The graph below shows thbp quv ao1pd;9h-)w,i(z9 ett e relationship between maternal age and the incidence of non-disjunction. What relationship is suggested by the data in the grap) 9b e,; tuwot-avphqzdp1 9(ih?

  Which stage of meiosis is represented in ts1lu) xmcpq a*2 y,h lka76,qqhe diagram below?

  The diagram below shows chromosomes during memcewc.spx 13 8eohi1a6 fz 31ciosis.


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 89nw c,)dez ckair/nxho * +fhcl;55m the number of alleles of a single gene which would be presenkfhdol wac;hr/8 , zxecci*955)mnn+t in the nucleus of a cell as a result of each process?

  Which keyword is matched to the corui*:90r.jf.bl sgz slrect definition?

  Which statement(s) about mitosis is/are trueap5.ri,z-e4/ ghvf vx?
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 lette .*jkutu q r1,k+2ifag.mv7sbr points to a cell in anaphase?

  During which stage of mitosiso6( 3gung8 fuxy zc-ejj )6hl- does the nuclear envelope break down?

  Which one of the following transport proteins only carries out active h8bdbtp p0.b3 transport?3t0bpbd h8pb.

  Which process does not happen in th*b-:erh(g toje shoot apex?

  Which type/s of membrane transport do/does not require energy expenditure? p w6w2 cdxxf 0fm677es
I. Facilitated diffusion
II. Active transport
III. Osmosis

  The diagram below represents a cell with a diploid zsan+k3ia v50 number of 4. Which stage of cell division is the cell currently underg+avak53 0nzsioing?

  The photomicrograph below shows a root tip meristem. Which of tc8 g5+hkxk8j (afc8or rp 61hshe following sentences correctly defines a mep8(f5coxhsr+hg1 kj r688c akristem?

  When does the random orientation of homologous chrvs snpn*ee +u3zr83 :vomosome pairs occur?

  Which process does not occur during meiosi2 1xew6-z mcnis?

  If a cell with a diploid number of 36 undergoes mitosnf 4 2o;fbge6wgz)p,sis, how many chromosomes will be present in each daughter cell a zp4;fbof ewg 2gs6)n,fter cytokinesis?

  The image shows a micr:hetto+2oswnl ot5(6 a- 1ijt:v wt0hograph of a cell.


What explains the appearance of the cell in the micrograph?

  Which statement(s) about homologous chroharbs*,0 q drwp4f,e2qy), ,4vkhqbkmosomes 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 ii ufno9 jt+4; -htsq7andividual with Down syndrome.

Which statement is not correct?

  In the cells of a horse (E. caballus) during prophase I sb)m u-lrdhzdmuvy(q211)d. of meiosis I there are 64 chromosomes. Wh su 1 b yd(h)).zduld1mq-2mvrat is the haploid number of chromosomes?

  Which arrow is pointing o3up5 92e nrh)0xbrfyy6dw4x to a chiasma?

  The diagram below represents ,v8xyleg22 ha the structure of a shoot apical meristem. Which row in the table correctly identifies yhg,2 l8a e2xvthe processes occuring in the structures labeled in the diagram?

  How does meiosis promote vahtsg81lk26 c /9 d)k+ktnnujfriation?

  Which of the following statements is/are correct for meiosis70u1: 6uk7zhbzml d 5dne:ta k?
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 c1hkf dw82w6 v s,wmr.+fhtx8rhromosomes.


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 rqc(:-z xni-l-rzwp9the formation of secondary tumours from primary tumours as a qx 9z-l:--rczin pw(rresult of the movement of cells?

  How many chiasmata are present in t8-utxq48p5ibn3 b fkfhe diagram?

  Which statement is a 6xggkyr y;7sn:xj,9 nsimilarity between cytokinesis in animal and plant cells?

  Which stage of meiosis is matched to the correct descriptiod34 (c9f8kep+f n7eqz ief1rkn?

  Which statement(s) are true of meiosis I but mau ej7nb05*d 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 the3*c 4rppmfpskuf ;i)/ first meiotic division. This results in the formation of one large cell fp;p mfp /3*s4c)rukiand one small cell. What is the fate of the large cell?

  Which row correctly describes :;)g h4xza asswek;gdgk(:3j diploid and haploid cells in humans?

  The following table shows the diploid chromosome number of a range of spenif+ .y3rd v9kcies.


Which of these statements is correct?

  What conclusion can be drawn from the karyogram beloec*vuyk -npars + s79+w?

  Which of the following processes is characteristic of the meiotic and nib3bqc j8g )g(sp0 p:sot the mitotic celq j 3sc0gp( :bpg8ib)sl cycle?

