The graph below shows the relationship between maternal age and the incidenxi ) *5.app-gaqhtz. g+j lzphj7r:+fce of non-disjunction. What relationship is sug zt+.i+ 7xlhpgzg . afj5*ra:q-p) jhpgested by the data in the graph?

  Which stage of meiosis is represented in th9ix t4 obe*xk1e diagram below?

  The diagram below shows chromosomes dtl* xu7gnh7s:(q 8 osruring 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 singla4roku/jf4fh2pu g fd4l76uu5q 5lw - e gene which would be present in the nucleus-/5aj6uufglf4oupdk 24u4 5 rhwfq 7l of a cell as a result of each process?

  Which keyword is matched to the correct definitionl q*g)62 kmbub?

  Which statement(s) about mitosiupc90 ym/1alzf7 )nc .pvdz2 bs 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, r(5z: gejj ra(xfn:zwa g/d8+ which letter points to a cell in anaphase?

  During which stage of mitosis does the nucleajfnwcf: jv4 7jlbrtc 5r/ 6r5kb7-8 fdr envelope break down?

  Which one of the following transport prote1yex 2o* is-uby)bflb(;, zmfins only carries out active transport?1;) xfosb* z,yf e (by2iu-lbm

  Which process does not hap +f,km ig5 j+nvk:h;;08i1bk+wavu/sqa udvipen in the shoot apex?

  Which type/s of membrane transport do/does no,/w3pfi(p)ulv oprw(s .bv1vt require energy expenditure?
I. Facilitated diffusion
II. Active transport
III. Osmosis

  The diagram below represents a cellk o(v01,k rm6bl;yk eu with a diploid number of 4. Which stage of cell division is the cell currently undekmr6(ok0y ,e bvl;u k1rgoing?

  The photomicrograph below shows a root tip meristem. Which of the foxm6 hl3fp rpb. ;l1g+tllowing sentences correctly defines a meristehm.1rlt 3l;f pgb6p+ xm?

  When does the random orientation of homologous chromoso yyd9j 0i n )28h3jpney owo:k;de*-flme pairs occur?

  Which process does not occur during meiosisb:x cyph5h)*znq3+ ndual2 b3 ?

  If a cell with a diploid number of 36 unde tt kti9)/(.oi/cbgtgrgoes mitosis, how many chromosomes will be present in k)/c / t.(gitt9otibgeach daughter cell after cytokinesis?

  The image shows a micrograph of a cell. ;x. fu2a es9+yh(dhgj


What explains the appearance of the cell in the micrograph?

  Which statement(s) about homologous chromosomes is/are nothw rt 0+xujs*4 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 ind8tm/06fq7t(;b sjla;i vz 5wwz wwj *bividual with Down syndrome.

Which statement is not correct?

  In the cells of a horse (E. caballus) du:w,ql52 vq97zama )-xqzx)o r 1yk(jg( fp oclring prophase I of meiosis I there are 64 chromosomes. What)(zokx:-2jp1, 5 gyaqq q ()m w9lo7lzcxavfr is the haploid number of chromosomes?

  Which arrow is pointing to a xtcy 7p8xzuip 0l*.r+llx ts y: 15qi, ,pgfq*chiasma?

  The diagram below represents the structure of a shoo)l(nl:1wo;z yd5me okt apical meristem. Which row in the tablee(l 1:own 5l zmd)yk;o correctly identifies the processes occuring in the structures labeled in the diagram?

  How does meiosis promote variationtyh:ahqz /j/ro1 .z2a ?

  Which of the following statemrzcwbr/* 5tvequ+4b( sn+k b*ents 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 0js mfkd 23c6**vzkv cchromosomes.


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 secondary235c4q ai9 7 / k vklrfyj5dm5nekl7vj tumours from primary tumours as l5k m9a4 njkvr 5lq2vcyf3jek/i7 7 5da result of the movement of cells?

  How many chiasmata are m93gtbh: g)yan43d3 cv1 )-agsiiuxv present in the diagram?

  Which statement is a similarity between co* j vd2i47tvsw..lgen9z8wtytokinesis in animal and plant cells?

  Which stage of meiosis is -x3uz u:b s(sh)qff7i matched to the correct description?

  Which statement(s) are true elj ,nm;u e fytv je 90/+:tg;skp1d-uof meiosis I 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 ; nbqx/+hzu uwo5d;-zin the formation of one large cell and one small cell. What is the fate of th dqn h;+- /5zxbouzwu;e large cell?

  Which row correctly d 4 -c7. l6 nodjn/u 3*yfebcyvunrw,g-escribes diploid and haploid cells in humans?

  The following table shows the diploid chromosome numbeu fcn-yk9cdpel3m 8t)af; 6; kr of a range of species.


Which of these statements is correct?

  What conclusion can be xm+7wn a/lm9v drawn from the karyogram below?

  Which of the following processes is char3ji 5wv +jk;czacteristic of the meiotic and not the mit;5kjj3icw v+ zotic cell cycle?

  The diagram represents a bud withpt5y)8,q a )otia)4k ivyk ;m4xxy 3cx 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 thyi+ +n6kd(ip8zz ae8ue correct chromosome number for different cell i8p ++z8d e u6ak(iyzntypes and cell division stages?.

