The graph below shows the relationship between maternal age and thn.c*nn+,fv2- .kvlx yt zfjx) e incidence of non-disjunction. What relationship isncn2j f+x ylft xv-nv.* z.,)k suggested by the data in the graph?

  Which stage of meiosis is represented in the diagram o)cq1gvv);bowam (6-sl: oby a)(bvg below?

  The diagram below shows chromosomes during meiosisc0i:+lmjnnr2+r fz; k:jf4y nwq2si6.


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 )g msg56 zj7itsingle gene which would be present in the njg i6mz st5g)7ucleus of a cell as a result of each process?

  Which keyword is matched to the corre-7 wonxnk2nobs1s. c, ct definition?

  Which statement(s) aboutrm.1u fw h-f53ie /q.bxnaur(02ejjh 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 lette(al p0ftvn;f7r points to a cell in anaphase?

  During which stage of mitosis does * cwj 9l*dt4laflj9w( the nuclear envelope break down?

  Which one of the followinx4uuu.a9sue8o k7 ww ;g transport proteins only carries out active transport? w7u ;ue8xauok w9.4su

  Which process does not happe1k y7z y-(wkc e-7b9nd n fas/zh2v;ghn in the shoot apex?

  Which type/s of membrawu5nf6w2+t6w(w hpka r. el6zne transport do/does not require energy expenditure?
I. Facilitated diffusion
II. Active transport
III. Osmosis

  The diagram below represents a cell with a diploid number of 4. Wh3,aw t 1uh2bvg wb90zgich stage of cell division is the cell currently undergoing3b1zwwg,0avgub t92h?

  The photomicrograph below shows a root tip meristem. Which of tc of b0f,16tlthe following sentences correctly defines a meris 1oftlbf 06tc,tem?

  When does the random orientation of homologous qe 9w+id2jk935y llrgchromosome pairs occur?

  Which process does not occur during meioyug+ omsi*v5u zc+u04sis?

  If a cell with a diploid number of 36 undergoes mitosit2ub,b ld1 f 0dhj.hev(e7)lgs, how many chromosomes will be present in each daughter cell after cytokinesise(, bu).hlld7fj20 1b dhvte g?

  The image shows a micrograph of a cell.; *dxzx1gfc8v *-wt hk


What explains the appearance of the cell in the micrograph?

  Which statement(s) a ekoz:wo6adjo /6k3 s/bout homologous chromosomes 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 q )ub 8;n,rv.dboj0 casyndrome.

Which statement is not correct?

  In the cells of a horse (E. caballus) during prophase I of meiosis I t s0niemnf,*;y+nf8-q6s cn ilhere are 64 chromosomes.n,;+n*fqcny8 -slefisnim 6 0 What is the haploid number of chromosomes?

  Which arrow is pointin bxy57q ;lr8 3qxst5s-ys bl+hg to a chiasma?

  The diagram below represents the stru.r1 :qk*h arixcture of a shoot apical meristem. Which row in the table correctly identifies the processes occuring in the structures labeled :.xqrk 1*irha in the diagram?

  How does meiosis promote variation ixql z:r6. y a/owf(wn,5weq:?

  Which of the following statements is/are2 i*o- 2wx.wm+l ujdar 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 chromos zu cgy md,7a:-wv5gl3omes.


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 forma 0,w :xqpp6uqf0arzb1kze()v tion of secondary tumours from primary tumours as a bp,v uwexq z kz0f0ar):16q p(result of the movement of cells?

  How many chiasmata are present in the diagramnu hj4fz5oak8)l.ia2 w +nqz/?

  Which statement is a similarity between cytrj0 3rixhmt 26okinesis in animal and plant cells?

  Which stage of meiosis is m01c nlsdt.qc4v2(cmuatched to the correct description?

  Which statement(s) are 7sr+ pposkz*; 0xml4w 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 oocytndnq)p2 5t gz:qe/1cg e after the first meiotic division. This results in the formation of one large cell and one smalden/qq z1c52pt) ggn:l cell. What is the fate of the large cell?

  Which row correctly describes doeh e+7;gtl5 p * ::xxyzmyd6biploid and haploid cells in humans?

  The following table shows the diploid chromosome number of al q4j zw 29.nvasn2hh( range of species.


Which of these statements is correct?

  What conclusion can be drawn from 1ahv+mv*m e. zthe karyogram below?

  Which of the following processes is character uax u9r9-c 7vpc5.nqkistic of the meiotic and not the mitotic 5 npu-crxkq9vc .97au cell cycle?

