The graph below shows the relationship between maternal xn tt flgc g3sfs (8u1fdy8 +1faz72q:age and the incidence of non-disjunction. What relationship is suggested by the data in the graph? 3u 8asy: s1ftzl gf17(d qn8+xff2gct

  Which stage of meiosis is rep3nv*xra(vz5f//p uuxfw j(x-resented in the diagram below?

  The diagram below shows chromosomes during meiosis.o:j czpcb jd)z8q:)r3


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 y9kbq c:0lmhr7jp6g, number of alleles of a single gene which would be present in the nucleus of a cell as a result of each pro9 p7m6 ,rq:kg0hjylbccess?

  Which keyword is matched to 4-bppmk2rj -i the correct definition?

  Which statement(s) about mitosis is/are true? bon+8b *u6j lp 492s+fyxv; ai y-wkpz
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, lbfi0twb562-q fyid5vwd5/ewhich letter points to a cell in anaphase?

  During which stage of mitosis does the nuclear envelope break down?gv4kqb m6es u .5z/b9q

  Which one of the following transport proteins only n-mwds+ lqn2 9carries out active transport? w2qndnls9m+-

  Which process does nx7+iu tnd8u.umu7ec gq 5jq4 ,ot happen in the shoot apex?

  Which type/s of membrane transporud f*3nv5a b10gzd b2 mh7oot8t do/does not require energy expenditure?
I. Facilitated diffusion
II. Active transport
III. Osmosis

  The diagram below represents a m6 9 vm/y*ahxmcell with a diploid number of 4. Which stage of cell division x /m*a h6mv9ymis the cell currently undergoing?

  The photomicrograph below shows a root tip meristem. Which o1ryy;9btx. r wf the following sentences correctly definwr r9y;x1bty .es a meristem?

  When does the random orientation of homologouq8i(2*bc kw os3hgq 2as chromosome pairs occur?

  Which process does not occur during meif 1feh)-v j,e w+93f.(zegz5 ylxsqrposis?

  If a cell with a diploid numpe9,usiy 0ij 8ber of 36 undergoes mitosis, how many chromosomes will be present in each daughter cell after cytok, p 8yis9euji0inesis?

  The image shows a micro un67g;1hhaanq3l,e;a 4op xmgraph of a cell.


What explains the appearance of the cell in the micrograph?

  Which statement(s) about homologous chromosomes is/are nv.)i dg5vsm da 7o (. 0rc)cwmpfx0ir1ot 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 witn:kz+nnu xo +/hv (xk/h Down syndrome.

Which statement is not correct?

  In the cells of a horse (E. caballus) during prophase I ofdr//. wj n3p ubl9idt3 meiosis I there are 64 chromosomes. What is the haplodt9 3.pn 3/rjb/lwud iid number of chromosomes?

  Which arrow is point-xrep u /yisg n6e3/y2ing to a chiasma?

  The diagram below representsaq(x oinzds k.y;c.wi3e ./,s the structure of a shoot apical meristem. Which row in the table correctly identifies the processes occuring in the str xzaoi; . e/y.3(.ssdwqcki,n uctures labeled in the diagram?

  How does meiosis promote varu,p6 x,0g7) 6q xzp8 jk .eeqnkqauz0jiation?

  Which of the following statements is/are coi b45azrxu3ca+ )rk /crrect for meiosis?
I. It is a reduction division
II. It involves random orientation
III. It produces genetically identical cells

  The diagram shows gametes produced fw(h6dva .*fj x;t.z jzvhq16b rom 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 formation of secondary tumours from ,c/ha5 wp /id l)mz2caprimary tumours as a result ofwma)l 2id ,zach /p5c/ the movement of cells?

  How many chiasmata are present in the dize2 e* ur)hnrit5;yw1 agram?

  Which statement is a similarity between cytokinesis in animal and plant kon5sdhh x.2.mw w1k8cells?

  Which stage of meiosis is matched to the corre 8isjy7wv(v0w h :kxha95w ;nwct description?

  Which statement(s) are true of meiosis I but not meirg,c3 y4skac a, yq+ox7yid :zh;4 :ososis 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 meiok3ezfd063boi4db qr/l- l 6mrtic division. This results in the formation of one large cell and one small cell. What is the fate of the fdb-zrb/l063lok4 3r6m iqde large cell?

  Which row correctly describes diploid and haploid cells in hu07lv m epcu2ux2cvom rt( 1v*y-kz/.jmans?

  The following table gz.j wzy. liueo15+4o shows the diploid chromosome number of a range of species.


Which of these statements is correct?

  What conclusion can be drawn from the karyogram belo;3i/424k0qqv ccem9hrma syp w?

  Which of the following procie epj,-,wdn*73uur cesses is characteristic of the meiotic and not the mitotic celc, p3n,eu7*uidw jre-l cycle?

