The graph below shows the relationship between maternal age and the stxx2+d,x1akm 3/uz 1hssvi0 incidence of non-disjunctio2x,m1xti zsd+ xs 0 3s1ahuv/kn. What relationship is suggested by the data in the graph?

  Which stage of meiosis is ira asbx9/63l df0kw-represented in the diagram below?

  The diagram below shows chromosomes during mmmtq2ejh4mo1.1y )x ceiosis.


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 gene whcf3 f.hzs9t n,ich would be present in the nucleus of a cell as a result of ,nf3sfc. t9hz each process?

  Which keyword is matched to swax+8,f2nzmv l :d/* zz2rgbthe correct definition?

  Which statement(s) about mitosi ss2z2/n5 )es2ye kuhos 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 to a cell inxhrybbup0+ :(,,t/b z4vffhgrnh9h jxa6 r) 8 anaphase?

  During which stage of mitosis does the nuclear envelope break dow7 ksaj q-u;xl6n?

  Which one of the followin dg 18d6yom;t qyh4nyu2g,vxw-ywh/9g transport proteins only carries out active transport?nw dgqmyytw d;h,/vo -y9hx 16g2uy84

  Which process does not happen in thdo5w: p kxnx3kg s8:)g/cyyr 3q 3uv9ce shoot apex?

  Which type/s of membrane transport do/does not require energy expenditure;t)0 y w(h*7wbu o6w 1pcduygu?
I. Facilitated diffusion
II. Active transport
III. Osmosis

  The diagram below repre(g-8v;a (pm3defn *fw jgg7 rusents a cell with a diploid number of 4. Which stage of cell division is the cell g(;dg8 jme(-3*uvg aprf7nwfcurrently undergoing?

  The photomicrograph bel bfpm-dy(* fxwyr- *pmpy3*; mow shows a root tip meristem. Which of the following sentences correctly defiyy(*p pb*-mwyfm 3r d fm;*px-nes a meristem?

  When does the random orientation of homologous3;h*vas-gmno .yjks :fb5(hu chromosome pairs occur?

  Which process does not occw rpn8d r.snqb/ +2wtuj8:qp-ur during meiosis?

  If a cell with a diploid number of 36 undergoes mitosis, how l,j2u )s45iep,oh m d b5irq(rmany chromosomes will be present in each daughter cell after cytokines bp ri 2ujq5h4e 5(,s,omr)ldiis?

  The image shows a micrograph of a cel;kh j,c kl6v6ll.


What explains the appearance of the cell in the micrograph?

  Which statement(s) abo1m,r h;nthqb2 c rq:-nut 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 individual w)f bm-e8xn, nww-xk5mith Down syndrome.

Which statement is not correct?

  In the cells of a horse (E. caballus) during promb:tps 9 brsp*ced3 c406fn( qphase I of meiosis I there are 64 chromosomes. What is th6qpbmtrcf:pd0 4 * 3 s9nbec(se haploid number of chromosomes?

  Which arrow is pointin-m r vyb*+9vrbg to a chiasma?

  The diagram below represents the 2csaxz,g:* vsstructure of a shoot apical meristem. Which row in the table correctly identifies the processes occur :g*ca2zs,vx sing in the structures labeled in the diagram?

  How does meiosis promote va. oi80kozl /t7;rft1 rfydo1a riation?

  Which of the following statements is/are correct f3k- zwkmde o hn7qbjs3 -s*8v3or meiosis?
I. It is a reduction division
II. It involves random orientation
III. It produces genetically identical cells

  The diagram shows gametes produclet2 bi 7)wkj2s5diaogso1 5 2ed 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 primary tumoursj6w+,7wrj ywy as a result of the movement of cell7 w6,wjy yjr+ws?

  How many chiasmata are pree8x iu5 cdv/iupi 62cq1v-h.xzn )e0osent in the diagram?

  Which statement is a similarity between cytokinesis ink6xr86 y j;ej5uhd v:y animal and plant cells?

  Which stage of meiosis is makz/y19bgldt y5yt; (vtched to the correct description?

  Which statement(s) are tra4hwrm sd5i97zn)jt + jg,ln(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 afteroyy2kf9f i0t emi*prra-se 6k1(p2 i, the first meiotic division. This results in the formation of one large cell and one small cell. What is the fate of the2ipitsrae y pyi k r6f-0*ok9(2 ,1fme large cell?

  Which row correctly de6qgc95v jty)yscribes diploid and haploid cells in humans?

  The following table shows*)b(b r f3rmuy the diploid chromosome number of a range of species.


Which of these statements is correct?

  What conclusion can be drawn from the karyogram bekf-+eud4j;4 +7yz (ilf nbcndlow?

  Which of the following processes+z c(sos :-r x:v(tniu is characteristic of the meiotic and not the mitotic csor(z t:+x:( i-uscnv ell cycle?

