The graph below shows the relationship between math7xr+jtx6i-4:ez+ i,; yn(ag ruhfb sernal age and the incidence of non-disjunction. What relationship is sf xjs a;+ 74hinb:(hiur yxze g,r+t6-uggested by the data in the graph?

  Which stage of meiosis is represented in the diagr6wgwwip d(9i 6am below?

  The diagram below sht ,ybugyunzyk w:)kn8f(:. e0ows 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 alleles of a singec9 pphl* ,i)sle gene which would be present in the nucleus of a cell as a li, e*ph psc9)result of each process?

  Which keyword is matched to thederx x4+ t. v q:/+g3nohsxd:i correct definition?

  Which statement(s) about mi wn+t h2t1pc .rw(/bab;ynk v:tosis 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 a cell in anaip4fu: -+o a3cughu9 vphase?

  During which stage of mitosis does the nuclear envelope break down u,c7zs(2 paltfjug85?

  Which one of the following transport proteins only carries out activs m;bty 5fl/8ae transport?lb/ 58mf;ay ts

  Which process does not h57nup)pg0fd cappen in the shoot apex?

  Which type/s of membrane transport do/doeixwbp3 *4 y)0 v+(swgoev+ ss*rtaf ,js not require energy expenditure?
I. Facilitated diffusion
II. Active transport
III. Osmosis

  The diagram below represents a cell with a diploid number lgsawn,*,x j-of 4. Which stage of cell division * gwlxs-a,j n,is the cell currently undergoing?

  The photomicrograph below shows a root tip merist9sn:f fzh 10 j)df;oceem. Which of the following sentences correctly defines a c1;9fnf :oefz0d s)hjmeristem?

  When does the random orientation of homologous chromosome p c)y) v0o.vhbdairs occur?

  Which process does not occur during meyu+*m2)sunoj6 d8yv i i*b 3cdd7p3vjiosis?

  If a cell with a diploid number ourxm+s w8re 70f 36 undergoes mitosis, how many chromosomes will be present in each daugh +sr wm0ux8e7rter cell after cytokinesis?

  The image shows a micrograph of a ceun15 ;6.bdee/-f ni q6p;lhb vzrv+d vll.


What explains the appearance of the cell in the micrograph?

  Which statement(s) about homolot:55 lh f8)gifx5vffzl3 ni4kgous chromosomes 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 individual w it nsx m90ug4g tsvq;wz)5.ux m24sv-ith Down syndrome.

Which statement is not correct?

  In the cells of a horse (E.a lerig,-8 fp9tn3 ne5 caballus) during prophase I of meiosis I there are 64 chromosomes. Whti gn 5- rfnalp83e9,eat is the haploid number of chromosomes?

  Which arrow is pointing to a cxj -prb whtp9o2.ab1)hiasma?

  The diagram below represents thnj+ 8o v7n nrsbn49hn*e structure of a shoot apical meristem. Which row in the table corren8 s*+vrbh4 ojn9nnn 7ctly identifies the processes occuring in the structures labeled in the diagram?

  How does meiosis promote variati6 k sbqma*kcv,;62u zion?

  Which of the following statements is/are correct fmkjg b8:y:j9yl (ul7jor 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 homol9 nuk lmd1htwm7i81v5 ogous 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 prqavp* 0 w,j2kg/ytx qe0 )kz-oimary tumours as a result of the oa,pyx/*0 ze)- 0gkkw jt2qq vmovement of cells?

  How many chiasmata are present in the dia.v e jg5akv5tugcjki 3)wdz7(-ehl kv b+ ++)jgram?

  Which statement is a similarity between cqka z.)eqjmd, oub+vllw,2) 0ytokinesis in animal and plant cells?

  Which stage of meiosis70h-wg r z x+. r)br(v7uhxxwwxp+-sl is matched to the correct description?

  Which statement(s) are true of meiosis I but not mgjk7adr3 ,m-5 yxm9nj eiosis 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 division. This results 6d;lj m :z tz,wwig2u/in the formation of one large cel2ld wi zgmtu/:6wzj, ;l and one small cell. What is the fate of the large cell?

  Which row correctly describes diploid and haploid cells in huma :ni z*8chn 9sdf0q/shns?

  The following table shows the diploid chromosome number off p5jeq*a(dk bsr*x3+ a range of species.


Which of these statements is correct?

  What conclusion can be drawn lmk.gchg t (+ a9k3s5nfrom the karyogram below?

  Which of the following processes is characteristic of the mex x3d-t. 9s5jh0x5izhy*ublzv /b5 mkiotic and not the mi5h-zy .tbxjv k53xu 0dsibmlz/h 59* xtotic cell cycle?

