The graph below shows the relationship between maternal age and the incidean:2 hprx5jf 9 -gryh0nce of non-disjunction. What relationship is suggested by the data inag9x-jyhrfh5:0n2 r p the graph?

  Which stage of meiosis 1/wba 9o ger:vis represented in the diagram below?

  The diagram below shows chromosomes during meio69.cysio/jj-6 wd zzva3ebi 0 m z)4gvsis.


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 allelesb6qw(dw:yqt ) of a single gene which would be present in the nucleus of a cyt6wq ):( dbwqell as a result of each process?

  Which keyword is matched to the correct definit3g11x.o kp)rajj5u dgion?

  Which statement(s) ab)orm2 m24*xf6 7dfs j 5fkslqcout 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 to a cell in by3r2sa:-r ).k cko jfz zpn2p.e* l6banaphase?

  During which stage of mitosis does the nuclea g6vyd7kdkuw r;uz;u(f:(enia s:61b r envelope break down?

  Which one of the followi0cvr b)fv-92 q(qdy vbng transport proteins only carries out active transport?y(29 )vvbqcvdf-b q0r

  Which process does not happoljozd t n t7vfywua80; c)03;en in the shoot apex?

  Which type/s of membrane transport do/does not require en( p+/1m1gfpyan7 qgavergy expenditure?
I. Facilitated diffusion
II. Active transport
III. Osmosis

  The diagram below represents a cell with a diploid numqw bmpp4b 2vju pm531m q76i9kber of 4. Which stage of cell division is the cell p32w 1k6 b45q7ujq bppm9vmm icurrently undergoing?

  The photomicrograph below shows a r4klcc*chp 9 v3oot tip meristem. Which of the following sentences correctly*cchk94l vpc3 defines a meristem?

  When does the random orientation of i xb/y3h3tx:/ ; niozt6tjoc1 homologous chromosome pairs occur?

  Which process does not ou + ea+ivq ze+n:)umv;ccur during meiosis?

  If a cell with a diploid number of 36 undergoike*1am -8jmzavn/qj4x; yd; es mitosis, how many chromosomes will be present in each daughtev a8m4a1k;ey;-mijzq*/ nj xdr cell after cytokinesis?

  The image shows a micrograph of a/q7yxgdl(hw7 cell.


What explains the appearance of the cell in the micrograph?

  Which statement(s) about homologous chromosoesu/6;nv(n x umes 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 m9nvb*y .ns, 3fda ;pzwith Down syndrome.

Which statement is not correct?

  In the cells of a horse (E. caballus) during proph:tro.nn:kxvao n 9jl -c;g. h/ase I of meiosis I there are 64 chromosomes. What isxoljkn t.ac r-gn9o: /;vn.:h the haploid number of chromosomes?

  Which arrow is pointing to9(ulukssnl e;s 0lh2v.z(.ff a chiasma?

  The diagram below represents the structure of a shoot apical m9elhdzuh g+us ofhfi*em;.p7t,1 r )(eristem. Which row in the table correctly identifies the processes occuring in the strli9 *u+z7f(toh.ruedm )hghpsf , ;e1uctures labeled in the diagram?

  How does meiosis profrzbb1he me:bsly07j p 8,)j;mote variation?

  Which of the following state neh r0oh4mh23ments is/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 two homologous chro.y a1o2 g xam.4or 0ebohy9k+nmosomes.


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 pwy by /)s7( js;iracb/rimary tumours as a result of the 7(wi)as syjbr cyb ;//movement of cells?

  How many chiasmata are presentyc+ *h5;nzxqi in the diagram?

  Which statement is a simild/p 8d8 chyxj* yw6(bearity between cytokinesis in animal and plant cells?

  Which stage of meiosis isy s0, tga.vl:qmrjj03 matched to the correct description?

  Which statement(s) are true of g7 iw8ia k6ci4meiosis 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 5c;v99,j pn *r smpy,s/tctn joocyte after the first meiotic division. This results in the formation of one large cell*jn srpnpm;s/tvtj,c5y 9 ,9c and one small cell. What is the fate of the large cell?

  Which row correctly describes diploid and ha -p+ ct0wk2v5wmvqop9 ploid cells in humans?

  The following table shows the dipgj vzi32m5 b6 l*y+uvrloid chromosome number of a range of species.


Which of these statements is correct?

  What conclusion can be drawn from the karyogramvpyl)-x dm/3 q below?

  Which of the following processes is characteristic of the meiotic and not the miq,m ggi6 q2fm8totic cell cyc86f 2qgm,gm iqle?

  The diagram represents a budhb7o y ka* t-23nsd*ty7r 4o z;dm*ntiu.*mke with 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 trofb e* x(h0 qu;5ubqww)v)h t)vglodytes) is 48. Which row shows the correct chromosv x)(;w)v5*bhfeuqb) ht w0 uqome number for different cell types and cell division stages?.

