The graph below shows the relationship between maternal age and the incidencex /y ksrbr1q: jnasp5+,d ,t66m*jbas of non-disjunction mt1qryj / kr+nxa :b,,bjss5pas*6 6d. What relationship is suggested by the data in the graph?

  Which stage of meiosis is represented in the diagram below? 0t,cgi; q8 h8 y7tmydm

  The diagram below shows chromosomes dunt9.4k8oaohdxvmkh 02(d o p,ring 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 s.t,uf:vdr ik -fuk:x* 6 yn ugq*d7qo6tates the number of alleles of a single gene which would be present in the nucleus of a cell as a result of each process?gu uqi6*.ntv:q y,fd6-k7r udk *:fox

  Which keyword is matched to the cfuxphkn;y/6kve3t 2 3orrect definition?

  Which statement(s) about mitosis is/nwkmiji1 vm/ltara1i7a4 5r( ,5w) aoare 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 beloh2i4wpwl/ wggix. 4) gw, which letter points to a cell in anaphase?

  During which stage of lcul1kp j.uj4f+)l . zczl+-g mitosis does the nuclear envelope break down?

  Which one of the following transport proteins only carries out thf*p6r0as6e active transport?06p h*r aefs6t

  Which process does not di0 v0,haoe)ppm6l)9 i mfo(zhappen in the shoot apex?

  Which type/s of membrane transport do/does not require energy expenditu9vinh(8b/l 9 w zvr7zdre?
I. Facilitated diffusion
II. Active transport
III. Osmosis

  The diagram below represents a cell with a diploid number of 4. Which st q 5,+ .y9hdbslvbrqp,rxmf e(.,lm-aage of cell division is the cell currently undergoing? +s b-,f(lmmry95qa..r pq d,h ,vbx le

  The photomicrograph below shows a root tip merf:w u;p:5jup5u-0eh, w uqhzo, veyc)istem. Which of the following sentences correctly def5:eew )puj0uqyu,cofhzpvu-hw5:; , ines a meristem?

  When does the random orientation of hom-nwp4sw8:im0uh4sgzk;t 4ebsy+ q 2 jologous chromosome pairs occur?

  Which process does not occurrom2 .qjp,k* r gk*me4jm; op8 during meiosis?

  If a cell with a diploid number of 36 undergoes mitosis wkb.):q :cre7v/j3xp g1c qsy, how many chromosomes will be present irpgc1c:v e. jw7qbq )x:3kys/n each daughter cell after cytokinesis?

  The image shows a micro *raf cf 9lfmc,a::f/vgraph of a cell.


What explains the appearance of the cell in the micrograph?

  Which statement(s) about homologous chromosomes is/are not tru ftzv3q-3/(kij(f kgsb2lg tly,q nry*/w , n3e?
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 Down swfn7jwq d.h0up.2v6 myndrome.

Which statement is not correct?

  In the cells of a horse (E. caba3;rhl hdxk8 *zf gxmm e4le2j( , zqt)66d2phvllus) during prophase I of meiosis I there are 64 chroz 6hg2;) 2tfmldrzjxd vm38 6hel(*hkp,ex q4mosomes. What is the haploid number of chromosomes?

  Which arrow is pointing to a chiaybs d.)du3hco)- 7 fshsma?

  The diagram below represents the structure ofsx h-k 5xu7(*/cct5zp gtg4 h,qplvx * a shoot apical meristem. Which row in the table correctly identifies the pr7 tq5 tgxs-p*h4 pkgvx,/hzxlu (cc5*ocesses occuring in the structures labeled in the diagram?

  How does meiosis promote variak *le(b03pffvg4 6y fation?

  Which of the following statements is/are 85ud(e pwg3fdjei tq6doc c6/65fnr 0correct for meiosis?
I. It is a reduction division
II. It involves random orientation
III. It produces genetically identical cells

  The diagram shows gametes producedxr6jbxq 62shtg(8. rr 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 secondary tumours from pr,hg e0n*1 mabcimary tumours as a res1hc0n*m, gabe ult of the movement of cells?

  How many chiasmata are present in tr 3r-pxaw5:a4i r b/cphe diagram?

  Which statement is a similarity between cytokinesis in animal and plant hu*c ubq(o v4x v1 m/po+y qqgny,;q79cells?

  Which stage of meiosis is matched to the correct description?t29w+ wp cno2o8t /lnx

  Which statement(s) are true of meiosis Ihng0ky9.uex*04f: xqjo. opo 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 aft(bj8;x d-kyyxs:b.ta er the first meiotic division. This results in the formation of one large cell and one smal sj8day-y b:(tx .xb;kl cell. What is the fate of the large cell?

  Which row correctly describes diploid and haploid cells in ;5hj d0nx3 0 etv7bzmmhumans?

  The following table shows the diploid chromosome n/x)) azt86 paofdqlq- umber of a range of species.


Which of these statements is correct?

  What conclusion can be drawn from the kary tu 6ui h .gg/*hx,2txz/nh81lzmo t;cogram below?

