The graph below shows the relationship between materh orc7ky axa/+1gx,g5gr 0y5 snal age and the incidence of non-disjunction. What relationship is suggested by th ggr/ oksgyh51xcxy+,0ar57a e data in the graph?

  Which stage of meiosis is represented oi4d +5enj:8f. e bdbjin the diagram below?

  The diagram below shows chromosomes6 shoy 1pm)t6h 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 allerj;j/kf:yf0oeb 8 x2rles of a single gene which would be present in the nucleus of a cell as a result of each 8bre0kf2jy / ;fj xro:process?

  Which keyword is matched to the cor:*t4bh oe7wh zmn)ir- (zbo3 yrect definition?

  Which statement(s) about mitosis is/aref ewu.q/p,ztytd, o0+h. /swr 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 1+2gdqcxf/ mu3m+bam f:ehtd,ttbdae 0a709anaphase?

  During which stage of mitosis does the nuhsclec3c ,9oz2z ,u.n9toks/yn*b i 4clear envelope break down?

  Which one of the following transport proteins only carr s5hz47um2olob dv( -2sdvd9ties out active transport?v od4 bu7hmsd lo2 tsd-v259(z

  Which process does not happen in ti(b ujkevbjw) 59u;r7he shoot apex?

  Which type/s of membrane transport do/does n35wc7yz3i v;p ,kw1zn0d jjleot require energy expenditure?
I. Facilitated diffusion
II. Active transport
III. Osmosis

  The diagram below represents a cell with a diploid number of 4. Whicheld exxf0/i9 d 74ez8ihd;v6ann2 uv 5 stage of cell division is the cell cu; id8v efna 0deiz 57e/ hvxnlu294dx6rrently undergoing?

  The photomicrograph below shows a root tip meristem. Which of the followilt sf,3 /*tbj nrv: )h;geie5a;z4d ssng sentences correctly defines a meriste*/t rzsifge5l ;s s ),ba:hj;4de nvt3m?

  When does the random orientation of homokk03 hjo;4b cr4ocw5;bma7 fllogous chromosome pairs occur?

  Which process does not occur during meiosi)pufqf/; 1;bfq0/1vt,k c:j b etalbms?

  If a cell with a diploid number of 36 undergoes mitosis, how manyl-m c z+eu3fauk7g snzu05+a3 chromosomes will be present in each d0-+5 uaen fu3gk+sc u3azlz m7aughter cell after cytokinesis?

  The image shows a micrograph of a fkc 60r iw4adpw9(jlvp.7mu- cell.


What explains the appearance of the cell in the micrograph?

  Which statement(s) abou1i /4)7 e bth3rrgn+cyvb d;eat 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 syndro gmfr)4t3( 3qe cpq6ukme.

Which statement is not correct?

  In the cells of a horse (E. caballus) dudput0x,d ts;2f;+s 3 pjjc r3zring prophase I of meiosis I there are 64 chromosomes. What is thpdd;02tzf s3 rcj,s p u;t3+jxe haploid number of chromosomes?

  Which arrow is pointing to a,ob(5x+hgn9 sd1k th7kmofop:a)qp 8 chiasma?

  The diagram below represents the structure of a shoot apical meristem. Which row9,gmmq y.y .le in the table correctly identifies the processes occuring in the struyy ,. 9q.gemmlctures labeled in the diagram?

  How does meiosis promote variatiox,3fdbd uu*u)5iig 1a -ff-bu5b 8h ybn?

  Which of the following statements is/are correct ) fovrw/ftm) d/6gp - 21wqwnnfor meiosis?
I. It is a reduction division
II. It involves random orientation
III. It produces genetically identical cells

  The diagram shows gametes produced from two5gcdmldcwl7dr :1s lp22kl2 2 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 of secondary tumours z7uq/;pcdou9 v 13z os6ub /ivfrom primary tumours as a result of thu vq39uszz7c pu;o/ 6ob1vdi/e movement of cells?

  How many chiasmata are present in the diagram?8lf8d :t* aqvz

  Which statement is a similarity between cytokinesis dx224vb7fnz e in animal and plant cells?

  Which stage of meiosis is matched to the correct desco h fmwxph.ndx ..x p)g)nd0/7ription?

  Which statement(s) are true of meiosis I butm6kl7tsc4 0yw 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 meiotic division. This resultsh(5,co ;t)x fpcs o1-zav./d a,/resvsn6waq in the formation of one large chv a/fo-; w6d(po. )/v,e,q stscraz an15scxell and one small cell. What is the fate of the large cell?

  Which row correctly describes 7yaqyk+ f ip 7yua4em8e8w5kr 3r/ h(xdiploid and haploid cells in humans?

  The following table shows the diplo .f/un5 ;qzq:rqnm. 4lstpbh8id chromosome number of a range of species.


Which of these statements is correct?

  What conclusion can be drawn from the karyograc2855cjmirnk1 ray+ ym below?