  The diagram represents a bud with a shoot apical meristem. bgem8ybfou4sd 80 2h3

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. Whyh;0cj5tqz m9 j3t *dcich row shows the correct chromosome number for different cell types and cell division stagem5hcjztq; 0*ytd 39jcs?.

  At the end of which phase of meiosis I does crossin x7f;-k5jv8b bxm;0zbcx / jmhg over occur, and what is the outcome z/;h c;-x bb07v fbmx8jkmxj5of crossing over?

  Which of the followin2i;hdhms,+ rz kyeoe/ 2 -ebn(g statements does not describe a step in the sodium-potassium p(2 ;n-/siedeo+er,h zk2h mbyump cycle in the neuronal cells?

  Which row in the table below is true of meiosiwex,wpp1qh* msl4-u 7s?

Membrane transport is important for allowing particl z52 akyed)7i(nqvrp 7es to move across the cell m7dy vkp r(i5z)a2 7neqembrane 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 ind355un6 gc ake02jlcj 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 cycl8v 0ah naek,pyv :cys9).8bsxins during the cell cycle. Which cyclin is invo.av 8hsbncsa0ekyv9y)8: p ,xlved in preparing for DNA replication?

The diagram below shows chromosomes during meiosis.-d e3t w32d)grbo. veo

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 invoprs2vd nhb2 61lves the separation of homologous chromosomes?

  The mitotic index of throat :hspq6;w fvy6jk x7d7tissues taken from 4 different patients is shown below. Whqkvw6 xjd;y7f7p: 6hs ich patient is most likely to have cancerous throat tissue?

1.Draw a labelled diagram to repn 6/cq9s-qd vl(qkgawt.;im . resent the process of crossing over.

2.Compare and contrast random orientation and crossing over.

3.Outline the stages of meiosis.

  The image shows an abrm/(,aw yywj +normal human karyotype.


What is the abnormality in this karyotype and its cause?

The graph below shows the relative amount of DNA in one3aq 0 jgt(hc57bu-yfx cell during one complete cell cycle. Each letq3ha0b-cyu tj 5fxg7(ter 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 between a male cat ww 3m;v1n myr)that is homozygous for brown, long hair and a female w ;3m1mvy)rwncat that has black, short hair.


Which of the offspring has a recombinant genotype?

1.Outline how polygenic traits can show a normal distribution.xjbup8i3(t5a j zf)w(

2.Outline the differences and similarities between homologous chromosomes.

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

  Which gamete can result from thce2udvs2 *) xze crossing over of non-sister chromatids shown in the diax2dcze *)suv 2gram below?

  The photomicrograph shows a pollen grain from L. candidum (Lily). Whikpon8qs2 b8 d h8/nhc rexg9s4x;l5gew6 z-*hch stage of meiosis is shownggcrwb2k8e8 s z nlp5h h8d6/qo 9nhs;x*4ex-?

1.Outline the events which would lead to an individual being born with Down sy9 r( ry/kn- m0zp niokl/5qto,ndrome, wkr,m r(5z n/yk/il9pt0on-oq hich 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 mwg,b ob6-afw1easuring plant growth. A study was conducted on wg fao-wb 1w,6bhite onions (Allium cepa), 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 ciz9)mjef7c 1o ells can divide. The diagrams below show two cells from fio9m e )z17cjan 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 gs( np(.ek1mm -ij arob7r:ss: ene 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, in different sb;-rif)wd7n8d 4uayx tages of meiosis. Which row correctly name)fdub-nyx8d a ;4w ir7s each stage?

  The micrographs show four phases of mei26nth rd:ec tx * zaiw,bd:00fosis I in a plant. In what order do these phases occur?n *th wcti260 :,zreb:dxa0fd

Mitochondria are responsible for supplying metabolic energy in eukatzb sp4h7,mz/ryotic 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 specie 4hb z/psmzt7,s, 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 the cell c9)*)p0ihusgdx- r iqlgwd )k(ycle in four samples of lung tissue from four patients. 9lugp) wsx()*kd-rh ii0d ) qgWhich tissue has the lowest mitotic index?

  The diagram shows the dominant cyclin/CDK complexesa46s r0kb1n-9iw ywu h at different time points in the cell cycle. Which cyclin/CDK complex activates DNA replication machrs9y6 k0awnb4w i1h u-inery?

  Studies have shown that genes such as Cyclin Depenwc :8pbez):lizc6qxv( ;o)go dent Kinase 3 (CDKN3) are highly overexpzx8bq))w 6eo (gz v ci::lc;opressed 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 thellvt tj u* vm/epa72t+*zt/f. cell cycle ?