The graph below shows the relationship 2xv tgr2 z*f/wulf0*r between maternal age and the incidence of non-disjunction. What relationship is *fw0 zfug 2v/rxrt2l*suggested by the data in the graph?

  Which stage of meiosis is repr kifjhv8i5 r2dxi dn*v 0)mr./esented in the diagram below?

  The diagram below shows chromosomes during meioxj*gx *c2lj t3 8-n.wm4d rpdlsis.


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 thvu/*fiqlj *5krtl, v (e number of alleles of a single gene which would be present in the nucleus uj tv*5 ,vll(ri kf*/qof a cell as a result of each process?

  Which keyword is matched to the correct def to+s-khk+szwc-h1 v t7 qk8g;inition?

  Which statement(s) about mitor, tn1q (yf- .sloah2bhy-aoi pvq+(4sis 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 anpj aivrcsqv+)l-c z+ /p9,4agaphase?

  During which stage of mitosis does the nuclear eose5 nj07)vqqp7gry- nvelope break down?

  Which one of the following transport proteins only carries out ac94j(khn0+l)dozfii/ ao n yb ;tive transport?kno) +oyjdi0i9 4fb;za/(lhn

  Which process does not happen in the sh;mpyk8j, jkife:whdy,i 3-n .oot apex?

  Which type/s of membra.n mbov--m ts*ne transport do/does not require energy expenditure?
I. Facilitated diffusion
II. Active transport
III. Osmosis

  The diagram below represents a cell with wxmfz9u x( ls**y w,y;a diploid number of 4. Which stage of celxx*,ymwufy9wl*( sz; l division is the cell currently undergoing?

  The photomicrograph below shows a root tip meristem. Which of th6xf6 n. )eu-is5axayxe following sentences correctly defines a meristem?x6-. xya 5esun6a if)x

  When does the random orientation of homologousy-;8r1z t 1jgcb1 grmp chromosome pairs occur?

  Which process does not occur e2wuo,p.ua-xmn nc 10 during meiosis?

  If a cell with a diploid nush3w p 2;r9gxw3uhg:df5) -xqc/q milmber of 36 undergoes mitosis, how many chromosomes will be prq9-;:xmhfqh) lg xu/dsc 5r23 ip3gwwesent in each daughter cell after cytokinesis?

  The image shows a micrographvv1,y5j+f3u 9jq0 s;wtg bnjo of a cell.


What explains the appearance of the cell in the micrograph?

  Which statement(s) about homologocu2w l:ej.0bm (cgr j2us 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 witm.b6rc l:h f 3yqyxnni:(+h1rh Down syndrome.

Which statement is not correct?

  In the cells of a horse (E. caballus) 3 zjqs:- svl)mz3+vi,0d6 kgvi.p kwu during prophase I of meiosis I there are 64 chromosomes. What is the haplqv 3vss, dj)miv:6 liz+g0.wpzku- k3 oid number of chromosomes?

  Which arrow is pointing to a chiasma?q y t4,z;oi7t*. gvydr

  The diagram below represents the structure of a shootw10 f6kvbrh-v6c8sm j apical meristem. Which row in the table co-w6 hf r8 bj1ksm0cv6vrrectly identifies the processes occuring in the structures labeled in the diagram?

  How does meiosis promote varids0p5b2hq: c mation?

  Which of the following stap8oxy2swjh8 x+8ta.aih s ) f u*j7ev4tements 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 gametes produced from two homologobmrz s(/ 71sosus 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 j2cvl6o4nh/tyg3 ,mp1xd mb ; from primary tumours as a result of the movement of 1yh/mo l4gc6xdjn m, vbp t3;2cells?

  How many chiasmata are present in t4(y3kutcc .fl7d: fq ehe diagram?

  Which statement is a similarity between cytokr9 :s/ 0mtrcupinesis in animal and plant cells?

  Which stage of meiosis is matched t+:y+ .yro5t*ix4 vnaee oq+wso the correct description?

  Which statement(s) are true of mqh;z.mqzl - 6veiosis 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 meioi9c. ewtmz2x( tic division. This results in the formation of one large cell and one small cell. What is the fate of the larm2e.9cxi( w tzge cell?

  Which row correctly describes diploid and haploid cen(e08lk pz3aulls in humans?

  The following table shows the diplo,o sf; moj47feid chromosome number of a range of species.


Which of these statements is correct?

  What conclusion can be drawn from the karyogram below?ogipey1 6 :ecs2if6w6yvno3 ;

  Which of the following proca3z sd*r h3c76, wffdresses is characteristic of the meiotic and not the mitotic cell3sa c h,f6rd3 f7drz*w cycle?

  The diagram represents a bud with a shoot apicvjb :bnxd-s7ov*ax*j 7 g 4i s3lr+/tval 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 chimp l 68x-;ogl+vajd5 esyanzee (Pan troglodytes) is 48. Which row shows the correct chromosome number for different cell types and celldy8lax+lg;s 56oj -ev division stages?.

