The graph below shows the relationship between maternal age+g+1vw2fm +c( cdk zgs and the incidence of non-disjun s1mf cgv(k+ +z2d+cwgction. What relationship is suggested by the data in the graph?

  Which stage of meiosis is represented iiq q2sl nuwblc m0a27h -(qz(/n the diagram below?

  The diagram below shows chromosomes during me314 zrpblr 2ywuea.fzcup6 0- iosis.


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 h pe/(ry(oo; jzx6vx7 of alleles of a single gene which would be present in the nucleus of a cell as a result of eachh/yepj(vo; x x7r6z( o process?

  Which keyword is matched to f7mbo9/ r i/oe-n(nnf4n -y*hueooi.the correct definition?

  Which statement(s) about mitosis is/are tru,ex4d25zcio m e?
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, whic33/qqc rlf+-k f0ohl1kboxx:k 5dxi/7/vt zvh letter points to a cell in anaphase?

  During which stage of mitosis does the nuclear envelope a e7- j00bq*)oosm ggfthvi(6break down?

  Which one of the following tranm zan-xosl4lor m4i3:6x. .sn sport proteins only carries out active transport?n-.snozim.6 xxl4l ao43sr: m

  Which process does not happen in the shoot w25d blh)r *x hbtunyn9ul91(apex?

  Which type/s of membrane transport do/does 65e pqz- yr*vdnot require energy expenditure?
I. Facilitated diffusion
II. Active transport
III. Osmosis

  The diagram below represents a cell with a diploid number of 4. Which stage oc) /yjxqkbz97 f cell division is thejc kq 9x/)yb7z cell currently undergoing?

  The photomicrograph below shows a root tip meriste2 pcl ,/k c/bfkcqy++bm. Which of the following sentences correclk ,fyp b+kc/+q2ccb /tly defines a meristem?

  When does the random orientshvei /* h6ptu* 9k*pvation of homologous chromosome pairs occur?

  Which process does notzfpq - tz9q,dh,(sa: n occur during meiosis?

  If a cell with a diploid number of 36 undergoes mitosis, how many chlpbogwns9 : 7l800yf2j0wkqo romosomes will be present in each daughter cell after cytokinksqj 0oof8l7lwpy0b 0:ng 9 2wesis?

  The image shows a micrograph of a cye k9mnx-sc w741rnl p9x ce(v.r +e,lell.


What explains the appearance of the cell in the micrograph?

  Which statement(s) about homologous chrom a7qp*6xq jo5z/a 9cgcosomes 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.qg-ood) 0kob Down syndrome.

Which statement is not correct?

  In the cells of a horuep(4wl ) rnxn31t */bjprlm0se (E. caballus) during prophase I of meiosis I there are 64 chromosomes. What is the haploid number of chromosomes1pnr w *u3r0tebxj)nl4ml/ p(?

  Which arrow is pointing 5y0fxmbb3-/is 9z o09 8 jhjlk dz5kgmto a chiasma?

  The diagram below represents the structure of a shoot apical meristempby0j)9 mcpsv5methw7. - 5hl. Which row in the table correctly identifies the processes occuring in the structures labeled in the diacp. yp5v j-h s75m)mhew9 btl0gram?

  How does meiosis promote vw)n:o jopjz 8w0f9( eaariation?

  Which of the following statements 79tm,aw6t r jwis/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 tm5ol/e;myc b 8mqjwm4v1(yd *wo 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 5 h02)hyofgtwprimary tumours as a result of the movement of cellwhoyf 2h0)tg5 s?

  How many chiasmata are present in t662hwg8 na dtuhe diagram?

  Which statement is a similarity between cytokinesis in animal and plant cellsv 2vqpov9oam9 7v06vc?

  Which stage of meiosis is matchvabubjsmi nz5 sx739vr997c-ed to the correct description?

  Which statement(s) a+db5d 8ng- xc (pf.tjare true 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. Thi;c mbdlwh8f.4 s results in the formation of one4 h8.mbdlf cw; large cell and one small cell. What is the fate of the large cell?

  Which row correctly descr,) 38vmo:gp ggy7bbj libes diploid and haploid cells in humans?

  The following table shows the diploid chromosome number skd 5h/tb4,p st:7 ravof a range of species.


Which of these statements is correct?

  What conclusion can be drawn mditjoz1h n4f+*tzb .fdx2( . from the karyogram below?

  Which of the following processes is characteristic of the meiotic and notzemjtj96j 8ukh/tyj1z)ie 9q + 3m3 jq the mitoti)jmkjh3jzeq/j 1y+jz9t tuq3689 me ic cell cycle?

