The graph below shows the relationship between m e;)(j wxvgfnu33mo2vaternal age and the incidence of non-disjunction. What relationship is suggested by the defv)( von3wj ;guxm32 ata in the graph?

  Which stage of meiosis is represente g. gd2s397,2zkmgdu.my yqy hd in the diagram below?

  The diagram below shows chromosomes d3mbe(: p6r avturing 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 n- 589rmofxbhr umber of alleles of a single gene which would be prer5 omf9xr-b8 hsent in the nucleus of a cell as a result of each process?

  Which keyword is matchev9 aqwcn4:bkxd :qq14 d to the correct definition?

  Which statement(s) about mitosis is/are taillq16 1z 6uwrue?
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.3pntk vzzq:h98*fejf+f/ on , which letter points to a cell in anaphase?

  During which stage of mit*,mdio02nr 9 yafz nl7osis does the nuclear envelope break down?

  Which one of the following transport +20dtbn4y7f 9ou rc*nz f0vahproteins only carries out active transport?hannoff +0dy0b7u4t2z*r vc9

  Which process does not happen in wpsv8i8(iw w 3the shoot apex?

  Which type/s of membranw / 6fk7ahkqj4e transport do/does not require energy expenditure?
I. Facilitated diffusion
II. Active transport
III. Osmosis

  The diagram below represents a cell w c/ecnzg(3xee ;p fjx),;eby;ith a diploid number of 4. Which stage of cell division is the cell currentj; )/ (3;gc yncxe ,exzp;febely undergoing?

  The photomicrograph below showsr 2.o+,lm;a*av gp cls a root tip meristem. Which of the following sentenc 2l; magvsa+,*o lcrp.es correctly defines a meristem?

  When does the random orientation of homologous chrom; ,nv+3xmr3oi* z gsymosome pairs occur?

  Which process does not occur dcy u- er*,*aq ;udn/zkju9f6puring meiosis?

  If a cell with a diploid number of 36 undergoes mitosis, how many chromosomesy0*+aq .agbh. d6.+ci yuj ipq will be present in each daughter cell .bhuiy+0+aiadj.gqq py* . c6after cytokinesis?

  The image shows a micrograph of a npuk//xa )*./zhyz(-pp 3qcjiqb ;pscell.


What explains the appearance of the cell in the micrograph?

  Which statement(s) about homologous chromo.n;ocb x -3ycrsomes 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 supis2y7v08)r.y8im5ubn iegyndrome.

Which statement is not correct?

  In the cells of a horse (E. caballus) during prophase I of ef:n6 :aarrkk/)af ;j+*wdn mmeiosis I there are 64 chromosomes. Wha+ 6a/ f;j:nrf: n *)kamderwkat is the haploid number of chromosomes?

  Which arrow is pointing to a chiasmayfftzsg wb.,l)ui36 +?

  The diagram below represents the structure of a shoot apical meris92vfg)nwsd)2 c upeb (tem. Which row in the table correctly identifies the processes upgvdf2c n)2bw9 se()occuring in the structures labeled in the diagram?

  How does meiosis promote varr o8thua6 r .bn(+gy(miation?

  Which of the following statements is/are cor ooid 5wb53;fi-/;hpph mdf 8qyt:ox:rect 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 chri4kox s)ij/,t omosomes.


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 a +u a1o5em5rb q/xq4k4hmdk )the formation of secondary tumours from primary tumours as a result of the movement of celm5rku o4+hdq q)/bxa m4a1ke 5ls?

  How many chiasmata are present in wp)x-itrj j4vfi 29 x,the diagram?

  Which statement is a similarity between cytokinesis i-bm+q /eg;4g ds bbw4en animal and plant cells?

  Which stage of meiosis is matched to tf srg5k0x0qd1i 9s88pup6 ytmhe correct description?

  Which statement(s) are true of meiosis I gwf0yeh p+o4( 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 first meiotic division. This results gatiii3wg (wp/7bm, 5in the formation of onewp( /aiwmtb ,i3g g7i5 large cell and one small cell. What is the fate of the large cell?

  Which row correctly describes diplojs cicz :m-ct-ilb :f8ue 9gtu74g :a-id and haploid cells in humans?

  The following table shosfb r ap,tl/4:-- x3gf 3pa ku*bcyvj0ws the diploid chromosome number of a range of species.


Which of these statements is correct?

  What conclusion can be drawn from the karyogram below,o1 n2xtj;iyp/ -xx:-hny aac?

  Which of the following e )0m gs4bhyn8bq,z3 iexma-oyg)3 9tprocesses is characteristic of the meiotic and not the mitot4 qxe8hg3bgt sz,-inym9 a0y) 3meo )bic cell cycle?

  The diagram represents a bud with a shoot apical merist(quz uywo- 0b1+v i.*na2 o6wg0ihjn tem.

