The graph below shows the relationship between maternal age and the incidenpy zy1+d(t p4cce of non-disjunction. t py1 4z(+cypdWhat relationship is suggested by the data in the graph?

  Which stage of meiosis is represented in the dip3/mk rw4d x 9/ hcqg..dkj9suagram below?

  The diagram below shows chromosomes during meiosis*x- z stnkt( u.n5cuk9.


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 y*vwj3x 19i*hvmgs- dof a single gene which would be present in the nucleus of a cell as a result of eahj iv*dy1swv9mgx *-3ch process?

  Which keyword is matched tow3 .imq6(eaj 8l. oq3 a/piuyu the correct definition?

  Which statement(s) about mitosis idx7y9 p/+ qxugs/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 vez;e)ytdrrc ggm;,y z :(a4 m1)8s tpin anaphase?

  During which stage of mitosi 0t-kp0ms8.u:wfhd zcs does the nuclear envelope break down?

  Which one of the following transport proteins only carries out a-cq--i wfw3d .my gv7dctive transport?-w3div . fy-m c7dgw-q

  Which process does not yo(ab(,rzt8kxkp1t0 happen in the shoot apex?

  Which type/s of membrane transport do/does not mcpzmjsxun/ ulkmm1 477d9+3 require energy expenditure?
I. Facilitated diffusion
II. Active transport
III. Osmosis

  The diagram below represents a celspac aj3b0 1u z*kw d15mf+k7 4hw6bdil with a diploid number of 4. Which stage of cell division is the cell cu40*w1 bbzd cupm5ik ha1 f7jd+k36awsrrently undergoing?

  The photomicrograph below shows a root tip mev0e:7l l*xkoqristem. Which of the following sentences correctly defines a mer70 el*ok qxl:vistem?

  When does the random orientation of homologous chromosltau*tk / 9iou)d xkq20l;w+yome pairs occur?

  Which process does not occx rd*ezb1ld 2tv8.u ksr7.k(fur during meiosis?

  If a cell with a diploid number of 36 undergoes mitosis, how many chromosogu5 o +nag/-snmes will be present in each daugno5/na-gug +s hter cell after cytokinesis?

  The image shows a micrograph ofd u0l3u: puj.p a cell.


What explains the appearance of the cell in the micrograph?

  Which statement(s) about hul58 jnnq yjsn3+0w cvs )q52jomologous 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 Down5qhqe;;ltfw;l01 n3yi d; brc syndrome.

Which statement is not correct?

  In the cells of a horse (E. caballus) during prophase I of meiosis I there (2n4+ vtgq*d wjv.f6qc vi (go3 gztq2are 64 chromosomes. Whatj tqtggz+2i.( *46q vvw d (fc3g2ovnq is the haploid number of chromosomes?

  Which arrow is pointing to a chias pzvauzv(73ii (k8d4mma?

  The diagram below represents the strucwew+(ksn28 i mture of a shoot apical meristem. Which row in the table correctly identifiese8kw+win2 sm ( the processes occuring in the structures labeled in the diagram?

  How does meiosis promote variatiob5nu ri *,zdjda;je8 cux, b 8k2t yfd0p37fx2n?

  Which of the following statements is/are correct for3k 2k :8jc+ (fqduzoua meiosis?
I. It is a reduction division
II. It involves random orientation
III. It produces genetically identical cells

  The diagram shows gametes produced p4iu . mz/y xyx1q/cx/z.ra)c 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 formar ne j 5 9zoc8+sl o1(vpe51tm;.jnlof:vvpw0tion of secondary tumours from primary tumours as a 85oj; p vn1:s150w+re nc vllpt9 oz fvjm(.eoresult of the movement of cells?

  How many chiasmata are p il8p bd69t*bdresent in the diagram?

  Which statement is a similarity between cytokinesis in animal aboli (jvy0uzvlr--j ; c,p: p4nd plant cells?

  Which stage of meiosis is matched to the correct descriptpygv(27fbk xf0/ 8v- bzkb6w vion?

  Which statement(s) are true of meiosis I but1uj5il cobngb ) hyr7o7 ng3.od 51ye+ 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 after the first meiotics*d 29yxodndb8q1)c a division. This results in the formation of one large cell and one small cell. What is tb8d q)1d*9 xd nc2syaohe fate of the large cell?

  Which row correctly describes diploid and haploid 9v6aunle2+. ostal:qlz w/p5tm+ j-zcells in humans?

  The following table shows the diploid chromosome number of a range of species. hf7clndg yt0 5o:w el;k,0cf )


Which of these statements is correct?

  What conclusion can be drawn from the karyog,)cpewheb:heqm -u bsq 1/5/yram below?

  Which of the following processes is chap4sk- /ewztsx1o .ou0 0ho 5poracteristic of the meiotic and not the mitot-.o z5w4up1spoot ox00/e skhic cell cycle?