  The diagram represents a bud witm 1)7cpfdp+xi h 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) is 48i1s+5 /oiyr u 0gpvxw8. Which row shows the correct chromosome y 8o+0w/viu5 r1xipgsnumber for different cell types and cell division stages?.

  At the end of which phase oq,4tju hnqi+lsa( d;m) 7ezb)f meiosis I does crossing over occur, and what is the oza7 se+)dmqu(l;q) i 4tnh,j butcome of crossing over?

  Which of the following statements does not describe a step in f3twn y.5*se;5c lb7 djnt2zbthe sodium-potassium pump cycle in the neuro7nybj stw5db 2l* fzc t.;n35enal cells?

  Which row in the table below is true of meiosisu3hq9 k t gz*dc+57u7ftxno0k?

Membrane transport is importanid 6rm1;0d qblt for allowing particles to move across the cell membrane and respond to changes in the cherld ;b 1i60qmdmical 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 cel -zy4ivk/uwwxr rmae0c* 9-haa1b -f2ls.

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 zc 5v i1zjd9n9cell cy5vij1 z9zdn9c cle. Which cyclin is involved in preparing for DNA replication?

The diagram below shows chro :e0d;4g ljw u/f1s f-rssdw9lmosomes 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 homologo )ex-bzr+ rqt pm6/1d ez+rz/tus chromosomes?

  The mitotic index of throaat8: cxz ltxjy/+o*u ,t tissues taken from 4 different patients is shown below. Which patient is most l: ta*ouczly/x8,+ xj tikely to have cancerous throat tissue?

1.Draw a labelled diagram to represent the process of cro brae. ls43g+u 6q;kuqssing over.

2.Compare and contrast random orientation and crossing over.

3.Outline the stages of meiosis.

  The image shows an abnormaldsj ch)y j( ;8 )9yr7bxyarot) human karyotype.


What is the abnormality in this karyotype and its cause?

The graph below shows the relative s;4:rhv1nbx 5g6tnnx5rutq 0amount of DNA in one cell during one complete cell cycle. Each letter represents one stagesurnxbg55 rt;n04h6: q1vtnx 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 3gv-pwu7vp b+ cross between a male cat that is homozygous for brown, long hair and vw7b +gpu -pv3a female cat that has black, short hair.


Which of the offspring has a recombinant genotype?

1.Outline how polygenic traits can show a normal distribution. ;s fqzz 0lj)5o

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-sisticc/1) c m2et-x zkc5ser chromatids shown in the diagram below?/1tc 2c5cx iez)cks-m

  The photomicrograph shows a pollen grain from L. cabhd,r17n veu .ndidum (Lily). Which stage of meiosis is s 1vbh ,rd.ne7uhown?

1.Outline the events which would lead to an injq c)t7/,to mfdividual being born with Down syndrome, which is characterised by the presence of three copies of chromosoq fot7)/j ,cmtme 21.

2.Explain how meiosis increases variation.

3.Outline the stages of meiosis.

The mitotic index is an indirect way of measurini.r 7i)q b;dxng plant growth. A study was conducted on white onions (Allium cepa), under controlled conditions in a lab, to inves.b7 ind;qixr)tigate 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 diagraii2muop ; x*d5( tt8tdms below show two cells from an organism with ;8tmi25x*du otid( pta 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 expression in stem growky 7qt.-.pzq mth.

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 different spi/p;3c+q;/aqda zxs; 8 aacztages of meiosis. Which row correctly names each stages+ p3/xaaa8z;iqc; qdp /zac;?

  The micrographs show four phases of meiosis I inq*):3g bhlrzx5:ykd+3bao l q a plant. In what order do these phases *:5kgqa+q obd3r)yzb :l xh3loccur?

Mitochondria are responsible for supplying metabolic energy in eukaryotic cellshkti51u:ax0j0q yu /st13y i t. 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 aj50yu1ty xk3t/0q1:tiis hu 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 stages of the cell /0 o,8 s4j +lv qcuxw:djey2xhcycle in four samples of lung tissue fdv,xsxhec4 :j 8wqloju+y/ 02rom four patients. Which tissue has the lowest mitotic index?

  The diagram shows thefi8 cm6, dzxo1 dominant cyclin/CDK complexes at different time points in the cell cyc 68iozdf 1,xcmle. Which cyclin/CDK complex activates DNA replication machinery?

  Studies have shown that genes such as Cyph+t8jh :85wo .zagd cclin Dependent Kinase 3 (CDKN3) are highly overexpressed in cervical tumours. ad8h c:zgop 8+t hw5.j


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 rp- n2r81y lnzd-l3 znhighest during the cell cycle ?