  At the end of which pslodmmyxzk50g sc zagzw.,,2 /4d:2dhase of meiosis I does crossing over occur, and what is the outcome oz4k5/g. 0 gzw ly m2 zs,x,adcsod2:mdf crossing over?

  Which of the following statements does not descrx0uq 3y)sw4+( tp lu piqm97vmibe a step in the sodium-potassium pump cycle in the neuronal cells 4pq7pvx) y0qut9s+lwi( mum3?

  Which row in the table below is true ohpvg ay1.uf1 h.m+bk9 f meiosis?

Membrane transport is important for allowing particles to move acrgc.4d3/cshh+ s )husuaa f j6-oss the cell membrane and -u+ .4cf3 hcjuh/s)6sagshdarespond 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 cyjd( /kza4w wtt9a0 1wells.

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 ofy lr tu-,nv,brh; ea,0 different cyclins during the cell cycle. Which cyclin is involved in preparingu0rt,rn eayhb-lv ,,; for DNA replication?

The diagram below shows chroot46 )lcvd vl/lqju0qp (* wm,fzho./ mosomes 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 involves the separation15o oc4bi0c ya of homologous chromosomes?

  The mitotic index of throat tissues taken from 4 different patientm1t *6+fedhxo4*nne 3v eo;yus is shown below. Which patient ox1*fum thn*6 +y4 deo; env3eis most likely to have cancerous throat tissue?

1.Draw a labelled diagram to represent the proc-pz :-jys cz1 ;kf5qwdess of crossing over.

2.Compare and contrast random orientation and crossing over.

3.Outline the stages of meiosis.

  The image shows an abnormal huip ;snjbe 0y 0a*r*2e-jslk8ydh e:e3man karyotype.


What is the abnormality in this karyotype and its cause?

The graph below shows the relative amount of DNnfcy6;ye2.p fd40caljh*(xd/ xy* cs A in one cell during one complete cell cycle. Each letter represents one stage of efddn. *s;f2l0xcyyca(x h/6j* 4c pythe 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 thb-9 z4lhk6 jpvat is homozygous for brown, long hbv9hj 6kzl4- pair and a female cat that has black, short hair.


Which of the offspring has a recombinant genotype?

1.Outline how polygenic traits ca:cbypk oo* k3l.(2mmf5s .zb;sop7dr n 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 oveareua f4 9a(u juyz6 0i1d1nn9r of non-sister chromatids shown in the diaea a a1ud99nz1r(un 6ufij4 y0gram below?

  The photomicrograph shows a pollen grain from L. candidtya5ans 7ug1z(-xzg 4um (Lily). Which stage of meiosis is shown? zganzga- 7(x1t ys 54u

1.Outline the events which would lead toa l-e)mz ay2z96g e,:qh ojyg6v3xem* an individual being born with Down syndrome, which is charaj:2*vm a exy,m-elgza6gq9)oz36 hye cterised 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 growwx joifet/ /na6lfgsroja2 : ry ,.:84th. A study was conducted on white onions (Allium cepa), under controlled conditions in a lab, to investigate the effect of soilr :firxy2e wj6tf oa/8j.,n4slago :/ 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 cells can divide. The 5eqbs2j 8hn4gdiagrams below show two cells from an organism w b28nej4g5sqhith 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 geny3s i..+x/klom*8 gns5mls s3n,lxt .9dpkene 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 ac6 q hfm()gb3z cell, with a diploid number of 8, in different stages of meiosis. Which row correctqgz6cbh )mf(3 ly names each stage?

  The micrographs show fourmmqq; 1m,qil, u6bhc4 phases of meiosis I in a plant. In what order do these phases occur? uh;6bql4mmq q,c,m1 i

Mitochondria are responsible for supplyi)+k 0j9oj4mx mnyqp(b ng 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 patterqb+x kyomnpmj 4j)(09 ns 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 diz9zc0 znwngw *h.2o jnn 1zn*658rjtdfferent stages of the cell cycle in four samples of lung tissue from four patients. Which tissue has the lowest 8dz *cztng 61nw jzzjo50nwr2*.hn n9mitotic index?

  The diagram shows the dominant cyclin/CDK complexes at differ od:+eywzppk2mypo ; z 20.8gjent time points in the cell cycle. Which cyclin/CDK complex activates DNA replication machioo yy:m8wzp.pd 2z20pg; j+ek nery?

  Studies have shown that genes such as Cyclin Dependent Kinase 3 (CDKN3) are h7f)tpmlnd)b- us0c7 v-: dtnqighly oveuf cp t-) bsqt70)dn7-d:vl nmrexpressed 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 h /vhalk /gk(v0/bj2i vighest during the cell cycle ?