The graph below shows the relationship betweas3 u w;y7)gw p.z,arsen maternal age and the incidence of non-disjunction. , au; pawgsr.wz37) syWhat relationship is suggested by the data in the graph?

  Which stage of meiosis is represented in the diagram b tioc/b:vnvo/3 m 22uho e6q6yelow?

  The diagram below shows chromosomes durio4m;tqw v.e 7h78xt9vu;ax so ng 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 aabez/f i.8tv 4lleles of a single gene which would be present in the nucleus of a cell as a resu/i4a tvz.e8fblt of each process?

  Which keyword is matched to the correct definitp*r, 2 jxclnc*ion?

  Which statement(s) about me51yh.qx qo-im nm5a r;1/gfqitosis 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 po v6,py 3p r;cg5xwb 6hbkj:,hqints to a cell in anaphase?

  During which stage of mitosis does the nuclearz q8f aq 6)rdqh*i*z-f envelope break down?

  Which one of the following transport protein2p nryu kd0(h)9l ncs x5m+t;ys only carries out active transport?ky0( s +u l;5tpcr2 9mdnx)nhy

  Which process does not h ty;po+ nqk(d8appen in the shoot apex?

  Which type/s of membran* iyp*ow ,e0c9jqu3 jim xys:)e transport do/does not require energy expenditure?
I. Facilitated diffusion
II. Active transport
III. Osmosis

  The diagram below represents a cell with a diploid number of 4. Which stao 7d85b mf4v eztbf1pnq nq+,)ge of cell division is the cell cu qb +m)47no,f bz5ned8fqpv1trrently undergoing?

  The photomicrograph below shows a root tip meristem. Which of v(+xixh5s8mtch7ko -:o0 lwc the following sentences correctly defines a mer0is8kh w lcx:-vo7hctm (5x+ oistem?

  When does the random orientation of hou5)r ous0ax) xmologous chromosome pairs occur?

  Which process does not occur during meiose,tio71,(h.zk9 +yyjs v jtiyis?

  If a cell with a diploid number of 36 undergoes mitosis, how many7u hu*f 6he(ug chromosomes will be present in each daughtf 6ghh*uu(u 7eer cell after cytokinesis?

  The image shows a micrograph of a cell./e1c)bf ddj5z kcb+3s


What explains the appearance of the cell in the micrograph?

  Which statement(s) about homolo ta,v3p+ ,coyugous 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 with Down sepyj3f 3dru7r +a ;j9syndrome.

Which statement is not correct?

  In the cells of a horse (E. caballus) during prophase I oac9vue i89an .f meiosis I there are 64i9v 8.a9ua cne chromosomes. What is the haploid number of chromosomes?

  Which arrow is pointing to a chias i5 ed;didgrfi-xm; 79ma?

  The diagram below represents th z5/af gnzzq/ a:n5wq/e structure of a shoot apical meristem. Which row in the table cor5 q/ gwfn/n:zz/azq5arectly identifies the processes occuring in the structures labeled in the diagram?

  How does meiosis promoteus/1 mpij c:1( n1n1fls eq5ss variation?

  Which of the following statements is/gjf3i3ls*yt .are 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 chromoso.b:)l s a iu2acy88tmm8juv e9p8(c xfmes.


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 svth e0,.r :amqecondary tumours from primary tumours as a result otma0re: v q,h.f the movement of cells?

  How many chiasmata are present in the diagramdgmk0e/2gbgs -fur)/ z-q4z4o y w:es?

  Which statement is a similarity between cytokinesis in animal and plerek x:r2 t)s;ant cells?

  Which stage of meiosis is matched to the correct desc *l9nswr5an+ a7ul;y qhohl1:ription?

  Which statement(s) are true27*yjx jh5ylyexkn7 z.e8e a* of meiosis 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 fw jm oe 6d0sulw,j(n6va607g h-y z,neirst meiotic division. This results in the formation of one large cell and one small cell. What n h,j06nwlm6-g,ye0ouj7vda( zw 6es is the fate of the large cell?

  Which row correctly describes diploid and haploid cells i(fth3. pmli *os pium0e8-b 1hn humans?

  The following table shows the diploid m 2rc bd:4ob+rchromosome number of a range of species.


Which of these statements is correct?

  What conclusion can be drawn from the katrj ays13r: h5 l.ixy/z4kqv .ryogram below?

  Which of the following processa/q)hxcik 01f es is characteristic of the meiotic and not the mito)01kqh c/xa fitic cell cycle?

  The diagram represent z 92ej.c+mmuws a bud 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 thetq6b93*anf n3zh 9djeie gjr a:h+)n) chimpanzee (Pan troglodytes) is 48. Which row shows the correct chromosome number for different cell types33b9)ain n6z *ef+ rhqjn9hgaj : tde) and cell division stages?.

