The graph below shows the relationship between maternal age and the incidepy x9gu;v;1n4,iv/ kj9q kczunce of non-disjunction. What relationship is suggested v1, jv99ukg;nuy 4kz;ip/x cq by the data in the graph?

  Which stage of meiosis is represented in the dd*)hg3 o rsu,diagram below?

  The diagram below shows chromosomes dmlv nqx9-c g53 og1;cburing 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 allek)gzpl9f+r 9 eles of a single gene which would be present in the nucleus of a cell as a result of e) 9+ 9lkfpzrgeach process?

  Which keyword is matched to the correct d; g3a7tz8g0nb ziej+g, i9a*wr qvha6efinition?

  Which statement(s) about mitosis isucd;gbqy)*;f /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 pointsd viq av/1d3h4 to a cell in anaphase?

  During which stage of mitosis does the nuclear envelq3awqx a,3im(s uq3cqf6 s:4u ope break down?

  Which one of the foll9yp6hksorxb8 1s )p)aowing transport proteins only carries out active transport?s 9s6r h)o8pybkpx 1a)

  Which process does not happen in the shoot ap: 9afg oh7mix27 ;hrifex?

  Which type/s of membrane transport do/does not require energy exg 1y ,/ekgbd)mpenditure?
I. Facilitated diffusion
II. Active transport
III. Osmosis

  The diagram below represents a cell with a diploid numbe+0 b ss3id6 ,azli;nokr of 4. Which stage of cell division is the cell currently undersobdl 0;6zs,ain i3k+going?

  The photomicrograph below shows a q3az q,wwjf9*root tip meristem. Which of the following sentences correctly defines93,z fwaq*qjw a meristem?

  When does the random oriel ja b.3eu/m:ontation of homologous chromosome pairs occur?

  Which process does not occur duq02o( *uf8 zqhhw+ mamring meiosis?

  If a cell with a diploid number of 36 undergoes mitosis, how many chromo )6yi/yxg 3p5gmnap7 /hq7 sumsomes will be px5sq7h/g7np)ma u pig3ym y/6resent in each daughter cell after cytokinesis?

  The image shows a mi lt/m)diizeuyk5 21;p k+fbx) crograph of a cell.


What explains the appearance of the cell in the micrograph?

  Which statement(s) about homologkvutz /-s9)s qrcl0azfs: . *oous 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 syndrome. q)r6usp i wd+e+qvsuty,66, fr63e sp

Which statement is not correct?

  In the cells of a horse (E. caballus) during prophase I of meiosis I there ah)f02b 4- :dvznjs brgre 64 chro:hj0 b2r4) dg vfnb-szmosomes. What is the haploid number of chromosomes?

  Which arrow is pointiwz2c pt(whe 06ng to a chiasma?

  The diagram below represents the structure of a shoot apical meristevex6q *eb8ce 2m. Which row in the table correctly identifies the processes occuring in the secqbe xv28e 6*tructures labeled in the diagram?

  How does meiosis promote 7+f wy) l0 3hytjh3scyvariation?

  Which of the following statements is/are correct for meiob3whb b0 r)x j ogok47n1:bmr;sis?
I. It is a reduction division
II. It involves random orientation
III. It produces genetically identical cells

  The diagram shows gametes produced from two homolm k91s;kxxer qn u(5(iogous 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 ft7u fpyt f,4u;ormation of secondary tumours from primary tumours as a result of the movement of c 4,u7 ftuy;ftpells?

  How many chiasmata are present in the di8: .brcfl9m 22mukh bay2 o,jragram?

  Which statement is a similarity between cytokinw4 xyzh7+w;7 ) w5gi c+yjrlktesis in animal and plant cells?

  Which stage of meiosis is matched to the2b ciqtw :k39e de4sdjv,a 0u3 correct description?

  Which statement(s) are true of meiosis I bougytnqx++b* -+iq2p ut 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 first meiotic division. This resulfx2ccu/idh u2vos+5 5ts in the formation of one large cell and one small cell. What is the fate of the large cells vhx5c25d/cuoif + u2?

  Which row correctly describes diploid and haploi;ccrih;l2r/lt 3j /8ubb,mv r/ 8 ufwgd cells in humans?

  The following table shows the diploid chromosome number of a hrp -0( : laypzp5eaa(range of species.


Which of these statements is correct?

  What conclusion can be drawn from the karyogram b7(fy ori:+o hnelow?

  Which of the following processes is characteristic of the meiotic andjlnre d1dw;+xm63 tr- not the min6mr+ex1dtr-jl;w3d totic cell cycle?

  The diagram represents a iy*mc14a.ol x+ m3qv rbud 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 (Pan6pm.a0v+z ymj troglodytes) is 48. Which row shows the correct chromosome number for different cell types and cell div m0+pv.6maj zyision stages?.

