The graph below shows the relationship between maternal age and the incidence of;shu)o d2xg -9 ejfrb4 non-disjunction. What relationship is2 x )9;obuhsefd4rj-g suggested by the data in the graph?

  Which stage of meiosisjwd*c*qcj8z b *fuz( + is represented in the diagram below?

  The diagram below shows chromosomes dmw 5dw,)4yd+ lduwy+uuring 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 alleles of a s+*.cnly.pps/d ll-hl(jgr+8 p. owjp ingle gene which would be present in the n pls.p*lcppl h-wyl j(. ro+dj/+n .8gucleus of a cell as a result of each process?

  Which keyword is matched to the correct definv i z/9/yh;uqgvj84qudl 9zh3ition?

  Which statement(s) about mitosi*yn5h5 /jt2px hi)c rns 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 lettrol/ywh,6 rc 8er points to a cell in anaphase?

  During which stage of mitosis does turo) 5,onon/cw h2 )tjhe nuclear envelope break down?

  Which one of the following transport proteins only c,70n,9mwx b8u/ s zoe0p-ss6 b kdutslarries out active transport?9 8l7dbstk,- b 06 /mwxusu0eo,pszsn

  Which process does not happen in 0h/ *olftz0y)nmcfw 5y.qyy 7 the shoot apex?

  Which type/s of membrane transport do/does not require energy expendit0xvsa(w tw9igs m v)u3cnt003ure?
I. Facilitated diffusion
II. Active transport
III. Osmosis

  The diagram below represents a cell with a diploid number of 4. Which stagqyxd3 x6j :6c,e-jku se of cell dij36jsk6 : ,u-cex qydxvision is the cell currently undergoing?

  The photomicrograph below showa w8hy5gxt/d cdi80m jg9 vncgy(mk.a: s1u03s a root tip meristem. Which of the following sentences correctly defines a mew8i5ns8m:( cydu 0/.gg9 tkyv3 h gajamxc 0d1ristem?

  When does the random orientation wk+4 aohek2(hof homologous chromosome pairs occur?

  Which process does not occur during meiosixrf k.0wv) zzv wrixos8:b( /7m,q2 pvs?

  If a cell with a diploid number ofu,c,j;p s9bz).5 zi6pfw vjck 36 undergoes mitosis, how many chromosomes will be present in each daughter cezu9bcpwjk.,,6 jf z)pi;v5scll after cytokinesis?

  The image shows a mi2l2v3* tj-b; sbs ehqqcrograph of a cell.


What explains the appearance of the cell in the micrograph?

  Which statement(s) about homologous chromosomes islg 1/3bx8e) kfig)wpv/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 indivfeqlfp d0h;y*+c4h(2kqts6 qidual with Down syndrome.

Which statement is not correct?

  In the cells of a horse (E. cabdkmq5( bmv m ld*6w)r3u7 ffi:allus) during prophase I of meiosis I there are 64 chromosomes. What is thel(mm5 ib rv)km w6d*3df7q fu: haploid number of chromosomes?

  Which arrow is point af)+6by;ws v;m7pjlj ing to a chiasma?

  The diagram below represents the structure of a shoot apical meristem. Wh fapcs ;g:2ci ,vuow bdeqkpo+0.-w7+ich row in the table correctly identifies the processes occuring in the structures labeled in the diagramcwo2.fe0,ipak+gwsqc 7 v oupb- : +d;?

  How does meiosis promotqp0.tx;( ji5lk z yzj f36*ihie variation?

  Which of the following statements is/are correct for me;k3hid ad bc63iosis?
I. It is a reduction division
II. It involves random orientation
III. It produces genetically identical cells

  The diagram shows gametesnpfr;3da/:n 6l3gpsa 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 forse0 ,m*u0s snbau,,/ ko8miacmation of secondary tumours from primary tumours as m0assb,k/,0* 8ca mu,es oinua result of the movement of cells?

  How many chiasmata are present in the dl9gm4x za *;:mwdrq6 rph( uq,iagram?

  Which statement is a similarity between cytokinesis in animp iyrc 38+v4.o/luzjeal and plant cells?

  Which stage of meiosis is matched to the correctm t,:/ fg8nm 8:w(akeuptg-cf description?

  Which statement(s) are true of meiosis I but not meiosis II? 56qjgg i:cwjx 1dv84 k3 y3mi,equ c+r
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 m54 1,ft nj0juwqe, ksteiotic division. This results in the formation of one large cell and0en, t 4 tju1sk5j,fqw one small cell. What is the fate of the large cell?

  Which row correctly des7 q 6vul2;oscfcribes diploid and haploid cells in humans?

  The following table shows the2bfk:v7(uc v72nrze x) ol (bj diploid chromosome number of a range of species.


Which of these statements is correct?

  What conclusion can b, i0n60z2 gygt lqzewhza k-25e drawn from the karyogram below?

  Which of the following processes is characteristic of the meiotia. ti*; oeg 29exev b+zt*pi(ec and not the mitotgbt2+e(*x*z9iai evotpe e . ;ic cell cycle?

