The graph below shows the relationship between maternal age and the incid fuwhsx( l:.15h lzp/- 4 qquweny5ci6ence of non-disjunction. What relationship is suggested by the data in 5lnfuxi4c-lp wq y(:zh e q uwh.5/s61the graph?

  Which stage of meiosis is represented in thedxcg 3h(f 1c 0png1lv3 diagram below?

  The diagram below shows-lh2:0ug w , ;q2 eykslehbms- 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 alleles bgo7li--gbz r8i 8x nu7wm6q2of a single gene which would be present in the nuclb8gwuq 6in- 28r7i-zmo gxb7leus of a cell as a result of each process?

  Which keyword is matched to the correct definitq 0u gv wymlt(r-26ln/ion?

  Which statement(s) about mitoso .h** j1zdbedlob;s;is 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 a s:gh 7 89fk)v6vokdrqtiob1*naphase?

  During which stage of mitosis does the nu6kv y8nz i( z2nd;c7vzs9* guwclear envelope break down?

  Which one of the following transport proteins only caze85v eknyxu6,cro q+*mmwks i*6gp t* 5/yp2rries out active transport?te/, x6o*ew pcm2uknk y6 5qp 5mv*+irz*gs8y

  Which process does not happen in yjr,4 w)khl wuez8tb8s,e,;uthe shoot apex?

  Which type/s of membrane tran-8kx;r: um;tgaxnx4jy1a0 njhma v2 hk/ )kq/ sport do/does not require energy expenditure?
I. Facilitated diffusion
II. Active transport
III. Osmosis

  The diagram below represents a cell with a diploid number of 4. Which sta11ezusaoh,x t utcl8x 0lrk,ul1q/- 8ge of cell , txuol8r, k-1a/8 hczxu 1l1tuqsle0division is the cell currently undergoing?

  The photomicrograph below shows a root tip meristem. Which mg ws pf4g1--xof the following sentences c4-pggx fw 1sm-orrectly defines a meristem?

  When does the random orientation of homologous chromosome pairs olzt;0*ltpcntf iv.(0ccur?

  Which process does not occur durf6ux)wu08olt une07fv4 y*y jing meiosis?

  If a cell with a diploid number of 36 undergoes mitosis, how many chromosomes:h0afyo y4(vkmrr d;1 will be present in each daughter (fa:rm 4h;1oyd r0yvkcell after cytokinesis?

  The image shows a micrograph of 6ejkb n4u4ubgdw ;;e2a cell.


What explains the appearance of the cell in the micrograph?

  Which statement(s) about homolos59d l19t8suyy d/rs fnh6e9z gous 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 individual wv(md vw kqf7j.2n6w)qe6tskq 5 x-rk)ith Down syndrome.

Which statement is not correct?

  In the cells of a horse (E. caballus) during prophase I of meio g fd-xuim:k19sj u7e :qp/zti/ 3+ ezcc/1xvosis I there are 64 chromosome :kpvd3c/: 1g i -o+1qms/jxez/e ufiu7xt9cz s. What is the haploid number of chromosomes?

  Which arrow is pointing to atxomk- l-zz8 obj 60t( chiasma?

  The diagram below represents th 2x nf8o 84lum)s7syaqe structure of a shoot apical meristem. Which row in the table correctly identifies the processes occuring in the structures labeled in the d )s2yu8q7nm48safolx iagram?

  How does meiosis promote f25n2bxx(0r4 idmqsx variation?

  Which of the following statements is/arc+kr5ds6pm9z fez ) s6e 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 chromosomes1(w5 p3 fhi anfm*ddl5os,yaim24ec / .


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 describes0bm)exs(/y/k; f- whp a6ztkw the formation of secondary tumours from primary tumours as a result ;s //w-a bz)60mexkpkhw t(fyof the movement of cells?

  How many chiasmata are present in th rvbe5 trkk67t /u(;abe diagram?

  Which statement is a similarity b *pqvl1+i 3l+4xmx rsvetween cytokinesis in animal and plant cells?

  Which stage of meiosis is matched to the corr ng x2z +gd66;ss*ubbgect description?

  Which statement(s) are true of meiosis I but not meiosis IIp 8n1i12c kfwm eewc+(?
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 results inqhd96;ti kd ff:nr6 2x the formation of one large cell and one small cell. What ihfx6; k2qr:dn if dt96s the fate of the large cell?

  Which row correctly describes diploid and haploid cells8f9ylqmq ru(q m t91/k in humans?

  The following table shows the diploid chromosom2li2+-en hqkz:q roi:g 2c:pq7 ag/h a*ce4ede number of a range of species.


Which of these statements is correct?

  What conclusion can be drawn from the karyogram below? wns9p 7 c5l9uem1zqv 6j0ixt -

  Which of the following processes is characteristic of the meiotic andifow-)hz p(gey 3k-7 8j 8wmtp not the mitotic cell cycle?zy -8po wikg7m (h t8j)pe3-fw

  The diagram represents a bud with a shoot apical me1tb yl af;ljo.7,,lk sristem.

