The graph below shows the relatidxsa4m (m2me: onship between maternal age and the incidence of non4xemads m(m 2:-disjunction. What relationship is suggested by the data in the graph?

  Which stage of meiosis is represented in t(c0l* x.hpc9khhnwo g jj c(15he diagram below?

  The diagram below shows chromosomes wfu0*gt1a 8ds during 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:lfu*aw d vtkro 84rth*ru6j:i3pk 80 of a single gene which would be present :6dirk*tv f3 8ku*r:phlw0ju8arot 4in the nucleus of a cell as a result of each process?

  Which keyword is matched to the correct definition?xf9uy+s 2+d3 z1yavej

  Which statement(s) about mitosw iz as+8og1p7is 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 lettein 7mk5rkyu/ u:cr*q*r points to a cell in anaphase?

  During which stage of mitosis doesnm: t2;nqh2r 8f mb.jfrtx4qc1 oo 48z the nuclear envelope break down?

  Which one of the following transport proteins only carries out a9g 8 s:kpbtp:gctive transport? gsp9gk btp8::

  Which process does not happenlu(5 19qw/o8 tkp ighi in the shoot apex?

  Which type/s of membrane tz da ry-kt7,e wvb92.fransport do/does not require energy expenditure?
I. Facilitated diffusion
II. Active transport
III. Osmosis

  The diagram below represents a cell with a diploidg /cfi*b rjx8 h(oivgi*y,j,- i;3f ow number of 4. Which stage of cell division isx /hj3iwv*;oib-( f8*cjyg, ,gr iiof the cell currently undergoing?

  The photomicrograph belo5 h+r0kmz) jzgkc (d3nw shows a root tip meristem. Which of the following sentences correctly defines a meristem?(mhr+dkng3j50k z)zc

  When does the random orientation of homologous chromosome pa0i3fkbr4 hrb 6 21xwvdirs occur?

  Which process does not occur4 lrx1a51u ubmscy mad x:i043 during meiosis?

  If a cell with a diploid number of 36 undergoes mitosis,j 9rtlj ybxu-lj3s6/ ;ov*h:gfz0cz+ how many chromosomes will be present in e 0+jlrc*j6zu:txf-3v o/y9hbg;j zl sach daughter cell after cytokinesis?

  The image shows a micrograph o;vsy8xok 1 ybh,*m8xk f a cell.


What explains the appearance of the cell in the micrograph?

  Which statement(s) about ho)yy*v2:,5x*v:vsge jscpjxngu0qu; mologous 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 with 4a gmn2 umc3xlyj,f qu7/a6s* . 5;,ccbyrji hDown syndrome.

Which statement is not correct?

  In the cells of a horse (E. caballus) during prophas nokq4gz1gxe vs*)v.2 e I of meiosis I there are 64 chromosomes. What is the haploidqvg x4gsz v.1n )k2o*e number of chromosomes?

  Which arrow is pointingxgxj )z( rlt;8 to a chiasma?

  The diagram below represents the structure of a shoot apical meristem. Whi6 u71:ikhrjxb)2 o1 y rgb9hvach row in the table correctly identifies the processes occuring in the structures labeled in the dh:)17boa912 b g6r hu kjrivxyiagram?

  How does meiosis promote 80* tjw4rttssvariation?

  Which of the following s9iu3o qn xy.1 1yve1zbtatements 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 game7qwub1;7z tnshce, yl o8n*7 ctes 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 formation of seco b.hh r33cl6kr bckr.tg 7.*nbcs(;gp ndary tumours from primary tumours as a result of the movement of cel 3bc3h *lk.p7s grr.;rnbtccgk 6.bh(ls?

  How many chiasmata are p m7mxyq8 yl0r j463ty(l:.rabff lpb/resent in the diagram?

  Which statement is a similarity between cytokinesis in animal and plant cells?qai48 e;msampxn6y / (

  Which stage of meiosis is matched to th. h/ *jwylud)me correct description?

  Which statement(s) are true of meiosis I but not meiosis r 0buydp2-1aiu0 x jp;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 oocytez74wlxo2 c, vc after the first meiotic division. This results in th2cxlc zowv,47e formation of one large cell and one small cell. What is the fate of the large cell?

  Which row correctly describq7cl6 /q2bijoeynwo;05w7 t fes diploid and haploid cells in humans?

  The following table shows the diploid chromosome nu 7p udm8/0uarzmber of a range of species.


Which of these statements is correct?

  What conclusion can be drawn from ytysg8,8w-mjet :; v at 36licthe karyogram below?

  Which of the following processes is charact-wyzvj 7qb),weristic of the meiotic and not the mitojv)7w w- ,qybztic cell cycle?

  The diagram represents a bud with a shoot apical 7*7-g/udji9l-of vzy/ycjtbyydh 8 4meristem.

