The graph below shows the relationship between maternal age and thxhyms w+4v h29g2,xvoe incidence of non-disjunction. What relationship is sugg4hhgv922+xsvyx,w m oested by the data in the graph?

  Which stage of meiosis is represented in th xem, k4*wqje+w uy,v7e diagram below?

  The diagram below shnz x5d:u+2b kss- ic*kzi/w +zk.oew 7ows 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 of a single gene which wouldj2wxn:k a4 gr1ri)3z( pf:4jvty 4/,al mzzls be present in the nucleus of a cell as a result of eayz(r jr m svzata 4:ljf l4i4x k,1pz:32wn/g)ch process?

  Which keyword is matched to the cor2kddns/ 3tp5a azyf-*ms(1il rect definition?

  Which statement(s) abd9l f thta-9z/out 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 cellv2) +g *mvhbgr in anaphase?

  During which stage of mitosis i11 mejglpw-k(g 0vd2does the nuclear envelope break down?

  Which one of the following transport proteins only carries out (lpcflf 4y 4b9r2egi-m; mx )dactive transport?b xlf- )p( 2;4rdgfim9cemyl 4

  Which process does not happen in thev5k9w4pxmfct /+ af r+ shoot apex?

  Which type/s of membrane transport do/does not require energy expebz.q/+ tpo mhudb3hf6i +w0:fh .fyb 5nditure?
I. Facilitated diffusion
II. Active transport
III. Osmosis

  The diagram below represents a cell with a diploid number of 4. Which stage of 2dqdk *dlkz:1wor*h5 cell division is the cell current*2: dk1r5 q*kozd lhwdly undergoing?

  The photomicrograph below shows a root tip meristem. Which of the followi p np,/s1alp:c(y ax)xng sentences co:x )nc(pp1al ay x/,sprrectly defines a meristem?

  When does the random zyv af+9.2s+k( zddxcorientation of homologous chromosome pairs occur?

  Which process does not occur duf-g4 cq1r8 kslring meiosis?

  If a cell with a diploid number of 36 undergoes mitosis, how many ch8f1khj a82r j j1hnosh* l0+cpromosomes will be present in each daughtlj1 80fc12 oshakhh* 8jnpj+ rer cell after cytokinesis?

  The image shows a microgrl l*jbvlflxa4e .8-/ raph of a cell.


What explains the appearance of the cell in the micrograph?

  Which statement(s) about homologous chromosomes ojwq:zb44-ar 4 0tty his/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 individual with Down synbsg (srf8uk5rea p 085drome.

Which statement is not correct?

  In the cells of a horse (E. caq2epff 2ah+5kcc/jg(e3 lp9wballus) during prophase I of meiosis I there are 64 chrg5efw l/p 23+c(ac qfhp92 kejomosomes. What is the haploid number of chromosomes?

  Which arrow is pointing to a chix yw (rladh.)ox.-3frasma?

  The diagram below represents the structure of a shoot apical meristem. Which ro3ykkv4v yr9i 1w in the table correctly idenvv y4r3y 9ki1ktifies the processes occuring in the structures labeled in the diagram?

  How does meiosis promotbor5 02/i0nu3r23- d a ;bfpcmswoakhe variation?

  Which of the following statements isjc/zv8s6 ow3 m/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 two homologous ch 6;2vkyedls93m yleq0romosomes.


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 secondar)krjdbjw1hr v9c .(v5y tumours from primary tumours as a resur rk dv.hj5b91w ()jcvlt of the movement of cells?

  How many chiasmata are present in the diagrag7 ffk56*4hui jlog9-k una,om?

  Which statement is a similarity between cytokinesis in animal +6ilre , g)x;cvla5vfdw/ufd3sg*.fand plant cells?

  Which stage of meiosis jz2z12 pncdlg)et 0r(is matched to the correct description?

  Which statement(s) are true of meiosib w1 )swp8v bym81f5egs 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 a h51i6g ld2zz fjnkehjk3g7*a. * 76klndv;evfter the first meiotic division. This results in the formation e.7 3z * h hgg6ve2 1n*dkjdjvfnk;liz lk6a75of one large cell and one small cell. What is the fate of the large cell?

  Which row correctly describeg3nmv5 ,jcc d-ql6h337wr pfms diploid and haploid cells in humans?

  The following table shows the diploid chromosome number of a rangwj8i 2q)ril3 oz;0b7tbq ;igri2h6oe e of species.


Which of these statements is correct?

  What conclusion can be drawn from the karyogram bexhivi5q usby0 o3n*42 low?

  Which of the following processes is characteristic of the me8rmr7v,n *w m,lavku8iotic and not the mitotic wk,, vulvm7rma n r*88cell cycle?

