The graph below shows the relationship between maternal age and the incidence fnac3hli7kd+yx c5* 6lljea+j,y+ :aof non-disjunction. What relationship is suggested by the data in hnal*c j dkl5l7+3yi,+6 afy :ca+xejthe graph?

  Which stage of meiosis is represented in the.v qzk gkvcl:5+53t cf diagram below?

  The diagram below shows chromosomes 4aam,91al ffs 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 t;3iq ;g 9dl li)adu.zbhe number of alleles of a single gene which would be present in the nucleus zl;3biq;)ld adg.iu9 of a cell as a result of each process?

  Which keyword is matched to the cofkox zvzh36 (p51 6ii.stk.uxrrect definition?

  Which statement(s) about mitosis is/dgy-ceddrw.u, rw37z2g n0 2l 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 poin, dw7b9os4 vz yn,nbd.(gqqzh omg42(ts to a cell in anaphase?

  During which stage of mitosis does the nuclear envely f*ia7yx *qxq68-lk,ziy 2 hrpz6f1 bope break down?

  Which one of the following transport prb. -jkt,c *uam)i;w(l5qnz ji oteins only carries out active transport?ba) w i;k.*n,-cm5 uij lzt(jq

  Which process does not happen in the shoxky9 v);g4o02mzw m;sr ku -jtot apex?

  Which type/s of membrane transport do/does not requir xis09dz m0+i*y tt qvq9;zm,ke energy expenditure?
I. Facilitated diffusion
II. Active transport
III. Osmosis

  The diagram below represents a cell with a diploid number of 4.fvf)3-wlc , 1af;w(bq uewm8k Which stage of cell division1) uq 3(;f-k,8emfvbwflwcaw is the cell currently undergoing?

  The photomicrograph below shows a root tip me g9o f)rgc9ek8ristem. Which of the following sentences correctly defines rgk8og99f)cea meristem?

  When does the random orientation of homologouk 1u3 v6o3hcbos chromosome pairs occur?

  Which process does not occur during me+ubv( (-f vyxeiosis?

  If a cell with a diploid number of 36 undergoes mitosis, how ma 13g:f1uuhzzy5b u vp/ny chromosomes will be present in each daughterpu5uvf1y h/b 1g:zu3z cell after cytokinesis?

  The image shows a micra;nk +c5/gju8 a 2k5k6hctqxcograph of a cell.


What explains the appearance of the cell in the micrograph?

  Which statement(s) about homologousii 0 hi 0oa3ywunl9+0a 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 Donyfc 3e4: qp1nwn syndrome.

Which statement is not correct?

  In the cells of a horse (E. caballus) during prophase I of meiosis I there are 66(y/u;nfv x3 p .nuaan4 chromosomes. What is the hap (pnv;3n a6faxuy /.unloid number of chromosomes?

  Which arrow is pointijdh4y0ii-y.3rm l hq2 ng to a chiasma?

  The diagram below represents the structujt*q kj kb-. 6cir7xp(re of a shoot apical meristem. Which row in the table correctly identifies the processes occuring in the structures labeled in the diag tijqckb.k-6 *pr x7(jram?

  How does meiosis progz 5ox)cya8byq* yd2-c-s0 k emote variation?

  Which of the following stata w.v z(uyneb2kv02 j0-c)fn iements 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 homolar bwhc 63ng349;yh zfi+v/th/rwex *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 secondad4*hg cy+ i4 hs*sgo;ery tumours from primary tumours as a resuh**4gd +gosie;y4hs clt of the movement of cells?

  How many chiasmata are present in the diagram2 p/g83ux djgdga)lm. ?

  Which statement is a similarity between 9 42mtni r2aq /cwuws-cytokinesis in animal and plant cells?

  Which stage of meiosis is matc oy)qqu v8lh64,qp ni:hed to the correct description?

  Which statement(s) are true of meiosis I but not m2)7m ,d4ixwl5ivjvth 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 division1s4mz4wzcq2fa79 fzsw ;7k nt. This results in the formation of one large cell and one small cell. What is the fatm w71wzkzca2s f7zs;tq 4f49 ne of the large cell?

  Which row correctly h)dv eqv8 f*v,describes diploid and haploid cells in humans?

  The following table shows the diploid chromosome number of a range of specie4td 5p3c.lk u u* y9a9g1pquvhs.


Which of these statements is correct?

  What conclusion can be drawn from thet1d.va)k y/rewrfg .6v ;ma 6x karyogram below?

  Which of the following processes is characteristic of the meiotic and not sq4n6k ham+z 4the mito+ qh6mk4 n4zastic cell cycle?

  The diagram represents a bu f,v7n9cums*e)j 8ns ud 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) nk3r a8db amjm.ni-*8is 48. Which row shows the correct chromosome number for differenba. r m-k3j8nan*d8 imt cell types and cell division stages?.

