The graph below shows the relationship betw:lvc(,w t, ttfeen maternal age and the incidence of non-disjunction. What relationship is suggestedc ttft:vlw(, , by the data in the graph?

  Which stage of meiosis is represented in the diagram bel,laa1)dm m.x cv;c ,qpow?

  The diagram below shows chromosomes q7 u72s +h/ dqoggox5hduring 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 sinx:xav ppbmh6pk4z*fnb *(,*ygle gene which would be present in the nucleus of a cell as a result of each proces*x:pk4*y b6mv*na pb z(p,fxhs?

  Which keyword is matched to thekr: +wjrao/); ng oou.)cti w-lll1j; correct definition?

  Which statement(s) about mitosis is/are trum:bw*-pr:syi x- a09n hz0r 8gwlqb* pe?
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 im4 p.ns9ha mz9n anaphase?

  During which stage of mitosis does the nuclear eqw 93 1;xnt)*t wmxeopnvelope break down?

  Which one of the following trsp1j1cc mi 3r5ansport proteins only carries out active transport?3cm 1s c51ipjr

  Which process does not happeqm kk+,mck* 0gn in the shoot apex?

  Which type/s of membrane transport do/does not requireje95yl c 6ey 0 y87:w2vtgfju r)zr0xr energy expenditure?
I. Facilitated diffusion
II. Active transport
III. Osmosis

  The diagram below represv9fxv :-dq 6ooy q;e7xents a cell with a diploid number of 4. Which stage of cell division is the cell currently undergoing?doq 7y;qx- :vv 9e6xfo

  The photomicrograph below shows a root tip meriste5vi a9m*shi(em. Which of the following sentences correctly defsm(iieh*9v5 a ines a meristem?

  When does the random orientatioedtt7 p)t5lvx5 ppz, 6yg10wqn of homologous chromosome pairs occur?

  Which process does not occur during meiosis?q dj0sr8me:exee+8l l0j 9 *uv

  If a cell with a diploid numbb7fj ,:fo hld+er of 36 undergoes mitosis, how many chromosomes will be present in each daughter cell after cytolf:j, hof7 b+dkinesis?

  The image shows a micrograph of a cell. .8rt;ild gv;v;d k 6bdc*vxk/


What explains the appearance of the cell in the micrograph?

  Which statement(s) ab+h grkhg4gl 12q8wf l;out homologous 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 4mglo1bbbxc hw j/j0ga.1 b7*v +1 yaaindividual with Down syndrome.

Which statement is not correct?

  In the cells of a hoa8vgqnnh5it3 /w z,zm6 2uhu2rse (E. caballus) during prophase I of meiosis I there are 64 chromosomes. What is the haploid 5zg,h6umn t a3i q 82/n2wzuvhnumber of chromosomes?

  Which arrow is point 0 og0-tx,c y.k;kzpsying to a chiasma?

  The diagram below represents the structure of a s.1xr aev; n wicz;k/-ehoot apical meristem. Which row in the table correctly identifies the processes occuring in the structures labeledce;akz- 1nexv.wi;/r in the diagram?

  How does meiosis promote v07a15 pcqrrat*: jnhi ariation?

  Which of the following statements is/apt;qv* ::p l0n4dpobt re correct for meiosis?
I. It is a reduction division
II. It involves random orientation
III. It produces genetically identical cells

  The diagram shows gamed d7dp .d/jmhun29 tg7tes produced 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 primsc j40h7x3ym (uvm9w)q8 pdnuary tumours as a result of thexh)msvnuw(8mj 4y q 07d3cu p9 movement of cells?

  How many chiasmata are p*mn:f d8w c5f)r iri7hresent in the diagram?

  Which statement is a similari9fdg o-ef *4wpty between cytokinesis in animal and plant cells?

  Which stage of meiosis i9knlw -4t ;myhs matched to the correct description?

  Which statement(s) are true of meiosis Iq6ohp4k w2o.x 7prc6 teq1e4 j 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 f jjj fer-;a9il3rs ;0the first meiotic division. This results in the formation of one large cell and one small cell. What is the fate of the lalr0jffjei9 3-jr sa ;;rge cell?

  Which row correctly dsi 5 rs*w:vvf a n/gnl3oe15)fescribes diploid and haploid cells in humans?

  The following table shows the diploid chromosome number of a range of species. dh1l 4(0b;tjb igan-0b dwmnk i:/cw1


Which of these statements is correct?

  What conclusion can be drawn from the kafo320+ 1zcac1vcn-px(wje/oyl qhy2ryogram below?

  Which of the following :rg 3,ra yy1suk.q5 hsprocesses is characteristic of the meiotic and not the mitotic cell cyclra ugr,yk1qy: hs.3 5se?

