The graph below shows the relationship between maternal age and the i,ok h0jy(s ie6ncidence of non-disjunction. What r,iyej0hko6s (elationship is suggested by the data in the graph?

  Which stage of meiosis is rx392lm trv1 m+d cx9jrepresented in the diagram below?

  The diagram below shoabgh/lz0s)5 mbz a1 +iws chromosomes 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 the number of alleles o9 kwb+f/qn .hof a single gene which would be present in the nb.kh f/nw+9 qoucleus of a cell as a result of each process?

  Which keyword is matched to the correct definition9 vg78njrt b+xi.uc4n?

  Which statement(s) about mitosis isw6uu1 *kuh*rx1c ido-ywyf+cm 3q 72s/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 l.1 dskbt ,cwi 7brw08netter points to a cell in anaphase?

  During which stage of mitosis does the 9tevwt 9 q8(3icijvsz6/ tuy;nuclear envelope break down?

  Which one of the following transport proteins only cmjk.;xj+ee h6arries out active transport?mj +e 6xejk;h.

  Which process does not happen in the fnlw 1(q k34 9 ge(j,z ll9y7zscl5vdpshoot apex?

  Which type/s of membrane transport do/does not require enp xl2vsz-ib bm3y+ n3pq)w8(mop*d k;ergy expenditure?
I. Facilitated diffusion
II. Active transport
III. Osmosis

  The diagram below represents a cell with a diploid number of 4. Which stage rxsk0: v 0c29dnlu oout,b l)6of cell division is the cell currently,2l0t)vounoxl6r u:9 dskc b0 undergoing?

  The photomicrograph below shows a root tip meristem. Which of the followin.+ 1kagce o*-fw9w omeg sentences correctly defines a eokm-1c* ea+ o9g wf.wmeristem?

  When does the random orientation of homologourdc1uxbu0p. x *ypkx(w1mu;3s chromosome pairs occur?

  Which process does not occur during mem:.o(c s7ichx1m gje-iosis?

  If a cell with a diploid number of 36 undergoes mitosis, how mal6gx 1) b1 ju(ko xot-zq3my6cny chromosomes will be present in each daughter cell after cytokim61 tyxgx1o-qjobk6 () c uz3lnesis?

  The image shows a mic+t:pt8bhgii95i3 *j o*fto c orograph of a cell.


What explains the appearance of the cell in the micrograph?

  Which statement(s) about homologous chromosomes is/are g t44wtghx7s 1not 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 indiv+ef1o,a.r tbb bj: 9blidual with Down syndrome.

Which statement is not correct?

  In the cells of a horse (E. caballus) during prophase I h9k:w4dfxa3 xof meiosis I there are 64 chromosomes. Wha x4f 3ahkwxd9:t is the haploid number of chromosomes?

  Which arrow is pointing to a chiasm0(ojxj 9d -w)d3ppgkga?

  The diagram below represents the structure of a shoot apical meristem. W6 (,d(imqydev hich row in the table correctly identifies the processes occuring in the 6(yvedq, (imdstructures labeled in the diagram?

  How does meiosis promote variatqoc,wtwg 0a,ku g,)(sion?

  Which of the following statements is/are corphz9 +xao/ +rrrect for meiosis?
I. It is a reduction division
II. It involves random orientation
III. It produces genetically identical cells

  The diagram shows game4ks8h q o2yy)c9. caxnz( q-zvtes produced from two homologous 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 secondary tumours from primary tumour; 5pv/9grxa.4j/r+; lt 0jio ym wyaebs as a result of the movement of cells? yry 4 5a/a ;pgrvlb j9jmw/i.o;xe0+t

  How many chiasmata are present in the dia w cs8r6xelf r ;g/sj9,g/ .u0v38semnmpyh.bgram?

  Which statement is a2zi5wu nb4-ifnda. :s similarity between cytokinesis in animal and plant cells?

  Which stage of meiosis is mas 7me1t-nzgu 9tched to the correct description?

  Which statement(s) are true of meiosis I but not mejbd7:ua b*r0e iosis 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 th 1mue tsl*s2 c,d,km,he first meiotic division. This results in the formation of one large cell and one small cell. Wha hse*mus,t, 2dm1,kclt is the fate of the large cell?

  Which row correctly dm8bl,a 2c k5spescribes diploid and haploid cells in humans?

  The following table show+l/erq6hpz s)s the diploid chromosome number of a range of species.


Which of these statements is correct?

  What conclusion can be drawn from kryux )/(l)5m1k tbkz -iuh1w the karyogram below?

  Which of the following processes is characteristic of the meiotic l 9 srl5zfq6u(4h4ahn and not the mitotic hl5fa 46(sz4urn ql9hcell cycle?

