The graph below shows the relatig+jxe1j v+.9zcpo3 fc zz6+zm onship between maternal age and the incidence of non-disjunction. What relationship is suggjpcz.vc+ 3e+1f+zj6gmx zo 9zested by the data in the graph?

  Which stage of meios q7 quif3a bkyqan4k5 11im/o(is is represented in the diagram below?

  The diagram below shows chromosomespsl mo8k2)c w- 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 sina-la- )sgw69s9 )idm dkc g+emhzmd32gle gene which would be present in the nucleus of a cell ass)slm6i9 -a ac9k3hg-d+z)g 2md wdme a result of each process?

  Which keyword is matched to fu )mie:52 pkhthe correct definition?

  Which statement(s) about mitosis i4x0t2vj7 6/-s z zw s5grvx-in7jahams/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 wl4 g9xb9gt 8viqg.4f4hy ;tyanaphase?

  During which stage of mitosis 3kmlsf8sq0yv3 1sow1.an zdol+g :d .does the nuclear envelope break down?

  Which one of the following transport proteins only carries out activeixn mg190r c3g transport?0 c1 ngm9xg3ri

  Which process does not hapy qi4k-mj,l6p b r7z)fpen in the shoot apex?

  Which type/s of membrane transport do/does not require energ/8c*fyju l vs3y expenditure?
I. Facilitated diffusion
II. Active transport
III. Osmosis

  The diagram below represents a celliv7c4r l0i7l:c novc9 with a diploid number of 4. Which stage of cell division is the cell curcc9ii n:v7o rl4l 7v0crently undergoing?

  The photomicrograph below shows a root tip meristem. Which o;nsp ,3uc.x5x ybliba89)pc ah9y an8f the following sentences correctly defines a merispuyh n) yc83caa9as 9pn.x bi;5xbl,8 tem?

  When does the random orientation of wgl0ypy9s5+ f8.wf(hadw1 gdhomologous chromosome pairs occur?

  Which process does n3 q87s pew dktb2dd42uot occur during meiosis?

  If a cell with a diploid number of 36 undergoes mitosis, how many chroo:nq yohf34rs h1 )o1+mstrk+ mosomes will be present i4tro)ho1+n fms :h+o3 kryq1sn each daughter cell after cytokinesis?

  The image shows a micrograph wbs7 1nok*8k,o)i etk of a cell.


What explains the appearance of the cell in the micrograph?

  Which statement(s) about homologous cvzpw .7p:u(- s,pmoxt/ jz n/ohromosomes 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 Downv ) yjx)alyqsf4p :*e( syndrome.

Which statement is not correct?

  In the cells of a horse (E. cabal w7w i o wu+upr5z1d,e6et-5ijlus) during prophase I of meiosis I there are 64 chromosomes5-zj peei6 duoi51,t+wrwuw7 . What is the haploid number of chromosomes?

  Which arrow is pointing to a 7+rzio6) q(g9 jm a1 vzikc2z;o7lf rrchiasma?

  The diagram below represents the structure of a shoot apical meristem. Wr8nz.: t 4naimhich row in the table correctly identifies the processes occuring in the structures labeled in the.zi4m atn:8nr diagram?

  How does meiosis promote variation i+(cgju2 fq:y/ du*wy?

  Which of the following statejj e)n)mc 7x; oumkg0vd:o3q4 ments is/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 chromosx0e l0:;zr lzdomes.


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 tumourek,r0 4gn5aoqexg8+ns from primary tumours as a result of the8qke05,nnxgera o4g + movement of cells?

  How many chiasmata are present89,fndi)v 9o9 dz,dxnl;jojx5z6dpc in the diagram?

  Which statement is a similarity between cytok54nss*q+yz k*j(lor vinesis in animal and plant cells?

  Which stage of meiosis is matched to the c1yw9n4 o+::bgao g n9dzhcm+forrect description?

  Which statement(s) are true of mm:.ep9.t :ycfnba( n+ft /eigeiosis 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 af q1cm)6jiw1vdn 7b. l1bsu(zb ter the first meiotic division. This results in theb7ib nl.1ds6qv zbm1 j1wc) (u formation of one large cell and one small cell. What is the fate of the large cell?

  Which row correctly descal/ f.ek :g6d6y:d sdj0dms,z1mi;rcribes diploid and haploid cells in humans?

  The following table shows the diploid chromosome num-pdcr7/ dpqnca 7 gr::wc/ss0ber of a range of species.


Which of these statements is correct?

  What conclusion can be drawn from the karyogram be( va6xt2l1ar69ophw t low?

  Which of the following processes d a /wi(9bl:a ywf;sy2is characteristic of the meiotic and not the mitotic cell cycle as:yyib;dwfw9l(/a 2 ?

