The graph below shows the relationship between maternal age and the incidencej9 p1y ad6brm4hv-v5e of non-disjuncaybp914 v dr 56-evhmjtion. What relationship is suggested by the data in the graph?

  Which stage of meios*yxf6qiz jv mt1f/l (r* u4,cuis is represented in the diagram below?

  The diagram below shows chromosomes during meiosis.d2;q, )vzjj.3 zy o*diz3hpdb


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 numjar-w3 ;ph6xh-xb 54a fll: bnber of alleles of a single gene which would be present in lxa-ar4365 wb;xjbln -fh:h pthe nucleus of a cell as a result of each process?

  Which keyword is matched to the tfcw -q,ea)h- correct definition?

  Which statement(s) about mitosis isz mjjw(v(bb9q18kvx cz5 0ag) /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 cel 0:s - ypktih)-z+*uf v 9ercq3qy6cfrl in anaphase?

  During which stage of mit .9o3q-gbbts a z.ncp.5jhbyf7ir2.posis does the nuclear envelope break down?

  Which one of the following transport proteins only carri6jou5lu88 q/ +6 :j nvejjmjihes out active transport?ej+8u6:io6qj8jhv l /uj m5jn

  Which process does not happen in the shoot apexeis:5ghffm ;ox 9:xt6l 5gbb8 ?

  Which type/s of membrane transport do/does not require energy expenditure? 4 4b7g0om*au+ kv plzz
I. Facilitated diffusion
II. Active transport
III. Osmosis

  The diagram below represeariw: ;k wk-q2. f a0a6,cinmonts a cell with a diploid number of 4. Which stage of cell division is ki-q;6,n o2 rkw mfwca.iaa 0:the cell currently undergoing?

  The photomicrograph below shows a root tip meristem.ud*z myz4p / t cet)11smwj4k: Which of the following sentences correctly defines a mey1w1dk*zmu4 ts/pjmec) 4 zt:ristem?

  When does the random orientation of homologous chromosome pairs occur6gi t1s3ez4j (3pmt74ao us fk?

  Which process does not occurpcne8*q5a es+h04htu during meiosis?

  If a cell with a diploid number-6q3c2xe7lx( rzk nxh of 36 undergoes mitosis, how many chromosomes will be present in each daugh 2 -3xzrn7 cle6hxqx(kter cell after cytokinesis?

  The image shows a micrograph - a48xnj-vvq1 zrf *ifof a cell.


What explains the appearance of the cell in the micrograph?

  Which statement(s) about homologous cy2/9z*ucm,91 lt8ti erpw+b m 4p.ls fvvj n+lhromosomes 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 indivq8qz s(ze.:sridual with Down syndrome.

Which statement is not correct?

  In the cells of a horse (E. caballus) durinei, mg*tk w/dq;v b 89j7uun3zsp/1kzg prophase I of meiosis I there are 64 7ubk/ 9p dq8in3sgmz ;w1* jv/u,tkez chromosomes. What is the haploid number of chromosomes?

  Which arrow is pointing to a chiap8ytt6ut r bbjbs u)(i /e09gd75w:pssma?

  The diagram below represents the structure of a shoot apical meristem. Which6fea +kgixh(9 row in the table correctly idh exk(f6ia+g 9entifies the processes occuring in the structures labeled in the diagram?

  How does meiosis promote variat67z el llcp/*kion?

  Which of the following statements is/are correct for meiosis? 6nwa ku-x+2c*zar r5s
I. It is a reduction division
II. It involves random orientation
III. It produces genetically identical cells

  The diagram shows gametes produced from two)xdrm3w ed y5on+(7h q 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 from primary tumours dno iu(,q)0jcas a result of the movement oio ,q )cju0nd(f cells?

  How many chiasmata are present in the diagrorx i5./b *l0ci )kfdvam?

  Which statement is a similarit/px*fc( / v6upbtm 3poaaee.- y between cytokinesis in animal and plant cells?

  Which stage of meiosis isy8w t, 6eq)ejv matched to the correct description?

  Which statement(s) are true of meik(jk5- xq 546zsiekdh5ezy +hosis 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: q sgx cq+/4momv59gk.l)iau an oocyte after the first meiotic division. This results in the formation of one large c xas9g.ok/u5mmc g)il4+q qv:ell and one small cell. What is the fate of the large cell?

  Which row correctly describesu ua*5xv08k vq diploid and haploid cells in humans?

  The following table showscl )ns:mb+d1gxsgtcw 1( cr+ 1 the diploid chromosome number of a range of species.


Which of these statements is correct?

  What conclusion can be h9h9)zgi3 +b erqow(ydrawn from the karyogram below?

  Which of the following processes sl *u5 gr p:h.2vb06 ipemvad-is characteristic of the meiotic and not the mitotic c d-pvl0sv ph*5gu2e bm:ri.6 aell cycle?

