The graph below shows the relationship between f;zyp 8x v3d2smaternal age and the incidence of non-disjunction. What relationship is suggested by the dataf xyp 2zs3dv8; in the graph?

  Which stage of meiosis is represented in the diagrpkl*ce ,3a fa)8 fd.bkam below?

  The diagram below shows chromosomes du/kop u:gm1t6lspxy. r )h36cyring 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 al e vqfj*zp)9t8 l/-iw(qo7umutz6v n 4leles of a single gene which would be present in the nucleus of a qm*utf)9uvj/8niqz74t6v (-ozpe l wcell as a result of each process?

  Which keyword is matched to the correct definitil)r, 61spgt yo)ite7jon?

  Which statement(s) aboupb7t /dwzwp6a5 s0g 6ht 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, which letter points to a cell in anaphaw d cz++i,br tv4kg1n5se?

  During which stage of mitosis does the nuclear en0ckt nln5.m;xq0a a 3cvelope break down?

  Which one of the following tra vac73 y o9kjvobk+(*wxui :n:nsport proteins only carries out active transport?ov u+ jc*ko9(ai:vw3x y:nb k7

  Which process does not happen in the a( jo9n1o r3xeshoot apex?

  Which type/s of membrane transport9.d .kb uct7;jftflx2q + x7zi do/does not require energy expenditure?
I. Facilitated diffusion
II. Active transport
III. Osmosis

  The diagram below represents a/wy l 6p3uom5q 2meg3a cell with a diploid number of 4. Which stage of cell division is the c33o le6uymwqagm 5/ p2ell currently undergoing?

  The photomicrograph below shows a root tip meristem. Which of the fh5v ei, qx/se0ollowing sentences correctly defines a me/ s5x,0 eivqheristem?

  When does the random orientation of homologous chromosome pairsk;*ihvcs/0r s occur?

  Which process does not oct h:uv6f9/lnljc 4hqk is4) i6cur during meiosis?

  If a cell with a diploid number of 36 undergoes mitosis, how many chromosomes 88hjs,cp 5l6/jfeq5j gnakw* will be present in each daughter cell after cytokinesis? hj8 e*5p,n8wjs5ja lgfq6/kc

  The image shows a micrograph of a celvj-+vhy 9xdhy)m:q; l nq4 o3ml.


What explains the appearance of the cell in the micrograph?

  Which statement(s) about homologous chromosomes is/are o;a)ln zun++ifzc: / gnot 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 fzw1gkx) d d12an individual with Down syndrome.

Which statement is not correct?

  In the cells of a horse (*bg1 tek*gt 7q4*njmy-dd .me E. caballus) during prophase I of meiosis I there are 64 chromosomes. What is the hapl e*qgt4n*jtk 7.dy*dmm e b1-goid number of chromosomes?

  Which arrow is pointing 9o+ojg .k9c7--wbj ziu(ltsh to a chiasma?

  The diagram below represents the structure of a sho3ai1:o +upyziot apical meristem. Which row in the table correctly identifies the processes ocy+ a3:zu1ip iocuring in the structures labeled in the diagram?

  How does meiosis promote vmr;kf 5nli+;*.xy qlaariation?

  Which of the following statements is/9vvxtbn8;grb -cspy 9e.b 8s :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 twr3u.ea55 xsgl o 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 sec1ko79veyza8 t bi3b:i ondary tumours from primary tumours as a result of the m3kae yov9b:z78 b ti1iovement of cells?

  How many chiasmata are tds /p(-7ek)kbe4i rk present in the diagram?

  Which statement is a similarity between cytokinesis in animal and pl4a zg3r+cb fi txi8*8b7mrdpuc:f v1h)7q qy/ant cells?

  Which stage of meiosis is matched to the correct descrz1bg0c0 kul (uodzy3)iption?

  Which statement(s) are true of meisl4e li xoe2fn7 k9 sneg(+gj q84i*m.osis 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 iny5bimi;)j.4 bfsyt6q the form5isbq )i.y64;jtmbf y ation of one large cell and one small cell. What is the fate of the large cell?

  Which row correctly describes diev2c7,qzm 3 ut /a9 jokurb 7*egsd2;jploid and haploid cells in humans?

  The following table shows the diploid chromosome number of a range of speciesc /krz: cq9l6rbbn) tgn4q w .72hgw9wav83 yh.


Which of these statements is correct?

  What conclusion can be drawn from the ka a,z:2ayy-gz jryogram below?

  Which of the following processes is character: -ys lourgrnx3ut-z*-)o2ags go;m-istic of the meiotic and not the mitotic cellos nzr-u -agxg t ;r:yo *g)32u-lm-so cycle?