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 shows t-7l1tfjhx vgrm*s.ug o1khoy 75twkc+,.z8v he correct chromosome number for different cell types zu*xg1m5y7l h,c. o f-.otkg h1+ s jrk87vvwtand cell division stages?.

  At the end of which phase of meiosis I does crossing over occurci/w (( uvf zg(xumx3/, and what is the /uw f(xiu( zm(/c gxv3outcome of crossing over?

  Which of the following statements does not describe a step in the 5ipb9+s6ei 5zsfdl nf+su,q ; sodium-potassiufnzsssi+ uqf p9,+le 55dib6;m pump cycle in the neuronal cells?

  Which row in the table be(e2ai vx k,0htlow is true of meiosis?

Membrane transport is important focmlsa86+6tcw :p b; akr allowing particles to move across the cell membrane and respond to changes in the chemical composition of the extracellular flui6k+ ;waa:btc6csp 8lmd.

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 c+c- mr+k16odpferp+ nells.

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 ): ji 5,k nmacukcr0ub6x4az:concentrations of different cyclins during the cell cycle. Which cyclin is involved in preparing for DNA repl,x:6b405uakz crmi)c jkan u:ication?

The diagram below showpv76ypzzd/n66: pbx2q vn u/bs chromosomes 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 separaqsnjs ,3*s* 1:+tso k0xzjixction of homologous chromosomes?

  The mitotic index of throat tissues taken from 4 different patients is shown b1iw 1r iab49 (xkw)dzbelow. Which patient is most likely to have c 1b i1kzbiw(r)9wdax4ancerous throat tissue?

1.Draw a labelled diagram to 4nwr, z1yenx* represent 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 kv8g( j7)r )g lwmdb.z.f. qdncaryotype.


What is the abnormality in this karyotype and its cause?

The graph below shows the relative amount of DNA in one cell durix akdz 4mx1a 2fcmu7w6 .toa4892 6yxvhgnas7ng one complete cell cycle. Each letter represents one 6caf d w7sx2a m 4mxunaka718ox 42zv6yhg.t9stage 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 homot6yiwb 1xw2 r x:yw+)dzygous for brown, long hair and a female cat th t62iy xr+dybx)ww:w1at has black, short hair.


Which of the offspring has a recombinant genotype?

1.Outline how polygenic traits can show a no1(sflllne+dn. lfw e.4 m6 e3frmal 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 croslb7*+kfz eu,hwd 3 hpce30s)t sing over of non-sister chromatids shown in3ewb,+ude 3zthsl )c7 fpk0*h the diagram below?

  The photomicrograph shows a pollen grain from L. candidum (Lily). Which stage o4osi lh69* 0usfusjdy 3us0: yf meiosis is show 0is*4hy9j 3u:doy 0u suf6lssn?

1.Outline the events which would lead to a12 h qmpbjj5/n3lryb; n individual being born with Down syndrommh nylj/1pjb2rq;b 53e, 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 inbs4b, )vft w*ddirect way of measuring plant growth. A study was cond*s4tbd)vbf w,ucted 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 akrly z2)*oz3hh/4sk which cells can divide. The diagrams below show two cells from an organism with a diploid number/ oszyz r3 h4lkkah2*) (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 el,/cm0mfm.5 c;9b9jrr roc toxpression 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 ;is (2kytzw*;utj dzdrtu1 /5of 8, in different stages of meiosis. Which row correctly namesd;d15t2*z i( us zk/rutwyt;j each stage?

  The micrographs show four phases of: wqm7risvyd)4 *;fd t meiosis I in a plant. In what order do these ph4dvy:qt*sf)r d7w m i;ases occur?

Mitochondria are responsi/dd u -ead-/vgtakf5 t:9 p7fnble for supplying 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 inhdd/euttf k5vf 9n-a-a/d7g: perited 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 di7ou*uis 0t8+. :u,p(m b(ufneldgc qkfferent stages of the cell cycle in four samples of lungt u( scuf*n+o8l ub0mgdpui7,:e. (kq tissue from four patients. Which tissue has the lowest mitotic index?

  The diagram shows the dominant 2 b1;3lj8 2rtrx)kqq w4pv1ptmz9b ty cyclin/CDK complexes at different time points in the cell cycle. Which lt )t4bqb 219;kr3yxvrq mw 1ztpjp28cyclin/CDK complex activates DNA replication machinery?

  Studies have shown that genes such as Cyclin Dependent Kinase 3 (CDKN3) r j 0igthxts10u z)b,lh-p,4 oare highly i-jt)t uplhh,rx0,1o 4s0 gzboverexpressed 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 *qs:ku )yci* wi1k,lf the cell cycle ?