  At the end of which phase of meiosis I does crossing ov eozr6 .i9tklx(3gh*b er occur, and what is the outcome of crossingk rbh e.3o(l9xtz* i6g over?

  Which of the following statements does not describe a step in the soik4 jcj:p)j-g dium-potassium pu) :4-jpi cjgkjmp cycle in the neuronal cells?

  Which row in the table below is true of meiosis?o2 vaxdse3/orfl:1 ):eb/wms

Membrane transport i/ irj m.e(rs1yp-kv7 zs important for allowing particles to move across the cell membrane and respond to changes in the chemical composition of the extracellular fvs1k.7-iz /j r rpm(eyluid.

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 iwi3(bt 3ot28xdk go,o lp..mgs 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 diffej/zkv.bs4:sotg c2g* rent cyclins during the cell cycle. Which cyclin is involved in preparing for DNA replicatosz vt*s .gc b2gk/j:4ion?

The diagram below shows chromosomes *+mq+ rlc6a4rf:v.z j) ipmso 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 separati7,boq yrqc/6u* fxthi ;1n-qjon of homologous chromosomes?

  The mitotic index of throat tissues taken from 4 different patients is s 5y229f+tptyjd+a zjohown below. Which patient is most likely to have cancerous throatt59 tzd2opj2+ayyj+f tissue?

1.Draw a labelled diagram to reprc,44yjg jx x0hesent 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 karyotype.(e;c b5vqch7dkm k/ y/


What is the abnormality in this karyotype and its cause?

The graph below shows the relative amount of DNA in one celxq)ix1uii 5i5l during one complete cell cycle. Each letter represents one i 5ui5x qx1)iistage 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 malejffq 0j b85(jckl;z r5 cat that is homozygous for brown, long hair and a female cjq z (5jjrb5lffck;08 at that has black, short hair.


Which of the offspring has a recombinant genotype?

1.Outline how polygenic traits can show qu3r3hk ,d+j v2 qehn3a 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 of non-sister chromatids s(ij yoju0-m.d(i s(uxt ,jnc *hown in the d *j(xt.y(mdunj j-0 (ucsioi,iagram below?

  The photomicrograph shows a pollen grain fromzbv cp p/l(s0 :af2ek;/*s ptv L. candidum (Lily). Which stage of meiosis is sh *f(l;v 0ea ppb svk/scpz2/t:own?

1.Outline the events which would lead to an individual being bornwjfuwe5.1h;oo) s0 w t with Down syndrome, which is characterised by the presence of three c0o15)wfj uw wt;ho s.eopies of chromosome 21.

2.Explain how meiosis increases variation.

3.Outline the stages of meiosis.

The mitotic index is an indirect way of measuring j11,h7x( ) foyuk-; b2r cedb2qoj bwoplant growth. A study was conducted on whityxq2cb1 oj-2bfo;)w7ue1r,b(h jk do e 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 two ways in which cells cay.oa49t dfas.jk b j,7n divide. The diagrams below show two cells from an organism with a diplks aa.,9fj4tbd7 y. ojoid 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 n-6y n h,96 f-pfp0zic vacvtr( t5ok4stem 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 akwev. rv ):j-zg */dvg cell, with a diploid number of 8, in different stages of meiosis. Which row correctly gz rgevj-:w*). /v vkdnames each stage?

  The micrographs show four phases j uf8m/t*xq6lr7/ (q,hgezc*7 ot xwvof meiosis I in a plant. In what order do these pm grq ztcu67fle j/th8,/7 xxovw(**qhases occur?

Mitochondria are responsible for supplying metabolic energy in eukaryotic cejl yw1zo; m9jttfa,dd6x6 2nx28tu,e lls. In most eukaryotes, which reproduce by sexual reprodud9fytojaw6u2jz t ,l; ne1 d2t,68xmxction, 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 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 cellsdx+/h,kf 12jhr:mr hj pyy(6 b8bei*f in different stages of the cell cycle in four samples of lung tissu61, :fyih bf/p*( 2+hhx8 brejr kjmdye from four patients. Which tissue has the lowest mitotic index?

  The diagram shows the dominant cyclin/CDKs7uses +/;pnpqq,h2xc- c,n k complexes at different time points in t27 qen,ks+;/s-cpsqp ,hnx c uhe cell cycle. Which cyclin/CDK complex activates DNA replication machinery?

  Studies have shown that genes such as Cyclin Depewrf,x8z (6wqo5ri a ,zh+,hsxndent Kinase 3 (CDKN3) are highly overexpressed in cervichaw hz8iq,6zr o+5 wxxf,,s(ral 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 cell wpy1r+oj xx (;cycle ?