The graph below shows e mr6t;jj)el- i hi2,gthe relationship between maternal age and the incidence of non-disjunction. What relationship is suggest thle)j2ie;-rgi j6 m,ed by the data in the graph?

  Which stage of meiosis is represented z8lfso+e 37qu)urcb 0xp q/o/ in the diagram below?

  The diagram below shows chromosomes during meiosisk- .un 5kj4zsh.


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 single gene which wou trc31rlq:g9l ld be present in the nucleus of a cell as agq19 :ll rrc3t result of each process?

  Which keyword is matched toldzq; t;m rkj ,9jpyiu*c4th(fb3 +r0 the correct definition?

  Which statement(s) about mitqyp o a ugb/2,z0u4-vlosis 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, whi,9: f5d rbrbzw syq -)/wm6sunzdo4v-ch letter points to a cell in anaphase?

  During which stage of mitosis* xy,(b x0w(ctkej/cw does the nuclear envelope break down?

  Which one of the following transport proteins only carries out active transport lh4x68;tumqyk0pr dx7lxk)6 ?8tur7ql pkxldy0mx4kx6 6; )h

  Which process does not happen in the shoot xjm01du9 d,+bi)/koap o k4 bjapex?

  Which type/s of membrane transport do/does not require jknw, a-7h/hg/ucgh; energy expenditure?
I. Facilitated diffusion
II. Active transport
III. Osmosis

  The diagram below represe;moybbn -v4l *)b sp1onts a cell with a diploid number of 4. Which stage of celyl ; 4os1*mon bb-v)bpl division is the cell currently undergoing?

  The photomicrograph below shows a root tip m w(2rdhg+ c,mieristem. Which of the following sentences correctly defines a mer dgmh,r+w2ci( istem?

  When does the random +p9/6yofx +in0t qbyd orientation of homologous chromosome pairs occur?

  Which process does not 2(9xfjy ia93e ;,h,s z keme2m0mwuox occur during meiosis?

  If a cell with a diploid number of 36 undergoes mitosis, how many chr+n4a37e swigu omosomes will be present in each dau4 s7ui+g3aw enghter cell after cytokinesis?

  The image shows a mix/5z*s2l5f t9k6 n bzqued qb 1r1g+bccrograph of a cell.


What explains the appearance of the cell in the micrograph?

  Which statement(s) about homologi2-g2eq wnfn g*lo:izvj*-( hous chromosomes 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 wet;(pc;b;d6ec z46n chi ,bbr-xw8 tlith Down syndrome.

Which statement is not correct?

  In the cells of a horse (E. ..54fvr eq,sv /igqul m q69fvcaballus) during prophase I of meiosis I there are 64 chromosomes. What is the haploid number of chlvgq s v5v6,i.efqf9qumr4/.romosomes?

  Which arrow is pointing to a chiasma? + nln wm gy*s*3)gkmh:

  The diagram below repreqjerr 2.n/6j9frx.xe sents the structure of a shoot apical meristem. Which row in the table correctly identifies the processes occuring in the structures l f./q nerjrj x.xr296eabeled in the diagram?

  How does meiosis promote variatin0jkd5 1v yt*q0:ssk won?

  Which of the following statements is/are correc 3nhcr*+)zd,9*oquta xas vy6 t for meiosis?
I. It is a reduction division
II. It involves random orientation
III. It produces genetically identical cells

  The diagram shows gametes produced from two homologous chromoso l9nk j9pq(5zumes.


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 c 7 5z5p x)zn)-czcddofg-,s)/wqdyotumours as a red7o,5-)do nz5ccc) xs/)wqz zgy pd- fsult of the movement of cells?

  How many chiasmata are present in the tx )xgi 0,w)xediagram?

  Which statement is a similar; kk+d5 fj/2 inpy2h/foh 2osjity between cytokinesis in animal and plant cells?

  Which stage of meiosis is math8dso08+i 6k e59hk1 vrby(;rgjyjx oched to the correct description?

  Which statement(s) are true of meioye1zf o* y9 vur7ldw42sis 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 / / . e*;c,xki5mgb oqphp5kmrresults in the formation ;5e/5i.,xoh/g*mcbp q kkr mpof one large cell and one small cell. What is the fate of the large cell?

  Which row correctly nu9mdd(ncil*qgb l zpn/u-:z. t(*+ndescribes diploid and haploid cells in humans?

  The following table shows the diploid chromosome number of a range of spe l75j 6dnw,mwmi 7*i1w aegkkr8.cz.fcies.


Which of these statements is correct?

  What conclusion can be drawne, os/lw*sa /v from the karyogram below?

  Which of the following processes is characteristic of the meioc-d3lqq0g6 gstic and not the mitotic cel 63- ggqqd0scll cycle?

