The graph below shows the relationship between maternal age anjhtg8r5f n ;7 ;cifpb*-wihbql 0t4y.d the incidence of non-disjunction. What relationship isycf;n7 j5 t8q;hhti0rl bi* w4pb-.fg suggested by the data in the graph?

  Which stage of meiosis isfutb 9i uu+/w)lvkr *3 represented in the diagram below?

  The diagram below shows chromosomes during me4p.rin6iqq7d q; jda4n2v.w eiosis.


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 f601dt w7f zjwalleles of a single gene which would be present in the nucleuzww6dffj 017ts of a cell as a result of each process?

  Which keyword is matched to the correct definitig6sak:xxa s,b u2p .h0on?

  Which statement(s) about mitosi 4d3ypy m53ky+;qf fnh1(pl dxs 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 leth. eb k9*rsl2 v*3nqvlter points to a cell in anaphase?

  During which stage o/zbh7 l8df2n+x 7 qbbxf mitosis does the nuclear envelope break down?

  Which one of the following transport proteins 4-as y;bwab4nj n c7c +qi,w:nonly carries out active transport?:insn c 4;aq7babwy +j c-,wn4

  Which process does not happen in thxr ekq;8 v9v( q8dcv h3adc75de shoot apex?

  Which type/s of membrane transport do/dd8,p*qk ti f;zoes not require energy expenditure?
I. Facilitated diffusion
II. Active transport
III. Osmosis

  The diagram below represents a cell with;. +jr nq8dutb a diploid number of 4. Which stage of cell division is the cell currently undergoiu +jqd. b;rtn8ng?

  The photomicrograph below shows a root tip meristem. Which of the following sez(rhiq /eu1 2 eo-ny6dntences correctly defi6 i-(/hr12yeuqzend ones a meristem?

  When does the random orientation ozl9s* g0 (yrizf homologous chromosome pairs occur?

  Which process does not occur during meiosiiej,c k*o)v3 ys?

  If a cell with a diploid number of 36 undergoes mitosis, howzw 3or fx7;p: n7kntl8wmz,s4 many chromosomes will be present tp78rznw ; 4ows37,l xfzmk:nin each daughter cell after cytokinesis?

  The image shows a micrograpadrflhl,-cp 0i5/xqknn9v0-h of a cell.


What explains the appearance of the cell in the micrograph?

  Which statement(s) about homologous chromosomes is/a+;7ew: im:n 94sosnmfybs(qire 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 syndr1x,ap/mm5z 3y8xzl hwut 57,yh3oplyome.

Which statement is not correct?

  In the cells of a horse (E. caballus) during prophase I of rhbct u gvv8fl nra*;w+42 b1-meiosis I there are 64 chromosomes. What is the haploid number of chrom +clut a2bbv8g *f;wr4r-1hnvosomes?

  Which arrow is pointing to a chias p)9.a0 w/y rx w6iriuwbmp/-mma?

  The diagram below represents the structure of a shoot apical meristem. nds hmt/yp n0*. qb x5s69j(blgo:6atWhich row in the table correctly identifies the processes occuring in the structures labeled in the diagrbl* .jd5p 6gsqbsn (thm6:xyt/ 9oan0am?

  How does meiosis promote variatioesfgy. zf1o5ifo lhiae8 9c2pa1)z85 n?

  Which of the following statements is t k:sd.1oadu )ht;m f*r.cho3/are correct for meiosis?
I. It is a reduction division
II. It involves random orientation
III. It produces genetically identical cells

  The diagram shows gam2) ac: v2mvey ,v 9x;tsavc5ihfv6 h,setes produced 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 formai5iy+u-*2hi m5 2l1rangslip4gc c+ption of secondary tumours from primary tumours as a result ofuip5ci 2yigmsa 4 +g*52chnrp ll-i1+ the movement of cells?

  How many chiasmata are pres5jv-k,wyo uc f/l6lkcj 0)r-xent in the diagram?

  Which statement is a simiypw8pf2atq)3o pb.7fa-eon: 0ql 1v klarity between cytokinesis in animal and plant cells?

  Which stage of meiosi xaszf2i;cny3+ ecf yi ;xe11(s is matched to the correct description?

  Which statement(s) are true of meiosis I but not meiosis II? 5/t0 4ix5 ys7ibjsndy
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 m-p(v kiwsb -m+tj.d)sdl2tji8 y 6 d0zeiotic division. This results in the formatbt.-j0)iw6sik m8(d -vd pl2d+jtszy ion of one large cell and one small cell. What is the fate of the large cell?

  Which row correctly describes diploid and haploid cells in humans eqbr;o-0l(m a?

  The following table shows the diploid chromosomnw0.i0wappgnu;c o2 t;2nam 1e7g0 cde number of a range of species.


Which of these statements is correct?

  What conclusion can bc. 4lp;;r6 0* u uzxbxiyspo0xe drawn from the karyogram below?