  The diagram represents 4 xfot8-ta rr: quf m ,n;e7dzq(q8/jja 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 the chimpanzee (Pan troglodytes) is 48. Which row shows t) zj ;4lh zug5tpam)j 5o/zc8yhe correct chromosome number for different cell types and cell di l5o tap;zj5)zmg/u48 zc )hjyvision stages?.

  At the end of which phase of meiosis I does crossing oo3p-m q4wbfn :ver occur, and what is the outcome of crossing ove-:4bnqpw om3fr?

  Which of the following statements does not describe a snsl /d7z0-h vctep in the sodium-potassium pump cycle in the neuronal - 0sn 7lcd/zhvcells?

  Which row in the table below is try7n5bs9p 1maeng aok2,3heb .ue of meiosis?

Membrane transport is important for allowing partiuj zbvlg f8i8 ),z;ftmyna11w04evo0 cles to move across the cell mz bi;0vatjfn0l f1,muv8g1o wez y48)embrane 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 cells. j jypkgzy )x4jd9p(v.)kk3f -z0r (yk

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 thecst pg 9 zip9v0cuhoc 3t4j906s.p4et cell c 93t.uch0e09 pg9jp sc 6o4tctivp z4sycle. Which cyclin is involved in preparing for DNA replication?

The diagram below shows chromow:fd - 9wgjj;f vt2d- ;hqx+xvsomes 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 involves the separation of homologovh -9yfqfz/ f.us chromosomes?

  The mitotic index of throat (muy ;-a0- e 6f)6qh()vtr dif zrxklqtissues taken from 4 different patients is shown below. Which patient is most likelqh eix-)(vfu6d )tfl-6 ;(qr zaky0rmy to have cancerous throat tissue?

1.Draw a labelled diagram to represent the process of crossing over.hti:ne9hgx;+/oj4v m. e kle .

2.Compare and contrast random orientation and crossing over.

3.Outline the stages of meiosis.

  The image shows an abnormal human karyo2g/)phd5i1t q3tb gbztype.


What is the abnormality in this karyotype and its cause?

The graph below shows the relative amount of DNA in one ced*mf 8 gj((h9to-b(:ys epodyll during one complete cell cycle. Each letter represents one s:o hdd(g*y9 soey8(pmt-bj f( tage 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 ca wl x3-9p1 wh/y(vp,ik8vaomrt that is homozygous for brown, long hair and a female cat thk(xvo1w/h8,wv 3ylpr 9map- iat has black, short hair.


Which of the offspring has a recombinant genotype?

1.Outline how polygenic traits can show a normal di)fytx+wiz* pc5 5n0h oe+ aov3stribution.

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 a4iy5y2:h9 u:eefzy j non-sister chromatids shown in the diagra:y5fi:a uze4e9y 2 hjym below?

  The photomicrograph shows a pollen grain w+ la8nk-sjdg8:oo 3j gyq5fwz 4z,l2from L. candidum (Lily). Which stage of meios5+ f :nzjsqa 8k8 g2o3jzl4dg- yloww,is is shown?

1.Outline the events which would lead 08yc;-bxbq,jk4/ 2fualkq kzto an individual being born with Down syndrome, which is characterisk,/acb4-kuj8 fq l;0zqyk2b xed 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 ofal(vrty5x m/,.v rew8d1wre 9 measuring plant growth. A study was conducted on white onio9 mrlevtrdw1,r v a8x.5yw/ (ens (Allium 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 u4peicq eghr +c 2 al u98zt9k3smt32;ways in which cells can divide. The diagrams below show two cells from an organism with a diploid number (2n) oz4ce9 ei28ua23hkq tr upts;+lmc 3g9f 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 ep9t962wdisg n nb6ak*xpression 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 ofe +rb+cbxk e;2 ho/gvv.;hds . 8, in different stages of meiosis. Which row correctly names each stevrv +/hk2 x+s .;bbe dg;.cohage?

  The micrographs show four phases o1j, imsr*cotv3 oze9.f meiosis I in a plant. In what order do these p 31*moszvrc ie9t.oj ,hases occur?

Mitochondria are responsible for supplying metabolic energy lm98oexb go2 5in 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 of humans. This is in contrast to nuclear DNA which is inherited from both parents. 9 obm2ge5 o8xlIt 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 of th rg gg( lq:ao0cv+s)z(e cell cycle in four samples of gl)q 0 a(vs:+zg(ogcrlung tissue from four patients. Which tissue has the lowest mitotic index?

  The diagram shows the dominant cyclin/CDK complexesdpeiq*)o-k /e at different time points in the cell cycle. Which cyclin/CDK complex activat* piq ee)/dok-es DNA replication machinery?

  Studies have shown that genes such as Cyclin Dependent Kinase 3 (CDKN3) are hire2zs c(:f-xe rvq (q8.d a,ovghly overexpressed in cervical tumourvev.d8cz(,fe: q( 2-sqr xoa rs.


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 c88u4cj4 b bk86flhxps ycle ?