The graph below shows thf+)k9syaei kua xh.h,(tc00ae relationship between maternal age and the incidence of non-disjunction. What relationship is suggested by the das9c)( ahet0x,0. ufa+yi khak ta in the graph?

  Which stage of meiosis is represented in the .2dmjl 9nfw)k;tj*)b2hkz z lc6z-vtdiagram below?

  The diagram below shows chromosomes duri 4nflal+)9by,hiq9u qng 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 gene which would be7gr0 my dz,d 2yuq1j1f present in the nucleus of a cell as a result of each proced u1 jg7z2,fy0mqry1 dss?

  Which keyword is matched to the correct defin1nrvr,m+ b r *ej*4rkvition?

  Which statement(s) abou.klm 8kvcng wws (j5;:t mitosis 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 pointz8o* / u nlyti8.l.lwis to a cell in anaphase?

  During which stage of mitosis+kv6t r vn35:/y c0gf ugyah)e does the nuclear envelope break down?

  Which one of the following transport proteins only carries out active transportk.es*e9 snmy2 szb/ p4?n 92.s*zes4 ms pybek/

  Which process does no,-dvtfhn--. i+l4fnh g zgv+yt happen in the shoot apex?

  Which type/s of membrane transport do/does not require energy expenditure?g qdcvu3ysc(67x 3.er
I. Facilitated diffusion
II. Active transport
III. Osmosis

  The diagram below represents a cell with a diploid number of 4)nbw 9/wd1au5 pm5zjo. Which stage of cell d/ow1n bm dzpu5)wj5a9ivision is the cell currently undergoing?

  The photomicrograph below shows a root tip meristem. Which of the fojmre(:gye+q .ii rp 6)llowing sentences cor rg )mii.e6y(qpr: ej+rectly defines a meristem?

  When does the random orientat;;6vmsxsy s41xy; a 64svyubbion of homologous chromosome pairs occur?

  Which process does not occur duringxkc:o2x :fg,,f3 ru y a(8;o* ahtuufp meiosis?

  If a cell with a diploid number of 36 under;qxym s. 1)-+uy a9nbfm4 jlusgoes mitosis, how many chromosomes will be present in each daughter cell after cyt b;9aqy 4synf1muxj-slu) +m .okinesis?

  The image shows a mi)qtcq izlpcl*26 e): o7apqc.crograph of a cell.


What explains the appearance of the cell in the micrograph?

  Which statement(s) about wk,wq uuf,fo 1sa33d )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 i;mm sskqf*0un t/t4d )fwq /.ondividual with Down syndrome.

Which statement is not correct?

  In the cells of a horse (E. caballus) during prophase ,i*vu1b5xyq2b 4dhw jI of meiosis I there are 64 chromosomes. What is the haploid number of chromosomeqbj b,2v5yxw4*hi 1 dus?

  Which arrow is pointing to a chiarhnx4 k 10tomj );lw3oadfn1; sma?

  The diagram below represents the structure of a shoot apical meristexfupmm3z/uw7;9 qfb;5vho37x go y8nm. Which row in the table correctly identifies the processes occuring in the structures labeled in the di pq u fo y8 7z5v3omw;;/fuxxghm7bn93agram?

  How does meiosis promote +hhyndl.(j.7wu-u3,h .u yqu.fkwa avariation?

  Which of the following statement0lb)u/ cgep1 qfn(v: ls 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:ubmn) o)f7 lc 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 formati)m wd7lm3, phyon of secondary tumours from primary tumours as a result of the movement of cells?d7mly ph m,3)w

  How many chiasmata are presydmr81 h6pzq :ent in the diagram?

  Which statement is a similarity between cytokinesidos f:yym1 ) c5,ale2ks in animal and plant cells?

  Which stage of meiosis is matched to the correct dey ofkb qf8u9;/scription?

  Which statement(s) are true of meiosis I but not meiosi5*f-z o5/bd uv-n4qgsrf1 cyns 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 ak5dt/1ahfv xrl t;)v )n oocyte after the first meiotic division. This results in the formation of one large tl v )5xr; 1tfd)khav/cell and one small cell. What is the fate of the large cell?

  Which row correctly describes diploid and haploid cells in humang56d(-7 d .1aabl ,mnccxsv hgs?

  The following table shows the diploid chromosome number of 3-r/pn ywgh0a a range of species.


Which of these statements is correct?

  What conclusion can be drawn from the karyogram below?u0oyhf kbh8t4z7mg -06 nkk7i

  Which of the following processes is characteristic 2ghnw1er,au,4tg5wu of the meiotic and not the mitotic cell cycle 25 4uwra,n ,1hggwute?

  The diagram represents a bud with a shoot apical meristem-t5 er/khrab0 .

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 chimpanze) foqycvw2r( +e (Pan troglodytes) is 48. Which row shows the correct chromoyc+)(w 2 rfvqosome number for different cell types and cell division stages?.