  The diagram represents a bud with a shoot apznwpc(:pnv x m;sv2 / v.6)ayiical 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 chi4797 t9/0oo u3h3y oo:ezu z kgawf6avk2nyblmpanzee (Pan troglodytes) is 48. Which row shows the ckoofzul9 9773k:/vzoob 0ye nu 46ya32htgaw orrect chromosome number for different cell types and cell division stages?.

  At the end of which phase of m *:m/yxjur p0b ow:if/q6z.7guebw0q8em9tjeiosis I does crossing over occur, and what is the outcome of crossing o j8yrg*bjo:76mq90 bu/epxe0 wt :q/zfiwm . uver?

  Which of the following statements does not describuz6pvo07j2ol e a step in the sodium-potassium pump cycle in the neuronal cel7o26v 0zjup olls?

  Which row in the table below (*) .i/xi w2pqzviswuis true of meiosis?

Membrane transport is important for allowing particles to move across t;q9i +vli*3 g zzscl ofv9/1kghe cell membrane and respond to changes in the chemical composition of th3o g9vikfq;cliz z9v+s1/g * le 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 i,zh (h scg;0*e/ dcjsds 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 shows th /34t xtq:ccjje concentrations of different cyclins during the cell cycle. Which cyclin is involved in cj :xqc/t3jt 4preparing for DNA replication?

The diagram below shofwoa .vm+,9 vnws chromosomes 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 chromosomes?h -il +:4-ch3 xxvo.ql/uwt pp

  The mitotic index of throat ta8 veovlc+ 6u(sp 0u(n.r y+znissues taken from 4 different patients is shown below. Which patiena0n(6.ru +pc8 ev lyvuz+ (sont is most likely to have cancerous throat tissue?

1.Draw a labelled diagram to represent the process of /7:arkbocs6 v3 8kkrjtu p;x9crossing over.

2.Compare and contrast random orientation and crossing over.

3.Outline the stages of meiosis.

  The image shows an abnormajshn3u-2/ 9ae wc*pvkvl;s/ fl human karyotype.


What is the abnormality in this karyotype and its cause?

The graph below shows the relative amount of DNA in one c;hitbb dv( ;eqpvp/ 8*ell during one complete cell cycle. Each letter represents one stage8ppi* h /et(bb;;v dqv 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 cslz mo-1(5mx2c1ot u cat that is homozygous for brown, long hair and a female cat that has black, short lz1stcoou(5 cm 1x-2m hair.


Which of the offspring has a recombinant genotype?

1.Outline how polygenic traits can show a normqh(h49yk cj89p bom r,al 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 chromatidsvd0 5ynqn3 ks5 shown in the diagram b5 53s nynkdqv0elow?

  The photomicrograph shows aba3qtd v n2s0khy l5g j667c-z pollen grain from L. candidum (Lily). Which stage ofz6chaq673kb 5ynls-d 2gtv j 0 meiosis is shown?

1.Outline the events which would lead to an individual being born with Dowrdpnrk)d(f 7); s4bms n syndrome, which is characterised by thf4(kdm n)rs)prd7s b;e 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:bz z8iekbj d6vu qm92,76 fly way of measuring plant growth. A study was conducted on white oije: f,26dzzv9lb ky8 b mq7u6nions (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 txzdst1q7 * cdohmh;z 8f6x.p3wo ways in which cells can divide. The diagrams below show two cells fr3m. *chdds6fqx78 to phx1;zz om 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;jsj 4tg09 r/zjs pbh) in 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 csgg5nsf,,0frlyen m ;,4 he8qell, with a diploid number of 8, in different stages of meiosis. Which row correctly names each stge4sg,srq5f l8nyf,he,nm ; 0 age?

  The micrographs show four phases of meiosis I in a rl ; w 8r;()a1njut2nthhq3 gcplant. In what order do these phases occ8l2()ntqt3 n a g;r; hc1hrwujur?

Mitochondria are responsible for*xouq8no 7.jwerdx:)pf:o )o 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 org e wj ou8:do. )xop)xoqrn*f:7anisms, 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 different stages of the cell cycle in f v;ve59xyj e9llck3ckti +50pour samples v kyep k5ll9c;x0c 95e+ jivt3of lung tissue from four patients. Which tissue has the lowest mitotic index?

  The diagram shows the dominant cyclin/CDK fw;cl6nt1zb s/ 0dr7z 3wsdd(complexes at different time points in the cell cycle. Which cyclin/CDK complex activates D3s(zds/lcw t67fdw nz01dr;bNA replication machinery?

  Studies have shown that ge9 xh3rqk f.r) jo19y+n2 )uibbq my4qjnes such as Cyclin Dependent Kinase 3 (CDKN3) are highly overexpressed in cervical tumours. 2jk q.1 bqby4o )f)ny3+rqm ui x9hr9j


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 cell cycle ?bzx4py 4 mq3aci vn(89