The graph below shows the relationship between maternal age and the incidence onhv + pv9,a*cxld37usf non-disjunction. What relationship is suggestevd h+ pa,s*xul 37c9nvd by the data in the graph?

  Which stage of meiosis is represented in the dl, jf 7ho,cy)+r7 smpbiagram below?

  The diagram below shows chrfxx t.7857i niyo6, oganmw4gomosomes 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 of a sing8x z epajgnspa((17+ttsei p6l+;5om le gene which would be present in the nucleus of a cell as a result7l;t(z (ijoet6s p+5an+m pe8gps xa1 of each process?

  Which keyword is matched to the correct definitzk x5dn7z)t/dj2o5 9oy nd.*4 rl xb;yrl b/ilion?

  Which statement(s) abouz f 0 bgcnub4r2*3thi,t mitosis 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 e i a30t.nfx/zto a cell in anaphase?

  During which stage of mitobt9k , hqbq: j1*bjdv7sis does the nuclear envelope break down?

  Which one of the following transport proteins only carries out actya,ic:3aw ,bciz6 w c*ive transport?z ay*c 3cwwc,6i:iab,

  Which process does ncpn sij.sq2(7 yng/ b0ot happen in the shoot apex?

  Which type/s of membrane transport do/does not require energy expendidn(,.hk t.bg + hfjj*jwx*cvr* k,wr-ture?
I. Facilitated diffusion
II. Active transport
III. Osmosis

  The diagram below represents a cell with a p.m) vccd2ig;)hjfu :jpy ,n3m0h:isas0 + wmdiploid number of 4. Which stage of cell division is the cell currentl, c2ncipv.i:h;) ghmm wf j0ap:uysmjs3d) +0y undergoing?

  The photomicrograph beldo ht:j;bgsz2i2k7 z-s nort,2 l60 qkow shows a root tip meristem. Which of the following sent2b6o:h d-g;7,k 0q zlzrnti2osks2 jtences correctly defines a meristem?

  When does the random orientation *00ry,uq0l,f iynp4)g2jxn-, nvx xrwgk3mn of homologous chromosome pairs occur?

  Which process does nonlnfx7g9kry/r/kz :4 t occur during meiosis?

  If a cell with a diploid number of 36 underh).5ss4jrmd pq1 d qc0goes mitosis, how many chromosomes will be present in each daughter cell after cytok4c. rdp50mjqsq)hs1d inesis?

  The image shows a micrograph of a celj rp7p4,xq:f,mqs 7w tl.


What explains the appearance of the cell in the micrograph?

  Which statement(s) about homologous chromosomes is/are notxm.d8l/lmzo n)uao sdfb6f - .q/kh+3 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 indiyz)9+ l-gm5soeb6c)kn x9y yuvidual with Down syndrome.

Which statement is not correct?

  In the cells of a horse (E. caballus8:bwn -bmk0ih ) during prophase I of meiosis I there are 64 chromosomes. What is the haploid number ofb0hn -w8b m:ik chromosomes?

  Which arrow is point;ox9l kidn-e92*gp nqing to a chiasma?

  The diagram below represents the structuw f5gcpkyn7 1aeeel9 .+7c6 ksre of a shoot apical meristem. Which row in the table correctly identifiep76 e ca1lks .+e9cfeyn7w 5gks the processes occuring in the structures labeled in the diagram?

  How does meiosis promote vaic u2/i*2cyx b va*fk. 5swkq3riation?

  Which of the following statements is/are+*e(: c1tib+twz z rgi correct for meiosis?
I. It is a reduction division
II. It involves random orientation
III. It produces genetically identical cells

  The diagram shows gametes prodsqq9um3l1 ygl,c **xa ( zho+kuced 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 oom;)uv :yiqf+f secondary tumours from primary tumours as a result of:;v om qiyf+u) the movement of cells?

  How many chiasmata are present in the diagqt/dvv or2. xhc p8(+hram?

  Which statement is a similarity between cytokinesis in tw 8adaq y8;im62q*bhanimal and plant cells?

  Which stage of meiosis is matched to the correct descript- 8h 6o3m9bihj9ruu/ hoa px9iion?

  Which statement(s) are true of meiosis I but not meios(1q xalw0ag -ais 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 me bgz/4;oqlhk3 r 37paeiotic division. This results in the formation of lqeoka g7h/p4 3rz;b 3one large cell and one small cell. What is the fate of the large cell?

  Which row correctly describes diploid f pgv,fhhm2a , (b+8sland haploid cells in humans?

  The following table shows thnxns fx t*qj.qq.1xi;()3 zks:tn ,sb e diploid chromosome number of a range of species.


Which of these statements is correct?

  What conclusion can be draw4e- w4ubr6vr nn from the karyogram below?

  Which of the following processes is characteristic of the meiotic and n.1ky)ukok6vaa ct 0r.ot the mitotic celk0v1y aaok6cru.kt. ) l cycle?

