The graph below shows the relationship between maternal age and the+: t-k;15rcf+gae + oddzcs4-*zr1iykdx ohg incidence of non-disjunction. What relationship is suggested by the dataox 51 y e+:kigdrtdfs1--+cka4g* +oc zzr d;h in the graph?

  Which stage of meiosis is represented 7 ft6bcd5z3 yf,hf8 ycin the diagram below?

  The diagram below shows chromosome6a;6 9.olul a0pvhdq e-wom j*s 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 statit9n 1 6 ;gzt5syydb(ges the number of alleles of a single gene which would be present in the nucleus of a cell as a result of each pron5 y bgz96t(g1is ;dtycess?

  Which keyword is matcheh 5/hqg7ji .gwd to the correct definition?

  Which statement(s) about mite9 g--x*: x2pjf/:s mimmjl glosis 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 lett/e0s+ql:r hxbj ; rh*tib,* buer points to a cell in anaphase?

  During which stage of mitosis7 ccd(71 pcu*5knj xbp does the nuclear envelope break down?

  Which one of the following transport prots78.d vazy -kieins only carries out active transport?-zd.s8y v7kai

  Which process does not happen i x:t cduds5o t+9ig5 6q-p koxb5g)f;zn the shoot apex?

  Which type/s of membrane transport do/doesutfd o fm8nb.pk w(-;za+:)iv not require energy expenditure?
I. Facilitated diffusion
II. Active transport
III. Osmosis

  The diagram below represents a cell with a diploid n77+jm u1am+r+f 5hzkgm nh9ltumber of 4. Which stage of cell division is the cell currently un km++7j9 5+anm7 rmfzlutghh1dergoing?

  The photomicrograph below shows a roor4 ;1 y6u4d)(2c sc z2rctbq5pcn2 kqsuzcy5rt tip meristem. Which of the following sentences correctly defines a merist)r(422r 5;c zk5ur4ys2 cncqc cyupz stbdq61em?

  When does the random orientation of homkwxqh d3ex1 /j u1jjeg:w7:o0ologous chromosome pairs occur?

  Which process does not09ukr (c q6giq e/jio/c0u8vrpmh/r1 occur during meiosis?

  If a cell with a diploid number of 36 undergoes mitosis, u()z3dffn8 ))o vaw )r g jl9hq(dzu5xhow many chromosomes will be present in each daughter cell after cytwld3o(q d)n x)8)(haz5 )jz fr ugfv9uokinesis?

  The image shows a microgom o3b4df628kz b grx7raph of a cell.


What explains the appearance of the cell in the micrograph?

  Which statement(s) about homologous chromosomes is/are nx, kd,2ijlvvl ks4;r6ot 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 anb9zgasxj tc: 7g19 .i: esudc) individual with Down syndrome.

Which statement is not correct?

  In the cells of a horse (E. cabax c-n.*t0:lmr8vo2tefug / ya8yp6 bj llus) during prophase I of meiosis I there are 64 chromosomes. What is the haploid numbert:o 0cgey* tbv.x 86-r m2n j8fpuy/la of chromosomes?

  Which arrow is pointing to a ci o+3yfdbx k:xur ,4n*hiasma?

  The diagram below represents them8zu cmtfe2 l3 0j g7(m*puqv05n 2dab structure of a shoot apical meristem. Which row in the table correctly identifies the processes occuring in the structu gf(t0q3bv 50n m7 p*m8eudzl2cm uja2res labeled in the diagram?

  How does meiosis promote variata12mhd0tq 2wk 3/4w rro-bgf jion?

  Which of the following statements is/are correct for me /y-ephw,p,wkiosis?
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 chromosom *yk /p 5( 2kv8q0 wq,k(j3nyutwh(uydh7kdzn es.


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 primar-o fcs mx+00klye6:az y tumours as a rc el0yk+6 x:oz-0asf mesult of the movement of cells?

  How many chiasmata are present in th8 h40jk7o3ynqfgz1xk e diagram?

  Which statement is a similarityku r8h6xydgt w/)ri 65qykv65 between cytokinesis in animal and plant cells?

  Which stage of meiosis is matched t5 :flj1; o) ,od6q e(glmeouflo the correct description?

  Which statement(s) arcb+ vx )wo-7 qe5cnpz1e true of 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 ) 3lk1m(7 cggz9yfi19wamrfvthe first meiotic division. This results in the formation of o fy(ar1 k1g 3)wficlvz9mg9m7ne large cell and one small cell. What is the fate of the large cell?

  Which row correctly describes diploid and haploid cells in /k8kptev-+ kn 6)q.ikr 7 xm zwhmbj(9humans?

  The following table sh- 7jroj:7d5mvigl5 ; nb ami7.afvf s5ows the diploid chromosome number of a range of species.


Which of these statements is correct?

  What conclusion can be dry,wum +jq/)d)un s+on h4ob7a awn from the karyogram below?