  Which of the following processes is characteristic of the memj)5n9, x rpe9sw wk u,c k+bra7.z5wdiotic and not the mitotic cjrrk 5 5b)m7c+zsp9d a .xk9 wnue,ww,ell cycle?

  The diagram represen hsc( 6+1lxkaets a 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 chimpanzee (Pan troglodytes) is 48. Which row showsr:vpgn g/)6v h7nri( p the correct chromosome num g( prgnvvi:h)pr 7/6nber for different cell types and cell division stages?.

  At the end of which phase of meiosis I does crossing over occur, and what is the370ljqgdvtt, n7c 2 cj outcome of cro,nt07g7cj vt jd 2lq3cssing over?

  Which of the following statements does not describe a step in the sodium-pox.((xbb+c1gznuxjwiw f9h. 9 tassium pump cycle in thfwwgbx j.+ n9. b91(xci xzuh(e neuronal cells?

  Which row in the table below is tltp na32 ymc7p2pp(v*rue of meiosis?

Membrane transport is important for allowing partihw4xq.q4 xz-scles to move across the cell membrane and respond to changes in the chemical composition o-z .xwx 4sq4qhf 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 ish)2mtk( uoc6f regulated 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 dir7rff2y7kw3ic,a t:m05mz n( jw6g gt fferent cyclins during the cell cycle. Which cyclin is involved in preparing for DNA rjk5nf7yraztc 0 m3tg2w g, (i:f m6rw7eplication?

The diagram below shows. dc h(t3n mpw,m-h j9ddyz:z, chromosomes 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 invoxq:7l ,,xf;up dvvsy0, y3isc lves the separation of homologous chromosomes?

  The mitotic index of throat tissues ta j)g((ou-1s7(rgfone bi4e 3id awg3iken from 4 different patients is shown below. Which patient is most lrsw a31)3idb u( e( 7g(ifn4jg-go eoiikely to have cancerous throat tissue?

1.Draw a labelled diagram to represent the process e4xl 5i;or:1g f 3clplof crossing over.

2.Compare and contrast random orientation and crossing over.

3.Outline the stages of meiosis.

  The image shows an abnormal human 5 4lpg4rdo e1ckaryotype.


What is the abnormality in this karyotype and its cause?

The graph below showsyp,+ouwc 0au* the relative amount of DNA in one cell during one complete cell cycle. Each letter repru cwu0yap+ *o,esents 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 that is homozygous for brys e 6g.y wkuxft21 cffw3150gown, long hair and a female cat that has5 tf k0gfcx1f3u 6ywge1.2wy s black, short hair.


Which of the offspring has a recombinant genotype?

1.Outline how polygenic trm6jpm7w+)6sefd+) htep 6qfm aits 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-siste7h:8,6lv m/jlph,x/ j mnbygyr chromatids shown in th nbym6mp:/lh,78yj jvx/gh,l e diagram below?

  The photomicrograph shows a pollen grain from L. candidum (Lily). Which stage ogamz65 xzhj1 3f meiosis is1zmx5jh3 za6g shown?

1.Outline the events which would lead to an individual bey93ezg6o, vm oing born with Down syndrome, which is characterm v 9yo,zeog63ised 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 indirectelbbvg0x 0 u07ms9a 0y way of measuring plant growth. A study was conducted on white onions (Allium cepa), under controlley9u7e0x0 b 0b0s vlagmd 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 divide. Th gp:.x1jd,aca8l s wtxgw 8)u/e diagrams below show two cells from an organism witx,saja 1ggw p:.dlw 8/)x c8uth 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 genyq4l*8g7 yrut r5 ozs.e 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, wita lp, :jjrs+b rym6 y+iv*a4i6h a diploid number of 8, in different stages of meiosis. Which row correctly names each :j,+y *a+y rsvljb64 rm pi6iastage?

  The micrographs show four phases of meiosis I in a plant. In what ,br fm+ljry54da v c,4order do these phases ocm 4al5jr vfbc,d+,ry4cur?

Mitochondria are responsib m/n,ra1fru -s bkd8g/jhv+6rle for supplying metabolic 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 caseg/- rmur ab,/8kv+f6nh1jds r 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 differ gtr-5)zwzl6y ent stages of the cell cycle in four samples of lung tissue from four patietz -ly5gr )wz6nts. Which tissue has the lowest mitotic index?

  The diagram shows the dominant cyclin/CDK complexes f 5*8r28:g pe, y gwkko7korieat different time points in the cell cycle. Which cyclin/Ckeyp72,:8*r ko5gw f rg8okei DK complex activates DNA replication machinery?

  Studies have shown that genes such as Cyclin Dependent Kinase 3 (CDKN33wog2. duc 5 qn1ehzge.(q wcj1lr6q3) are highly overex1.3ug j5dce.z 6 h(nwq1 eqlg2rqcwo3pressed 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 ug 34snvf(icw -js1(jof cyclin E the highest during the cell cycle ?