  Which of the following processes is characteristic of the meiotic (5/dosguk /ks m fnd*8and not the mitotic cellom5g/(ksddsf8*uk /n cycle?

  The diagram represents a bud with aj09p t rax)q sd;8uwd1 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 ckmq2z g +oa82wd3f(m9(nsjcjhimpanzee (Pan troglodytes) is 48. Which row shows the correct chromosome number for different cell types and cell divisionw (qmoam293 jg2(znd8ckf js+ stages?.

  At the end of which phase of meiosis I doa:pgr0 w13o okt9j7 ;bdwnrp8 es crossing over occur, and what is the outcome of cop78gd1kown jt;rwrp 9 30 :abrossing over?

  Which of the following statements does not describe a step in the sod)ivt nttx6v1s/aqy 3syn2n 92 ium-potassium pump cy2nn1)xy2aq nviy st93stt /v6cle in the neuronal cells?

  Which row in the table bexwzd :7l 5jkw6low is true of meiosis?

Membrane transport is impo6;bn7j)b d+35 lgveqsdevv1prtant for allowing particles to move across the cell membrane and respond to changes in the chemical composition of the extracellular flui gv)7 evqsnle13j bpd6d;vb+ 5d.

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 regql(otj 0x,fv 0) (g0ut0gt ktoulated 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 muaip b7 o5-:;vn9usra lb*4+;pnp nt the cell cycle. Which cyclin is involved in preparing for DNA puam4uv -+bois;:pn9b 7n ;rntp *5lareplication?

The diagram below shows chromosomes0y b49cigzqcybyt(u lt*(( j1 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 separation of wem4t9l :e2xxhomologous chromosomes?

  The mitotic index of throat tissues taken from 4 different pjz3bq9i 5f0 fkatients is shown below. Which patient is most likely to have cancerous throat tissue?5 ff z9iqk3jb0

1.Draw a labelled diagram to represent the process of crossing n*ua9a 2j 6l ja.er46((s e e-ewcqpsbover.

2.Compare and contrast random orientation and crossing over.

3.Outline the stages of meiosis.

  The image shows an abnormalm,r5pii9o :p 98g uvvv human karyotype.


What is the abnormality in this karyotype and its cause?

The graph below shows the relative amount o,ogiubx7 m secdz 73+0f DNA in one cell during one complete cell cycle. Each letter represents one stage of t g0s3d ,oim +ceuzbx77he 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 crpy0)c jyr2ice16lsgmn9) s,noss between a male cat that is homozygous for brown, long hair and a female cat that has black, short hnr2ilc)ssye ,c 1p0n6 y9mg j)air.


Which of the offspring has a recombinant genotype?

1.Outline how polygenic traits can shel9wx0 *cq so j-4syf (jznp2,ow 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 resultu9o9d/z96mttwum ; hj from the crossing over of non-sister chromatids shown in the diagram b96wt z oju9;m9t udmh/elow?

  The photomicrograph shows a pollen grain from L. candidum (Lily). Which stage : (lvua uzmij+9xp:a d.gc9a +xu8+auof meiosis is shown? j l+9u x+aa:u(m xud zapui:v98 c+g.a

1.Outline the events which would lead to an individual beingk6 9j duzl /ls1vdc,h- born with Down syndrome, which is cha -vd,6lhjzdc 9k1/ls uracterised 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 oj.m.5ctbf (f lf measuring plant growth. A study was conducted on white onions (Allium cepa), under controlled conditions in atbf (f5j cm.l. lab, to investigate 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 cells c+,b 5:t h;pe(1qptdlklg bhp-an divide. The diagrams below show two cells from an organism w:tp5bh( 1p;pq+,bt l he- kldgith 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 exyh*a4g15l ek aq(pfe3pression 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 number of 8,+ hoaw mv 18awoh /h20i 0p)/fjkx2hqf in different stages of meiosis. Which roo vapf/+8hh1)wkwo2h/ m0x2 f h iq0jaw correctly names each stage?

  The micrographs show four phases of meiosis I in a plant. In what order do the8y6*8au8it -twj p totse phases occur? 8j8out ywt8t-i6 a tp*

Mitochondria are responsible for supplying metabolic energy in eukaryos7 z+xa4;apxjh5+3n *ao yy esp 6yz,jtic 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 yz3 xyjse4+hp7j; z5n,xs *ao6p a+a ythat, 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 dinjt2ba s+9wr0fferent stages of the cell cycle in four samples of lung tissue from fwnrsb tj+9a02our patients. Which tissue has the lowest mitotic index?

  The diagram shows the dominant cyclin/CDK complexes at different time po t nt4 :1-75oxg lm/op bdp1 3)mg.ejvepzii+rints in the cell cycle. Whi+nm1oe /t7dpi3eg :t)j 1p vix -lm5p g.rzo4bch cyclin/CDK complex activates DNA replication machinery?

  Studies have shown tha*yv;2ox8)zb pibyc 9f t genes such as Cyclin Dependent Kinase 3 (CDKN3) are highly overexpy z ibbx)fv p2c9;o*y8ressed 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 during ff l5qo )9vqjrs+,blh4 *ijubkhp 3/,the cell cycle ?