The graph below shows the l):hdn+n( 5qbsjn( yl relationship between maternal age and the incidence of non-disjunction. What relationship is suggested by the data in the n:dn) n+ly5j qsb(h(lgraph?

  Which stage of meiosis is represented in the diax82: - l,c6dlozkp a)zafb-* wqrbsu :gram below?

  The diagram below shows chromosomes durwopsrz-5t ro)2l,r :sing 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 woulv ye* uy8j(g9vd be presenvevyg9 *8jyu (t in the nucleus of a cell as a result of each process?

  Which keyword is matched to the correct definitio:1:d teezd *sen?

  Which statement(s) about mitosis sueaavdk7t)( q:1 icx :91;itkqc5ez 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 6u+45jnf*a3t1 kyk(rw6dt9pvgvug z to a cell in anaphase?

  During which stage of mitosis dk6w em0n,7 6qrbygok5: g; 9/ugavnyg)bmz v (oes the nuclear envelope break down?

  Which one of the following transpw60:j:c s+,my tk :lyivbz:aport proteins only carries out active transport?:p:0jz bkav my6:slt:w+, yci

  Which process does not happen in the shoot m a5(t* cz8xwfswh y+/apex?

  Which type/s of membrane transport do/does no pe(jna0z ;qq/t*c :w0 dhaz6ha9hp/ct require energy expenditure?
I. Facilitated diffusion
II. Active transport
III. Osmosis

  The diagram below represents a cell with a diploid number of 4. Which stagew m +if*-lxuqk/0wq/ax )d;av of cell division is the cell currently unde-x)a*fv q/ww a;qm+k/liux0drgoing?

  The photomicrograph below shows a root tip meristem. Which of the followingdh o,,22b2, w mvaqfeemw: y(d sentencehdmyvboqw,wa d(22f2,e, m : es correctly defines a meristem?

  When does the random orientationivllqo u 1tru/lx(ke-f:*;kbn3uh / zt60 8xu of homologous chromosome pairs occur?

  Which process does not occur during7 g a9y2qxkfhfk/3;ytd 1d9ea meiosis?

  If a cell with a diploid number of 36 undergoes mitosis, how many ch n. /, q g4pgnabn5zli5+lli4vromosomes will be presb4nl ,n.q v5pilag5i z gnl4+/ent in each daughter cell after cytokinesis?

  The image shows a micrographm;aqr/is0 br c- juf7nty242e of a cell.


What explains the appearance of the cell in the micrograph?

  Which statement(s) about homologous chromosomes is/qd 81mn)t/mmhl3ns l 7e4k vy1are 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 Dhl;qg k co7*o/ 3g4vsaown syndrome.

Which statement is not correct?

  In the cells of a horse (E. caballus) duri-pk f6,xn kv 6va*d5tpng prophase I of meiosis I there are 64 chromosomes. What ipkn6v5f- td xv,p6*ka s the haploid number of chromosomes?

  Which arrow is pointing to a cld 6b +xzc-8we1y 4npr:fgg;w hiasma?

  The diagram below represents the stt94i+om jq(fb2ld; mue+c 0vyructure of a shoot apical meristem. Which row in the table correctly identifies the processes occuring in the structures labeled in th0dc ytmbu+ 4ilo2v;(9qjf+e m e diagram?

  How does meiosis promote vari4(,nh 8g 0vyt8lmoziration?

  Which of the following statements is/are cor0eqqj uk/kj4 )+pfak, rect for meiosis?
I. It is a reduction division
II. It involves random orientation
III. It produces genetically identical cells

  The diagram shows game8v)-8m0x m /l -qx+l cwenggvgtes produced from two homologous 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 formationa:um jdhh-t1* of secondary tumours from primary tumours as a result of the movement of m:ad1uhj-t* h cells?

  How many chiasmata are present in5ft qbc, v*ld9t4c*hn the diagram?

  Which statement is a simi kh(gz1x v9ny;larity between cytokinesis in animal and plant cells?

  Which stage of meiosis is matched 3v+j2 bhcbl ,csd)w ad0;:histo the correct description?

  Which statement(s) are true of meiosis I bubb ; zrs* f*3:mhzuv6tt 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 ow m:ms )f6fv z5( j -na ujg1rl:rm:2als8d6vgocyte after the first meiotic division. This results in the formation of one large cell and one small cell. What is the (f:8)6s5-s 6v jgw21rlu:m l:r gd aj mfamznvfate of the large cell?

  Which row correctly describes diploid and up4rxz g.,ze4 orf2u;q2cw 9dhaploid cells in humans?

  The following table shows the diploid chromosome number of a range of 9ht 4mu,kc ew n)h-b7nspecies.


Which of these statements is correct?

  What conclusion can be drawn from the karzdbs+;.bu/a i yogram below?

