The graph below shows the relationship f 42l8tjgvn3l between maternal age and the incidence of non-disjunction. What relationship is suggested by the data 4gnl tv83ljf2in the graph?

  Which stage of meiosis is represented in thnz *u+b6a* n t*j2njdve diagram below?

  The diagram below shows chromosomes;w0w5au/c z7,on9pm9pv sra g 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 single3 fkjksf l0m )x5il)v0 gene which would be present in the nucleus of a cell as a result of each prxkfjisl3 5) mf 0vlk)0ocess?

  Which keyword is matched to th7c7 qjn1rz.yle correct definition?

  Which statement(s) about mitosis is/are true;0wbdhhn:e,gzt v9b+ 8 r 2;yb vszm2q?
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, 1uz8 y qpxa37j rw(h+qwhich letter points to a cell in anaphase?

  During which stage of mitosis does the nuclear envelope brea-dwvoy+ezxa7+f3a. 29r on (jlps 3vt k down?

  Which one of the following transport proteins onlmt8 mmn6rw-*h y carries out active transport?m - rmwthn8m*6

  Which process does not happen ipnv*1qvkpu jz 3*isrk;ms 0 +*n the shoot apex?

  Which type/s of membrane transport do/does not require energy expenditure?) ri wp0n-yhs ( asbctjvsdwh: s8+00-
I. Facilitated diffusion
II. Active transport
III. Osmosis

  The diagram below represe-+ z4dgq4 ;a 5aeqeokents a cell with a diploid number of 4. Which stage of cell division is the cellqeko4 ; ee-54g+qadza currently undergoing?

  The photomicrograph below shows a root tip meristem. Which of bysala 7g+-ov 0f,jf(the following sentences correctly defines a meristem?l+(sob f0fy-gaj7a, v

  When does the random orientation of homologou(zdd( 1h/aw wxs chromosome pairs occur?

  Which process does not occur durv nvb ;;wx51zeing meiosis?

  If a cell with a diploid n w.* mcp+j2rzeumber of 36 undergoes mitosis, how many chromosomes will be present in each daug+2e. rpmzjcw*hter cell after cytokinesis?

  The image shows a micrograph of a cell.lkdv l.c jhcn:sz;p-q /5h(i;


What explains the appearance of the cell in the micrograph?

  Which statement(s) about homologous chromosomes is/are not truedn uj1jsl7pcjv02 /x4u* ga5t ?
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 Dotl z*qd72(t ttwn syndrome.

Which statement is not correct?

  In the cells of a ho kty/y uv;ie;)z(d i(srse (E. caballus) during prophase I of meiosis I there are 64 chromosomes. What is the haploidi)yudsv;iye z (kt(/; number of chromosomes?

  Which arrow is pointing to a cec11 y b03fctehiasma?

  The diagram below represents the structure of a shoot apical meriste (jdcn w k3hy-fqzmvjdj j335 3kc,b80m. Which row in the table correctly identifiesdfjk(wn-d3 0,j v5bcj 3hq 3jk38czy m the processes occuring in the structures labeled in the diagram?

  How does meiosis promote vnyoha,/h4p2u::js vy v2,n l5jk f9mc ariation?

  Which of the following statements is/are correct for meiosis/2bq9ve: , ,z(/ ym dvvivvszp?
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 z4ia:/r(k)-yueqpl d.rqp / j 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 primary tumomdyi os a;l,5,urs as a result o, ;oa5slyi ,mdf the movement of cells?

  How many chiasmata are prr oxf52p:4 mauig)n62zkj ;k cesent in the diagram?

  Which statement is a similarity between cytokinesis in animal and hkg3zb+) i;zk .+d 9tpjn sjo3plant cells?

  Which stage of meiosis is m(oimh/:1bo kgu: +6.d kkpovqatched to the correct description?

  Which statement(s) are true of meiosis I but notbye*e;+soh 743i wz lhqza,:b 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 af vbcgg ;oc56a vcyv41/t+v3pfter the first meiotic division. This results in the formation of one large c/yag v+p5cfv 6vcbo g;31vt4 cell and one small cell. What is the fate of the large cell?

  Which row correctly describes dip* a4qhy4xbsv/ z+vn5 iloid and haploid cells in humans?

  The following table sho,zra2mb c9 uw)ws the diploid chromosome number of a range of species.


Which of these statements is correct?

  What conclusion can be drawn from the karyogrq p 9-0oliuk, ,w zvzwfr17pn)am below?

  Which of the following processes i. p)znmns1fmd,jct24 ;t fj6us characteristic of the meiotic and not the mift2z n,dnfu.smc4;t m6)1jpj totic cell cycle?