  The diagram represents a bud with a shoot apical m3) wcfg 5uhxk 7)rkxr)eristem.

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) 6k8x7 bkp ki0j,4vhyais 48. Which row shows the correct chromosome number for different cell kh,k4kx p876ja 0iv ybtypes and cell division stages?.

  At the end of which phase of meiosis I does crossing over ;0c vil9dp4vd occur, and what is the outcome of crossing o40 cv ;vi9plddver?

  Which of the following statements does not describe a step in the sod1gch q;gaf gd*9bc37r ium-potassium pump cycle inh* ;7c931ggrgafd cbq the neuronal cells?

  Which row in the table below is trugzuumvkfwoo3: f)* ycfr (0);e of meiosis?

Membrane transport is important(yud6 zzg; nqc34 p/kx for allowing particles to move across the cell membrane and resz3p;yxck(dz / g4qn 6upond 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 regulap ,tco w+94t rpqd7((bl/ixfzted 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 dif3 l/)m,yfgia dzk t) u4bw1pi+ferent cyclins during the cell cycle. Which cyclin is involved in prepmfuwg t1,/yadzii+k)bp 4 l)3 aring for DNA replication?

The diagram below shows chromosomes during meio0a lyceivr-k+cd6)z*, ayh f1.-fo qb6kg4jpsis.

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 sepa2o5+l*g uuy w;flh6e jration of homologous chromosomes?

  The mitotic index of throat tissues taken from 4 different patienl5(w 2syh g5lkts is shown below. Whiy5h5 lws2g( lkch patient is most likely to have cancerous throat tissue?

1.Draw a labelled diagram to represent the process of crossiv6ikf z;5 nrfclz18l1psyl17 ng over.

2.Compare and contrast random orientation and crossing over.

3.Outline the stages of meiosis.

  The image shows an abnormal h;kz9 ,*:lrxj5pwe+ogl nzx8i uman karyotype.


What is the abnormality in this karyotype and its cause?

The graph below shows the relative amount of DNxs57wa a v-+wl1d 4gvlA in one cell during one complete w54l7v a-dv+x 1lgsa wcell cycle. 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 shows a cross between a fo8zy-+:duvz, u:yc wmale cat that is homozygous for brown,-+zzc dy fvyu :8uwo,: long hair and a female cat that has black, short hair.


Which of the offspring has a recombinant genotype?

1.Outline how polygenic traits col;3/j/ owfp/ny1gb 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 chroma 5 6pj)wt vz1-14+ sctpbbucvqtids shown in the ) p5 pv46ts1ctucqbwb1-vz+jdiagram below?

  The photomicrograph shows a pollen grain from L. candidum (Lio.v g,q:plck(2 z0glfhja 93: qj.zlily). Which stage ofckhz ( : lz:f aj9,. 0qg.gi32opvlljq meiosis is shown?

1.Outline the events which would lead to an ind;fic +uwz f,17+ 4nw.xtbl rdk2r :hntividual being born with Down syndrome, which is characterised bwuw;z fl+n:nt hf bdi,4 x2.7cktrr 1+y 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 rytc pctqy 6* ,1gf35mindirect way of measuring plant growth. A study was conducted on white onions (Allium cepa), under controlled c1r*5,6qt g3 tcfy cmpyonditions 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 7*0ek)o7 tjwxjo lp10euyk-z two ways in which cells can divide. The diagrams below show two cells from an organism ow0 1yko*jjt0xe 7 l7u)-pke zwith 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 gekai ;1y3/q 0rjpj p.aone 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 stagepz4 r0j;khmri.jn 9*cs of meiosis. Which row cor4 jz; npic.*kjmr0hr 9rectly names each stage?

  The micrographs show four phases of meiosis I in a plant. In what qy9jf+ g*sp,h ;qoqsput9*c/ y *i4gkorder do these phaq*49gt/gj+ q h si9c;s* yky u*oqpf,pses occur?

Mitochondria are responsible for supplying metabolic ene)vdv4 pmb x133rfat5b rgy in eukaryotic cells. Ib1ra 3pbt v xf3)54mdvn 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 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 st x kz7r+g8mrlry:vy1:ages of the cell cycle in four samples of lung tissuxgr m1yl8 r+7y:kr:z ve from four patients. Which tissue has the lowest mitotic index?

  The diagram shows the dominant cyclin/CDK complexes at different time point xen28zn3a9t (7 xsosc;b ki.as in the cell cycle. Which cyclin/CDK complex activn asx 9(3;t izbxac87. nokse2ates DNA replication machinery?

  Studies have shown that genes such as Cyclin Dependent Kinase 3 (Cry/i*1q *vqsi5fl2j dDKN3) are highly ovf/sd 5j* 1ir*2ivqyl qerexpressed 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 thq i(7apsfv-w -e cell cycle ?