  At the end of which phase of meiobqt:4)fpj dd2naw bk 13ah3v gkh81s (sis I does crossing over occur, and what is the outco t2d 3 bh4vnd gj8bq3):p1hks(aafw1 kme of crossing over?

  Which of the following statements does not describe a q1i7 ahl s*js-a2lva701hdns step in the sodium-potassium pump cyc27 7h0s1q nlad a*1lsjvi-ahsle in the neuronal cells?

  Which row in the table below is true of mewx*8zzaiga-3z7e 7s1l9t cxiiosis?

Membrane transport is important foo8lf;v pu u at5p7(0cv(c f0ccntw6 f.r allowing particles to move across the cell membrane and respondf . 5tpu(vfcwcp;6u al c00v7nctof(8 to changes in the chemical 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 mitosi:mqb-wc :ar x,s is 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 the concentrations of diffe9s ke;rcifhrq5 q356*p)xb ywrent cyclins during the cell cycle. Which cyclin is involved inc5ef6*ib s)yq5xrhq ;w 39k pr preparing for DNA replication?

The diagram below shows chromosomes dur1ob5e sgw 2jhpwp i m8y3ga(/.ing 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 1g dtuy1f duq40b q*n)chromosomes?

  The mitotic index of throat tissues taken from 4 different patients is shobe/ub tcwf,7s( k spp( 6ac;7ewn below. Which patient is mk sb( ,7 baepucepct/sfw;7(6 ost likely to have cancerous throat tissue?

1.Draw a labelled diagram to represent the process of cr7 rt)i:te )0o)sj,n/wtb2pgj-veg1 ppd 8 jg nossing over.

2.Compare and contrast random orientation and crossing over.

3.Outline the stages of meiosis.

  The image shows an abnormal human kax4xpgiyruq8 -i k;0:dryotype.


What is the abnormality in this karyotype and its cause?

The graph below shows the w:oqd i mz+44mrelative amount of DNA in one cell during one complete cell cycle. Each letter represents one stage of mw :4ido+4mzqthe 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 tj 2(y/x-tt.e qvtrd jx*a/ftm2af .p. hat is homozygous for brown, long hair and a female cat that has black,ay ttejtf */( rd.x xja vfp2t.-2./mq short hair.


Which of the offspring has a recombinant genotype?

1.Outline how polygenic tg /-b,,/ uyl tk02 kaqnqvjs3craits 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 crossinqtti/(04 zlp mg over of non-sister chromatids shown in the diagralitmp4/0qt (z m below?

  The photomicrograph shows a pollen grain f8-j z)gdmkacdt:f 6z)rom L. candidum (Lily). Which stage of meiosis is s-)df 8gad6m:zzk)cj t hown?

1.Outline the events which would lead to an individual being born with Down3e5/e.,ia5;yi 4ep c+edmys bxcjkz* syndrome, which is characterised by the presence pydej.5iiae*+xe;k5bcs,ey4m/ z3 c of three copies of chromosome 21.

2.Explain how meiosis increases variation.

3.Outline the stages of meiosis.

The mitotic index is an indirect *uyrev*c nx3y g9p(e)way of measuring plant growth. A study was conducted on white onions (Allium cepa), under controlled conditions in a lab, to investigate the effect of soil *r(9gc n)v ee*3yuy xppH 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 d1qptw d qp/ 0:)egatx,ivide. The diagrams below show 0tq:pawtd,e 1) x g/pqtwo 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 exzbnqvw1 4u+unh w7.5j pression 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 cell, withyrf :hi9pmw/ 0yfm8m : a diploid number of 8, in different stages of meiosis. Which row coryipf8y:wr9m h0:/mf mrectly names each stage?

  The micrographs show s1lnao 563kwrbr)g-i)9 pp mefour phases of meiosis I in a plant. In what order do these phases o63)5 i- lwgpre rk1oasmn)p9bccur?

Mitochondria are responsible for supw;fsmbs. eobqwp2*/ h(2,q5ii7z emrplying 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.qsmr*/ pe(22wm ef,sibqz.5 wb;i ho 7 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 diff zo t8r*w6nmr6 f4ohh0erent stages of the cell cycle in four samples of lung tissue from four patients. Which tissue has theoz 40oth *6fnr68 rwmh lowest mitotic index?

  The diagram shows th83*skc5o alxae dominant cyclin/CDK complexes at different time points in the cell cycle. Which cyclin/CDK complealsa 3 o*ck58xx activates DNA replication machinery?

  Studies have shown that genes such as Cy+g8c7slm:v/5e yqps s clin Dependent Kinase 3 (CDKN3) are highly overexpressed in cervical tus+y8s gv5 sqmlcep:/7mours.


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 hyqyy8 ;w9; rgf- ooig,ighest during the cell cycle ?