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. Which ouxy n(x,sg3- r*/er;h ,.il mvbj)nf.svrz6 row shows the cor v3b.xf;i nvornmhzyx/s -,u.,jlrg* s)e(6rrect chromosome number for different cell types and cell division stages?.

  At the end of which phase of meiosis I does crossing over occur, and robigv d9pt hyvotfk 0chwv)w *0* 30 /)6hhn-what is the outcome of 0 w9ki 0v/nhrv)gphybcth od** wv 03) hot-6fcrossing over?

  Which of the following statements does not qje-tfrc 4.f+ 7z ;m3vug64yno8 liyc describe a step in the sodium-potassium pump cycle in the neuronal cell +fy f4z86qi3clrej4.cny7vtom- g u;s?

  Which row in the tables p37d1wl ionp(ive.z fe, /j9 below is true of meiosis?

Membrane transport is important for allowing particles to mc gwb76a z,7dp yip0y1ove across the cell membrane and respond to changes in the chemical composition of the extracellularzi yy 7bpagd,p0w176c 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 regulatehzkhz)nlc ko:0004 av d 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 during the cell fue*w/ ybt*:ocycle. Whi/etb*of *y:uw ch cyclin is involved in preparing for DNA replication?

The diagram below shows chromosomes during bmnrx:-1ss7eg io r3: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 invy/j8:f k 4njfaolves the separation of homologous chromosomes?

  The mitotic index of throat tissues taken from 4 ds1 (81 q97mza m xj*lkys;uxrlifferent patients is shown below.r89lmu1qx1 k*sa j l s;7mz(xy Which patient is most likely to have cancerous throat tissue?

1.Draw a labelled diagram to reprp m4gow83q,c /w-5nwq1dp s ezesent 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 1s-xvukwj t7 z-w*:91g rwal ihuman karyotype.


What is the abnormality in this karyotype and its cause?

The graph below shows the relative amount of DNA in one cel2o1xc,osk/s nl during one complete cell cycle. Each letter represents one stagxs nsco,21k /oe 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 cros0dv,je sy:/5p5qt bdys between a male cat that is homozygous for brown, long hair and a femalsqy55 v,et b: yjdd0p/e cat that has black, short hair.


Which of the offspring has a recombinant genotype?

1.Outline how polygenic traits can show a normal d6,ek jsq01v ljistribution.

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*grf i;t 1i7t; zksk:w-sister chromatids shown in the diagram belo; ir7tt:s kwi 1;zfgk*w?

  The photomicrograph shows a pollen grain fp rk7t9a6ms;x a9b:k drom L. candidum (Lily). Which stage of meiosis i kma;pab7:69t9rskx ds shown?

1.Outline the events which would le:j vrk/ev oe(92ays,had to an individual being born with Down syndro,kv/yha (jovs :2ree9me, which 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 ind c*)f7i8rd-hk( uxu twirect way of measuring plant growth. A study was conducted on white onions (Allium cepa), under controlled conditions in a lab, to investigate the effect of soil pH on th*c-rw8d ()7tkiu hxf ue 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 bt6/yv4f;dpjkhme.mfq s+/ , cells can divide. The diagrams below show two cells from an organism with a diploid number (2sfmmkb+/. ,jpydqht4/f v6 ;e n) 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 growbi /,0r m qdvzvtpb2tfh6 )jz(vt2*o/th.

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 ag uz+4y/7tg48rd. /e axowdsz diploid number of 8, in different stages of meiosis. Which row correctly namewdyr/ t d7g+ o.8x4zzg4sae/us each stage?

  The micrographs show four phases of meiosis I in a plant. Inab. q,x chihfn 6(qvmkj,9uyg.) )zl0 what order do these phases9) ,,kufhicqv lzn) qym.gx0(6a jh.b occur?

Mitochondria are responsible for supplyingo,yx,s( fa3 a l(vyw9)fn aw:m 7evqc6 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 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 betweenc7x:v6elf(a, msayvq yfa)w,(n 9 wo3 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 thbk4otjw*6 p39fh/8av i fn2m: )agql be cell cycle in four samples of lung tissue from four patients. Whichb 2p owkij3tvlb )agf4h8 69m*fqan/: tissue has the lowest mitotic index?

  The diagram shows the dominant cyclin/CDK4buf i lm3wzdwj09e/7 complexes at different time points in the 7uief zj mlw943/bw0dcell cycle. Which cyclin/CDK complex activates DNA replication machinery?

  Studies have shown that genes such as Cyclin Dependent Kin1,gwv-rlo.pwf tqjx+ b v) )+vase 3 (CDKN3) are highlrq)gx)t+,w.1o- +wv pfv vjbly overexpressed 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 highest durcwqd- m1y((oy0y jhm k..g9w6ov0 vcking the cell cycle ?