  The diagram represents a bud with a spj(cvj0e4,z f hoot 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// q5qis* g fygsga/ jk/)*m5ajb3jnahe correct chromosome number for different cell types and cell division s //qj/iygknb5s g3q m)jaaf5g*a/* js tages?.

  At the end of which phase of meiosis I does crossik*+ra)vilj-k3 gx -srng over occur, and what is the outcom- kvsjlri- )x+ 3krag*e of crossing over?

  Which of the following statements does not describe a step m7(t, kpgxxkspl (3u(in the sodium-potassium pump cycle in th7px, xup t((g(k k3smle neuronal cells?

  Which row in the table benr*le rw*+qp1 low is true of meiosis?

Membrane transport is important for all/wd: mlhunx3nhco/94owing particles to move across the cell membrane and respond to changes in the chemich4uw/ln/n 39mh dco x:al 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 rwp4 be5m66xax egulated 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 cyclins during the. :d ;na/zpa-ae4v.h xmp- jla cell cycle. Which cyclin is involved in preparing for DNA r.amdx z4 e;j- a avp:.h-npl/aeplication?

The diagram below shows chromosomes during meios3hhu* 6 ;m cki0l1ymvjis.

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 0*-f/je9agz yb8pzeb chromosomes?

  The mitotic index of throat tissues taken from 4 different patients ifk/j93 cwljq r. ib,8is shown below. Which patient is most likely to have cancerou ljcw3 fi9rb/qi,8.jks throat tissue?

1.Draw a labelled diagram to represent the process oips/ m8ob2 zt)f crossing over.

2.Compare and contrast random orientation and crossing over.

3.Outline the stages of meiosis.

  The image shows an abnorr 2e :alm+x-ppmal human karyotype.


What is the abnormality in this karyotype and its cause?

The graph below shows the relativ0l/ ge,d kjs4- wp,:uw bzr dk;0x3cmee amount of DNA in one cell during one complete cell cycle. Each4ekzpwjwr-,0k / b03:mscd u,dgl x;e 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,m rras/lk25r a cross between a male cat that is homozygous for brown, long hair and a female cat that has black, short 2slrrm/ k,5ra hair.


Which of the offspring has a recombinant genotype?

1.Outline how polygenic traits can show a normal c7yxw11gy gtsm f 0klzg90 . odwyd:/7distribution.

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 su1- pba0axfj 5hown in tj0a5fap 1bux -he diagram below?

  The photomicrograph shows a pollen grain from L. cand 8 ,ri7 qx7(ogbclqy8nidum (Lily). Which stage of meiosis is sxcng,q(lib8 77 rqo 8yhown?

1.Outline the events which would lead to an individual being bohxjcn97mml,rvsg1f 3 h3o9.m rn with Down syndrome, wnr9og, h 7lxmf m3j9. 13mshcvhich 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.* -mwuqnw dfwuud9-e wm(9 o)+ A study was conducted on white onions (Allium cepa), under controlled conditions in a lab, to investigate the effect d9 +)-uwqwmodm efuw9w-n*u(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 cells can divide. The diagrams below*9( u9tum:tud iy;dve show two cells from an organism with a di:9 yudtv tm;9 *edi(uuploid 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 groy 6b-tklxzo9tky 9rq+/qr/e7 wth.

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, in different stagn-;3lffdr 9ty 1*b tsoes of meyt; fodb-f19 t *s3nrliosis. Which row correctly names each stage?

  The micrographs show four phases of meiosis I in a plant. In what orderrtewgb*t2,gag 86 pfu9s ee.; do these phases occ* t, se; 2wptg a9re.gefub68gur?

Mitochondria are responsible for supplying metabolic energy in eukaryotic cellsz 4nes;byx :5g. 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 bg4 y5zexs: ;nmtDNA 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 dj u+4 od3vzzq f mudh-37(m0b9yfr(ethe cell cycle in four samples of lung tissue from four patients. Which tissue has the lo d(bf j7m3-0+qhuy o3rzddv(4fm u9ez west mitotic index?

  The diagram shows the dm)b dnhr* gbf7gb;6l):.ou ok ominant cyclin/CDK complexes at different time points in the cell cycle. Which cycgogn)bo;h 7 bm.r)6 *bfd:ulklin/CDK complex activates DNA replication machinery?

  Studies have shown that genesk2gx hu/5bps*z 27o vk such as Cyclin Dependent Kinase 3 (CDKN3) are highly overexpressed in cervgbzxps52kku h7 *2o /vical 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 higherk+sekuetp:pw .:0 6f70gplbr y a50p st during the cell cycle ?