  The diagram represents a bud wit6lh xp+hq*(2twd8lgb h 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 chimpanze:;5tl+ bm+e o;xzndv le (Pan troglodytes) is 48. Which row shows the corree;l nbvdzol;+ +5tm:xct chromosome number for different cell types and cell division stages?.

  At the end of which phase of mh8s rxk, n-+kieiosis I does crossing over occur, and what is the outcome of crosnrhk8x,is+ -ksing over?

  Which of the following statements does not describe ampm 2hr,, jls- step in the sodium-potassiuml ,rms-j2mh, p pump cycle in the neuronal cells?

  Which row in the table br7hr rm /wfw 3uu 78/kgqaw+9lelow is true of meiosis?

Membrane transport is important for allowing particles to moqwgczeimap5 5q89t* 6ve across the cell membrane and respond to changes in the i*qa55zwp ge tqc98m6chemical 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 regu+u7,r w7p+,gdm ifeqblated 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 concentrations of different cbshq g5 ax8ri(h(w3,oyclins during the cell cycle. Which cyclin is ig ,a8(ihbsrq3xw 5oh (nvolved in preparing for DNA replication?

The diagram below shows chromosomes dur0uz jh-q3f;y -7paxzl ing 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 homologous chrofq lgeq9q:p 9r8d 2t2cmosomes?

  The mitotic index of -9n21 scq joeathroat tissues taken from 4 different patients is shown below. Which patient is mostoeas-1c 9q 2jn likely to have cancerous throat tissue?

1.Draw a labelled diagram to represent the process of cro y1 xl xyhfbxv1u8np16v;j 6ni :ujx,)ssing over.

2.Compare and contrast random orientation and crossing over.

3.Outline the stages of meiosis.

  The image shows an abnormal human karyhy48)e7nsy pe5r h gww07en,q otype.


What is the abnormality in this karyotype and its cause?

The graph below shows the relative amount of DNA in onj;;k qrj.dgc;; ncn*ge cell during one complete cell cycle. Each letter represents okn q ; jcg;*.;rcnjdg;ne 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 for bro:(s)4 pry jf-/, xe8q ozficdhwn, long hair and a female/ 4jdo)p- ,s:8ihqffxecr (zy cat that has black, short hair.


Which of the offspring has a recombinant genotype?

1.Outline how polygenic trg)f(4u1( xt s, yaw *.vrgrhqmaits can show a 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 over of non-sister chromatids s;j7ss ktt5 ;yrhown in the diagram bs5trt ;sy ;j7kelow?

  The photomicrograph show . y0ujxtg-wni la;1t6s a pollen grain from L. candidum (Lily). Which stage of meiosis is shown? xjt. i-l61twy;ag un0

1.Outline the events which would lead to an individual being born);k u(y5 oo:7)rby srobfjame27.jeu with Down syndrome, which is characterised by the presence of three copies of chrom5y ) e.(o ;ou2 ub)ybso7 7e:rjrfmjkaosome 21.

2.Explain how meiosis increases variation.

3.Outline the stages of meiosis.

The mitotic index is an indirechbr ud6d+ 8yw a21fsv/t way of measuring 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 mitotic index r8f12 asdv+ bdh6/w uyof 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 whv *q hiq23*u+bd tpy qxp6nhk)+pd96v ich cells can divide. The diagrams below shoqkd+6 p) **pd qyhv xuiq 3hp6n29+vbtw two cells from 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,z x+ i:qerb,2g t3thc 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, inzuo:w84pg2rt* n2 csk different stages of meiosis. Which row corsunt pkz2c go842r: w*rectly names each stage?

  The micrographs show four phases of meiosis I ing:byyesmn (l* 3+cjz 0 a plant. In what order do these phagclz n+y :*ejy0b(ms3ses occur?

Mitochondria are responsible for supplying metabolic ener640ydmb w, azigy in eukaryotic cells. In most eukaryotes, which reproduce by sexual reproduction, mitochondray64, zm dw0ibial 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, 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 stag3a.kqevmnx gn25ky 3;)2 s fxco-j-oues of the cell cycle in four samples of lung tissue from four patients. W-)3 vmsgx5a ; 2.oe2ju -koqnckxf3 ynhich tissue has the lowest mitotic index?

  The diagram shows the dominant cyclin/CDK complexes at dyrk f,7v q xoyc0./4cro1 jfn:ifferent time points in the cell cycle. Which cyclin/CDK complex activates DNA replication machno1 j4 .c,7k/vyq0 xr rfocyf:inery?

  Studies have shown that genes such as Cyclin Depe,bshw 1+rb /f3ux.g dbj0 os0wndent Kinase 3 (CDKN3) are highly overexpressed in cervical tumou,g0s3.jw/0u +sdwo bfh bxb1 rrs.


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 dug 8muwwnry 0 wg(w*v25ring the cell cycle ?