  The diagram represents a bud with a shoot api3 3iqal;al7hecal 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 troglodyqr7 xmb;ylm7(j7a3eam)ych 0 tes) is 48. Which row shows the correct chromosome number for different cell types and 7q; jmh(73cx lrbyam )ae0m7y cell division stages?.

  At the end of which phase of meiosis I does crossing over occur, and what is th/a3a.oge;+nd5 invw w e outcome of croo av3da;.n5w+ge/nwissing over?

  Which of the following statements does not de rp.472ggi g/ yjzlnk7scribe a step in the sodium-potassium pump cycle in the neuronal c2/ijgypk7 l4z rgg 7.nells?

  Which row in the table below is truec9v6d1 j-g pwp of meiosis?

Membrane transport is important4ttb2 o,a9;5/xwapkdxo+q 5tydt c :a for allowing particles to move across the cell membrane a:9 acyaxxb; p5awo4 tt2dqtt5d,o/+ knd respond to changes in the chemical 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 cellnqf+dg84v u; o2gvyi0 s.

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 cn/ kp+qm7j vr)ell cycle. Which cyclin is involved in preparing for DNA replication/7 )j +qknmrpv?

The diagram below shows chromosomes during 17a ow,c /wwoxmeiosis.

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 homologous chromosomesvo ou;81l( euo?

  The mitotic index of throat tissues taken from 4ol f88gn,uh8y different patients is shown below. Which patient is most likely to have cancerous throat ti 8gnl8yo h8f,ussue?

1.Draw a labelled diagram to represent the process of crossix 0qxbr q/( itq+5rc;dng over.

2.Compare and contrast random orientation and crossing over.

3.Outline the stages of meiosis.

  The image shows an abnormalvj2/e9tdr gxfn3t4+ + etlyn; human karyotype.


What is the abnormality in this karyotype and its cause?

The graph below shows the +k vt*dyiia)5 x+d7 ehrelative amount of DNA in one cell during one complete cell edidiaxhky5 7+ *t+v )cycle. 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 betwee z+i alr+;5rdm-eh vsjt)5*hon a male cat that is homozygous for brown, long hair and a female cat that has black, shorteivo;l a -5rh+ms th5z*d+) jr hair.


Which of the offspring has a recombinant genotype?

1.Outline how polygenic traits can show a normal distribl06 moxc ;t9wl32k3bt biw5bvution.

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-sister chromatids sh xv,e80*k cs)b.nqt yoown in the diagram b, nk8txe)co y.sbv0q*elow?

  The photomicrograph shows a,sin3mi(c :f 0q;wif+j5heni pollen grain from L. candidum (Lily). Which stage of meiosis is shown? qi ; is3 0f(ncei,m+iwj 5f:nh

1.Outline the events which would lead to an individual being .tz+c9l ne 4fg 6kldl6born with Down syndrome, which is characterised by the presence of three clnldztf6 6c4lg.e+ k9 opies of chromosome 21.

2.Explain how meiosis increases variation.

3.Outline the stages of meiosis.

The mitotic index is an ind 1ynsnc m+a.d/irect way of measuring plant growth. A study was conducted on white onions (Allium cepa), under controlled conditions in a lab, to investigate the effect md.s+y nac /n1of 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 whb8ho ww*um vt80sxhdaf 2.72 nich cells can divide. The diagrams below show two cells from an organism with a diploid number (2nhsu w*x27 fav dth.88om02 bwn) 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 in3adi/ /f ugek. 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 num ;9wt9p wv2 8myfrr,o-qry+ve99 kdxw ber of 8, in different stages of meiosis. Which row e+ry8wm9rv2-t9wy9fpk ;or,9qxvd w correctly names each stage?

  The micrographs show four phases of meiopg :0sae+jsnuf5ajee6cc2dv o eg7- *:. vv/ csis I in a plant. In what order do these phas0 c: fsvvag.es*2/cpcvegen jue+6-do7 5: ajes occur?

Mitochondria are ress+,4iwa lmk q7ponsible for supplying metabolic energy in eukaryotic cells. In most eukaryotes, which reproduce by sexual reproduction, mitochondrial Dm+w7l,i qas4 kNA (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 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 cy5z)u; :ye lvnccle in four samples of lung tissue from fourv5ucyln ez :;) patients. Which tissue has the lowest mitotic index?

  The diagram shows the domi e:: (t;usb qmggf7bx0nant cyclin/CDK complexes at different time points in sb0x 7 :g:e;utg(mbfqthe cell cycle. Which cyclin/CDK complex activates DNA replication machinery?

  Studies have shown that genes such as Cyclin Dependent Kinase 3 (CDKN3) are hig- /j it jbr6w/- lc)a4 zsfl-)pbu0brghly overe-)cr)4ui-plj0 babsglbw fr/t6/ -jz xpressed 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 cq 8io n4lo1swh .+suq;yclin E the highest during the cell cycle ?