The graph below shows the relatio+b )j+*ql wqfx9z- m:(mymq lunship between maternal age and the incidence of non-disjunction. What relationship is sugges j +qu9mm)qm+:bz*l- yx(fwlqted by the data in the graph?

  Which stage of meiosis is represente aqv-+ :sux0qkd in the diagram below?

  The diagram below shows chrolz5t w r/)4gyomosomes 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 single g+r-wwen0 zrk *ene which would be present in the nucleus z e+w*-k0rnr wof a cell as a result of each process?

  Which keyword is matched to the corr:0fvmq(fzm :0xz ixn 1 77oupzect definition?

  Which statement(s) about mitosis isx iid5:g9t v0sy v6c7j/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 7 q83ez1 lmltm32hg hza cell in anaphase?

  During which stage of mitosis does the nuclear envelope6sirc.,l2t lu ltns9 e a,/u0h break down?

  Which one of the following transport proteins only cavuhem 2xy2gx x2 21b06,kirqcrries out active transport? ,ikx0uc62 1gr 222ymxvhx qbe

  Which process does not hojb 3ib0n,g +dm r/cl-appen in the shoot apex?

  Which type/s of membrane transport do8ft:e5: l++mdd7cp6i p clzfe/does not require energy expenditure?
I. Facilitated diffusion
II. Active transport
III. Osmosis

  The diagram below represents a cell wiju1e1i tl,anb/ jpj;0th a diploid number of 4. Which stage of cell division is th;aipb10 juj/t,jen1 le cell currently undergoing?

  The photomicrograph below shows a root tip meristem. Which of the followihbbfx7 ) 5 w41l 4 o(ykqq8h*hktjyyg2ng sentences correctly defines a meristemq*12kh 5)t 4fkhy(qy 8gy7bowx blh4j ?

  When does the random orientation of homologop./vm0cqaf* r us chromosome pairs occur?

  Which process does not occur durinp+ 8v1r *a b*4cehsi+).gvby. fpnq qng meiosis?

  If a cell with a diploid number of 36 undergoes mitode:bdiq:nc e. hw 6+w0sis, how many chromosomes willd+ie.wbe:q0d w c n6:h be present in each daughter cell after cytokinesis?

  The image shows a microgr**p ,o 0eai3he-jf bstaph of a cell.


What explains the appearance of the cell in the micrograph?

  Which statement(s) about homologous chromosomes is/are c: 3pvak7b+ruvmmtu64x/ )b wnot 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 individualq+i6f/ k dpe/n6qmv 8t with Down syndrome.

Which statement is not correct?

  In the cells of a horse (E. caballus) durintjik*n5 hi* n+g prophase I of meiosis I there are 64 chromosomes. What is the haploi*hn kn ij+i*t5d number of chromosomes?

  Which arrow is pointing to a chiasma2b 53ix5x ejeg?

  The diagram below represents to:w( hby 2f2wmhe structure of a shoot apical meristem. Which row in the table correctly identifies the processes occuring in the sm2bwy(wf: h2otructures labeled in the diagram?

  How does meiosis promote variation8 (1oc ur naalbc.;eo /iodsu14scc.+ ?

  Which of the following statements is/are correct for meyv2tkx)h:ypz+ mt.i 3m 9u 6foiosis?
I. It is a reduction division
II. It involves random orientation
III. It produces genetically identical cells

  The diagram shows gametes produced from k8;n pdnco4vgo,(fvh-.ni ( k6 +dwzm 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 tumour)d+plvn5aj q;nds.m j:a hpokop28(-s as a result of v+.pp)o m;oqak anldjsp2n (8j: h-d5the movement of cells?

  How many chiasmata are present iniey*3;;oi4h;id+ g owy rzhxbt 1,8e o the diagram?

  Which statement is a similarity between cytv7qo9cbr( 5euokinesis in animal and plant cells?

  Which stage of meiosis is matched to *n ,iqmy b(ooz+pqb51 the correct description?

  Which statement(s) are true of esrbcrg+ )/ d3meiosis 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 aftec4ay ;xr,ed3t2 uy0 clr the first meiotic division. This results in the formation of one large cell and on rtu04ce ;2dly3,axy ce small cell. What is the fate of the large cell?

  Which row correctly describes q90lz *zt:,ek/d havd*xw5yp -sa a .idiploid and haploid cells in humans?

  The following table w(b 0ot9 xiq;mshows the diploid chromosome number of a range of species.


Which of these statements is correct?

  What conclusion can be drawn from the karyogram b73 +lz)g-ow e y+nbpotelow?

  Which of the following processes is charactyd x:24gho,lw eristic of the meiotic and not the mitotic c lw4hyg:2o, xdell cycle?

  The diagram represents a bud wimg3t:ac,gweidg- 8o.oar f+:pcd4i *th 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 48,lpp:nd0u h(a-3 d8 kqkgh2 ;fc+ek dk. Which row shows the correct chromosome number for different cell types and cell divplg:;,d8+ ceh3 kfk dkn0qdk h2ua(- pision stages?.