  The diagram represenr:1.osk3hbm h ci6: pwts 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. Whimsi5f 5ezy: kru9.bj*ch row shows the correct chromosome number for different cell types and cell division stages?.uer: z9ijbk*yfs5m5.

  At the end of which f+jrli tti1hw 3)b1o27 4k ec -ij3iujphase of meiosis I does crossing over occur, and what is the outcome o 2k)fjhl1bo- +ijtirt1e33j c7u4wiif crossing over?

  Which of the following av071l1dzn 4azudf p4,yjr 7 -t 6ncuestatements does not describe a step in the sodium-potassium pump cycle in the neuronal ce efyp n4-uald4,nt 7uva7 6101jz drczlls?

  Which row in the table below is truio7 4fh(ce; a* bul9nre of meiosis?

Membrane transport is important for allowin(8rn: m- fktwhg particles to move across the cell membrane and respond to changes in the chemical composition of th ntk8wr-( mhf:e 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 in cellcyx 1o cbmg3 jse-f,n ,5-r5bls.

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 concentrations3 sd -z4(t,i k 9w:/us9tclfcp*s uizj of different cyclins during the cell cycle. Which cyclin is involved in pftuck zzc*3tup99 (i:i-/s sjw,dl4sreparing for DNA replication?

The diagram below shows chromosomes durindnl6vp5jd e(yp w701thqlm 7 8+ cuz1ng 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 involves tri4b zowi 8nl,u0e .tru,g3o2he separation of homologous chromosomes?

  The mitotic index of throat tissues taken from 4 different patients is-bqq y8u 1a 5;nkvwd.v shown below. Which patient is kyb.dqn-avq v81 u ;5wmost likely to have cancerous throat tissue?

1.Draw a labelled diagram to represent the procet.wy v3kp( .ydss of crossing over.

2.Compare and contrast random orientation and crossing over.

3.Outline the stages of meiosis.

  The image shows an abnormal huma-/ -pch z:lccmo)1h s-1ziafjn karyotype.


What is the abnormality in this karyotype and its cause?

The graph below shows the relative amount of DNA in one cell during one cot2v87fpy )ah/tujy /v vc8i(gmplete cell cycle. Each le uv fp8(ji/v)c ttay27gy/h8vtter 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 male cat that is homozygous f .bdwo1 ri.(un + pz(f6dxq9ykor brown, long hair and a female cat tkyo. .n9(ru+wx iq6(fz d bp1dhat has black, short hair.


Which of the offspring has a recombinant genotype?

1.Outline how polygenic traits can showop4l f/4+l2 ahx(cdlh 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 wla oq93.) a8qxjue;t of non-sister chromatids shown in the diagram9 ojaqaqx;l)w38u.te below?

  The photomicrograph shows a pollen grain frop)0 z;jfqzj2f2 a hd,gm L. candidum (Lily). Which stage of mgz p;2d fa qjj2)hzf0,eiosis is shown?

1.Outline the events which would lead to an individual being bo;seqk jut wp:zny77, xi bjp;wj3t9 84rn with Down syndrome, which is characterised byq, t7yt3s ek:z 4 pj7i8;jpwx; jnb9wu 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 growth. A study was coi ;cid)) 0gwudnducted on white onions (Allium cepa), under controlled conditions in a lab, toi;i gd)d0 uw)c 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 wae0nue8)) zf1ear 7q qqys in which cells can divide. The diagrams below show two cells from an organism with a diploeu )q 7rqnq)f10z8aeeid 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 expressi dytvlb z2 acw1/:6n)qon 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 dyc7 ,-rj( mxewifferent stages of meiosis. Which row correctlyw jm(y, rx-ec7 names each stage?

  The micrographs show four phases of meiosis I in a plant. In je3wx0b(ko r1xz g +;mwhat order do these pha+mk0( bzrg;3 e1oxjwxses occur?

Mitochondria are responsible for supplying metabolic energy in eukaryotic cellvsu :k:iq 4t;xs. 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 pai 4 kxs;q:v:turents. 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 stages of the cell p4hm6 vq.,w 5y- t8mvgczz3q ocycle in four samples of lung ovv58wqmh6.z gp tyqm -z4c3, tissue from four patients. Which tissue has the lowest mitotic index?

  The diagram shows the dominant cyclin/CDK complexes at dcg 59f d/rh*suifferent time points in the cell cycle. Whhru/cg 59s *fdich cyclin/CDK complex activates DNA replication machinery?

  Studies have shown that ge.ek6at5swh1 4y kwbiw) lj+9snes such as Cyclin Dependent Kinase 3 (CDKN3) are highly overexpressed iwe6lb9w )kya4j.1st+i5swh kn 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 concentros4r z-dm 4(6aq u+m/yaq.0uemtf r 0gation of cyclin E the highest during the cell cycle ?