The graph below shows the relationship between maf z8kg5+k3s3cgwan5a ternal age and the incidence of non-disjunction. What relationship is suggested by the data in thekzg cg+ 8n5k53fa 3wsa graph?

  Which stage of meiosis is represeuv:,ctb trj8-7xlysq38o71z z mv / zynted in the diagram below?

  The diagram below shows cuo r6pw-mk3, h 8,i dp uudh/imi.j1q7hromosomes 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 alxvuee*z1 azna ,710 mtj( kyhlyye81orl*04yleles of a single gene which would be present in the nucleus of a cell as0a*yarzeu vzynle o*8hx l m1t0,141y7yj k(e a result of each process?

  Which keyword is matched to the correct defs( htlk)3 mkn)inition?

  Which statement(s) abo1ojl p va/b ( kgfs6wiq 2/pv+h-4u(vlut mitosis 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,m-r;q.hzg;xlp92 8d qyp.q cp which letter points to a cell in anaphase?

  During which stage of mitosis does the nucleaykxatu9za7/3zu,kqx k-+o9s r envelope break down?

  Which one of the followi-boxh0c lf+.p 3fm .cong transport proteins only carries out active transport?cmo0+f3bhp.c .-xo lf

  Which process does not happen in the shoot apek31s x vf+g- psa*ukgy1gqs a2/ w;i2rx?

  Which type/s of membrane transport do/dog(1ec xo v/+t. udkw4fdq )e51 ustx4zv2au0ces not require energy expenditure?
I. Facilitated diffusion
II. Active transport
III. Osmosis

  The diagram below represents a cell with a diploid had (u2ppcx x,cpyz3sxd58 ; *7k mc0pnumber of 4. Which stage of cell division is the cell c8kmppx c52yx03 d;asd (pzcxch7, up *urrently undergoing?

  The photomicrograph below shows a root tip mmxr omz/b 6+hz q/)eiut+ y+u5eristem. Which of the following sentences correctly def56zxyuoh u+e/btm q+z/ri m+ )ines a meristem?

  When does the random orientation of homologous chromosome pairsm0+s89u c.nw k;u kn4)lon(zvy)i pqs occur?

  Which process does not o,9jwi8)o pcalccur during meiosis?

  If a cell with a diploid nwg80l0qe +fub umber of 36 undergoes mitosis, how many chromosomes will be present in each gw0be80+q lu fdaughter cell after cytokinesis?

  The image shows a micrograph29rivoa9f . qq of a cell.


What explains the appearance of the cell in the micrograph?

  Which statement(s) about homologous chromzd ygk-w90 hapq2*:ul(r yypn5z8 2c wosomes 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 individualfy z)ni8*t s+p with Down syndrome.

Which statement is not correct?

  In the cells of a horse (E. caballus) during prophase I of meiosvrezpob v0r,z0v5d)g di, )u/is I there are 64 chromosomes. What is the hapzu0vb go0zveirv,)5/ pd,d )rloid number of chromosomes?

  Which arrow is pointing g5ew7n+ 5lst 2-kvdesl.6 l srto a chiasma?

  The diagram below represents the structure of a 4+b zptfr-mz4/4gibi 2u45j db4b eeishoot apical meristem. Which row in the table cor 5bp4rj+ /mzit4 i4bb4-e bgiefz 4du2rectly identifies the processes occuring in the structures labeled in the diagram?

  How does meiosis promote vawvjq 7l 6sb) br)5 axg996vvgqriation?

  Which of the following statements is/are correct for mwtlm d-vml* tqx.s/v)+ kz17 feiosis?
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 chromoso3- cm1:wg7rq:hdk ovkmes.


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 tumours ascit. 35*xx jr;:cugk v a result of the m5 ccirkx;:tuj3vg.x * ovement of cells?

  How many chiasmata are present in the diagra+w2v rmgg ed:*m?

  Which statement is a similli2 mod7(o(laarity between cytokinesis in animal and plant cells?

  Which stage of meiosis is matched to the corr . ,wevtftt.:v cmwp 0/no.z;uect description?

  Which statement(s) are true of meiositzj m*3uni4pjs4) o)xs 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 oocytyj zfpldwn/x,;7z jy( /i;n4le after the first meiotic division. This results in the formation of one large cell and one small cell. What is the fate of the large cewfxi;j y7l;(nd p/ /y4jz,lnz ll?

  Which row correctly describes diploid and7chevg)cpw ,w6,e. a,u zc*mk haploid cells in humans?

  The following table shows the dip u bd6hxx8 yc*f5o4tsj18 *fnjloid chromosome number of a range of species.


Which of these statements is correct?

  What conclusion can be gbgy5uq mb8.()5i cdf1w9 psbdrawn from the karyogram below?

  Which of the following procesu;zfzl r/zv(g :ib7/5w7obi cses is characteristic of the meiotic and not the mitotic v:or /5u;7cl7 z/fibb(zg i wzcell cycle?

  The diagram represents a bud with a shoot apical meuqux5//,t 4 y ifsuev*ristem.

