The graph below shows the relationship between maternal age and the incidence3tqdj:4a c qmf( x/c3f of non-disjunction. What relationsh4 :cqa 3xdqjf3ftc(m /ip is suggested by the data in the graph?

  Which stage of meiosis is represented48s o;dps 8vno in the diagram below?

  The diagram below shows chromosomes m2f.deeyty q 4( n)yo9during 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 wouy k hf6p(0qe3lld be present in the nucleus of a cell as a re( lh fqp6ye03ksult of each process?

  Which keyword is matched to the corredze/d2.z -+3jl h1vfy:szvd c1 (qdqlct definition?

  Which statement(s) about mitosis is/are h 9cbp6kbvr7m 3-s88fvm3 odx 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 cqki/ s.f d2-va cell in anaphase?

  During which stage of mitosis does the: mw ;ow0ds /prt 8 jtauh52kp0dy4(tv nuclear envelope break down?

  Which one of the following transport proteins only carries out acti3njn 4l4hyg1q ve transport?nq 3n 41lh4gyj

  Which process does not happen in the shooixmwqa b. 5l5-t apex?

  Which type/s of membrane rz*:p*- mbd*vmm txf 0kpm*m,transport do/does not require energy expenditure?
I. Facilitated diffusion
II. Active transport
III. Osmosis

  The diagram below represents a cell with a diploid numb px8pb ih)+yfru6;0h3t m.oi jer of 4. Which stage of cell division is the cell currenhhp;fo.)8 3 pty+u j6irxibm 0tly undergoing?

  The photomicrograph below shows a root tip meristem. Which ofquc 8pz 7x9d-g the following sentences correctlx8c9zg7-q u dpy defines a meristem?

  When does the random ohumje8*v4j3 cpy;v8g rientation of homologous chromosome pairs occur?

  Which process does not occur during meiosist3v;,h 68dd y.v wp49hkrrkn x?

  If a cell with a diploid numbys;h/0nyjk*6eloq;wa l 2 x e*er of 36 undergoes mitosis, how many chromosomes will be present in each daughter cell after cytokinesis?*xo q26;sy nhlej*el /kw;0ay

  The image shows a micrograph otq2uxk4 i7-oxmt;(nvf a cell.


What explains the appearance of the cell in the micrograph?

  Which statement(s) about homologous chromosomes is/are not/ /d2 q kenpt 2d3tyu4y8n:jmt 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 withyb:2yhwmp 8 a f.pg6p: Down syndrome.

Which statement is not correct?

  In the cells of a horse (E. caballus) during prophase I of meiosis I kshk( 3 zspg .ju+ pbu7231fxbthere are 64 chromosomes.7 (xb 3k p+gshf3p 1ub.2zksju What is the haploid number of chromosomes?

  Which arrow is pointing1rxfe.g ka2,j*lr9h m to a chiasma?

  The diagram below represents the asndj ) p mlkv,(dw72)jwh0c5cu (:mostructure of a shoot apical meristem. Which row in the tabljdu)cmp50a(kmwnh d:olvwc (j7 2 s ,)e correctly identifies the processes occuring in the structures labeled in the diagram?

  How does meiosis proe;p+ 8jd+w/g y2qhkepr-f ) drmote variation?

  Which of the followin4awz e eu.a lzfou.p 4q 10amj(/fw)9hg statements 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 chromo)vfx *3 q1bqfmsomes.


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 formatv:qxcbnz36 3s/k:owjion of secondary tumours from primary tumours as a result of the movement3b3v6 : wz:s/kcojnqx of cells?

  How many chiasmata are1f -jci; )osut present in the diagram?

  Which statement is a similarity between cytokinesis in animal andg sw sj5g9s79 gv7xvoe/y*8zc plant cells?

  Which stage of meiosis is matched to tiyf nkv3 k j7l354qh 8r6bhko4he correct description?

  Which statement(s) are true of meiosis I butl:z7bu4f+m1b secl ty ilt2.1 a 3be *)r6erdo 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 thbn1dupk i+ ee3;zs0q(.6s l2l.lompz e first meiotic division. This results in the formation of 3q1mb;62 0usl.ze (epi+ol sz.kp n ldone large cell and one small cell. What is the fate of the large cell?

  Which row correctly describedbq7osw4vg* j ho/:bkfk7p 40s diploid and haploid cells in humans?

  The following table show/rj05; 9e-9 v-p fa7iso st hbtvblzy+s the diploid chromosome number of a range of species.


Which of these statements is correct?

  What conclusion can rfm jdqy3. --pu* 0x iosz/;pwxd2.n hbe drawn from the karyogram below?

  Which of the following processes is characteristic of the ( u46 . v.sd 6kgud7t7dvnszgwmeiotic and not the mi. v d7t4udw.vnsg6(uk67szd gtotic cell cycle?

