The graph below shows the relationship between mater)b1s :lg vej0nnal age and the incidence of non-disjunction. What relationship is suggested by t s)0be v:lg1njhe data in the graph?

  Which stage of meiosis is represented in the diagram below 9b .l8vyuduk5?

  The diagram below shows chromosomes during meio,6py4z+k rga g yq 7ly.;f scf0gy12mmsis.


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 singd wrbb+( mp55llyrpf7u2le ;/ le gene which would be present in the y75b ; 5brfrp(+/ew2d u mllplnucleus of a cell as a result of each process?

  Which keyword is matched top:1 9(usu btrd the correct definition?

  Which statement(s) about mitosis qg8b:5yn p9 vu*1/b7gzl zetmis/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 sf7n: pq4puvzf cel,3/:b r;cpoints to a cell in anaphase?

  During which stage of mitosis does the nuclear e5tr2 hyqp+e,+wsb ev4nvelope break down?

  Which one of the followie g1q3 ig7lekq2kja,2 ng transport proteins only carries out active transport?ee73k 2,alqkj1g g 2iq

  Which process does not happen in the q( wmh qcp.3oqq od0 -c2ym510epb2cy shoot apex?

  Which type/s of membrane trans:)mfb )bb 5 ugbeauk37port do/does not require energy expenditure?
I. Facilitated diffusion
II. Active transport
III. Osmosis

  The diagram below represents a cell with a diploid a9oj2rz1e2oq number of 4. Which stage of cell dirjez 9 21oa2oqvision is the cell currently undergoing?

  The photomicrograph below shows a root tip meristem. Which of the followinkt cav)2thzoi3/;j pa1k4*w h g sentences correctly defines piv)/4h1jht kt2kc;a zo* a3w a meristem?

  When does the random orientation of homologous chromosome pairs occurl z*jdv++,xul?

  Which process does not occur during meiosis8am4zjd4s u f*?

  If a cell with a diploid number of 36 undergoes mitosis, how mafrl3e/ p9- dlzny chromosomes will be present in each daughter cell after cytokinesise/ l rd3zl9f-p?

  The image shows a micrograph of a cel bo7xx8u d,xwz4+t m9 4gt:krcl.


What explains the appearance of the cell in the micrograph?

  Which statement(s) about homologous chromosomes is/are zchvt 5tw *x+(un n/4fnot 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 i5j0wmch s 0rg86y5o +tfdpmi(ndividual with Down syndrome.

Which statement is not correct?

  In the cells of a horse (E. caballus) during prophase I of meiosis I there are a7e0e/rbwgkstcx 0chh/.2dl 30px 2p64 chromosomes. What is the haploid c03g h0pl x/e/2cph7tdsr. xae0 k bw2number of chromosomes?

  Which arrow is pointingqrx tc 3(ey2 (uffp1i) to a chiasma?

  The diagram below represents the structure of a shoev*t zz kx)q3(4evi. not apical meristem. Which row in the table correctly identifies the processes occuring in the structures labeled in the eqnx)ztz * 4kv3.vie(diagram?

  How does meiosis pro5 jta6oqyl4pc8ay wf+wc , w kwh2da/ 6o8z:b+mote variation?

  Which of the followinma/( gt,r2bfcz.ry,4od wk 5j g statements 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 progt.k 02j)qv gzduced 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 tumours as ueo r;. yq8oi0a result of the moq8ro. iy e0;uovement of cells?

  How many chiasmata are present in the dir/-nkqn akkd c;m ;:3oagram?

  Which statement is a si39mm9 : fdxjclmilarity between cytokinesis in animal and plant cells?

  Which stage of meiosis is mauwm75 f9a n+latched to the correct description?

  Which statement(s) are true mg8/9zi xa/o xof 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 after the first meiotic division. This ri kl p/l;i+a+eesults in the formation of one large cell and one small cell. Whai;+kael+ lip/ t is the fate of the large cell?

  Which row correctly descr :n-fqpog+po/ ibes diploid and haploid cells in humans?

  The following table showqe9u)929 h pfgda rvb192 ak nb;vla(es the diploid chromosome number of a range of species.


Which of these statements is correct?

  What conclusion can be drawn lt0 hw7 svs3:afrom the karyogram below?

  Which of the following processes k*/ ,g4itck,s5n 4vjk 8nkanris characteristic of the meiotic and not the mitoas,vcgt,k/k5k *n j4ni48knr tic cell cycle?

  The diagram represents a bud with a shoot apical meristl.2 ho 5w5 f5crm(hoenem.

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. Which row sh5-qiqc0cnfqcf ,a -;lows the correct chromosome number for different ceci5nc;fq-lq 0c,q-af ll types and cell division stages?.