  Which of the following processes is characteristic of the meiotic and not ) qz o.n*vl:xk7jqa;cthe mitotic cell cycl7;ockxn .:q) qj*zlv ae?

  The diagram represents a bud with a gqyz5i-o +os4tx2pg sh 2*;obshoot 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 5dbwz448 pgqk3c ai(lshows the correct chromosome number for different cell types and cell divi8(gcl5bw z i q4pka4d3sion stages?.

  At the end of which phase of meiosis I does crossing oveeqn up7qsv)3mi r/fbrv 1zlmq * .+/2ur occur, and what is the outcome ofvuqq*veps7l/.nzq23f+ umbi r /1r)m crossing over?

  Which of the following statements does not describe a ste q0l h+wdrow b/v394tdp in the sodium-potassium+ww4b9t30dhq dvo l/r pump cycle in the neuronal cells?

  Which row in the tablexuc) 0w6/cu .f rc/vdf below is true of meiosis?

Membrane transport ijfjsp/c vu8z/ 8 y -amsc:7tb5vx/kx3s important for allowing particles to move across the cell membrane and respond to changes in thexajcvfs/7pmuyk :bzvj3 s/t 8-/85 cx 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 reqg,/9g(z l(vwx gcc4k gulated 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 concentration orq5;tc i +6jstfke*1s of different cyclins during the cell cycle. Which cyclin is involved in preparing for DNA replica56tjri1qto;* fs+ ce ktion?

The diagram below shows chromosomes during meiosis.ri50dg t9tz uo z:;u2b

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 sepaw*v+u zv3e+ci5mz.va) zm/ yiration of homologous chromosomes?

  The mitotic index of throat tissues taken from 4 different patients is shown bea*s;dop t p+h6low. Which patient is mos+a;hp*6os t dpt likely to have cancerous throat tissue?

1.Draw a labelled diagramlj)8re o1 d8z3rxkh bbtg(6o5 to represent the process of crossing over.

2.Compare and contrast random orientation and crossing over.

3.Outline the stages of meiosis.

  The image shows an abnormal human karyoo1p4it -nr; 9dpwkqc )type.


What is the abnormality in this karyotype and its cause?

The graph below shows the relative amount of DNA in one cell durih-r z6 6ihiv(ijjyrwu , 2/d+xng one complete cell cjyhi,xh2jr 6dui6vz +(w- r/ iycle. 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 crj23 ne6uxtq n*u2:x ejoss between a male cat that is homozygous for brown, long hair and a fema xu3:xujt26e n*eqj n2le cat that has black, short hair.


Which of the offspring has a recombinant genotype?

1.Outline how polygenic traits can show a n 5hx,v h /t9lrvczl;t9ormal 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 crossingx c(pajxw)b-;yao p0 s5c(ag, over of non-sister chromatids shown in cao-apab((x, y;g5)j wc ps x0the diagram below?

  The photomicrograph shows a pollen grain from L. candidum (Lily2ps qak)xxxsg 5h(w)o4v 4-2k *wv qgf). Which stage of o4k4( )w) xsqhv x sg*xw52 -v2afkpgqmeiosis is shown?

1.Outline the events which would lead to hn-4 zcrl;c /m0j-a kyan individual being born with Down syndrome, which is yj nlz4 m-0rck ;hac-/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 ih/e7gi.rkz3 t ndirect way of measuring plant growth. A study was conducted on white onions (Allium cepa), under controlleke3/. 7itrzh gd 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 cells can dividegn o/ k(kfceuv)ss. ::. The diagrams below show two cells fro /kk :sc.e unvf:)(sogm 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 genec9 uec.66bqnw6wrz/l 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 stages c2ltvy2 vi9nzlb*9 y 8of meiosis. Which row correctly names each stagzy2 l9 t9bcnvvyi82 l*e?

  The micrographs show four phases ofdkro+j (x :fi5esvja+; iyi;5 meiosis I in a plant. In what order do these phases oc+v +55id;e ifrj( oy:k;ixsajcur?

Mitochondria are responsible for supplying metabol 6n6+gummvsj. 4ch dp. lyy:f:ic energy in eukaryotic 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 speciessd ln6g+:.pf.yh4mm yujc 6v: , 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 9(b j8xn xq(nodifferent stages of the cell cycle in four samples of lung tissue from four patients. Whi(x(8x n b9nqjoch tissue has the lowest mitotic index?

  The diagram shows the dominant cyclin/CDK complexes at differenwyk.y:w e 8,spt time points in the cell cs:,kyywp.8 e wycle. Which cyclin/CDK complex activates DNA replication machinery?

  Studies have shown that genes such as Cyclin Dependent Kinas.lch3h4;)f/ dwpvuocmdi2 ,je 3 (CDKN3) are highly overexpressed in cervio)dhlhfi p, d j. 4vwuc;m3c2/cal 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 the cell 7r l3ipc)2wqng. g(wjcycle ?