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 chimpgel(ms rz1) 0nanzee (Pan troglodytes) is 48. Which row shows the correct chromosome number for diffsrg z)e0lm1n( erent cell types and cell division stages?.

  At the end of which pe uq ,/i8iy,eohase of meiosis I does crossing over occur, and what is the outcome of crossing ov8/iiey,oq,u e er?

  Which of the following statements does not describe a step in the sodium-2,j8xw)m0c r mdzt1g ypotassium pump cycle 0 xydc,j1)28wgtr m zmin the neuronal cells?

  Which row in the table bf +vs bkm1dn4*366yl:nobbibelow is true of meiosis?

Membrane transport is important for allowing particles k8p2k k+okg pugdw:71 -+mi ytto move across the cell membrane and respond to changtpi8gyomkw1 +pukkg 7+d-2 k:es 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 mitosintqn ih:yi7ql/ j-ra. ;bn4j 0s is regulated 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 concentrar :g4 thy-+hrations of different cyclins during the cell cycle. Which cyclin is ig:yrt4 r+h-hanvolved in preparing for DNA replication?

The diagram below shows chromosomes during meiosi 4)bfp ;a)tpols.

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 separation of homologous chromosomes?h6- ukf*h)eur

  The mitotic index of throat tissues taken from 10+w g1pdh:ew a a0afg4 different patients is shown below. Which patient is most likely to have cancerous0g+ 1e:0pwhwaag1af d throat tissue?

1.Draw a labelled diagram to represent the pro na) to pk:*39wzvx,vlxx (ig/cess of crossing over.

2.Compare and contrast random orientation and crossing over.

3.Outline the stages of meiosis.

  The image shows an abnormal human kx30wk0xgd:o y8 yh59hev c )qearyotype.


What is the abnormality in this karyotype and its cause?

The graph below shows the relative amount of DNA in one cell during ovmup*uvyoa;np g x /588el 3l:ne complete cell cycle. Each letter represents 83o xyuel augp vn8/ml:*5; pvone 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 homozygous yjw, e8 x*v3sk-gxa3e for brown, long hair and a female cagjkexw, 3 38-ev*xsay t that has black, short hair.


Which of the offspring has a recombinant genotype?

1.Outline how polygenic traits can show a noj6cu 7dmbttu .7vh*sh66kp(xee g*xy, ap38xrmal distribution.

2.Outline the differences and similarities between homologous chromosomes.

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

  Which gamete can res5unzkd h qkw(.v:8+qcult from the crossing over of non-sister chromatids shown in the diagcdq(. +uqk:nvzkw8 h 5ram below?

  The photomicrograph s trxwl7zc1s.lq ,l,f 3hows a pollen grain from L. candidum (Lily). Which stage of meiosis is shown?,tr fqzl c37w, ls1x.l

1.Outline the events ;gfm*lgk+-b- mb f/ mgwhich would lead to an individual being born with Down syndrome, whicmf*;ml bgg/f --kb+g mh is 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 pjz;y;qx 27 zy127ku:tyluajm(x1 enn lant growth. A study was conducted on white onions (Allium cepa), under controlled conditions in 1x:u jjq2;zmn21nzet7u ly 7k (y xya;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 it6fbwhewv3x1wgt.1ym43 s9qsni + l 2n which cells can divide. The diagrams below show two cells fromb1 qwe2s6nwi34 9v.xw 3l m1g+fhys tt 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 ge,a4gm adn 5v p-x gfmtb4o5:i(ne expression in 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 difs*wc0yu2 hr-lhm:ug 4ferent stages of meiosis. Which row correctl-lu:cghu 40 wh2*mr syy names each stage?

  The micrographs show four phases of meiosis I in rmy fuht6r.fj: 6pi-t55vvvd o 7g(yqn8e /(va plant. In what order do these phasetv5gq( uoh6: (.df /fv78yrmivn6tp -5ryv jes occur?

Mitochondria are responsible for supplying metabolic energy in eukaryotic cells.fz;ue ,t+ u/vzzd0s3 k 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 hybz/0e;vu3 t f+z,dku zsrid 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 dif,ai.(e91aiuyhceo . t-jym 1p t+zat/ferent stages of the cell cycle in four sample paa-t/, e.ey+h1 ytt.u19iazoi cj(ms of lung tissue from four patients. Which tissue has the lowest mitotic index?

  The diagram shows the dominant cyclin/CDK,3g(frl2g- s lzlh5gm complexes at different time points in the cell cycle. Which cyclin/CDK cls g-rmf 52g(,l zg3lhomplex activates DNA replication machinery?

  Studies have shown that genes such as t(;j3rn5 oe pri. / rajou +e2(hpgp;xCyclin Dependent Kinase 3 (CDKN3) are highly overexpressed in cervical tumours5hio;gj; jn 3ep2+/.eu oxrrarp(p (t.


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;lgvo:dmglm3c)-2;d) (tka k xmu,mg highest during the cell cycle ?