The graph below showsim:8 tm-o*oe k* aog;oab(eq oh6s2 0i the relationship between maternal age and the incidence of non-disjunctio oioam; 0io6ht*2 a(o*ebsoeg: -q8kmn. What relationship is suggested by the data in the graph?

  Which stage of meiosis is represented in the diagram below?(ask75kh a)p e xpb.v- aj/oq3

  The diagram below shows chromosomes during meiosis04:59zcvcn7v wcakgs .


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 states6kpb*x. x 1rne*awkj0 the number of alleles of a single gene which would be present in th kek*jp* .x1xnb0rw a6e nucleus of a cell as a result of each process?

  Which keyword is matched to the correct definprwi5je7aj/ -dxucx, 53 2fto ition?

  Which statement(s) aboqdu(o1v ynk.)) x1rqu ut 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 le+sm/ 2 jimu(ws* ie;foc *qj:atter points to a cell in anaphase?

  During which stage of mitosis does tr:;ctg okb:pq 3-,hv phe nuclear envelope break down?

  Which one of the following transport proteins only carf5 9x-ft.hax wries out active transport?5xx .ha-f 9twf

  Which process does not happen in the shoot s5r j;.gedxf,o7 gphge zw1 29apex?

  Which type/s of membrane transport do/does not require energy expend y- zdzh /n3 kh-bd9gg(n51pexa+; xlviture?
I. Facilitated diffusion
II. Active transport
III. Osmosis

  The diagram below represents a cell with a diploid numb2srw-utlq5 b /er of 4. Which stage of cell division is the cell currently underl2ru-5 wqs/btgoing?

  The photomicrograph bel (e2*+ogsvwz(g33g w2db g gkeow shows a root tip meristem. Which of the following sentences correctly defines a mer*g(zgges3d 2 v2wog+ek 3w(bgistem?

  When does the random orienu y q,ud0wkbczn4 m3:,tation of homologous chromosome pairs occur?

  Which process does not ocyww*e1 cwp r cyphoa+:f+ :81zaw-wy- cur during meiosis?

  If a cell with a diploid number of 36 undergoes mitosis, how many chromosomes w7nuhfioqhx/(tb7 / qzf4g/ 0t ill be present in each daughter cell aftert( /o/qf4if zh/707 hbn uxqtg cytokinesis?

  The image shows a microgrqedi+uf 6o i/(aph of a cell.


What explains the appearance of the cell in the micrograph?

  Which statement(s) about homologous chromosos6v 2:irtr0 oqmes 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)3p0g pakp/dioo9p wi 3o2ic,me.

Which statement is not correct?

  In the cells of a horse (E. caballus) during prophase I of rz l29yw)t v2gmeiosis I there are 64 chromosomes. What is the haploid number of chromosomes?zvy2 gt9lr 2w)

  Which arrow is pointing to a ch*p4snqt-ra 0b 6p8lw,)eek mpiasma?

  The diagram below represenoo97tl yj3m+it/9rl zts the structure of a shoot apical meristem. Which row in the table correctly identifies the processes occuring in the structures labeled o9t3y+jz9rli ml7 /toin the diagram?

  How does meiosis promote variat -,otxd/ku5cvion?

  Which of the following statemen)y 6zg-jmk5f6)hxg; zhx l *3 1fkjnjots is/are correct for meiosis?
I. It is a reduction division
II. It involves random orientation
III. It produces genetically identical cells

  The diagram shows gametes pror549,gy6at x znw5cqbduced 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 ,)wue*x f spd8the formation of secondary tumours from primary tumours as a result of the movement of8su*pexd ) ,fw cells?

  How many chiasmata are pro deex7nq(5o/avu:15/jpc bf esent in the diagram?

  Which statement is a similarity between cytokinesis in animal and plant )3e,sfx *adn mcells?

  Which stage of meiosis is matched to the correct descrip s/d(xb:(nti;b hptlek 7(so)tion?

  Which statement(s) a,: 01xp6cnhahp6t hvmre 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 oocyte after the first meiotic division. This resulg oe6 5rfi.sx9ts in the formation of one large cell and one se6isfr9 x5.gomall cell. What is the fate of the large cell?

  Which row correctly describes diploid and haploidh 8e-wnbv7kq ,x; 4ekr cells in humans?

  The following table shows the diploid chromosome number of a range of speciespv73 ha4wtj 3-mr f.fkmr*tx,.


Which of these statements is correct?

  What conclusion can be drawn from the 9o7at*ogw g ,mkaryogram below?

  Which of the followinf/ n0fjd s,0wvg processes is characteristic of the meiotic and not the mitotic cell cyclsnw0 v/df, j0fe?

  The diagram represents a bud with a shoot apical merisgq 3 -g0b,c.2gcndgmm tem.

