The graph below shows the relationship betwe 5bm.z (h0ctlh /drf-uen maternal age and the incidence of non-disjunction. What relati/hdmfc(0u b .hl-t 5rzonship is suggested by the data in the graph?

  Which stage of meiosis is represenx)y0outa1 pwv2d+j uhgo (: z0ted in the diagram below?

  The diagram below sh 4ixhm59rmhvw z49 ebmi;f6eyc;sf2/ ows 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 whicxjgn/ wlo982jjn4 mh:h would be prj h:lgj/x2n98 4n mowjesent in the nucleus of a cell as a result of each process?

  Which keyword is matched to t 1tzm1q(vz x 9o8ee vp-j4r(*i aael9ahe correct definition?

  Which statement(s) abo u5v9 6;9 zokjfqb9u dh jqb(+jezy:9mut 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 anaphau; *5p9r tbemase?

  During which stage of mitosis does the nuclear e83rai+c,*y 0 rn;owqroixbprvoh5u:0 3 pp*l nvelope break down?

  Which one of the following transport proteins orcnu4q (/j,kldiy tic12 1i,dnly carries out active transport?ur, d2 4icdkcn1,(/lytj1 qii

  Which process does not hojlfi7 yo4m iw3e7e;7 appen in the shoot apex?

  Which type/s of membrane transport do/dos d +,2 dvkb:2(spxrcves not require energy expenditure?
I. Facilitated diffusion
II. Active transport
III. Osmosis

  The diagram below represents a cell with a diploid number of mu c;nnwtkb 4 v87oh/;4. Which stage of cell division is tt nv87;bmo4 c/ku ;nwhhe cell currently undergoing?

  The photomicrograph below shows a root tip meristem. Wh;l9r vdkmawya4-e k+/ ich of the following sentences correc;4-kmw+ra ydv/la ke9tly defines a meristem?

  When does the random orientation of homologous chromorz6 y4b+c)n fasome pairs occur?

  Which process does not occur during w8kbmj;a . m3v(-.px 9tfs ypcmeiosis?

  If a cell with a diploid number of 36 ;8miw ch 5e(f:odxo1vundergoes mitosis, how many chromosomes will be present in each daughter cell after cytod15oi:o; hec( w fvm8xkinesis?

  The image shows a micropd6slpg aet1d *ylz*x7 (rk i(r)+hx 4graph of a cell.


What explains the appearance of the cell in the micrograph?

  Which statement(s) about homologous chromosomes e1,s: nccer)hrz. 2bf 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 individual with Down syy//ksi:r,ns:b wdmxx sf (y1)ndrome.

Which statement is not correct?

  In the cells of a horse (E. caballus) during prophase I of meiosis I tq3w n)b 6xzrl:gje. e.here are 64 chromosomes. What i qwern3x 6 zlbj..:eg)s the haploid number of chromosomes?

  Which arrow is pointing to a chiacpdsne1)6xy/. 8wm wd6wmjz) sma?

  The diagram below represents the structure of a shoot apical meristeg2zg69 tmz; ozm. Which row in the table correctly identifies the processes occuringz ;g6zz2m9got in the structures labeled in the diagram?

  How does meiosis pro9at54cje-ot d6q skkz+3 tmf 9mote variation?

  Which of the following statements is/k ky36f id wbp1r0fx3g ;axo73are correct for meiosis?
I. It is a reduction division
II. It involves random orientation
III. It produces genetically identical cells

  The diagram shows gametes prod8a1ris 0cl z1nuced 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 (btt cvks6hajro7 ),* of secondary tumours from primary tumours as a ra (bjhc ro7kv*)s6tt,esult of the movement of cells?

  How many chiasmata are preseb+xu3xre zkyp/ ito ho9. 2ti45j:p+vnt in the diagram?

  Which statement is a o1k8oha)hp2 vsimilarity between cytokinesis in animal and plant cells?

  Which stage of meiosis is matched to the cor xgb teml398*lrect description?

  Which statement(s) are true of meiosis I but u k6l-xccz)acjmatdi* 1.9 7 knot 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 r4 jhikg 09/ px,nosv hbt/p-p:esults in the formation of one large cell and one small cell. What is the fate of the large cell?pjb9hp4 /s-htpon :xg/ k, v0i

  Which row correctly describes diploid and haploidd)p -r luckz38 p )onihk39:ym cells in humans?

  The following table shows the diploiesa1);sz 3s v b4ba(tid chromosome number of a range of species.


Which of these statements is correct?

  What conclusion can be drawn from the aehf1 ad+ mmdd7( 8b0ekaryogram below?

  Which of the following processes is characteristic of the meiol;(rd pwuppu5 ll.z2rl/;m -u tic and not the mi d;l w 2p5ru.;u/llmp( prulz-totic cell cycle?