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 thx-ao*x*eme7 wz 4fik;e chimpanzee (Pan troglodytes) is 48. Which row shows the correct chromosome number for differentewz7* f-k o* xem;a4ix cell types and cell division stages?.

  At the end of which phase of meiosis I does crossing over occur, and what is the3 w*ncj3kgdk8j3* gckw8 nkd3 outcome of crossing over?

  Which of the following statements doeszv.p4bl+7dia m94rcplzfuruc 5mhs;()* z 8n not describe a step in the sodium-potassium pump cycle in the nep9svdubaliz.n4 7r; zmrh (u*p+ l4)8 zfccm5 uronal cells?

  Which row in the table be: -b8v+htclfrlow is true of meiosis?

Membrane transport is important for allowing particles to move across the cell r6(hfad2 s*.u iz e0fui by1b7membrane and respond to changes in the chemical compositio z2ib1 *(y fusd0rfa.7h6uibe n 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 rrw - -hf*yuys5egulated 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 concenp3 q+x4bhb bs:trations of different cyclins during the cell cycle. Which cyclin is involved in preparings: 3pq4bbxb +h for DNA replication?

The diagram below shows chromosomes duxx3pov veaku: f1f,-6ak*-yr ring 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 involvest2,z5; ;z +j exve6b:abihjsz the separation of homologous chromosomes?

  The mitotic index of throat tissues takei*bl q67;x2clz wqb;/4: yrccg(eeaby;d: xhn from 4 different patients is shown below. Which patient is most likely to have cancerous throat 2 :;* ;dcicbz lxexr c4qlyygaq(7b eb6:/hw;tissue?

1.Draw a labelled diagram to represent the cz6kp0y8ooc / ec5cc-process of crossing over.

2.Compare and contrast random orientation and crossing over.

3.Outline the stages of meiosis.

  The image shows an abnor8b .qo:b m+l/ mnqmdk*mal human karyotype.


What is the abnormality in this karyotype and its cause?

The graph below shows the relative amount of DNA .(+kksx2 xq4t xsil/cin one cell during one complete cell cycle. Each letter represents one stage of the+xxqi2tl s(k/ kxs4.c 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 betec .h +q4eh+tiween a male cat that is homozygous for brown, long hair and a female c q chh+e4i.t+eat that has black, short hair.


Which of the offspring has a recombinant genotype?

1.Outline how polygenic traits c)c70odc nzup-an 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 cro(zdh b0 m8,apf7 c4jkossing over of non-sister chromatids shown in the k4hbdfp0 ,j7 am(zo8 cdiagram below?

  The photomicrograph shows a pollen grain fr24l pksxlk jid cy 6rg9s(q5kf: (7xg;om L. candidum (Lily). Which stage of meiosis c62475s glfxy :kkqg k(;9pdxlji (rsis shown?

1.Outline the events which would lead to an individuas:+h:v/8w8sgls c fmyoc0j7rkq h+ (yl being born with Down syndrome, which :0h7hs(jrqy8sl8gfv m+ows c :/yk+cis characterised 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 growth. A study was con 8(s w l:c6liqezz75xdducted on white onions (Alliucezxid6z78 :( w lq5slm 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 divide. The diagrams belry*hcwuho-x) 9, g 4uaow sh w-a4r ch)uh uxo9g,*yow two 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 expression in stem grow yjumbrdw.95 mtp52ci.avyq0p4g )j -th.

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 celjpzncfb4 4jf3b 8uq) -l, with a diploid number of 8, in different stages of meiosis. Which row correctly names each st8jq4zcp4f )-jbnub3f age?

  The micrographs show four phases of meiosis I in a plant. In what orderd-g8p(zak8 ;g q8pbpw do these phases occur? 8p;a(8pbgdpkqw-zg8

Mitochondria are responsible for supplying metabl; jk9812yj( 1uv c+o rgowkrlakq09lolic energy in eukaryotic cells. In most eukaryotes, which reproduce by sexual reproduction, mitochondrial DNA (mtDNA) is inhg8(9wr9;j1 u 0kvk+ l2olk 1l coyjraqerited 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 numb52* zclq q*w zd/(xlscer of cells in different stages of the cell cycle in fourlclz*wq qd5 zs(cx*2/ samples of lung tissue from four patients. Which tissue has the lowest mitotic index?

  The diagram shows the dominant cyclin/CDK complexes at different timezla xis/7 ;ed(4y7wut points in the cell cycle. Which cyclin/CDK complex activates DNA replicat; yl(et4u/i wsxazd77 ion machinery?

  Studies have shown that genes such as Cyclin Deyegd7 p;ve wdiy0r352pendent Kinase 3 (CDKN3) are highly overexpressed in cervic 7p2iyyg drewe5;v0d3al 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 h*okj iont73 u-pu d- v ss(+q,es4*dhthe highest during the cell cycle ?