  At the end of which phase of meiosis I does crossin0un 6id9avu* t cu/nb.g over occur, and what is the outcome / u.atbu69idn 0vc*u nof crossing over?

  Which of the following statements does not :owbv,,6mmaz z3j3 u ndescribe a step in the sodium-potassium pump cycle in the neuronal,z 3u3 a6m,zno:vm bwj cells?

  Which row in the table bnar8o /5v g)90 qfpkljelow is true of meiosis?

Membrane transport is important for allowing particles to move across the cell 2rrejrqn2 8 j+membrane and respond to changes in the chemical composition of t2njj8rr q+r2ehe 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 r3lo5zj msa5bc;v v8u6egulated 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 differep pvdae gi0v(kk-i*yim 3;t*d+4x m+xnt cyclins during the cell cycaii4m(* t v+;yx0*ep d+ 3kvkgpid -xmle. Which cyclin is involved in preparing for DNA replication?

The diagram below shows chromosomes during meiosisfnau;.9mhq (w(htezh:fv+d xy5s +f -.

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 chromose p8yom pt kt ,s;l/0pfwvs-:/omes?

  The mitotic index of throat tissues lp9 d9bn;pa:bo 7ik.ztaken from 4 different patients is shown below. Which patient is most likely to havlppib 9 bnozad.;79 :ke cancerous throat tissue?

1.Draw a labelled diagram to rbe6:/o*rl,i be nha67botls - epresent the process of crossing over.

2.Compare and contrast random orientation and crossing over.

3.Outline the stages of meiosis.

  The image shows an abnorm422xpyyw)awzs a 1x0otml16 cal human karyotype.


What is the abnormality in this karyotype and its cause?

The graph below shows the relative amount of DNA iny,5t( it0i/5 , m,pmopeox ut,w ujl;n one cell during one complete cell cycle. Each letter represents one stage of the cell c5xi,ppm0 , no tu,(mj5 tul y/t,w;eioycle.


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 thaecvx dsce)k06* spupfc;c:hh .g*20at is homozygous for brown, long hair and a female cat that hapsccu6 *20fhsc* )e :dxk0 ;.g hapvces black, short hair.


Which of the offspring has a recombinant genotype?

1.Outline how polygenic traits can show a nc9uqtj8y m 7+40wgejnormal distribution.

2.Outline the differences and similarities between homologous chromosomes.

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

  Which gamete can result fromtulbz(v 1-upfq3w/: g the crossing over of non-sister chromatids shown in the diagram below? (1bp:ft lwv /qu-3uzg

  The photomicrograph shows a pollen grain from L. candidum (Lily). Wh fm9sf-7 0v*hnc6y bmbich stage of meiosis is show* v h06ns ycbf-7b9mfmn?

1.Outline the events which would lead lz ye5j xyp2s tix)5:8to an individual being born with Down syndrome, which is characterised by the presence of three copies of chr5syjyz i :et 5x)82lxpomosome 21.

2.Explain how meiosis increases variation.

3.Outline the stages of meiosis.

The mitotic index is an indirect way of me0 6-ev2zdx a4y1gqbnw3qrw u2 asuring plant growth. A study was conducted on white onions (Allium cepa), under controlled conditions i1vd6yb4wa30wug -xrq 2n 2qezn 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 cell-8 jqb jek0y k2.fb/kx/f ur:gs can divide. The diagrams below show two cells from an f y j /ke.8kgxuk :0/jqr2b-fborganism 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 genej ev/5ftz ;ra6 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, with a diplosxbq c8)e :bsv*y0w3 vwz ty,+id number of 8, in different stages of meios3y0q* tz swvwcsvy+ e )8:bb,xis. Which row correctly names each stage?

  The micrographs show fou .(9l :qqdmic8dj,yu myk*zk+ r phases of meiosis I in a plant. In what order do these phil8dy* qq,mukjc9y .: z+km(d ases occur?

Mitochondria are responsible for supplying metabmlu28+ i nib:b h4g3ibolic 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 u8:4in gib + l2bmbh3ihas 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 stages of the cell cycle in fof9rrw 1 5gwwbvik4-z2ur samples 5-9k wwfg42w b 1rzivrof lung tissue from four patients. Which tissue has the lowest mitotic index?

  The diagram shows the domin,+c0mfoual9wy9y tp 7sn7 y2qant cyclin/CDK complexes at different time points in the cell cycle. Which cyclin/CDK complex activates DNA replication mpc 7s2 n+9wyt0fq9ao y,7 yulmachinery?

  Studies have shown that genes such as Cyclin Dependent Kinan ufj0l99o/et se 3 (CDKN3) are highly overexpressed in cervioefj0 t un9/9lcal 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 y2 +s0gagx- :w ykn,knby3)cy cycle ?