The graph below shows the relationship between maternf3rp/vdz8) i (wshfd :al age and the incidence of non-disju83fri:z dwhd/s f p(v)nction. What relationship is suggested by the data in the graph?

  Which stage of meiosis is represented in the d 0oj h mxzb0vdk(:9+pjrp*dr(iagram below?

  The diagram below shows3bh cwthk02s9by f52u chromosomes 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 alle xcjfz vkzb :,h,5qbxc 1u*4y:ra-l r2les of a single gene which would be preb,j2lqyu: vzbc5 cr 1x r*ah-x 4,f:zksent in the nucleus of a cell as a result of each process?

  Which keyword is matched to the correct definvrl ,vrm8 8b0wition?

  Which statement(s) about mitosis jg60 qi-iswflw5 s f)ovlnp);g.o7.c 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 cejxr4gg:4o-ltxgru fl(q,c;x 0d :rf; e+ dd)jll in anaphase?

  During which stage of mitosis 6l hao+drpxw s4frk0c50f l,.does the nuclear envelope break down?

  Which one of the following trand2xq.qt6md7h8nv9jq q (t8zs sport proteins only carries out active transport?(768tjn dt q.z8q2dh qqv9msx

  Which process does not happen in the -u/1vgnao/eek fx,5w shoot apex?

  Which type/s of membrane transd,8qxc1 h .+sdi+x oof rl)5eaport do/does not require energy expenditure?
I. Facilitated diffusion
II. Active transport
III. Osmosis

  The diagram below represi--sa6fl h.tj8pvf ur7e)s*w ents a cell with a diploid number of 4. Which stage of cell division68.-h*riwe7 - l)spfst jufav is the cell currently undergoing?

  The photomicrograph below shows a root tip meristem. Which of the following s8:hcuncrw5c ht. r.7geif 4a3entences correctly defines a merifca34whn e.8u. rcrhgt 7i: c5stem?

  When does the random orientation of homologous chromosome payvxb)8 yt k*h8irs occur?

  Which process does not occur during meiosi7c lkc y4l84his?

  If a cell with a diploid number of 36 undergoes mitl601tvr j n0axz6wk6 vosis, how many chromosomes will be present in each daughter cell after cytok 0l1 6jnarxktwv06 6vzinesis?

  The image shows a micrograph of a cell.qo +6gik n00hf


What explains the appearance of the cell in the micrograph?

  Which statement(s) ab(m7 7 flvj/o rb;h7g ull52 8pteagbm3out 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 individua2w pbmo.- kb(eck c *ko zk*i-iui9-y:l with Down syndrome.

Which statement is not correct?

  In the cells of a horse (E. caballus) during prophase I of meiosis I there are l(*vd y1dgfwa81 afk064 chromosomes. What is the haploid number of chromos1v 0 y8wdkaa*f1fldg( omes?

  Which arrow is pointing to a ckz 6rr9skq33fhiasma?

  The diagram below represents the s gwx*0 vh(4b:nsf*cqrtructure of a shoot apical meristem. Which row in the table coqsw *4fcn:h g0xv( b*rrrectly identifies the processes occuring in the structures labeled in the diagram?

  How does meiosis promote var;p9s 6p5pj-u-b8 c 2i88kdaqqjwpsjz iation?

  Which of the following statemnb,5 ,cytvoxry +(dmb*.tn:pents 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 produce:woend1n : i9sd 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 tumhoe vv,hs1 ;+68scix0vf v5gnours as a result of th 58,envcgossh6vfxvh i;+ v01e movement of cells?

  How many chiasmata are present in lx cvb3 1p*7,0we6as*qa nr mothe diagram?

  Which statement is a similarity between cytokinesis in animubs79x7rnve iocodm/s8/6 p9 al and plant cells?

  Which stage of meiosis is matched to the correct descriptiq9s lgdx)x*l-y3u*)a0xrd rgon?

  Which statement(s) are true ob 8iq399vw,qdyd nd p.f 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 *(0k.zjd4 rdtid+mxlcxq8 6roocyte after the first meiotic division. This results in the format6 d0(+rjik lt r8cxd.xq md4*zion of one large cell and one small cell. What is the fate of the large cell?

  Which row correctly des axsra29f 9df1n1j+g6 pt fwv-cribes diploid and haploid cells in humans?

  The following table shows the ve s cv9/hj 0j f,/:t6qsf2rkddiploid chromosome number of a range of species.


Which of these statements is correct?

  What conclusion can be drawn from the kary(vls(7qshnvwwrm 3 58 ogram below?

  Which of the following heqx0f-a,l hm yt 8(p a10h3ceprocesses is characteristic of the meiotic and not the mitotic ctaq80x-l ym, 31h chphef0e a(ell cycle?

