The graph below shows the relationship between maternal age at j.uci 5v0g-jqrj)d7nd the incidence of non-disjunct qvjgj5tjd 70c. uri-)ion. What relationship is suggested by the data in the graph?

  Which stage of meiosis is represented in the diagr8b/wzp (i9osnam below?

  The diagram below shows c b* ua5oqsc05u+tdmn+hromosomes 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 of a single70cwy shg wbawub (a9*m1m m68 gene which would be present in tws7a0w(1baw*mh6um gmc 8 b y9he nucleus of a cell as a result of each process?

  Which keyword is matched 2,vy)i.p4y f d.m xbdoto the correct definition?

  Which statement(s) about mitosis is/ar 864zz3 x0,ajg-aofz ts cg5bze 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 leo98mt3xekc+ r tter points to a cell in anaphase?

  During which stage of mitosis does the nuclear envelope break 5rh,-u unmz a g.ol5:adown?

  Which one of the following transport proteins only carries out active transport9d iswq-a8/m u?a iwuqd98/ -ms

  Which process does not hapct9i oz7al ( 23d(hdqtpen in the shoot apex?

  Which type/s of membrane transport do/does not require energ4.l )yjyi+geqn p29c 0c8kb zhy expenditure?
I. Facilitated diffusion
II. Active transport
III. Osmosis

  The diagram below represents a cell with a diikv+ o1a(0lpiploid number of 4. Which stage of cell division is the cell c+vi lo01(ak piurrently undergoing?

  The photomicrograph 9-l:u8 b8h ljdu9thh abelow shows a root tip meristem. Which of the following sentences correct:ald-u 98hlh j8h9tub ly defines a meristem?

  When does the random orientatip x d9y:lzv r(q8a6v(con of homologous chromosome pairs occur?

  Which process does not occnpf k 6tjfq,sb9 i6hs3u6+;ez ur during meiosis?

  If a cell with a diploid number of 36 undergoes mitosis, how madld5nq 0y+xf s8/1xbrny chromosomes will be pres1b/sdqyl 0xfd5 xn8 r+ent in each daughter cell after cytokinesis?

  The image shows a micrograph of 9du(ho +j*8h 3lixmxga cell.


What explains the appearance of the cell in the micrograph?

  Which statement(s) about homologous chromosomes is/are not true? *a7uzd3oiv7r
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 individual wi/* 6t* zaqmw gwwb:qk17gkuu;th Down syndrome.

Which statement is not correct?

  In the cells of a horse (E. caballus) during prophase I of meiosis I thebef0/u b6jmq:s 9h/h dre are 6s u6h0qj b: /de9/fbhm4 chromosomes. What is the haploid number of chromosomes?

  Which arrow is pointing to a ch rl42/d2aljzi:;xmy 5mo4r wl iasma?

  The diagram below represents the structure of a shoot apical meristem. Whichamas,n/qnp r(qdxa7nz (b+4y 9nc+s : row in the table correctly identifies the processes occuring in the structures labeled in sanpd+4a(a9mc7z n,n+ xq(yns/qbr:the diagram?

  How does meiosis promote vakr4p/ cduirjhqm/6vd7zb rpv8/7 1 ,wriation?

  Which of the following statements is/are corre me4blhn; ( w;3ugfnc/ct for meiosis?
I. It is a reduction division
II. It involves random orientation
III. It produces genetically identical cells

  The diagram shows gametes produqt5u mln08 fh +zpd4,tced 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 pe )va4ptth6) cs u99)vpdrv*orimary tumours as a result ocp* hvae))uto9ts94vpr )d6v f the movement of cells?

  How many chiasmata are prp9czcnf, t1+ f:9onh ,a 9 ohgv3x-kxjesent in the diagram?

  Which statement is a similarity between cytokinesis in animal a1v))xm+ ) graz ym-iyynd plant cells?

  Which stage of meiosis is matched to the correheqx+tb 7e/ y55 -hzhkct description?

  Which statement(s) are true of meiosis I but not meit1t:vat amrrkwh 8-).u:j 9ndosis 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 rbqdp yuc9 ibx-t5;,k8esults in the formation of one large cell and one small cell. What is 9 58xpbkdutqibc ;,-ythe fate of the large cell?

  Which row correctly describes diploid and haploid cells iuz7p qm)ii( :0tzh +ggn humans?

  The following table shows the diploid chromosome number of a range of specd)3e5 t5tt+,urp dp xmies.


Which of these statements is correct?

  What conclusion can be drx2- )lwvp*ehrvk47 xfawn from the karyogram below?

  Which of the followinpnb62j/l xzo)g processes is characteristic of the meiotic and not the mitotic cell cplz /noj2b 6x)ycle?