  At the end of which phase of meiosis I does crossing o k6e1ilc.yt1e he. m3z/xvp6pver occur, and what is the outcome of crosscyh kp1el6p 1/ev.e6.txz3 i ming over?

  Which of the following statementsuwdvc txh: tdw mf .m82b,5i:;f)o5jz does not describe a step in the sodium-potassium pump cycle in them )twmdcw: djbf2t5,.i 58 zuf;:oxvh neuronal cells?

  Which row in the table below is t 0 knr+xxs4 m g/bkmflx hcy).93hhb95rue of meiosis?

Membrane transport is important for -;bftju4pt: pn(yahmx8miyz74m tr zxh3 *4 4 allowing particles to move across the cell membrane anhb4:f z u8a npmy 4 iyhx4m4tptx37(j;- r*tmzd 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 ce fgi8 cvi38;y4em1y( p:rvol hlls.

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 a 9d1un7- gjdt6sbo)t different cyclins during the cell cycle. Which cyclin is involved in preparing for DNA repl s 6addot)bgjt1-n97uication?

The diagram below shows chrob7 9cvo ke;u,xn0nk7lmosomes 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 homologous ujzq;xuo55 n9 chromosomes?

  The mitotic index of throat tissues taken from 4 different patienz:d *nmu njj40kbfj1 7ts is shown below. Which patient is most likely to have cancerous throat tissufkj10z n4 jdnm7:j*ub e?

1.Draw a labelled diagram to represent the process of crossing ovewozv6rip(m t6p- 18fq y6ifm6r.

2.Compare and contrast random orientation and crossing over.

3.Outline the stages of meiosis.

  The image shows an abnormp4 hcl0v4 ddp d1ppbjsh:yog4jx/+t2aq-8 e 7al human karyotype.


What is the abnormality in this karyotype and its cause?

The graph below shows the tx 5gt6*nkj9h relative amount of DNA in one cell during one complete cell cycle. Each letter jxt 9g6*k hn5trepresents 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 a male cat that is homozygous for bee-4t6ep; rvw rown, longr evepew;t -64 hair and a female cat that has black, short hair.


Which of the offspring has a recombinant genotype?

1.Outline how polygenic;r7)petq2jn/qm(fh7fc8 )py d-mu bc traits 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 reswkx86i p:i e myt9sb:(ult from the crossing over of non-sister chromatids shown in the diagra 9wmib6 p:8(se tx:kyim below?

  The photomicrograph shows a pollen grain from L. candidum (Lily). ps p(dhc(2fw: Which stage of meiosis is shown? p(2f: wh( cdsp

1.Outline the events which would lead to an individual being bo 3ses re8x h41+2.caci*od mzyrn with Down syndrome, which3a1 e zxo iy4c rs.+meh*28scd is characterised 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 wayis ypzz tze 8z(z* /o.,5/nnqj 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 /8*n,qsyj(p ozz ./5zztein z 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 t3ubdp- p1a,mb6ocy ,--hx c-cx cgp0two ways in which cells can divide. The diagrams below show two cells from an organism wtu, ,bc-byd -x pomcpgc1 c3xpa-h06-ith 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 gene expression in stem gpsgg(4u 0of7*kza 1 eirowth.

2.Outline how growth is controlled in the shoot apex of plants.

3.Explain the process and applications of micropropagation.

  The diagrams below show ae2soc4y-a;8)ktk6zr kiks 9pij +7ei cell, with a diploid number of 8, in different stages of meiosis. Which rc s8i2k9 koisk 4ekz+)76ejy-;ptai row correctly names each stage?

  The micrographs show four phases of meiosis I in a plant. In what order do thesek+ hh ti)xs(k/ phases occur? k(s /iktx+ h)h

Mitochondria are responsible for supplying metabolic energy in el7ybuo7 -8z5/um x 9 f-7swq+qxn wjjmukaryotic cells. In most eukaryotes, which reproduce by sexual reproduction, mitochondrial DNA (mtDNA) is inherited from only one of the parents: xm bz 7-ol+sqj /w9-uuxy58qjm77 fwnthe 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 inuvp p +s)nh ro)8 taay32evx*usz42+x different stages of the cell cycle in four samples of lung tissue from four 28s *xtoa pue vap+s+4u)h) rzx2yn3 vpatients. Which tissue has the lowest mitotic index?

  The diagram shows the dominant cyclin/CDK complexes at diff -zzhd-cqp2 oj*k;do(erent time points in the cell cycle. Which cyclin/CDK complex activates Dd2dkqp -(zoz;o*hjc-NA replication machinery?

  Studies have shown that genes such as Cyclin Dependent Kinase 3 (,nhabm2: fbt-,yjyh 0kh)2r c CDKN3) are highly overexpressedk,bj-t0 ,b2y)c hn:a mhy2fhr 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 concentratip565jq4o4qttg .g,vyusr/w son of cyclin E the highest during the cell cycle ?