  The diagram represents a budsm2v:x iq k03/h m4ltkh5y1ix 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 troglodytes) v7c0ma* m quq7is 48. Which row shows the correct chromosome number for a *v qcqu70mm7different cell types and cell division stages?.

  At the end of which phase of meiosis I does crossing over occur, and what:a .(/ss2v+uelm eib z is the outcome of crossingb e.l(:i +aesuv zm/2s over?

  Which of the following statements does not describe t-dakvk8 y*7 ta step in the sodium-potassium put 8*dvkyt k-7amp cycle in the neuronal cells?

  Which row in the table below is true of meios4s- m(gaiwl:k-8aa fe+ f4nkuul 6b q 3drj1)gis?

Membrane transport is important for all86xa vryigj4s, udr6 5owing particles to move across the cell membrane and respond to changes in the chemical composition of the extracelluyr, v8dasx g5j6ri46ular 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 i;goazrvkw( dc3875 vriyx +.tn 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 differh+ l b,vk;0efkent cyclins during the cell cycle. Which cyclin is involved in preparing for DNA reb+k;v0hf ,kel plication?

The diagram below shows chromosomes during mesyge/v ab mv9t9d/ d )z5;7ik2o* qyxviosis.

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 invo,( doa:gnvy:l q*9jjr z793 wt5ugdwklves the separation of homologous chromosomes?

  The mitotic index of mv6gxo243 ij(tcpq y;throat tissues taken from 4 different patients is shown below. qmctyp ;62 gv3iojx4(Which patient is most likely to have cancerous throat tissue?

1.Draw a labelled diagram to re 8g+*jtxo :j unzj9v)mdz;hk 2present the process of crossing over.

2.Compare and contrast random orientation and crossing over.

3.Outline the stages of meiosis.

  The image shows an abnormal human karyotype. ya 1t:m: :d em--+r:fbiuexzq+cqc.o


What is the abnormality in this karyotype and its cause?

The graph below shows the relative amount 0u)a*+aqwdam hx 9*fji +01bbpyqj;c of DNA in one cell during one complete cell cycle. Each letter represents on0yphi*wcqx9 m* j1au f0+ aqdba+b;)je 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 d(2w l ,(ophyegcc9r:male cat that is homozygous for brown, long hair and a female ca 9ehlcp(gdcoy2rw ,: (t that has black, short hair.


Which of the offspring has a recombinant genotype?

1.Outline how polygenic traits can show a./ 6s,ekorcdia( fe8kagxz0 + 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 of non-sister chh x6s.9 rqma0oromatids shown in.a xq m0hr9s6o the diagram below?

  The photomicrograph shows a pollen grain from L. candidum (Lilbljwd:(c 0 br1qlrng+ 9f-o p8y). Which stage of meiowo8ncllr0qf1bj p(g: d9 br+ -sis is shown?

1.Outline the events which would lead tjo7yt3jtrc06 b kn; k:o an individual being born with Down syndrom7yt 0 kno 6r3;jktb:jce, which 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 way of measuring plant growth. A l6;r 6 itz0enhtp:6a ystudy was conducted np;te6ai6 h60z:lytr on white onions (Allium cepa), under controlled conditions 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 can divide. The diagrams b0 baesk)li1 de0+sqt leb.e( +elow show two cells from an 1 lse.(ibel t+0qd+ke 0abse)organism with 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 sd93k2mx)jywr du9 dw*tem 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 diploido b* wh 6uh*fl48i,4e3ktpmpk number of 8, in different stages ,i 8l*pe3obm46ptk hfhk*4u wof meiosis. Which row correctly names each stage?

  The micrographs show four phases of meiosis I in a plant.47(st, bq (;krtr+rpqrbi ry1 In what order do these phases occur? trq1(+;b7r si rt4rbq,kr(y p

Mitochondria are responsible for t(ta*e k-* y 11cejaepsupplying 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, inheritance patterns of mtDNA found in hybrid cells, which are the result of sexual reea-a je 1t1pt (*c*ekyproduction 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 fya75htp5 6vi4c rrhu0 j4mdvf4gp 2(nour samples of lung tih aid6fpc0pmj2u5rryvth 447 n5v( 4gssue from four patients. Which tissue has the lowest mitotic index?

  The diagram shows the dominant cyclin/CDK coy5a(h *rb 0rhpmplexes at different time points in the cell cycle. Which cyclin/CDK complex activates DNAr hh(y0ab p*r5 replication machinery?

  Studies have shown that genes such as Cyclin Dependent s12 t*qvv*e ius :8crkq7hl7n Kinase 3 (CDKN3) are highly overexpressed in cervicsrkq e 1*qvhl77tsn u82i* c:val 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 cyclin E ma2..ti zv+.ae) wo9y bx)yhathe highest during the cell cycle ?