  The diagram represents a bud with a shoot apical meri7cmw76xd- u eestem.

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 tehf/9 yq6. f2beibp6x)+gwvz roglodytes) is 48. Which row shows the correct chromosome number for different cell types and cell division sfqg 2zbw/x ev ) 66pebf+.i9hytages?.

  At the end of which phase of meiosis I does crossing over occur,sd *imk3 :upe ad3*o 8pyuhtlr2:5* wl and what is the outcome of crossing ove*w dm:3d aik*:t3 *p8lhyue2up 5olrsr?

  Which of the following stat4wo ,+gu jda/gements does not describe a step in the sodium-potassium pump cycle in the d /juag+4w,og neuronal cells?

  Which row in the table 0ht.ny5kg gk. below is true of meiosis?

Membrane transport is impx tk4h4d,s-cl ortant for allowing particles to move across the cell membrane and respond to changes in the chemical composition ok4 cd4x-htsl,f 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 il rf7d 8 ab,ksr::f,. 4hurvwrn 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 differx712)tb l1xbzem3*pu vija e 2ent cyclins during the cell cycle. Which cyclin is involved in prepaatbui*2e 1) jp7ev2 1xmb z3xlring for DNA replication?

The diagram below shows chromosomes during meios7f*7uhhycr 5 fis.

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 c)zap-k uz6w,homologous chromosomes?

  The mitotic index of throat tissues takea zx1sua650r kn from 4 different patients is shown below. Which patient is most likely to have cancera5u xsa0 z61krous throat tissue?

1.Draw a labelled diagram to represent the process of crl:f3 ebfw*8rrossing over.

2.Compare and contrast random orientation and crossing over.

3.Outline the stages of meiosis.

  The image shows an abnormal human kar56d/.ogm *o* 5a +cxiagu gctmaqh3g1 yotype.


What is the abnormality in this karyotype and its cause?

The graph below shows twwdig x 79cdsg k07el8+4 f:pqhe relative amount of DNA in one cell during one complete cell cycle. Each letter represents one stags8lkw7d exgqdi:097 cw4g pf +e 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 alj4 04:fcnn ftqfri1/ male cat that is homozygous for brown, long hair and a female cat that hasql 01tc4:i/nf rfj4n f black, short hair.


Which of the offspring has a recombinant genotype?

1.Outline how polygenic traits can nj dq 8/rf4e/db5r+szshow 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 over b1ytv keu9b 6o(l ,dbc3c6m(nof non-sister chromatids shown in the diagram be 6 6tckcyum( 9voeblbdn(,13blow?

  The photomicrograph shows a pollen grain from L. candidumnhu),yy( v9lv (Lily). Which stage of meiosis v(n9 uhl yv,)yis shown?

1.Outline the events which wou 5/ouu(zzgmq;qw y9 1hlfg 7c1ld lead to an individual being born with Down syndrome, which is characterisedowgu9q( luf m15zh/c;q1 7zgy 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 i q gjrq: .*we:n:+v2ity ibbg*ndirect way of 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 mitotic index of th:ne.*vjb irw 2b+q:iy qt*gg:e 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 way8)gysf;v9 b4z rjffp1f x +:wqs in which cells can divide. The diagrams below show two cells from an organism with a diploid number (2n) of 8ff w8fysfq :) vz4 r1+gpbxj9;.


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 growth. :3o + d0ookd9xm,k rtj

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 ,cc :vvzx r+cw,9 ds3scell, with a diploid number of 8, in different stages of meiosis. Which row correctly names each v9c3c:w v dsrc ,,xsz+stage?

  The micrographs show four phases of meiosis I in a plant. In what orderp* d9jw )tvew( do these phases occur?tvw ()9*wdpje

Mitochondria are responsible for supp b7sb(q)pcbp3mv d6z4lying 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,3dbqz ppcsm4)bv7 6(b 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 stages of the cell cycle in djq0c 2*jt;htv 7)n ayfour samples of lung tissue from four patients. Which tissue has the lowest mitotic ijaqydnv)j th*; 720tc ndex?

  The diagram shows the dominant cyclin/CDK complexes at different time poy*an.(l i*pgas,;idsints in the cell cycle. Which cyclin/CDK complex activates DNA replication machini*lgd, s;iasy* (n .apery?

  Studies have shown that genes such as Cyclin Dependent Kinase 3 (CDg,y40n8/ b rd-i. (smiweje bkKN3) are highly overexpresse gnd bbiyek ,8i4(/-wem.0r jsd 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 cycr b)r,xqlo ;lp*yniual-97 p-lin E the highest during the cell cycle ?