  The diagram represents a/ og t hkry.c5p4;5etb bud 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 the9: u p oduptor8djz5y52x 7 if*;dkl)n chimpanzee (Pan troglodytes) is 48. Which row shows the correct chromosome number for differko*:8fu)pn2p5; yd7ojudz i t xr5d 9lent cell types and cell division stages?.

  At the end of which phase of meiosis I does crossing over occur, and jklj0 d j 1lx ri ++u/i7f9c.hi2wrbh)what is the outcome ojr uh7 /9ib )jk1dc xhl2.0lriwj++iff crossing over?

  Which of the following statements does not describe a step ird hfuwi c3:,*n the sodium-potassium pumpr i3fhucd *:,w cycle in the neuronal cells?

  Which row in the table below is true of meiogf .1yf**cmil)d6 a zh6cy cfdt++o9zsis?

Membrane transport is important for allowing particles to move across the cellvyvtxl0*/1 hdg2q xb: me tbx21 :/v0gdvhl*qy xmbrane 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 mitosis is regulated in cell)mfp n; hnr.u6l jv;z)s.

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 d5: yvek3;d1/l b tijmpuring the cell cycle. Which cyclin is involved in preparing for 1y ; kmjl5b: d3tv/epiDNA replication?

The diagram below shows chromosomes dayd5 )usc3r p;uring 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 id)kn7z k4r0ff.ow- ie nvolves the separation of homologous chromosomes?

  The mitotic index of throat tissuescd - (zjs eu98x m3)ceuv,8mvt taken from 4 different patients is shown below. Which patient is most lis9tezcv3v mx8e,cu )(mu j-8dkely to have cancerous throat tissue?

1.Draw a labelled dia) zq9f lls3fv(gram 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)*)gqb2wv yyp karyotype.


What is the abnormality in this karyotype and its cause?

The graph below shows the relative amp dw--r 3kfm-aount of DNA in one cell during one complete cell cycle. Each letter represents pkm--d3af -w rone stage 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 male cat that is honyrg1 :fpbfus)a2;db):xk-sir 04 mvww:;n c mozygous for brown, long hair and a female cat that has black, s 2wyn rbm4skw);-:scu )n ;p:g:0xidafvrfb 1hort hair.


Which of the offspring has a recombinant genotype?

1.Outline how polygeniwr0hh1rd,hw,8bcz tu za ori;7q c (/ns n,g:2c traits can 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 crossing over of non-sister i39fn: ec3-qrbtq d.xchromatids shown in the diagraq 9 if:.ebqn3 dr-ctx3m below?

  The photomicrograph shows a pollen grain from 74gn3ub6 beqovv*zvbf)* yn* L. candidum (Lily). Which stage of meiosis isnyeqv6n4b7b)** fog*z 3v vbu shown?

1.Outline the events which would lpc f-q9kb/l s7e8d 1yxead to an individual being born with Down syndrome, which ikly78s q xd -9eb/cf1ps 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 waym))nm gnpske6 i6+su1 of measuring plant growth. A study was conducted on white onions (Allium cepa), under controlled conditions in a lab, to investigatgup6)knn eis6s +m) m1e 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 twekm2)s, )ducxof*v3a o ways in which cells can divide. The diagrams below show two cells from an organism with a diploidufe,a)mc*x 3k o 2dvs) 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 inx8eqa 3p 85ioq 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 of 8, in differe uedy +a6z)vl:nt stages of meiosis. Whic:yld uvz )e+a6h row correctly names each stage?

  The micrographs show*m+jtlkgkb/28( cb 1sou o v 32sdf*gp four phases of meiosis I in a plant. In what order do these ph3k kcvd( jlgb*s m/8+ gou2*o1sf2bptases occur?

Mitochondria are responsible for supplying metabolic energy in (tqc awjix43i fe/ do*8ux 5;feukaryotic 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 betweefjx3* cit5;qui8o( d/eaw4 xfn 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 differen:3zf4 qbe ij9(kg2tnet stages of the cell cycle in four samples of lung tissue from four patients. Which tissue has teb j2n( ti943g:f zqkehe lowest mitotic index?

  The diagram shows the domi ; /slx.o/ snjcw/he+zh c9w;anant cyclin/CDK complexes at different time points in the cell cycle. Which cyc snlcoj;/ahh .c/ x+we;9w sz/lin/CDK complex activates DNA replication machinery?

  Studies have shown that genes such as Cyclin Dependent Kinase 3 (CDKN3)cve/+veh.;zlfr+ s 9b0 ihbwc :x, q,y are highly overexpressed in iex+.+: /lh,e q0cfcvzbbs;9hvy,rwcervical 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 c2c4fvq:o 7wrn;hu qj 9.m+bl cycle ?