  At the end of which phase of meiosis I does crossing overldu)3n g 1no)o,arxq/ occur, and what is the outcond)) gonruqx 3l/a 1,ome of crossing over?

  Which of the following statements does not describe a step in the sodium-potui-* c qho s42twu7 tu:w7qw yz+ro7.yassium pump cycle in wt-wqco uy*h qsy+o2u r i7tuw7z47. :the neuronal cells?

  Which row in the table below is true of m*ywf9;9vp9(/qvvg ib5 :fz 6 lp ecmpdeiosis?

Membrane transport is important for allowing particles to move across th 0gzow/n 54up 8:wkvi/hx7qy we cell membrane and respond to changes in the chemical composition of the extracellu:y0 iwwvq/up 45n7 h8g/oxwzklar 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 reguluma k r+ u8z jluitem5(k7vq/ 30vwv3)ated 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 different cyclins during the ct uq/m0huk.3 pell cycle. Which cyclin is involved /.0h pk3qtumuin preparing for DNA replication?

The diagram below sh)/g f/brw2 eyi;wl o)cmd-8 ppows chromosomes 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 involve6vh sun fzq8-e:(4 mrex, nm5ns the separation of homologous chromosomes?

  The mitotic index of throat tissues taken from 4 different patients4wk 7d4cqqwfj os,5xj;z*dg1 is shown below. 7qw j4gx z;4sqcfko j,1 d*wd5Which patient is most likely to have cancerous throat tissue?

1.Draw a labelled diagram to represent the process of crossrlbcdr5)) h v4ing over.

2.Compare and contrast random orientation and crossing over.

3.Outline the stages of meiosis.

  The image shows an abnormal c)pjn89 wor(;nj ub (uhuman karyotype.


What is the abnormality in this karyotype and its cause?

The graph below shows the relative amount of DNA in de(5x0i/,y4+qb*tyt,p zfg+g5s7l ghpaj hl one cell during one complete cell cyp+4t* h7qe(lghl0f i jd/ ,t g+pygby,55zxascle. Each letter represents one 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 cr0*8egt62cg:o:my alg myoq/.bznn5 e oss between a male cat that is homozygous for brown, long hair and a female cat that has blackg nl/: 8yomyeo5mn: beqgz6ga 0c.2*t, short hair.


Which of the offspring has a recombinant genotype?

1.Outline how polygenic traits can show a normal d a.ydi sz02gtri+n;, gistribution.

2.Outline the differences and similarities between homologous chromosomes.

3.Explain why expected and observed Mendelian ratios may differ.

  Which gamete can result fr a f-eb3n)1 cd(za2qnpom the crossing over of non-sister chromatids shown in the 2eaaqd-n( pz 3cnf1b)diagram below?

  The photomicrograph shows a po7id:3ph dp66ays pn -nllen grain from L. candidum (Lily). Which stage of meiosih6- n dasn :3ppi67dyps is shown?

1.Outline the events which would lead to an individual being born (jt)rzwo gkv0r by08(with Down syndrome, which is characterised by the presence of three copies of chromosome 21. 0)b w(vrrkjt y(zo8 g0

2.Explain how meiosis increases variation.

3.Outline the stages of meiosis.

The mitotic index is an indirect way of ri-)8rj da2 grtt58iu measuring plant growth. A study was conducted on white onions (Allium cepa),i)u grd5ir2aj 8rt-t 8 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 8ua -x iyyz(a:t3z0wtways in which cells can divide. The diagrams below show two cells from an organism with a diploid number (2n) of 8aya u0(-ix:3twtz yz8.


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 inj5-uh hbw zr 8v4w8w-h 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 numboh5ypj e0dxpn 0f8s)(5un p a.er of 8, in different stages of meiosis. Which row correctly na ux .0)ns0dyoejp85p5ahn fp(mes each stage?

  The micrographs show four phst3 gl5t/j eh3f1wgx+ ases of meiosis I in a plant. In what order do these phases ocst3 +hfg 3j1ewxl/t5 gcur?

Mitochondria are responsible for supplying met qkw1lp8p8 cydl. og; imuy361abolic energy in eukaryotic cells. In most eukaryotes, which reproduce by sexual reproduction, mitochondrial DNA (mtDNA) is inheriteiy8 pk61g; cul q .oypl3dmw81d 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 cells in different stages ;i;rqi 0 *khyq val.ck0kx1/t of the cell cycle in four samples of lung tissue from four patients. Which tissue has the lowest mitotic indexq*vktky;qiacr l/. k ix0h; 10?

  The diagram shows the dominant cyclin/CDK complexs5qs 9a52mr dkes at different time points in the cell cycle. Which cyclin/CDK complexq525drak9ss m activates DNA replication machinery?

  Studies have shown th7wdi b-.1 qmvpft+, zdat genes such as Cyclin Dependent Kinase 3 (CDKN3) are highly over+f zb ,qvi.t-pm1d7wd expressed 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 twu-d8/b gw w-yhe highest during the cell cycle ?