  The diagram represents a bud with a shoot apical meristef8wv1u+s00sd q cfsb) m.

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 tro r5j1 petc1b8yucb: (t7zuu;gglodytes) is 48. Which row shows the correct chromosome number for different cell types and cell division stages? turbb c;t g(j:u58cz1upy71e.

  At the end of which phase of meiosis I does crossing over occur, ann/dk1r(dx adk,y1w5 pd what is the oxdp,k/y(d 51nwk1 rad utcome of crossing over?

  Which of the following statements does not describe a step in the sodium-q kl2 ly0 2t4flqy16ckpotassium pump cyclyqqcl 02 l41 2lk6tkfye in the neuronal cells?

  Which row in the table below isos:y+c/ gpg,x true of meiosis?

Membrane transport is important for allowing particles to move acros kh cw8nmm +fyn8f-g/+ r -os/0ks3wqas the cell membrane and respond to changes in the chemical composition of the nr8sw0-ymhc/ nokwf8+fk/sq3 -ga+m 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 regulatclh/y41xv ; q d9esnor/n-2zv ed 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 th 16dd2)-i +p edcqg9j-ptoqpmt 1 bh2ke cell cycle. Which cyclin is involved in pr6pq2 c1-d 1qtpm kgb opdhe2j) t9+d-ieparing for DNA replication?

The diagram below shows c/qb ;qy/bv* uxp,.0 ftz:ejt zhromosomes 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 invo06(mh/22ah n8g )jfx l; jruxvc.kwmtlves the separation of homologous chromosomes?

  The mitotic index of throat tissues taken from 4 different patirxek7vce/hdteouwaw;zm*a u7. - :0,ents is shown below. Which patient is m:t ,*0uz hxrvwe/am .cuoee a w7-7d;kost likely to have cancerous throat tissue?

1.Draw a labelled diagram to represen z/ncdy5;e:vgc zbgl+pwf; gi(/cw :,7nlm;g t 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 human karyoty)v+fu47 0x: n dwll, mdoop.gepe.


What is the abnormality in this karyotype and its cause?

The graph below shows the relatiqu7guf )dd9i8ve amount of DNA in one cell during one complete cell )d8uf9g u7qidcycle. Each letter represents 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 .25 k*q mo 5xl1hhyxhyuu*mq4a male cat that is homozygous for brown, long hair and a female cat that has black, shorq1u. xyh*holuk2mhy55 m4 q*x t hair.


Which of the offspring has a recombinant genotype?

1.Outline how polygenic traits can show a normal distributioh0t)jr xy 0.xp2d7to tn.

2.Outline the differences and similarities between homologous chromosomes.

3.Explain why expected and observed Mendelian ratios may differ.

  Which gamete can result ;ty5-0ug axp(pl;m+g du ir 1afrom the crossing over of non-sister chromatids shown in t( dy1m5a tr +g;iup;g0ulapx-he diagram below?

  The photomicrograph shows a pollen grain from L. candidum (Lily). Which stage n;s)lljhmms (/a--c 3jy( bc zof meiosis iz)bl cy ( hsnsjl(/ja -mc-;m3s shown?

1.Outline the events whichekd 6+j7c) ned+gtt0g would lead to an individual being born with Down syndrome, which is charactt+e 7+g gjdted)60nkcerised 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 3 f sl,b/h gj1-ogwl.w8 fxtz4of 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 the mihfw/3 1xg8ll,jgt4w.z-bs f ototic 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.qk1w*:rai; qm3 jq0 db The diagrams below show two cells from an organism with :*;bamwqdk0q r1qi3j 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 genu 9+zgr+hr*zpa7 rg8le 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, with a diploid number of 8, in dvwo k b5 5dpl3*(zyrel5m .,cn- jmuz9ifferent stages of meiosis. Which row col9kdm(jw, o.vzzp5y rn*l5ucb -53me rrectly names each stage?

  The micrographs show four phases of meiosis I in a plant. In what orderf spi(q4sw4,)k6 *-sypgcoi n do these phapsyoifn*gc (w -s44 6s,kpq)ises occur?

Mitochondria are responsible for supplying metabolic energy in eukaryotic cells2iva,xljdx: 7. 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 rea xx:v27jdl i,production 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 stages of the ch wb6hk vj5r9y01k: dcwuy6w,ell cycle in four samples of lung tissue from four pck9 w:05wyjbk6 u rhh1w,dvy6 atients. Which tissue has the lowest mitotic index?

  The diagram shows the dominant cyclinh9is;cv : auq)5cm kz7/CDK complexes at different time points in the cell cycle. Which cyclin/CDK complex activm5aisqc u ;k) :v7hc9zates DNA replication machinery?

  Studies have shown that genes such as Cyclin Dependent K-ic1aoh ptf- 4kuog8/inase 3 (CDKN3) are highly cfk -4ig1o/ohtpu 8-aoverexpressed 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 6bo4ns:: dlseof cyclin E the highest during the cell cycle ?