The graph below shows the relationship between maternal age and the incidence ofsk ygcg9 h-mwim, 0n4) non-disjunction. What relationship is suggests )m0n4hk,wyg mgc- i9ed by the data in the graph?

  Which stage of meiosis is represented in the diagram be.* duryj5+ kw2l*odl e d78as;et/onglow?

  The diagram below shows chromosomes during mei8:fokm7 4 3mle+euc8ljm*ism eua9x 2osis.


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 g*8e pe,);z6 .2e1zy ilgs eogi-fzcgvene which would be present in the nucleus of a cell asiz8cey;)g6oel.*g-2szv e z ,1gipf e a result of each process?

  Which keyword is matched to the co5 t up2q4 hrbg3ysw*x*rrect definition?

  Which statement(s) about mitosis is/ar,nt+ y*)8 efgsy,xh ade 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 belo sd:n 0zverc7pi1q; n* 5rxp5mw, which letter points to a cell in anaphase?

  During which stage of mitosis does the nuclear envelopegm+us 7-i 1vk z)zg:dn break down?

  Which one of the following transport proteins only carries out active t6 p39tr -* cjesvwbyg:ransport?psvc: t wy-je6r3b *g9

  Which process does not happen in the shoot a1ma+kcfsg (f5o (w.vu pex?

  Which type/s of membrane transport do/does not require energy exp ;1a7csumgbp/ 7 y0rp,ckjeb l79s di5enditure?
I. Facilitated diffusion
II. Active transport
III. Osmosis

  The diagram below represents a cell with a diploid number of 4. Which stage ofsbgq-5jmcj*7 n)f8masy+ x i : cell dmn xb *8+s)i:c 5afmjj-gqsy7ivision is the cell currently undergoing?

  The photomicrograph below shows a root tip meristem. Which of the folltd-ksh.l-j g pu (j(dl bs7 a6mcw)t;-y u0h7nowing sentences corn.y-) (g ljdk hld7cs;0-hu7sw- putbma (t6jrectly defines a meristem?

  When does the random orientation of h dyt9h ayzqwuw+8-sh/tt )57eomologous chromosome pairs occur?

  Which process does not occur during melio51+y g0+zg ripji h+r)o o-iosis?

  If a cell with a diploid numbe9dxqdj ;z6(7fsp or.cr of 36 undergoes mitosis, how many chromosomes will be presentcx6 . f jzrqp;9(sdod7 in each daughter cell after cytokinesis?

  The image shows a mic r bqv4z(,ft8srograph of a cell.


What explains the appearance of the cell in the micrograph?

  Which statement(s) about homologous chr /lkg9sfghym/-7 x 1as(g,oq pomosomes 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 wwn(0yz,h;*l e 6onxlc o(0mran individual with Down syndrome.

Which statement is not correct?

  In the cells of a horse (E. caballus) during prophasclaqc p71jlrsi j+.uze ,k t/g;7m2+fe I of meiosis I there are 64 chromosomes. What is the haploid number ou/;k1jzgm.rt l2 p je+sqa ,c77i fcl+f chromosomes?

  Which arrow is pointi2ktu+0 h6zss xun.m:vng to a chiasma?

  The diagram below represents t i)l tnzcg/ .m199lvbxdg4e ,xhe structure of a shoot apical meristem. Which row in the gic .texln 1gm) ,4bxz9 9v/dltable correctly identifies the processes occuring in the structures labeled in the diagram?

  How does meiosis promote variatgagfpox m .6+9ion?

  Which of the following statements is/are correc.qii6 ld-w fo/d0 .fvo.ee*t ct 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 homolo ld.zcx q3e7r3gous 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 tumour :.(vttj2shgl/0fl3c r(gx gys as a result of the movement of cell0g(:ctx3gt/2 y(grf sh ll.vjs?

  How many chiasmata are present in the diagrte1fpny702 * cdo-yf fam?

  Which statement is a similarity between cytokinesis in animal and plant cellt t /ulv5js :82vd7j aqj-h/jgs?

  Which stage of meiosis is matchedg7u qowp ;ka11av0ll 24(u p 5xnw,pqb to the correct description?

  Which statement(s) are tr)p(m mbm0yc,m ue of meiosis 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 resuqi )atjvxnt3 k6k16 ,soa7)kdlts in the formation of one large cell and one small cell. What is the fate of the large c6x731 ktvn aik sk,tad) jq)6oell?

  Which row correctly describes dihzkqm7x+ (d1f9,li u uploid and haploid cells in humans?

  The following table shows the diploid chromosome numblt dwxkcw5k5 (84s i3i)z.k krer of a range of species.


Which of these statements is correct?

  What conclusion can be drawn from the et*d4o 0;cr(7guj z wakaryogram below?

