The graph below shows the relationship bp ;vyo gq, n7kbpoy332etween maternal age and the incidence of non-disjunction. What relationship is suggested by the data in th37ovp y,nypq ;3kogb2 e graph?

  Which stage of meiosis i dcsvrb +j8 ttrmg(9e8bd198os represented in the diagram below?

  The diagram below shows ac9ikuc3b31brh0 7r uchromosomes 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 gaq y3(jm.s) g*auht:hvvir -xt(d80 z ene which would be present in the nqx3v*z dau8a jy0h-ts. (rh)v g:m(t iucleus of a cell as a result of each process?

  Which keyword is matched to thm28hlia q m /ljrlz).-x3 nl5,9s iathe correct definition?

  Which statement(s) about m8oyey4d g.c5 ,1exscc,e*+ i3aiubhwitosis 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,cn 3:d 9b5np*ts uzdk5 which letter points to a cell in anaphase?

  During which stage of mitosis does th v0q,fhvhjj 08e nuclear envelope break down?

  Which one of the following transport proteins only carries omuqqv vg64t p.7 w6fr;.(lcptut active transport?f vq6w. mlgtrc4(quv6.pp7 ;t

  Which process does not happen in the shoot apexfrp3bl yd* 7g0;yh( zeqky76fa:bb v:?

  Which type/s of membrane transport do/does not require energy tee,l 4.p(h ggexpenditure?
I. Facilitated diffusion
II. Active transport
III. Osmosis

  The diagram below represents:s n6qs) gj:hw a cell with a diploid number of 4. Which stage of cell : qhssgjn w:6)division is the cell currently undergoing?

  The photomicrograph below shows a root tip meristem. Which of the 4)m7 l0 nnqbfqfollowing sentences correctly defines a0nl n 7mf4bqq) meristem?

  When does the random orientatiol dt)t 1myf0;fn of homologous chromosome pairs occur?

  Which process does not occur during wz ctp j:qw)t1g6y+e nh; bs.5meiosis?

  If a cell with a diploid number of 36 undergoes mitosis, howx8f7xsqh2f 8k many chromosomes will be presentf sk8x2hqx87f in each daughter cell after cytokinesis?

  The image shows a micrograph of auml 4k6ong2vk; -. l j*zuxn(u cell.


What explains the appearance of the cell in the micrograph?

  Which statement(s) about homologous cadn0u+ 4ql w9hhromosomes 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 with Down syndrom;wthlz e:y) ;9ffowf-,m w)gce.

Which statement is not correct?

  In the cells of a horse (E. cabi pmr5+0ikqm5i ()fsaallus) during prophase I of meiosis I there are 64 5p( iiqf r)m+05saimkchromosomes. What is the haploid number of chromosomes?

  Which arrow is pointing to q4t3;zu9gbjv a chiasma?

  The diagram below represents the structure of a shoot u63t/tsoxn vyvfqjt0b0/20w apical meristem. Which row in the table correctly identifies the processes occuring in the structures labeled in the tyxs o//3qwvvt00nt buj206 fdiagram?

  How does meiosis promote variap+* afeo;9q xbtion?

  Which of the following stats+ox-8 aw e+x-v8nxwtements 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 chromljsfx9 7* :cutosomes.


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 tumours axea4hf;agq 2 fiu, d)+h3fji,aq61rss a result of the movement of ce+ 1iqhe;ru dq6s3jafgfa) x a hif,2,4lls?

  How many chiasmata are:-xqq ya8:srus-voy j2na/7z present in the diagram?

  Which statement is a similarity between cytokinesis in animal and plantlgw :c6zn3 g8b cells?

  Which stage of meiosis ps6oo bld*9p o88v;gdvu)dx *is matched to the correct description?

  Which statement(s) are true of meios7+fklmt f*yo4kl4id)hirpy+ ; c9 )zfis 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 after the first mes nfnr77fp 1a-iotic division. This results in the formation of one large cell and one small cell. What i anp-fr7nf s17s the fate of the large cell?

  Which row correctly describes diploid and haploid +nlk ue 1f68ghaw312 w1mwvxj cells in humans?

  The following table shows the diploid chromosome number of a range of species. *qin wq1+34sz g,t1;x ngzpd iu)r/ ia


Which of these statements is correct?

  What conclusion can be dr0p;i3 v3.e rzw tzejih*, m epkkv3r-0awn from the karyogram below?

  Which of the following processes is characteristic of the meiotic and not the nuyln;r,p0o/1 / :khhylq 1kamitotic 0 1 ;k1a/nkoy,h n :ulrhpyql/cell cycle?

  The diagram represents a bud with a shoot apical meristn7gsgiu9b,ng o 3h1z95y m. i )aism9xem.

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.xyftfz3otf:d4cm ,:md0b) 6k Which row shows thzfdmf b)xyk3t0o: m:46 t,dcfe correct chromosome number for different cell types and cell division stages?.