  At the end of which phase of1r,s tz 7)rek2jjdr* q meiosis I does crossing over occur, and what is the zr se*j1rjtq2),d r 7koutcome of crossing over?

  Which of the followingr3u*c pn 32yp(+ b7el* ygddoh statements does not describe a step in the sodium-potassium pump +y pu n oe2* 3b73dgyrpdlc(*hcycle in the neuronal cells?

  Which row in the table below is true of meis 8gv/h7 vj 14cjuzbs1osis?

Membrane transport is important for allowing particlecgotdhe5du cwa7-khx 0- 5e(th0s,( s s to move across the cell membrane and respond to chuxe0a eshk 75(--wt d,(5ctcghos h0danges 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 mitosis is regulated in cellj,+csh53mgy0f)q lfys.

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 concentratio, wd.7paf7ptmns of different cyclins during the cell cycle. Which cyclin is invol,dtp7fw7.a m pved in preparing for DNA replication?

The diagram below shows chromosomesl:1+o:gy5 5zwquhyaxe*xv r , b95q om 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 sephb0zf31qznrm h l/d hd,56lg- aration of homologous chromosomes?

  The mitotic index of throat tissues kw 3 ijnre:hx to6; .5kktrn81taken from 4 different patients is shown below. Which patient is most likely to have cancerous throat.nxrto;e 5 tnrjwkk68k i 3:1h tissue?

1.Draw a labelled diagram to represent thzunw+7si p2tn*bty9. 9*w reqe process of crossing over.

2.Compare and contrast random orientation and crossing over.

3.Outline the stages of meiosis.

  The image shows an abzu3q; 8jonqnjq :i9njk5 d*5wnormal human karyotype.


What is the abnormality in this karyotype and its cause?

The graph below shows tkf;emd 85z 2wthe relative amount of DNA in one cell during one complete cell cycle. Each letter represents one stage of the cell ;dz2ftk m8ew5cycle.


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 homozygous f;y :dli5wfkq: ; dq8vfc4 b7qfa oii0/or brown, long hair 8o ckq:74fdydii5i ff:l0;;v q q a/wband a female cat that has black, short hair.


Which of the offspring has a recombinant genotype?

1.Outline how polygenic traits can show a normal distributjf66slhh t+ 8,v g+9jptdp 8urion.

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 r q atzpc32:m(e7t(ww - y/7vmri5o kuover of non-sister chromatids shown in the diagram belo -q rk(vcoi :wp 7u2mre(zy5w m7t/a3tw?

  The photomicrograph shows a pollen grain from Ln o5mp6;mi+4 ,qnwuemi*-fh c . candidum (Lily). Which stage of me45mi,unqh;o+-fmpm 6cw n*ie iosis is shown?

1.Outline the events which would lea(a. ,w 0l3 f)o+oe6ezbtm* amao6tmrt d to an individual being born with Down syndrome, which is characterised by the presence of three copies of chm0zo(6oeltt m ae+mfr 36,* )wbta.aoromosome 21.

2.Explain how meiosis increases variation.

3.Outline the stages of meiosis.

The mitotic index is an indirect way of measuring plant growth. A study was con o)pb dw8*rv-2oksu,/svi* xzducted on white onions (,ik -p8s/ rb*s*u)ovozv2xwd 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 can divid6r;6 k s lrg,-fy,ik j5tavq8qe. The diagrams below show two cells from an organism with a diploid number (2n) of 6v6qa,t,kkq j-8y5rils g ;rf 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 su;u5 sn0ojh5daz5 c 5htem 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 diploid7.+zsfu/iy5s chf560wioa j -kbu6 si number of 8, in different stages of meiosis. Whichz yofh/suc jf-0w5 bi6i5uksa6s + i.7 row correctly names each stage?

  The micrographs show four phasesg6in 4knkrxt4p p/+ b 70xwol* of meiosis I in a plant. In what order do these phase/kx*w0g4 kn+rlboi t xp 674nps occur?

Mitochondria are resnh04xk, ti+dl ponsible for 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 organisms, inhld 0k,nix+ h4teritance 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 ofu79lz(exmn z yke1 1y( the cell cycle in four samples of lung tissue from four patients. Which tissue has ty(x9z(eek17umy lnz1 he lowest mitotic index?

  The diagram shows the o4 nhfe*ef30n dominant cyclin/CDK complexes at different time points in the cell cycle. Which cyclin/CDK complex activates DNA replication machiner3n nhe* 4ef0ofy?

  Studies have shown that gene ;1i3an pfs;(cp;zump s such as Cyclin Dependent Kinase 3 (CDKN3) are highly overecpa;;p3 fsu n(m1;z pixpressed 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 thp8r;f a hekw2zza.rk9 ow;l./e cell cycle ?