbr6omologous chromosomes?

  The mitotic index of throat tissues taken r;w5 wq)dxsc7l54aoufrom 4 different patients is shown below. Which patient is most likely lu;7wqc5drwax o5s)4to have cancerous throat tissue?

1.Draw a labelled diagram0e, nyzzl pzg6d.(6rp,u41dil x9mqy to represent the process of crossing over.

2.Compare and contrast random orientation and crossing over.

3.Outline the stages of meiosis.

  The image shows an abn7 c5nl c6 friibcs:,i5hu (gy-ormal human karyotype.


What is the abnormality in this karyotype and its cause?

The graph below shows the relative amount of DNA in one cell during o 5koi;a zf3xs.d/ ziv*ne complete cell cycle. Each letter represents one stage of the cell cycvizk5/s3 f o*i z;xda.le.


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 2bk.hfhx6 n tt4*en2lbetween a male cat that is homozygous for brown, long hair and a female cat thtkhex.bn 6t*2 h2l4nfat has black, short hair.


Which of the offspring has a recombinant genotype?

1.Outline how polygenic traits can show a n2wk0f efx)zd z 8tpk,j06j*wuormal distribution.

2.Outline the differences and similarities between homologous chromosomes.

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

  Which gamete can resuo f kgct89 4f(giqggjs8x m7-0(agfn7lt from the crossing over of non-sister chromatids shown inmsofc f n(7x90gajgg8qg(t-4f7ig8k the diagram below?

  The photomicrograph shows a pollgc .t;-tgcv:zm4x tm,c6rbl *en grain from L. candidum (Lily). Which stage of meiosis is shown? gl;rtx,tgm.6ccmtczv*4: -b

1.Outline the events which would lead to an individual being born withqlx:dfi28hz,0sn ev 5 Down syndrome, win fvq2zex:s 5,l 8d0hhich 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 o;yrvdc .n* )thf measuring plant growth. A study was conducted on white onions (Allium cepa), under cont.d;ntv* )cyrhrolled 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 dia- milh.rnes(g/k h6 2g2mle )dgrams below show two cells from an organism with a diploi)hs 62 e2hlrgeim-./dl (gmk nd 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 gronbr 0do7 t84greg1+cfm;ac r9 wth.

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 different 8a jznp cl 1ek(89jk*istages of meiosis. Which row correctly names e(k z81* 9nkpajcl ei8jach stage?

  The micrographs show four phases of meiosim8m4 vil 56a-4fjwccw s I in a plant. In what order do these phases 544 wa8cvcwmif-l 6mjoccur?

Mitochondria are responsible for supplying metabolra60vndluv i; +ma3q7wk gp:8ic 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 differw87vrkdqanu i la;g63pm 0 v+:ent 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 stages of the o.7og/ 1sab+ t5ifl :f:so mnjcell cycle in four samples o/b5aoo.f1+fms :7tl:is on gjf lung tissue from four patients. Which tissue has the lowest mitotic index?

  The diagram shows the dominant cyclin/CDK complexes at di8 sx++(g2k*x5 r5 hhz 9l hsqxild4do3mvw7 hkfferent time points in the cell cycle. Which cyclin/CDK complex activateoxvw k 2xzkm+hhg8793+xdllh(*qs i h rd55s4s DNA replication machinery?

  Studies have shown that genes such as Cyclin Dependent Kinase ruc 9nmw a,8 q+jx85jv3 (CDKN3) are highly overexpressed inr aq 88,jw5u+mxvjnc9 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 yxo 507 kke y4*qwqcd)E the highest during the cell cycle ?