  The diagram represents a bud with a shoot apical meristemsv 10rgox tp;7.

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) is5jkq+ rdm rz;*yr/ )ki 48. Which row shows the corrz ;*r5rkikjrmq+ dy /)ect chromosome number for different cell types and cell division stages?.

  At the end of which phase of meiosis I does crossing over occur, and whathw*p/x / yf(pt is the outcome of crossi hxf/(t pw/*ypng over?

  Which of the following statements does not describe a stev 03 :q:f 46qymo-pt*;r )chproohevop in the sodium-potassium pump cycleeovfpc4hq r* 3p:ov 0-rq6y; omtoh :) in the neuronal cells?

  Which row in the table below is truh;.wb 8mxreo *n ,b0mfe of meiosis?

Membrane transport is important f vg5 -uld5h5q)j,bvb for allowing particles to move across the cell membrane and respond to changes in the chemical 5 l)budf5b ,hgq- j5vvcomposition 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 regulji1nhf4 v4zfcb.1z1wc9b0 kqated 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 diff7mvq 2kb+ccnk5roav4 g 1c8dpb0t*4d8 moe2ferent cyclins during the cell cycl n m47kcacoo2rkd01mgcb2vt4+qbd f5*8pe8 v e. Which cyclin is involved in preparing for DNA replication?

The diagram below shows chromosomes during meiosis. ek jxfb)yp x -7rm51p0

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 meiosiswpj,2ql4 v hanw1d* f* involves the separation of homologous chromosomes?

  The mitotic index of throat tissues taken from 4 different patients is shown beo8kgiwez3 -2g5d h:jclohk5g3wi j:g dec 8zo2-w. Which patient is most likely to have cancerous throat tissue?

1.Draw a labelled diagram to represent the process o,;aben ) bnk) u:(p oh.l1/pli xiyuu(f crossing over.

2.Compare and contrast random orientation and crossing over.

3.Outline the stages of meiosis.

  The image shows an abnormal human karyotype. lr bq.b j-biiqd1/vo9 xg )rq- gnjlt3;5i5u.


What is the abnormality in this karyotype and its cause?

The graph below shows the relative amount of DNAms eubhgg+-fw 4:i7n6;; bgpg in one cell during one complete cell cycle. Each letter represe 4-; h +m7ggw6gbupsfg in:eb;nts 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 browdg84 raq/ wq4fn, a4qf4/dg8wr q long hair and a female cat that has black, short hair.


Which of the offspring has a recombinant genotype?

1.Outline how polygenic traits can show a norl,ih tyiat-/,mal distribution.

2.Outline the differences and similarities between homologous chromosomes.

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

  Which gamete can resulty+l ,yca09c1nsf 1d izb;jb 5z from the crossing over of non-sister chromatids shown in the dia d 1bc,sf+nyl acjyiz9z1b50;gram below?

  The photomicrograph shows a pollen grain from L. candidum (Lily). Which stag fb2.exp6h w+0 c7sfsee of meiosis is showf+e.f76cxwshp b2 se0n?

1.Outline the events which would lead to an individual being born with Down ccd,:1ub(wen syndrome, ucwceb1, (:dn which 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 gya;4 kp8 h;1,bi.gqvsp(bt mdrowth. A study was conducted on white onions (Allium cepa), under controlled conditions in a lab, to investigate the effect of soil pH ohb; .vq a4 (t1bkp mpysi;8,dgn 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 diagramsjhes5 ymy/-h/ below show two cells from an organism with a diploid number (2n) y mj h-s//hye5of 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 growt)w-kqssxt d*m.r3m 5qh.

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 numnzuav* ) +7sbbco 51qnber of 8, in different stages of meiosis. Which row correctly names eacc)1nzb qo +anubv 75s*h stage?

  The micrographs show four phases of sbrk4 bz4lm. 0 13 jryay bb9h4el-,uwmeiosis I in a plant. In what order do these phases ocr4 bw, s- m4zb9.0huj3ylyr4a e b1klbcur?

Mitochondria are responsible f 8e:rzc;ajq2 mmdz9n.df +6 rlor 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 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 izq+e8md n6a m 2r. lfcrd:9;jznfluenced 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 cycle i;akz (hy546ou vzxd1gn four samples of lung tissue from four patients. Which tissue vzaxo u zd; 6k5ygh4(1has the lowest mitotic index?

  The diagram shows the dominant cyclin/CDK complexes at different time pptl/ q+p nb6(b /0tjguoints in the cell cycle. Which cyclin/CDK complex ap b +ujtb/lqgnp6( t/0ctivates DNA replication machinery?

  Studies have shown that gfkwpfohy2:4cu(3 mc+enes such as Cyclin Dependent Kinase 3 (CDKN3) are highly overexpressed in ce+3kfwumfy2 op:c( h 4crvical 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 0 3r a32w)cukqprq- nsof cyclin E the highest during the cell cycle ?