  The diagram represents ak.fn 7 j pi)u6pta/wjl613xfn 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 chimpanze1:vfqz3n w- ige (Pan troglodytes) is 48. Which row shows the con gifv3:-1 wzqrrect chromosome number for different cell types and cell division stages?.

  At the end of which phase of meios kyeb0 n7ix/t1is I does crossing over occur, and what is the outcome of cross/ye1kbi nxt07 ing over?

  Which of the following s4vf yk3 0bv;;fk:gq-h0+wkpf wha. f vtatements does not describe a step in the sodium-potassium pump cycle in the neuronq;fk3 kwp;4ah.f0vf0 v g+:hy-v fwbk al cells?

  Which row in the table ut4n6abbl/; gx /hv:qbelow is true of meiosis?

Membrane transport is important for allowita9*69sd:/u0 oq mb pr drovf6ng particles to move across the cell membrane and m: datfs u9 orrp69b* /6vd0oqrespond 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 regulate96kg*gy *su.h5qhlpj d 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 cyclv twnv;zkk*0()inm7x ins during the cell cycle. Which cyclin is involved in preparing f)xnv;mtw*k7k (v niz0or DNA replication?

The diagram below shows chrocc8 7:f;b kg xfpk,uj2mosomes 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 involvfg7 f. fsiu:6ndhlv)p *7g yglgy f (;n50e9hies the separation of homologous chromosomes?

  The mitotic index of throat tissues taken fro* )kr0s 1fquqhm 4 different patients is shown below. Which patient is most likely to have cancerous throat tissur)q1 kuf0hsq* e?

1.Draw a labelled diagram to represent the process vc0r.0zd8 n9k t so:ld:va0jiof crossing over.

2.Compare and contrast random orientation and crossing over.

3.Outline the stages of meiosis.

  The image shows an abnorma. 5b rpxrxk2v(l human karyotype.


What is the abnormality in this karyotype and its cause?

The graph below shows the relative aqmf; g7-l gu kg2yg*+smount of DNA in one cell during one complete cell c ggq+-kg;us2g* yflm 7ycle. Each 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 shorn mwc n8+bg4k6y *e-lu:bxp9ws a cross between a male cat that is homozygous for brown, long hair and a female +y:px8c-nl6k9bw4ug* rmn becat that has black, short hair.


Which of the offspring has a recombinant genotype?

1.Outline how polygenic traits can show a no* ce9gh 5ss* gp;(l8mtmuve-a rmal distribution.

2.Outline the differences and similarities between homologous chromosomes.

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

  Which gamete can result f/phpz s482 t9 scxtej6rom the crossing over of non-sister chromatids shown in zj 6/sps4e t xt9hp2c8the diagram below?

  The photomicrograph shows oo,flr5zbm62 a pollen grain from L. candidum (Lily). Which stage of meiosis is sz2r5 mf,l6boohown?

1.Outline the events which w;(9-1(af im -hdin(qecjb n hfould lead to an individual being born with Down syndrome, fhjd-f hem((q9-inc 1abi;(n which 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 plant growth. A study was con zmvo7h0qhv4 :c,-mupducted on white onions (Allium cepa), under controlled conditions in a lab, to investigate the effect of soil pH on th vvo p0m4:hm-7uq,zch e 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 cells can divide. The diskm5wg1r vxk-/ fg 4t9i(ue-magrams below show two cells from an orgaitmsw-4-vre1(/ gxu5k 9k gmfnism 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 expression in stem growfa3qp,y fwg;0.w9d p *c. iuq3wzvthsdn6 y6- th.

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 d kmf hv +:f3 8141 6 swbbcul6uzguo1hhw;pvq5iploid number of 8, in different stages of meiosis. Whiu 4k116 lh6cbw+wfuu8hvv fs 5b z3op :;h1mgqch row correctly names each stage?

  The micrographs show four phases of meiosis I i4kl m1c/+ )b/sh- lbvo7vvyu mn a plant. In what order do thesesu ovb/cm h4 7v+km1/)-bllvy phases occur?

Mitochondria are responsible for supplying metabolic energy in eukaryotic cell,d i )+uirbuo q6n(4jas. 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, could qo( )i4iduj6 ,n+brau 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 the cell cycle 78/ t;-l uri-u zgmje,eefm:x in four samples of lung tissue from four patients. Which-e: ;u tg/lfe -ujzi, 8x7rmme tissue has the lowest mitotic index?

  The diagram shows the dominant cyclin/CDK complexes at dwn2d8o h;pw o*ifferent time points in t po;ow 28*dwhnhe cell cycle. Which cyclin/CDK complex activates DNA replication machinery?

  Studies have shown that genes such as Cyclin Dependent Kinase 3 (CDKN3*meg 1h7qps k ;wx*md3) are highly overexpressed in cervical tumommsxg7p d*hkw*qe; 3 1urs.


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 highesa 6rpk0 9eb 6w;v6tvlzt during the cell cycle ?