  At the end of which phase of meiosis I does crossing over occur, and what is t/ zb: fpowxf-+hezfw/po b-: +fx outcome of crossing over?

  Which of the following statements does not describe ahb:,mqq 5us 6y9 z(dhg step in the sodium-potassium pump c6uqb5 (hd:mq y,sg9zhycle in the neuronal cells?

  Which row in the table bemq; )l88 6 z )xjfwwa4dkpzcs(low is true of meiosis?

Membrane transport is important for allowing particles to move across the:7 x- 5pgpz n2znjyo1p1 ida-nc:3oxq cell membrane and respond to changes in the chemical composition of the extracell1 2nn xo 1:oczy:5a7g-n3ppjqipz-x dular 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 regulae6 m)ex5xxa 8l7hcsa9:fzs3 dted 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 hf0a7+tbp n2h.7liqc+hs n e3concentrations of different cyclins during the cell cycle. pn+c0q727e3ilhh hf sb. tn+aWhich cyclin is involved in preparing for DNA replication?

The diagram below shows chromosomes during 2mg8d o,cwni ;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 involvs-04xv-y q ntn9;s axe6jbo- bes the separation of homologous chromosomes?

  The mitotic index of throat tissues taken from 4 different patients is shrduy20 ,rz7vky 2jd9 j4x+rxfown below. Which patievz 4xd +0dr 2,urk9fxyj 2y7rjnt is most likely to have cancerous throat tissue?

1.Draw a labelled diagram to represent the process oz dx5i9s uq.c4f crossing over.

2.Compare and contrast random orientation and crossing over.

3.Outline the stages of meiosis.

  The image shows an a,ft/r(u c/qjmbnormal human karyotype.


What is the abnormality in this karyotype and its cause?

The graph below shows thna szr,b.sy.d xa:x6qn, : 76ump 4hipsc7v m:e relative amount of DNA in one cell during one complete cell cycle. Each letter represents pm4,cnha. p iby,ss7 :7:n : dmx 6q6ruzx.vasone 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 y/eos:f3o gy rn1 26p;aoqpi; a cross between a male cat that is homozygous for brown, long hair and a female cat that has/361ayngpo: rsyoop ;e2i;qf black, short hair.


Which of the offspring has a recombinant genotype?

1.Outline how polygenic t.:( f0epcvs fonqa5tj3z dm4(: wj1wbraits 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 crossing ovehz 56dbu-24d:be9x5/8fe jg az quqt mr of non-sister chromatids shown in the diagram bf 9eba /d8ub5qqumhg-x62 dte: 45z jzelow?

  The photomicrograph shows a pollen grain from L. cae 9z ;q00zq8zwzpw nm3ndidum (Lily). Which stage of meiosis i0 q3;mwz9zq0zwe8z p ns shown?

1.Outline the events whicbg9dhuil8eh ;7/ zp*uh would lead to an individual being born with Down syndrome, which is characterised by the presence of three copies of c* zhe upd9i8lu7 /hgb;hromosome 21.

2.Explain how meiosis increases variation.

3.Outline the stages of meiosis.

The mitotic index is an indires9ay8kk oo s*;ct way of measuring plant growth. A study was conducted on white onions (Allium cepa), under controlled conditioy; o kks*8sao9ns in a lab, to investigate 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 ca+y5:ul 95e lphf.dz m9ri;w +,yzxgodn divide. The diagrams below show two cells from an organism with a diploid number (2n) of r y;9.m:zwpd+5l+ylh e5 u xod 9fiz,g8.


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 expyp g,d4rjonn7na6:dk7 *usixya6r 7(ression 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 differefsvp(l286fm 6wm h* swnt stages of meiosis. Which row c*w6fvlm6sf h(2ms8pworrectly names each stage?

  The micrographs show four phases of meiosis I in a plant. In what order (oq*6:/aku*mx n emwq do these phases6 wua(mxe/k*qnmq *:o occur?

Mitochondria are responsible for supplying metabrbh. ) tm5c)*xs rifp7olic 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 eukary*m57)x psrr. b)iftchotic 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 ofig b. ypdl .l ,:c;zct,cr0qo- cells in different stages of the cell cycle in four samples of lung tissue from f,g:q ;topl 0dlzyc,c. bic .-rour patients. Which tissue has the lowest mitotic index?

  The diagram shows the dominant cyclin/CDK complexes at different time points ,l vzfju 2/od,in the cell cycle. Which cyclin/CDK complex activates D,z2jo /duvf,l NA replication machinery?

  Studies have shown that genes such as Cyclin Dependent Kinase 3 (CDKN3) are highm(v bbuh -*0inly overexpressed in cervical 0v ub(*in-mbh 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 concentratiou urqbpd*lf0o zh2*)5n of cyclin E the highest during the cell cycle ?