  The diagram represents a bud with a shoot apicaux nl-fh 9-(bjr 1okw9/e/k zp87fpgal 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 36b cwva ry;g8row shows the corr6 vyra8c3gw b;ect chromosome number for different cell types and cell division stages?.

  At the end of which phase of meios.wn/o.e u6mp bx5zi- 6zc p5ndis I does crossing over occur, and what is then.x6zcip o.b 5nm e u6-pzw/5d outcome of crossing over?

  Which of the following statements does not describe a step in the sodium-potar ohhcz raqs.( cd-1a 5n(2c0wssium pu(rhdzh.qa1-n 2arw 0cc sco5 (mp cycle in the neuronal cells?

  Which row in the table beldg8+ brv,o8* fusu:1p;s yq jhow is true of meiosis?

Membrane transport is important 9a:(rh dq:mki for allowing particles to move across the cell membrane and respond to changes in the chemical composition of the extracellular flm ::( idrkq9hauid.

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 4olrpsz38,6ppw1qzr9-ihqh 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 cel zjl-)j s.j2wu3 )p2nv(nigwml cy 3j)j(lisvmnn pg wu)2-wjz.2cle. Which cyclin is involved in preparing for DNA replication?

The diagram below shows chromosomes during meiosis:8um. q;6wano u:y/3fx fl,ne7stvn f.

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 invol74nw;9yn k cogves the separation of homologous chromosomes?

  The mitotic index of throat tissues taken from 4 differ0 l2wzl(usl.r ent patients is shown below. Which patient is most likely to haveuzls (l2 w.0rl cancerous throat tissue?

1.Draw a labelled diagram to represent the process of crossing ovehlwjl+nb 7d0hl .3uk, (qn.t)ifb sq0r.

2.Compare and contrast random orientation and crossing over.

3.Outline the stages of meiosis.

  The image shows an abnormal human karyotype5)eg* b4qbdpca + u,id.


What is the abnormality in this karyotype and its cause?

The graph below shows t0f3g1h 4jqlu phe relative amount of DNA in one cell during one completep1gf 03l jq4hu cell cycle. 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 12n,lak 7 ywi9v5x(2envfgie cross between a male cat that is homozygous for brown, long hair an( ,eiav9l i 72n k1x2vf5gnwyed a female cat that has black, short hair.


Which of the offspring has a recombinant genotype?

1.Outline how polygenic traits can show a nc1vjey(s*de )ormal 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/14jqy 9 omkqw of non-sister chromatids shown in the diagram bemkj4 oqqwy/19low?

  The photomicrograph shows a pollen gr g8tp,e v+g8pbain from L. candidum (Lily). Which stage of meiosis igv,88b p+ pgtes shown?

1.Outline the events which would leadmu y0o)nyz*:q;t4 om f to an individual being born with Down syndrome, which is characterised by the presence of three copie*fty m) n0zoo;: yqum4s of chromosome 21.

2.Explain how meiosis increases variation.

3.Outline the stages of meiosis.

The mitotic index is an indirect way of measuci23 c3sgqekn;/zh i(pq 3le1 ring plant growth. A study was conducted on white onions (Allium cepa), under controlled conditions in a lab, to investigate the effect of soil pH on the mitotic2kln /c1;q3gh ( ipcee 3szi3q 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 divide8z4y8-)smfbb t juuz4. The diagrams below show two cells from an organism with a4 ju)bz8fbsm-48tyzu 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 sta*0frbuli*s1 em 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, wit0iqk b fgvq-:1h a diploid number of 8, in different stages of meiosis. Which row correctly names each sq0bfvq-k 1g i:tage?

  The micrographs show f3)u g; w.c49fc a31/rvt9yivus tj bckour phases of meiosis I in a plant. In what order do these phases occur?us34v9ft ik;c rgj1.w 9tbacv y /u)c3

Mitochondria are responsible for supplying meta bjri/wghi3:p g8h4l 3bolic 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 o3w :j hibh4p3/g8lg rif 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 fr5vtnc y(9 0fcells in different stages of the cell cycle in four sam0fnr (ty59cv fples of lung tissue from four patients. Which tissue has the lowest mitotic index?

  The diagram shows the dominant cyclin/CDK complexes az*hqpxl i+up+a 3 2k(f+n:olat different time points in the cell cycle. Which cyclin/CDK complex activatlpnxi a zq+u3l2+pfohk: (+a*es DNA replication machinery?

  Studies have shown that genes such as Cyi w ./dr g/ic;er--rpaclin Dependent Kinase 3 (CDKN3) are highly /rw-cdiai-r ;g .e p/roverexpressed 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 the cell clsi m. 4xokj- fqa1x g5s1+mjpg,+up6ycle ?