  Which of the following processes is characteristic of the meiotic and not the m(jn.rbo vog+ag0oo:;itotic celon0 ; ao g.jg+:oobvr(l cycle?

  The diagram represents t6ab-*byml.b a 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) am2lk k+ t-l9gamy nj24 t3,5f(y ue/wpum9g wis 48. Which row shows the correct chromosome number for different cmt4a/95wkyf wmma(lpgg +u 9ly32t e,2-njuk ell types and cell division stages?.

  At the end of which phase of meiosis I does crossing over occur, and what is t;sh *+ l3up)8lddit lnhe ouuslld8 ;t+)lnd *i3hp tcome of crossing over?

  Which of the following statements does not descri7bl5s z9h1ws dbe a step in the sodium-potassium pump cycle in the neuronal cells?1sw79hz 5d slb

  Which row in the table below is true of meiosi qqum fq55f )* k2se1+6owcieis?

Membrane transport is important for allowin9; povwmf wu,0g particles to move across the cell membrane and respond to changes in the chemical composition of;,wo pv9mwu 0f 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 regulatt.f: 5b(fur9 kz*lfcued 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 differentgwo )gtxg 9n/;r,a9mn cyclins during the cell cycle. Which c g;wn, amg ot/r9gx9)nyclin is involved in preparing for DNA replication?

The diagram below shog nvinsu17zge0c/f2+,mma 4t ws chromosomes 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 s e(q-ub/fj7rj ,ern 8yeparation of homologous chromosomes?

  The mitotic index of throat tissues taken from 4 differen2zl hncv/ro j8g:4+law uy3 gzgio1) +t patients is shown below. Which patient is most likely to have cancerous throat tlhg 31yaz)ol2 zw/oc+ 4jin u:r+8 vggissue?

1.Draw a labelled dia 8*zvrea,tdsl ( d,8cggram to represent 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*uem9 smi 7)brr*+fya human karyotype.


What is the abnormality in this karyotype and its cause?

The graph below shows the relative amount of DNAg /pz.hig( ym*ws-:ay in one cell during one complete cell cycle. Each letter represents onga -h*yyp :sim.wg(z /e 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 cazj6vjxja 0fpva,);vup6v( ,ht that is homozygous for brown, long hair and a femal0zjuv;fxp6ava p(vh), j ,jv 6e cat that has black, short hair.


Which of the offspring has a recombinant genotype?

1.Outline how polygenic traitdr , cg,8-ngmhs can 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 cros7zi (b0h8rn)uo*yc )6yaz(hri)v lbdsing over of non-sister chromatids shown in thdl()ah y*8)v7rzh)ii b0u(crb yozn6 e diagram below?

  The photomicrograph :ck,s:x 3 yu-k6p:bxa ozskd(shows a pollen grain from L. candidum (Lily). Which stage of meis,az:xpck: (b6kx3os:ky - duosis is shown?

1.Outline the events which would lead to an individual being born with Dow, + o8fcifpl7;gmebz 9n syndrome, which is charactee;8fo7fl+, cgp b9zmirised 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 pl) v;y lxq-r-2f8f(n wvtsiq p ;61cczuant growth. A study was conducted on white onions (Allium cepa), under controlled conditions in a lab, to investigatxscz ;qt-v1;(ry )8fnp6fcil -uv2 qwe 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 can divide. The diagrams below s:)ftjbcbc j +8how two cells from an organism with a diplo t+: f8ccb)jjbid 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 exae6tgm 7.s6 lipression 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 n4l6f v6uo pq)bumber of 8, in different stages of meiosiv6blf6po u)q4 s. Which row correctly names each stage?

  The micrographs show four ph kd:vma6ih2r:ases of meiosis I in a plant. In what order do these phas2m:hi6ad r:vk es occur?

Mitochondria are responsible for supplying xgl;9/.r4p icckm5 g)d7a emvmetabolic 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 d4em/g)r7lxm;g 9c5kvicpa. 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 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 different stag622p) rbp96iw,-7vvrb r kcos*z xrlw es of the cell cycle in four samples of lung tissue from forx9kzc2vbwpo ,66r sivb r pw2rl7-)*ur patients. Which tissue has the lowest mitotic index?

  The diagram shows the dominant cyclin/CDK complexes at differeeb 4ij3l ;d;p8h:wjw d2lfq)hnt time points in the cell cycle. Which cyclin/CDK complex w ;w b2hjl)dl;e4q :fdj38phiactivates DNA replication machinery?

  Studies have shown that genes such as Cyclin Depende g(5 zd:9 aysnehywdrd6g /q00nt Kinase 3 (CDKN3) are highly overexpressed in cervicad6w0gdr n/has0yz g 9 e:5y(dql 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 highestavt0i1y)y . td during the cell cycle ?