  Which of the following processes is chad,6oe:jqd +*cf ttxu :racteristic of the meiotic and not the mitotic cell qt et6fd+ ou::dc,j*xcycle?

  The diagram represents a bud with acazp38z02l 9a:vpb jhs6 a 8wi 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 showszd -nveqby:0ge 60+ur the correct chromosome number for different cell types and cell division -bv urez +qeg0n yd6:0stages?.

  At the end of which pha(+h hj:*ct,ygrbjvk h n97kj3se of meiosis I does crossing over occur, and what is the outcome of cr,nhv kcbh j +9g h:*(jjyrt37kossing over?

  Which of the followi at th9c778uozng statements does not describe a step in the sodium-potassium pump cycle in the779o8tth za uc neuronal cells?

  Which row in the table gow qo p ,lj),,2tj4xvbelow is true of meiosis?

Membrane transport it7ong. zchru+dl.psqe x83. c;-/ r xrs important for allowing particles to move across the cell membrane and respond to changes in the chemical composition of the extraces r crnd.zcx;u/x 8pg.hot +erl7-. 3qllular 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 inrgcy. *hv d0-a 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 concenzr)kx;q.rw 7qsxu) 2dtrations of different cyclins during the cell cycle. Which cyclin is involved in preparqxrrs k2)uw7qd.z;x )ing for DNA replication?

The diagram below shows chromosomeslq(v z ;9k*jh 8azujv3 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 homol8fdr-m:ldm,6etvk kv(qi d68 ogous chromosomes?

  The mitotic index of throat tissmrq z38)++*bl.o gxkbcbj a/eues taken from 4 different patients is shown below. Which patient is most likely to have cxmbjale o*z3 b /cq+g+8)brk .ancerous throat tissue?

1.Draw a labelled diagram to represent t/4 d(ld)gi 5 uw rl3vc3fzcm9ohe 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 karyotyn7pfea2 9y-v7ij guk(7 0nl p6ugw6 qnpe.


What is the abnormality in this karyotype and its cause?

The graph below shows the relative amount of DNAlk,af.v rn +f- in one cell during one complete cell cycle. Ea. k,vf -+lnrfach 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 cross bemx5p0fi w ;0deak x1e.tween a male cat that is homozygous for brown, long hair and a f1d.500ew xmxpi;akefemale cat that has black, short hair.


Which of the offspring has a recombinant genotype?

1.Outline how polygenic traits can show ay xwdd (3 ;d34cby:bpe 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 ovezwfp585f47ec lsvof1r of non-sister chromatids shown in the diagramfco lfzep 5 4w5v18f7s below?

  The photomicrograph sh ut kh8 pancou3a)m k1k9/h+;5a(x debows a pollen grain from L. candidum (Lily). Which stage of meip3dk a;/5ox uc(a8thkhbuk )e1n+a9mosis is shown?

1.Outline the events which would lead to an individual being bo4zqk wehwgn* 19 6h1crrn with Down syndrome, which is characterised by the presence of th kq61cwgr zwhe1*49nh ree copies of chromosome 21.

2.Explain how meiosis increases variation.

3.Outline the stages of meiosis.

The mitotic index is an indirect w1h lun3 /cs/eye2cg ;qay of measuring plant growth. A study was conducted on white onions (Allium cepa), under controlled conditions s 2c3hgu/1 /lcyn ;eeqin 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 wb/q+ *p bvt/pdv6) zfqb8,yblays in which cells can divide. The diagrams below show two cells , 8pf 6*/b+)ztq y/qvpbbdv blfrom 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 gene expressio,c bz 0i0hl3mwn 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 hqz9qe;2nk a:p) hxt 4cell, with a diploid number of 8, in different stages of meiosis. t9 xq)nhp2za;4:e hkq Which row correctly names each stage?

  The micrographs show foul28 m p-oa*ikyr phases of meiosis I in a plant. In what order do these phase- *p kmyao2li8s occur?

Mitochondria are responsible for supplying metabolic energy g 3xt .3*mv q8pe wrygrce1h/4in 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. 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, couly.c w1p/ghm t*rqveex 43rg 38d 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 th30a4dwntq68 e2a szcne cell cycle in four samples of lung tinctaqza84sd n 0w e236ssue from four patients. Which tissue has the lowest mitotic index?

  The diagram shows the dominant cyclin/CDK complexes at 8k6/ alby h(todifferent time points in the cell cycle. Which cycll68abok/ h ty(in/CDK complex activates DNA replication machinery?

  Studies have shown that genes sujy p9r/ l2t:5vq-ksx: kw/ogxch as Cyclin Dependent Kinase 3 (CDKN3) are highly overexpressed in cex/opy5skvj:lx29w gt- krq/ :rvical 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 E9:;x z6 sai1za kk5kso the highest during the cell cycle ?