  The diagram represents a bud with a shoot apical meristem yw-mg) wc,i5e.

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) i4;bmqeyu0gr t6pm8) h )bvf*rs 48. Which row shows the 0)f qgyme)bu;rrv8tbph *m 64 correct chromosome number for different cell types and cell division stages?.

  At the end of which phase of meiosis I does crossing over occur, ane 9 y7k4jaycv6d what is the outcome ofavyc6 4j e7k9y crossing over?

  Which of the following statements does not describe a step in the sodm83zehn1 2af z8vhf3s ium-potassium pump cycle in the neuronal celnz1z33mhvf88 e fs2h als?

  Which row in the table below is true of)w joh8te.e; c meiosis?

Membrane transport is important for allowing partosst5);;b nirf onbf6- bwgo1es0 b .3icles to move across the cell membrane and respond to changes in the chemical composition of s 5nf0-orfbwn6o. e;bibso3t)sg b; 1the 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 imklapsxv,u4,ow*8(yp6( jbk n 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 d28ob o:hk 2*espoc(hiuring the cell cycle. Which cyclin is involved in preparicoo sie2:p*28ho(k hbng for DNA replication?

The diagram below shows cle iemieqi+ s qiar05,.de+2imlq61hy/ z*j 0hromosomes 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 fw.vaqx xuau1-eka hp-6 n2 .+homologous chromosomes?

  The mitotic index of throat tissues taken from 4 different s.*zlabn 7*syj +9b ptpatients is shown below. Whic bb+ ja*n7zs* yt.lp9sh patient is most likely to have cancerous throat tissue?

1.Draw a labelled diagob--1)9wekwmp pvif8d2t f s,ram 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 abnormal human kar(huggyj))u( w yotype.


What is the abnormality in this karyotype and its cause?

The graph below shows the relative amount of DNAw;. qc0do ,ueb(v7 yys in one cell during one complete cell cycle. Each letter represents one stage of the cell,y oesd.u(q0cvb7yw; 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 homozvc;cqbm hz-+t,k *sd 3ygous for brown, lonmz h+-v3;tk* c dsb,qcg hair and a female cat that has black, short hair.


Which of the offspring has a recombinant genotype?

1.Outline how polygenic traits can shx;i* 9g9h9p oqs n.bsdow 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 crossing over q1i:/y oh4xp e3s07w/rnow+(ofbath of non-sister chromatids shown in the diagram b e/w: ab3sow1tn y70ho (if/ qp+x4horelow?

  The photomicrograph shows a pollen graalhvkg /z.( ygx8.p-x wrnj64in from L. candidum (Lily). Which stage of meiosisrxkw.pl8a/ 46( zn yjgv.x h-g is shown?

1.Outline the events which would lead to an individual bl b dcwxk: ba m31hfr;ac4(2f+eing born with Down syndrome, which is ca xc+mahf1kb3 w2cf4(lr: ;dbharacterised 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 measuring plant growth8yrb;23ynxplc-k o. us f- vp6. A study was conducted on white onions (Allium cepa), under controlled conditions in a lab, to investigate the effect of soil pH on thecp32 p68l.fyo yku sx; -n-vrb 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. -px -jr2)hbspkp9/fm The diagrams below show two cells fro9m 2 x-hsbj/f pk)-prpm 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 expressi mbi303s hr-:,0 w1vjd ivqmfmon 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, with a diploid number jnxtnkm: n1 rwm 9)flg69h5-wof 8, in different stages ft5-k g9l1 x)9w6nmnmhjn w:rof meiosis. Which row correctly names each stage?

  The micrographs show four phases of j)-cyaft4 zg -z8ylj., zo9fumeiosis I in a plant. In what order do these u cy),fjz94jf- zo8-gt.z aylphases occur?

Mitochondria are responsible for supplying u5lv7naf h()z gkr( 0q;ny/tjmetabolic 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 different yeast species, could be influenced by t; nzy hjua0gt/nqf) ( 5(vlrk7he 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 numbe04)f osghnj3vr of cells in different stages of the cell cycle in fou40jovn3sh ) fgr samples of lung tissue from four patients. Which tissue has the lowest mitotic index?

  The diagram shows the dominant - ua)(pry 9hiecyclin/CDK complexes at different time points in the cell cycle. Which c -(ir)9ue yhpayclin/CDK complex activates DNA replication machinery?

  Studies have shown that genes such + 9a58jyh7 w nyxb1upsas Cyclin Dependent Kinase 3 (CDKN3) are highly overeynp+x9s way8517jb hu xpressed 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 during the een/nb;ms0 g u hy+3u5z4(mmqcell cycle ?