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 trogloz7lb49y -kh; shj6gke dytes) is 48. Which row shows the correct chromosome bhe9; szgjl6-kk7y4hnumber for different cell types and cell division stages?.

  At the end of which phase of meiosis I does +nn g/j2* wzn5ggu;9vr gwf 8fcrossing over occur, and what is the outcome*g w9;2+8urgzn5n fvnj/gw gf of crossing over?

  Which of the following statements does not describe a step in the sodium-pota/d kpj, x4nq1mnmd- u,ssium pump cycle in the neuron-qmpd/xm, knu4 1,njdal cells?

  Which row in the table below is true of mexsp0em(ey7w2ye:.1t ( jlx u3qxlck:iosis?

Membrane transport is important for allowing particles tr8rd (ek(q *w,w/qzc m 7emzo-o move across the cell membrane and respond to 7rozzm8qem,ce w- ( kqd/(* wrchanges 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:pf3zkuw htacg9 w806 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 concentrac s 3j72wap-fmtions of different cyclins during the cell cycle. Which cyclin is involved in preparing for D jf3sa 2c-m7pwNA replication?

The diagram below shows chromosomes during t: mc9 g,ut5 hn:wbu d-3zfi0hmeiosis.

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 inl +sznfn 8455(kci/hsr4* gq7jc yt knvolves the separation of homologous chromosomes?

  The mitotic index of throat tissues ta5g4oo b4.pmnj v1tqzpcdm.k i9m/ 1a9ken from 4 different patients is shown below. Which patientk4pjd9.1qm9mzao. 5p/g vmi bon41 ct is most likely to have cancerous throat tissue?

1.Draw a labelled diagqg2zcx;lui d c i))yk93w. l4yram 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 h7 .wvdk9xklb 6:47vxo 3psy, -lek dfmuman karyotype.


What is the abnormality in this karyotype and its cause?

The graph below shows the relative amount of DNA in one cell during ox/qc5*4dbug*v4pp jm ne complete cell cycle. Each letter represents one stage o*m4b c4pv *uxqpdjg 5/f 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 betweeur0by fyv5,/o0biiu u5v; t.k+x c4wzn a male cat that is homozygous for brown, lb5ofv5viuy+ rz;i x0.ycu u wkt /,0b4ong 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 normal diwdb n,w ))zlctn(cf ,8stribution.

2.Outline the differences and similarities between homologous chromosomes.

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

  Which gamete can resuq3qkqs s 2wk 4oy8h2ku3)4asrlt from the crossing over of non-sister chromatids shown in the diagram bekw2r)3q qkq 2s4ku8 y4o3as hslow?

  The photomicrograph shows a pollen grain from L. candidupr,t 6lhi(3c mm (Lily). Which stage of meiosis is show3il,pr6 ht m(cn?

1.Outline the events which would lead to an individual bde:kg6e .;+nx kpo)sc eing born with Down syndrome, which is characterised by the presence of three copies of chromoge)6kskd xne + po.c:;some 21.

2.Explain how meiosis increases variation.

3.Outline the stages of meiosis.

The mitotic index is an indirect way of measuring plaj /qz6wnuh:i: 2d)q 7abb1waunt growth. A study was conducted on white onions (Allium cepa), under controlled conditions in a lab, to investigate the effect of soil pH on the mitotic id q1zqn:wbhaj:67 ubw/a2u)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 dividen8189mbe eb xe. The diagrams below show two cells from an orgbex88m1ebn e9anism 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 gene expression in stj2cg (p1w.if- wbhy1 rem 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, withoq4i-j 0wd) qg a diploid number of 8, in different stages of meiosis. Which row correctly names each stage? )d i wj0g-oqq4

  The micrographs show four phases of meiosis I in a plant. zi7 crd m,t5:gIn what order do these phases occur?:i7cgmr 5 dzt,

Mitochondria are respo yt2(b hxf*yzvd*z(mw8 qz ;h9nsible 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 *yfbz*tv8mz yxhq(;2 z9(whd 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 numbe+ dg)*bfnxx l2r of cells in different stages of the cell cycle in four samples of lung tis +blg)*x2xnf dsue from four patients. Which tissue has the lowest mitotic index?

  The diagram shows the dominant cyclin/CDK ru+h ;hvuxp yi8 b;)8jcomplexes at different time points in the cel;ub8yi +v p)hrjh x8u;l cycle. Which cyclin/CDK complex activates DNA replication machinery?

  Studies have shown that genes such as Cycl-uud9lr:u9 4hk ykguh-3 ub:win Dependent Kinase 3 (CDKN3) are highly overexpressed in cervicu yrub9:3:- w9u lduhgu-4khkal 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 tkch32o vr+32j:kv:5 et ebiezhe cell cycle ?