The graph below shows the rylki : i*:fjx go3a1(helationship between maternal age and the incidence of non-disjunction. What relatioyglj ihxao * k:1(i:3fnship is suggested by the data in the graph?

  Which stage of meiosis is represented in tvak99q9xpc dk3q yz:,gy0 p1the diagram below?

  The diagram below shows chromosomes during meio(+x21jzabatzier,2 /qp i r u:ffke6:sis.


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 st o2h*3x6ze tebates the number of alleles of a single gene which would be proe32te*x b6zhesent in the nucleus of a cell as a result of each process?

  Which keyword is matched to the correct def w1 szc*nf x8g4xep5f7inition?

  Which statement(s) about mitos( eoglgdtgthce; , e0rc ;y(:.is 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 letter points to a cell in anaphiqpf5 vc97;wwase?

  During which stage of mitosis does the nuclear ef6 o1dw)4 knvrnvelope break down?

  Which one of the following transport proteins only 4jd3)6psjagr k2vc1 2fulb /fau (/lscarries out active transport?sajs1 l64f )f /gka pvb2l3(r2d juc/u

  Which process does not happen in the sh6xn)+r jwkf/qoot apex?

  Which type/s of membrane transport don+bad2c+0j 9f v7wdil/does not require energy expenditure?
I. Facilitated diffusion
II. Active transport
III. Osmosis

  The diagram below represeqalys*k8it ;:7 )ezxynts a cell with a diploid number of 4. Which stage of cell division is ;8yaz s7 xq*i)tye:klthe cell currently undergoing?

  The photomicrograph below shows a roo 0- nv a1tu7;snv:qvzt tm+5yp68tpzft tip meristem. Which of the following sentences correctly define8 ftazu: ttn qn-mz 56vtv0+sy71vpp;s a meristem?

  When does the random orient 7wzpu k20n mdr d4gqd9h1rd/-ation of homologous chromosome pairs occur?

  Which process does not ocy/) 1 d0 rcn93llr1kbvrhsr9 d,6r knpcur during meiosis?

  If a cell with a diploid number of 36 undergoes mitosis, how : m ns5+: ufha;nphkw1many chromosomes will be present in fp+wns nkm : :ha;5h1ueach daughter cell after cytokinesis?

  The image shows a micro:ax,9o 7rl bzngraph of a cell.


What explains the appearance of the cell in the micrograph?

  Which statement(s) about homologous chromosuu.uz*lity1a-3isu3k z6l d5omes 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 in puzn+c-i1 lcn(*7 4k(x nfwp5b*yhu vdividual with Down syndrome.

Which statement is not correct?

  In the cells of a horse (E. caballus) during prophaseukpia)f1 iey/yr oi* rd//*4r I of meiosis I there are 64 chromosomes. What iype//ra)if1 *irudo4ir yk* /s the haploid number of chromosomes?

  Which arrow is pointing to a p kdo4p,h/ j20ra;mxgn/ . cr7hi)p cie0j)i ichiasma?

  The diagram below repre:1hdlwi 4j/ h4tlq:wasents the structure of a shoot apical meristem. Which row in the ihltjh4/d:lww 1qa :4table correctly identifies the processes occuring in the structures labeled in the diagram?

  How does meiosis promote var/:0fq)*1ln rhz q e)f cntahd1iation?

  Which of the following statements iqp0 l bb-7tz8js/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 produced frbjy,d bu49:,ftvh3 jmom 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 primary tumours asp2xc 1zi( a1cz a result of the movem(zxc1i2acp 1zent of cells?

  How many chiasmata are present in the d 2u6k 5 e,hjaupdv a*j(4emzej 65r5tviagram?

  Which statement is a similarity between cytokinesis in animal apk :e xko4o7bajv:6(z nd plant cells?

  Which stage of meiosis is matched to the correct+)u q:oz1cpo j4jw s3r description?

  Which statement(s) are true of meiosis I but not me49,bp3grai *ulkf2 7fx+ d djeiosis 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 aftq8+m)gon022u rih jajkm +ep8er the first meiotic division. This results in the formation of one large cell and one small cel8ehrg 2omj 0q+2im)p jkn 8au+l. What is the fate of the large cell?

  Which row correctly describes(e diut,ubr u27p 49endg nv*. diploid and haploid cells in humans?

  The following table shows the diploid chromosome number of a range of species. . 1/y/w5 urztyobk55/qtbu x j


Which of these statements is correct?

  What conclusion can be drawn from the karyogram bec-(c 0jew e0jelow?

  Which of the following processes is characteristic of thg igz0oyzo fhs* /b3jky y0428e meiotic and not the mitotic cj3* i fo0g8byzzy/ 2so0ghk y4ell cycle?