  At the end of which phase of meiosis I does crossing over occur, and w rpk 5ywujfe akzayh/9)+2s ai*k62w 3yabk1 *hat is the outcome of crossi ae3 aa*r*5 2+pkzw ki/u bkk6yaf9jy1)s2 whyng over?

  Which of the following statements does not describe a steptk(;mr*g5 tnm in the sodium-potassium pump cycle in the neu 5kt m;rtn*m(gronal cells?

  Which row in the table below j5j* 21(omq ekvkwq)jis true of meiosis?

Membrane transport is important for allowing partq1;)t+rm pmfb icles to move across the cell membrane and respond to changes in the chemical compositio)mmrb1+; fqt pn 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 xdqyzz)a xc8fmwt-- (dq/ b3: 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 concentrations of different cyclins duringl9-puo8a1)*z0of k fyv0d s df the cell cycle. Which oo)zl0f0dak 8*vf-pu1sy 9 fdcyclin is involved in preparing for DNA replication?

The diagram below shows ch1 q ggst1aod3r418 zd;ffa 7wtromosomes 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 cz:dgen*qva n4sck (;b1* toh, hromosomes?

  The mitotic index of throat tissues tako m8sy8 :qle,i i n-r7fwad58aen from 4 different patients is shown below. Which patient is most likely to havef :8l7wiaa imyor 8eq5-s,dn8 cancerous throat tissue?

1.Draw a labelled diagram to repres3 (ufd7huw n,g1/h+kw ai0ywl ent 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 karyotyp -aff73 5b0rm) dh:lha kz3cdge.


What is the abnormality in this karyotype and its cause?

The graph below shows the relative amount of:nt h4ggv;fbo*9 jlh; DNA in one cell during one complete cell cycle. Each letter represents one stage of the celh; ;hf *9l4ojv btn:ggl 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)j q cp.0d*m0 .jo9eqtn i: osti6xfg; a cross between a male cat that is homozygous for brown, long hair and a female cat that has black, short .0 ije. 9g;q:)qs mic0fjtp6*n dxtoohair.


Which of the offspring has a recombinant genotype?

1.Outline how polygenic traits can show a norma f2c-8j5wa eocl 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 omv ae:rpjmm 3.f4rso (i3s) s.ver of non-sister chromatids shown in the diagram belovams:o 4 m.r)r esp3f3im (s.jw?

  The photomicrograph shows a pollen grain from L. candidum (L7f:bd2ol7 0v td4nr 93 tzccoyily). Which stage of mct o:lydc0tfn9r3zo v724 b7 deiosis is shown?

1.Outline the events which would lead to an individual being bors u1usz(a2gid*j +6z xn with Down syndrome, which is characterised by the pr6g x us2 sz1u*+ajzdi(esence of three copies of chromosome 21.

2.Explain how meiosis increases variation.

3.Outline the stages of meiosis.

The mitotic index is an indirect waysq8kaa05wy* t2-s6qh f s6ziz 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 mit izt8 0sqafhz2 w-aq 56s6s*kyotic 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 -wuiq 2crht,gf7k4/mv i: e+ wcells can divide. The diagrams below show two cells from 2im ck:fw4q+w- ughv r 7e,ti/an 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 ge;b+c l j56jg7hlqj(zcne expression 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, witc cj,- y,mu.p akx4bpsiaf/1 :h a diploid number of 8, in different stages of meiosis. Which row correctlukj/ca-pf1y.iax , pc, s4m:by names each stage?

  The micrographs show four phases of meiosie dv57p z*k7l5 vuk.6oftf 3ops I in a plant. In what order do these phases ou6zkt5e*dlvpk 5ofopf v3.77ccur?

Mitochondria are responsible for supplying megl34pk r:9ysuaup, e/.seq8/aabnq3 tabolic energy in eukaryotic cells. In most eukaryotes, which reproduce by sexual rp a33 s:a uqr e/na4l. sk/qgby8p,e9ueproduction, 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 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 cells2tohvt+y1 eu(gg(pcsy/ wu * / in different stages of the cell cycle in four samples of lunu(cvy+ gsw(2 e 1pohy/t*/tgug tissue from four patients. Which tissue has the lowest mitotic index?

  The diagram shows the dominant cyclin/CDK complexes at different tfqj8y j+ 8xqok+1zhg/cr 9lg/ime points in the cell cycle. Which cyclin/CDK complex activates DNA replicationxh gzqrqck1y+l fj98 //og8j+ machinery?

  Studies have shown that genes such as Cyclin Dependent Kinase 3 (CDKN3)(i9ws)7ctlliyz; or 4 are highly overexpressed in cerl)c z4y(; tw7is ir9lovical 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 mp o.ct*y,wi 1of cyclin E the highest during the cell cycle ?