  The diagram representspxk/y 5pw2g+l a bud 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) is 48. Which4jlrwcyor/ 5x+v fq on 2adzfri/*257 row shows the correct +7*aqndzcovfr fr ljr52 i4w/ yx5/2o chromosome number for different cell types and cell division stages?.

  At the end of which phase of meiosis I does crossing over occur, and,-d 0z jj9d r8fvrv+ei;mke )c what is the outcome of crossingidv ed)9e -j8 kfz ;c,mrvj0r+ over?

  Which of the following statements does not describe a step in the so5acehab e uox7+)(l3 tdium-potassium pump ca7(ua+h to 5)eexb3cl ycle in the neuronal cells?

  Which row in the table below is pb fnm5wyj b5):6y.ec true of meiosis?

Membrane transport is important for allowing particles to move across the celwha fxt + 0na5g82y9usl membrane and respond to changes in the chemical composition of g0 w hs59+t8n2fay auxthe 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.fr 9 td0 fjyb6j:gwb6lls.

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 different9ld8+n. mqfsgdvt9 4b cyclins during the cell cycle. Which cyclin is involved in preparing for DNA replicationd8+ 9sbln 4fmgv dt9.q?

The diagram below shows chromosomes during meiosis.av* (o.vsx1 ilyid/dl2p 17fb

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 chrompt. d5wfjreh)2d) ) zcosomes?

  The mitotic index of throat tissues taken from 4 d. q a37u2di *pfixf:wiifferent patients is shown below. Which patient is most likely to have cancero:q2 3fai.fd iu w7xip*us throat tissue?

1.Draw a labelled diagram to represe5t(/inm 02n4sh*qhwlee y2 k bnt 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 kar;;rm; -9cvzdd q,owd 2nhk y9dyotype.


What is the abnormality in this karyotype and its cause?

The graph below shows the oa aci 3v1whk97 12jjlsf :0dcrelative amount of DNA in one cell during one complete cell cycle. Each lettelw c0jh1so 3 7c fv1k9dji2a:ar 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 jnsq3abn a7p(v -rh )*that is homozygous for brown, long hair and a female cat thanvbja s-p(r3na *hq7)t has black, short hair.


Which of the offspring has a recombinant genotype?

1.Outline how polygenic traits can show a normal distribubnxu:j4 t pys/miflz187x+ t4tion.

2.Outline the differences and similarities between homologous chromosomes.

3.Explain why expected and observed Mendelian ratios may differ.

  Which gamete can result feypo/h0;o:z8yg3 e o1du v y.crom the crossing over of non-sister chromatids shown in the diagram belouec8yh10yd ;y/zo:3.pgoev ow?

  The photomicrograph shows a pollen grain from L. ch b 1fp*vjrit4-bpmg228 o mqal(3/ejandidum (Lily). Which stage of at1qiejjlb hgo-m2 / rp38 m*p4(fv b2meiosis is shown?

1.Outline the events which would lead to an individual bv v/jdn- 9t)nem :ctf4eing born with Down syndrome, whic v9d) 4tj:nvefn/-tcmh 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 )n9 ,w2cl.g 7sn;i8qhgnpspn(rw/r kplant 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(qpnsin7gwsr/ l8 9n;h nw2rp g .,kc) 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 diagrams8u u 2t5hh* vbpiy,+or below show two cells from an organism with a diplui*8 5v2t,yh uopbh +roid 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 g-3lf:v jusw pq.n6 jp)rowth.

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, 25fnaz: mvp 7d+ bnf;mwith a diploid number of 8, in different stages of meiosis. Which row cor2 v a;7nzbn5:mpdmff+rectly names each stage?

  The micrographs show four phases of meiosis I in a plant. In what order do theh6 x7sshy3 )gese pxshgy h7s) e36hases occur?

Mitochondria are responsible for supplyx w9s .,-tip5m(a3 * oirgtbjling metabolic energy in eukaryotic cells. In most eukaryotes, which reproduc.5 rs i-x jmo*iag(tt9 3lwp,be 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 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 stabnrtectx)v i:5q 97h 1ges of the cell cycle in four n1957xqh tci)vtbe r: samples of lung tissue from four patients. Which tissue has the lowest mitotic index?

  The diagram shows the dominant cyclin/CDK complexes at dif9 ,sy)zm zhid n:;jv,nq+2mm -iyrim9ferent time points in the cell cycl m):z;-m 2n9nr9zsvh yjiqyi+,mdi,m e. Which cyclin/CDK complex activates DNA replication machinery?

  Studies have shown that genes such as Cyclin Dependent Kinasrsxg : ico630he 3 (CDKN3) are highly over c0s3iohgxr:6expressed 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 of cyclin E the highest during the cell cyhqd(v/*s1ekdyh-t(y4 q-h,b s y/ tmi cle ?