  The diagram represents aa1 k)813tkxufo kjl e4h3p 8pn 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 48q+o(,6h*z)r z5 onivd rl 2xwh. Which row shows the correct chromosome number for different cell ( hl6d5niozxqov h,z2) rw*+rtypes and cell division stages?.

  At the end of which phase of meiosi, .q wt,oyn f/5ud(hxum*4lmy s I does crossing over occur, and what is the outcome of crossing o(5xq,m4 *lmh.tu/no , fwyy duver?

  Which of the followinzfuat 7:iv l6t1x0+mmg statements does not describe a step in the sodium-potassium lm izmvt:7+ufx0 1 ta6pump cycle in the neuronal cells?

  Which row in the table below is true of meiosi67-unw v3l htds?

Membrane transport is impor* q6ixwtv m/d,tant for allowing particles to move across the cell membrane* ,xdiqw6v/mt and respond to changes 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 in cells. eb( (crb g00 leelk+y7

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 different cyclins duz7wga;ww c0 n0ring the cell cycle. w7wan0zw0g c;Which cyclin is involved in preparing for DNA replication?

The diagram below shows chromosffcj- j4 op9v4omes 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 invol4e-la l fqhyoos3/2i v-)* rolves the separation of homologous chromosomes?

  The mitotic index of throat tissues taken from 4 different patients n+, xhfd+e.ypis shown below. Which patient is most likely to have cancerous thro.,+f+h py dexnat tissue?

1.Draw a labelled diagram to repr,04hsm 92bcog)jxuhp okl+x2ou z.9v esent 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 human karyt.-v5-mn jlsu yye-+afx 5d3 xotype.


What is the abnormality in this karyotype and its cause?

The graph below shows the relatim., x3-7oeci6ixk-q5 6au xlc; v( riagd5zgyve amount of DNA in one cell during one complete cell cycle. Each letter aa xiez .u;ro i3-6 ix mv5lcg,d 6k7y-5c(qgxrepresents 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 homo w,ez) -v*s((vtpip.d ea p zk/q-+vxczygous for brown, long hair and a female cat that has blavpp )tai+(cw p.- de /k(x,v sqev*-zzck, short hair.


Which of the offspring has a recombinant genotype?

1.Outline how polygenic traits can show a normal distribution.q109n*iw p3cb ey,eku

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 chromatx p20xx5mbvg8ocmfw ;u17myb+j++2nnl q m s;ids shown in the diagram xnmx + mfo2+ cw7bn521uylsb0+;xjvm;qm 8pg below?

  The photomicrograph shows a pollen grain from L. candidum (Lily). Wrdrek vqvf73/6 r8 0zevthh54hich stage of meiosis is v eh / eqfzdr607r48v53r tkhvshown?

1.Outline the events which would lead to an individual being born *bda63dnv: +sh::u*nb dtt sgwith Down syndrome, which is characterised by the prbtds sg ta:3+*u b6dvnh:*dn:esence 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 growthjv+i4ga( od:fuy 5u y( c.gb4q. A study was conducted on white onions (Allium cepa), under controlled conditions in a lab, to bgjafq u :4(45+yd. gv( yiuocinvestigate 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 s248uwqt*c 1 nta8bsdcells can divide. The diagrams below show two cet4w8d nq * tc8baus2s1lls from 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 expressoqd/, gunsotkbh+780; .w h jhion 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 numbe iph dad0i ay*.-15bz1;qtpekr of 8, in different stages of meiosis. Which row correctly names each stage?i.5pye1;ab a-i 0z h*qtdpdk1

  The micrographs show four phases of meiosiszos fuc). e8 kbwfprarr3:+k)/lf2+hm,2ep m I in a plant. In what order do these phase,k+.2f fwflhem3r:+m2r acpkozr ue/8s)b ) ps occur?

Mitochondria are responsible for supplying metab0yi89stx4 j q;enho*6uo d+wm mb7ol ;olic 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 from8q+ h46 7jelx;0 wmmu ooty;sno*bi d9 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 numbq:annn v94 g52ixdlo)er of cells in different stages of the cell cycle in four samples of lung tissue from four patie n:x)dno49g5viq ln2a nts. Which tissue has the lowest mitotic index?

  The diagram shows the dominant cyclin/CDK compl01ri +c* yw k zk7yekrs4c-ca1exes at different time points in the cell cycle. Which cyclin/CDK compleer c+a4kyiwsz *ck1c-1 7rk y0x activates DNA replication machinery?

  Studies have shown t4+jbkoy vi++fs k) yfn7m3oj(hat genes such as Cyclin Dependent Kinase 3 (CDKN3) are highly overexpressed in cerv+3 ji kffb+komnoys7y( )4v+jical 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 hedg(f+ 7z.lvion/mt 0ighest during the cell cycle ?