  The diagram represents a bu7 oxh*sc-b ve(ceo5;zd 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 troglodymhm z4qm.io +*tes) is 48. Which row shows the correct chromosome number oi z+4.mm*mhq for different cell types and cell division stages?.

  At the end of which phase of meiosis I does crossing over occur, and what icckg-i3 o2o2b s the outcom- kgb2c3o i2coe of crossing over?

  Which of the following stateme1t 11iaaf8r 2,fvhlg6f ebif5nts does not describe a step in the sodium-potassium p51i,et av12 fbfhlg 86f rfa1iump cycle in the neuronal cells?

  Which row in the table below is true of mei.dp2 wfhrz xu3 xhc9 k3:zp8qta:3/ymosis?

Membrane transport is important for allowingb 4e7eysj* kxuy0 .rx2 particles to move across the cell membrane and respond to change40e.*sx27yr ebk u jxys 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 regulatewtnv 8 m0n0qa(8v5caqd 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 of3of e;*jo7c w7i0*7 lf ,o(gaer f 46yegybrrj different cyclins during the cell cycle. Which cyclin is involved 0yfre6;e7 l cj*w7yrr o7j3a4g eifb*o,gfo(in preparing for DNA replication?

The diagram below shows chromosomes during meemvco ;cxg00m)9 on (z9fefx3 iosis.

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 separation of hk/ oxx p0io4r;omologous chromosomes?

  The mitotic index of throat tissues taken from 4 die9uwo9,.tccx my (y7rfferent patients is shown below. Which patient is most yox um9y9 c.(7t,we rclikely to have cancerous throat tissue?

1.Draw a labelled diagram to represent the process of crossingebg:/ighmb ygnn o,d6(0pcl7y -i0qy32d1 b w over.

2.Compare and contrast random orientation and crossing over.

3.Outline the stages of meiosis.

  The image shows an abnormal human karyot pvbz58l5um am m9)ikl8/hv+qype.


What is the abnormality in this karyotype and its cause?

The graph below shows the relative amount of DNA in one cell during;bgw ,*)-zcixbdnn9e7 g 1jam one complete cell cycle. Each letter represents one stage of the cell cniz9m;*x)cebg- baj g, w7dn1ycle.


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 homocqdunb)a5) k (zygous for brown, long hair and a female c)ankub c5d(q )at that has black, short hair.


Which of the offspring has a recombinant genotype?

1.Outline how polygeni 1yenc7 cdkz 7(wxqz m13a6d+hc traits 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-sister chromatids sxw3k n4e +ubetti /); +fua0cwhown in the diagram below? ;ic4 a fn+k wtext/3)eb0uw+u

  The photomicrograph shows a p)jmx18e/ff xrgzpiy.31b zd+-ws,uv ollen grain from L. candidum (Lily). Which stage of meio m-gb1fd, v re +xx8/zy31s)i zufwjp.sis is shown?

1.Outline the events which would lead to an ind h((gem j:pny)ividual being born with Down syndrome, whiy)p(j gnm e(:hch 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 growth. A study wyk18ih4i* fd9z +v futas conducted on white onions (Allium cepa), under controlled conditions in a lab, to investigate the effect of soil pH on the mitotic index of z89ukt fi4yhv1* +dfi 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 cells4e: ep 6yk )s8derutn3 can divide. The diagrams below show two cells frske6 3tpr) dne 48:uyeom 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 gene expression in stem um h87uw 47e3cv gktr5growth.

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, ift q7s3f3nksmi kj 7bz+ a+8o+-ni2lvn different stages of meiosis. Which row correctly names each stfo q7+ itv7ns za++j-3b32 snfmik8klage?

  The micrographs show four phases of meiozkntb hp g3/suq+7ws+.fv) )jsis I in a plant. In what order do these phases occur? q) vj+.tf7snw/ k sh3uz+p)bg

Mitochondria are res s4 :ppxodc/u2w4,tv pponsible for supplying metabolic energy in eukaryotic cells. In most eukaryotes, which reproduce by sexual reproduction, mitochondrial DNA (mtDNA) is inherisdvppw2t/pcox,4: 4 uted 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 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 difa 3gk3uz:)3xirgu5my-) e z c:mrv hb,ferent stages of the cell cycle in four samples of lung tissue from four pati3uv:3 iz 3 e :,k )mux)acmgzgr-yhbr5ents. Which tissue has the lowest mitotic index?

  The diagram shows the dominant tnx6od ,; 84(e7q-;oua rm+ jwvbpp txcyclin/CDK complexes at different time points in the cell cycle. Which cyclin/CDK complex activates DNA replication machinern ;( p 8q7xrdxbt4+ t;wopujeavm-,6 oy?

  Studies have shown that genes sucht5wi2*qxw1gc as Cyclin Dependent Kinase 3 (CDKN3) are highly twq1 2gi c*5wxoverexpressed 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 of cyclin E the higheswfj9 suae :w09t during the cell cycle ?