  The diagram represents a bud8bdhlyzc ;dv8(bwavue87 gz2 :h9t7d 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 chip1j fvq2 uku2cf-dw-4 mpanzee (Pan troglodytes) is 48. Which row shows the correct chromosome number for different cell types and cell divisiowvdpucf-4 21- 2qukfjn stages?.

  At the end of which phase of meioe(vy3 xlf)bc 0h10 ltwsis I does crossing over occur, and what is the outcome of 3(0llb v1txcf0yew) hcrossing over?

  Which of the following statements 4 n9 *vdwhrd2ldoes not describe a step in the sodium-potassium pump cycle 9dln4 r2 dv*whin the neuronal cells?

  Which row in the table below is tjf 1cs 11.cqnv rh4w(frue of meiosis?

Membrane transport is important for allowing particles to move across the ceig, 53bmv ig6hll membrani,5 hmvg6ibg3e 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 c cbz nmk4v6ml-7* tv9in 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 u upcr3,u60.:wu 3pte; atdp kof different cyclins during the cell cycle. Which cyclin is involved in preparing for ;u rtpu 6kuuwc:e,.0tp dap 33DNA replication?

The diagram below shows chl,/ +kustwo1un ct5 fw0dr5p+romosomes 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 hom(pi) ce yarx06ologous chromosomes?

  The mitotic index of throat tissues taken from 4 different patiesd 7n.l qmo,:dk l*tp;nts is shown below. Which patient is most likely to havetqs dlo.p,7:;dnm l*k cancerous throat tissue?

1.Draw a labelled diagram to r*hbvns1la p) r97ave75 tira4epresent the 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 kp:qw+bgr6d* karyotype.


What is the abnormality in this karyotype and its cause?

The graph below shows the u/xoieh3 m +q)relative amount of DNA in one cell during one complete cell cycle. Each letter represents one stage of the cell cycle.hm iu+oe/xq) 3


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 p72lr5nr9 . -hs7i voqlpq bd1homozygous for brown, long hair s b 2q7dphol1 vq9i-pl5r.7rnand a female cat that has black, short hair.


Which of the offspring has a recombinant genotype?

1.Outline how polygenic traits can show a normal distribution;d ssh83i h pnzv58ua(.

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 non-siste7ed dq9cga8p z 608mb1hw2a/zdgzc1vr chromatids shown in the diagram below86dgzd8dgzh9 c1pzqvcea/m7 b20 1a w?

  The photomicrograph shows a pollen grain from L. candidum (Lily). Which stage 5kzm.fc, 7*/rxpaa*u5efbncof meiosis is showncafrm fe */cnbk5 a uz*,x7.5p?

1.Outline the events which would lead to an individual being born wp j(5yt q-xz w ;gtiraih9i-(+ith Down syndrome, which is characterised by the presence of three copies of chromosome 2g+wjx-rz yq9ip(;5t -iah it( 1.

2.Explain how meiosis increases variation.

3.Outline the stages of meiosis.

The mitotic index is an indirect w 7a4zw wiz0zx7zvj/4n ay of measuring plant growth. A study was conducted on white onions (Allium cepaz j7wiz 4 7zwzn/4xv0a), 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 ways in which cellx-cmu0iozc. 9s can divide. The diagrams below show two cells from an organism with a diploid number (2numco 0c9-izx .) 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 geneco;cg5t17 elp )mosgzp))au, k )pz5l 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, wi5e6ll5u oktb6 hnf94lth a diploid number of 8, in different stages of meiosis. Which rfo64 htb5lel 69l n5ukow correctly names each stage?

  The micrographs show four phases of meiosis I in a plant. In what order do tj uoft5 d jm 2mxzjs 6u4a6/mm3n:/3a+lteq1b hese phasesj tne 4o/x1 +t3d mbu5amqz2lu/ :6m3jmf 6jas occur?

Mitochondria are responsible for supplying metabolic energy in eukaryoq*mqu 7nrf ot*4gl 80 *kf/zddtic 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 4d*ult 8rq*7mfzdfq 0o/ngk* 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 cellsbgis 91060-dwxb vers in different stages of the cell cycle in four samples of lung tissue from four patienbb600x i9w srsv-e1 dgts. Which tissue has the lowest mitotic index?

  The diagram shows the dominol 9+e wo*y2lxant cyclin/CDK complexes at different time points in the cell cly 2w+e9ox ol*ycle. Which cyclin/CDK complex activates DNA replication machinery?

  Studies have shown that genes such as Cyclin Dependjyl cg4e*x/ r(ent Kinase 3 (CDKN3) are highly overex/*ylj xg4 rec(pressed 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 cycle ? ce5* 5 ruxm7pc