  At the end of which phase of meiosis I does crn(6twfof mg o9-l8rlyh5:d4u ossing over occur, and what is the outcome of crossing ou mn:y(54owrd- h6lgl8 ffo9tver?

  Which of the following statements does not describe a step in the sodium- qdomg95iz -htidz +p894bafar o9f )5potassiumrh4f9da z )t5 gifi5+mp9oq9-8odb za pump cycle in the neuronal cells?

  Which row in the table below is true of meiosi1gsf6d sjb 1;ps?

Membrane transport is important for allowing particles to move across the cell kyk/ rv 0wfft j:c l(2oiy3jdc6rjek1 ,(bo7 /membranek2 fv/(oije7tj (3, o6ljrf/y1wdc :y 0ckbrk and 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 rei9 )t11,z undafvtu+15xqwragulated 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 7+a .;ikn)0yn pr1k vx tdmur;during the cell cycle. Which cycli.k+k) 1rrxmpa7i tn;ydn ; u0vn is involved in preparing for DNA replication?

The diagram below shows chromosomes during mexr gq (qn9gxg 6uctqr cx;(7.q1)(apdiosis.

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 chro: o4 4 )wxmqipe/r8ekl.xeazv/ q71 rxfy;m5vmosomes?

  The mitotic index of throat tissues taken from 4 different patients is s+ov b s)-cxzzv,6v f5ihown below. Which patient isv - ,fvcs vxb)zio6+5z most likely to have cancerous throat tissue?

1.Draw a labelled diagram to represendpb6 a6)v ;t0 n/ i*o y0swagmr4rjj/ot the process of crossing over.

2.Compare and contrast random orientation and crossing over.

3.Outline the stages of meiosis.

  The image shows an abnormadc+0. rz8k;tlzf i7zal human karyotype.


What is the abnormality in this karyotype and its cause?

The graph below shows the relative amount of DNA in one cell durif01+ 8;yxdqp*mj gm wmng one complete cell cycle. Eacx+mwm 18fgmy0 q*pdj; h 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 between a male cat that is7q3n, cl/yciatyu43k homozygous for brown, long hair and a female catakq3 in7/ylcy,3 t4cu that has black, short hair.


Which of the offspring has a recombinant genotype?

1.Outline how polygenic traits can show a tb(* mv3qil*a s- vd.f*qls4hnormal 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 crossinlnuv7pyg/- v-hh*9y43 ljcolg over of non-sister chromatids shown in the diagp /nyhull7-c934vvyjlh-* goram below?

  The photomicrograph shows a pollen grai1y fp 8-kloot z,ssq:/n from L. candidum (Lily). Which stage of meiosis is lsost1kzf/y8, p : oq-shown?

1.Outline the events which would lead to an individual being bor aidk1azl5oi;u k4 (5bn with Down syndrome, which is characterised by the presence of three copies of chro5 kl4;kd a5 (zaiioub1mosome 21.

2.Explain how meiosis increases variation.

3.Outline the stages of meiosis.

The mitotic index is an indirect way of measuring pyr/ah )h7 v9owlant growth. A study was conducted on white onions (Allium cepa), under contrwyv7/ h)ha9roolled 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 canjlazm tskv:;l, tgi8oh /-- 8p divide. The diagrams below show two cells from an organiipm-t8 /h kzlsl;va jg:o,-8tsm 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 expressionwg;) 4hi keq(h 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 dif wrh, *)qpe1rdn;u9wsferent stages of meiosis. Which row corr;r9r1hq)w,ud epn * swectly names each stage?

  The micrographs show four :67d w 7ib-) vtxaeqtoho6o 1wphases of meiosis I in a plant. In what order do these p7do-:6 )7ovh waxo1ttqib 6 ewhases occur?

Mitochondria are responsible for supplying metabolic energy int)sdcp 0n (ace6 5q9fk 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, inheritandqeta( p 6fscckn9)05ce 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 stag5u41yh2h9,(bk h smqi0 znboges of the cell cycle in four samples of lung tissue from four patients. Which tissue has the l q 2n0z,gohmuhb91s y k5(ihb4owest mitotic index?

  The diagram shows the dominant cyclin/CDK complexes at difw(6mkn) fz9 dlferent time points in the cell cycle. Wkwm (f6)nd9lzhich cyclin/CDK complex activates DNA replication machinery?

  Studies have shown that genes such as Cy c9,u)otj bhs4clin Dependent Kinase 3 (CDKN3) are highly overexpres9huscjbt 4) ,osed 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 8t,3jsc ib,kv of cyclin E the highest during the cell cycle ?