  The diagram represents a bud with z 9h+ajykfv: )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 chimpanzd8t bkuwfd6-3ee (Pan troglodytes) is 48. Which row shows the correct chromosome number for different cell types and cell divi-kbud f386t wdsion stages?.

  At the end of which phase of meiosis I does crossing ove*+;j zq3wf ii1em y8bar occur, and what is the outcome of crozwbefi13m*; iy+j aq 8ssing over?

  Which of the following statements does not describe a siq4 l.lk0 ybt;tep in the sodium-potassium pumpiy0qb.ll4k t ; cycle in the neuronal cells?

  Which row in the table below is tncr e vr7*cala2u ik2.c*om3 0rue of meiosis?

Membrane transport is import ygwqux w8o*(tu1-* fqant for allowing particles to move across the cell membrane and respond to changes x *qg uot1 u(-*qwy8wfin 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 ituscgk qh v8u7 1i9jeglsc,).3v + et3s regulated 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 different cyclins duringipk4w prx:, 3d the cell cycle. Which cyclin is involved in preparing for DNx:ppd34,wkri A replication?

The diagram below shows chromosomes during meiost/ 78q8ljwy6idyi6wn is.

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 homologou e)t6* f nc,rrfrkq1o7u(d/j8o4buc us chromosomes?

  The mitotic index of throat tissues taken from 4 different patients is shown bef j)f)-gui/u glow. Which patient is most likely to have cancerous throat tii )f)j/u-f uggssue?

1.Draw a labelled diagram to represent the process ofqb6hsvs/. 0m tqbut;5 crossing over.

2.Compare and contrast random orientation and crossing over.

3.Outline the stages of meiosis.

  The image shows an abnormal hum; j s -038qderca7tqgban karyotype.


What is the abnormality in this karyotype and its cause?

The graph below shows the relative amo cx25) vi pxjma5lf(2aunt of DNA in one cell during one complete cell cycle. Each letter representap5ial 25 xv2xmfj) c(s 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 3dik90jf2j a1u27vm0moyfrh kpa) s* brown, long hair and a female cat vmd 3s r2ok219jh7aujf0 ia0k )pm*y fthat has black, short hair.


Which of the offspring has a recombinant genotype?

1.Outline how polygenic traits can show a normal m ybko ez(7t;g+c:1s 3* iihjsdistribution.

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 nvx ;sw t5me* v/(vq;inon-sister chromatids shown in the diagram below?vitvqvnxw* (/; ms;e5

  The photomicrograph shows a pollen grain from L. canf1 a6s),qorw ndidum (Lily). Which stage of meiosis )own s16,f rqais shown?

1.Outline the events which would lea6pf-g;q0 x1wx j(wqoxf tm86ed to an individual being born with Down syndrome, which is characterised by the presence of thre 6(jf mxwx6xo-01 wgqqfe 8pt;e 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 con a4y *u3yttsd8 z-y6w/i3bjn hducted on white onions (Allium cepa), under controlled conditions in a lab, to investigate the effect of soil pH on the mitotic index ob4id 363auw h- t8zn*t/ syyyjf 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/ho9j wir 26 rv5bh,3 n9plboy which cells can divide. The diagrams below show two cells from an organism with a diploid bv,2r/oj9i9 n6h b5 lh 3oyprwnumber (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 genw3iol)wij 030wa dt :re expression 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,fg3l0y0yq5 tlxc,ths* +-fo c with a diploid number of 8, in different stages of meiosis. Which row correctly names each stf x0,c 5q l3lht o0ygfcyt-*s+age?

  The micrographs show4tvr;nc4ihalw k* -q- four phases of meiosis I in a plant. In what order do these phases occl4- kainrq*v4- wtc; hur?

Mitochondria are responsible for supplying metabolic energy in eukaryotic ceh iuo;/ bpdr8v(c(k- zlls. 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 o8bic( p;(vrd- h/zkubetween 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 numbm20jwq 7 9sxgrer of cells in different stages of the cell cycle in four samples of lung tissue from four patients. Which tissue rs7 0jgxqw2m9 has the lowest mitotic index?

  The diagram shows the dominant cyclin/CDK complexes at diffe2hrav54swhsm- .hb). ne1pn n rent time points in the cell cycle. Which cyclin/CDK complex activates DNA replication machineh mpvneshn swr2b.4 n)h5a-.1ry?

  Studies have shown that genes such as Cyclin Dependent Kinase 08g-nis jj6gl/5csm,b-mwyixf0w g:3 (CDKN3) are highly overexpressed ing m- 5:8ijg i6gwm ,s-/00x wnsjylfbc 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 highest during the cokphu7vrr:,/, nvk v,0vp z. aell cycle ?