  Which of the following procesr zw:7k 2aju.s4k)xph2sbev + ses is characteristic of the meiotic and not the mitotic cell jpbxh2 r z+k2:) avuwkes4 7s.cycle?

  The diagram represents a bud with2(.73yolxexr 0hox te 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 row shows rh i 1,ao,j xov*83(zcnlpnc0the correct chromosome numbej,(30z l, hcon8xocpnv ira*1 r for different cell types and cell division stages?.

  At the end of which phase of meiosis I does crossing over occur, akbeqrnv4 56a rt .mg:5nd what is the outcome of crossing ovekge . nrqratv 6mb455:r?

  Which of the following statements does d xu s1;kyza5/not describe a step in the sodium-potassium pump cycle in the neurona1ky/ zxa;s5 udl cells?

  Which row in the table belmhoji rb. di(;-+i;w qow is true of meiosis?

Membrane transport is impori5a,5 hqk 2 r;q2ifmj9lss1w 5 hqv0aitant for allowing particles to move across the cell membrlh55 2;2imi1rsa,95qk jwq fs0ha viqane and respond 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 mitosis5 vl4ko6t6bes 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 differe)v/6. xpcyg3idlylg-hb1 dq w3zmz2ud, 4u,qnt cyclins during the cell cycle. Which xg qp6b hd ciydzm4)u2,vq1y udg z33l,l.w/-cyclin is involved in preparing for DNA replication?

The diagram below shows chromosomes during meiosis.qmw .u)3wg y0r(y.a+qy;t m1wkcsa s 6

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 sfh(yr;p e ae37eparation of homologous chromosomes?

  The mitotic index of throat tiss g22d f5+qja*jrtg x5je4tz3)p qjh-aues taken from 4 different patients is shown below. Whichhjegpttqf az 4gx-dj j+j55ar3q2)2 * patient is most likely to have cancerous throat tissue?

1.Draw a labelled diagr6l vi,;i9) affzu9yy tam 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 karyo7d y2nl) bjwuz/5;hveu(v k.q type.


What is the abnormality in this karyotype and its cause?

The graph below shows the relative amount c+)/seuwgk,fi9v+.lhe*agq ;o zo3 rof DNA in one cell during one complete cell cycle. Each letter represents one stage of the cell cycle. wog+*3k cg+i; )aeho l,qrzev9/fus.


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 crossub5wwk. y/b8aq:pk a* between a male cat that is homozygous for brown, long hair and a female cat that has b8*b:w/a.bqku p5kyw alack, short hair.


Which of the offspring has a recombinant genotype?

1.Outline how polygenic traits can show a normal dif*i:4 gtu)imwstribution.

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 chromu8ri ;g8hme(7-ep i2u cbvs3i atids shown in the dcir8sgbh ;m veu-u 3i(7eip82 iagram below?

  The photomicrograph shows a pollen grain from /z5 d1omcqe km **dxz/L. candidum (Lily). Which stage of meiosis is sz**5z dmm/xedo /qk1c hown?

1.Outline the events which would lead to an individual being born with Down sye xze4nz pa *(a.zk36endrome, which is characterised by the presence of th na*e.pzek63ez4z( xa ree 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 growthvcl q-e1uy tx s38b:(g. A study was conducte-1lxq8s v3gctybe(: ud on white onions (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 t 9lx+kb dkse05wo ways in which cells can divide. The diagrams below show two cells from an organism with a diploidle95bd 0xk+ ks 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 gro:ez ,8qshvf/7 j1mdp twth.

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 nu9ccit*om z )gt 56ds)xd+pyxc;zl8f 2mber of 8, in different stages of meiosis. Which row correctfm)lixzy8dtt*6;o) s5d pc+9c cz2gxly names each stage?

  The micrographs show four phases of meiosis I in a pla+, hn+tsv.f/a/tmq dent. In what order do these phasessqt+ve/ +/. m td,afhn occur?

Mitochondria are responsible for supplying metabolic energy in eukaryotic cells.s8b h gn3q9(ea+rwg9g0)e t-sj ru4o s 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 betweengqs0+subs w 9)-9garn8(ot 4 e3jrgeh 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. -1k pd7,nce-lwotdwxlza a+c )ggq1r 1(8w a in four samples of lung tissue from four patiengar eawcdo-zw x-tall 1 n1k(7+1c,)pwg8 qd.ts. Which tissue has the lowest mitotic index?

  The diagram shows the dominant cyclin/CDK complexes at different time poin1nwre3 vmya8l6yru- /ts in the cell cyy /83v-r16wa yrue mnlcle. Which cyclin/CDK complex activates DNA replication machinery?

  Studies have shown that genes such as Cyclin Dependent Kinase 3 (CDf lbsr5/ /qd3owlzsj 8f6d.b 4KN3) are highly overexpressed in c6f5 /lqdo/ r3 jz4swsfl d8b.bervical 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 concentrati+x .r po7i5juyon of cyclin E the highest during the cell cycle ?