The graph below shows the relatiougdb-6 g3lx sf 4cmy77-gd0d gnship between maternal age and the incidence of non-disjunction. What relationship is suggested by the data in thebf3 6c d07g 4xs-dggu- mdg7ly graph?

  Which stage of meiosis is represented in the diagram be)cg0mda wm9pjys, ;+clow?

  The diagram below shows chromosomes durimv+- fum.q9lf ng 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 2d:60/y f7x aql tjbt+ 5ztjipbe present in the nucleus of a cel:5zyjxajfql/ttpb 6 2 0t7+dil as a result of each process?

  Which keyword is matched to the0sjsdy:(nj8 n+ ljd/j correct definition?

  Which statement(s) about mitosisepc.9vkdo ( n- 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 c/imnyu2/ykk do)w;gy)5c,p* t4zj 0b -xvoeeell in anaphase?

  During which stage of mitosis does the nuclear envelopelsqau-1cvo*8 b-j bc0 break down?

  Which one of the following transport proteins onliy-k0*3p ff amo m)oq+y carries out active transport?opoy +f3*faq m) ki-m0

  Which process does not happen in thw+i (*.auxxrx e shoot apex?

  Which type/s of membrane transport do/does not zy:o-/np) hwbl* lgs3require energy expenditure?
I. Facilitated diffusion
II. Active transport
III. Osmosis

  The diagram below represents a cell with a diploid number of 4. Which stagghopl3 sn*iqf p:as;)h* .4 -jq8lhwsu51iwje of cell division is the cell currently undergoin aw;fs:qq)s1hs jwl.*p*i lh op54 h3i u8gjn-g?

  The photomicrograph beloj ( e6 .4zlx0xr8itizgw shows a root tip meristem. Which of the following sentences correctly defines a m8 (rz0lgxij6t zie 4x.eristem?

  When does the random orie /ab/upcde k nti)9a d+;uf.u1ntation of homologous chromosome pairs occur?

  Which process does not occur during meiosis?b7 mixos u6pd.i5c0 :t

  If a cell with a diploid number of 36 underh3 +gc)kmqo65vrl1q lgoes mitosis, how many chromosomes will be present in each q +5lg 3q1kc6hom) lrvdaughter cell after cytokinesis?

  The image shows a micrograph ofdeg cuc). ,/sw4 wwn+a a cell.


What explains the appearance of the cell in the micrograph?

  Which statement(s) about homologous chromosome,pm2x (d+ htyl,jl l(5b xvlky2p1r0ls 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 Dow7,x 4lmh4xy8 x 7hjtogk80yx d;7fnbrn syndrome.

Which statement is not correct?

  In the cells of a horse (E. caballus) s93:eyam,b bcduring prophase I of meiosis I there are 64 chromosomes. What is the hsy9eb, m:a 3bcaploid number of chromosomes?

  Which arrow is pointing to a chiasmoofhfziukv /oi36 ro*zr45 *3 a?

  The diagram below represents the structure of a shoot apical merisx wn-ms/bu.bm0+9,vxn+y g hutem. Which row in the table correctly identifies the processes occuring in the structures labeleds+v +.x-wuny,m h09 /nmb buxg in the diagram?

  How does meiosis promote variatics7b qaz682h- 3nwttqon?

  Which of the following statements is/are correct f j:8m u0-a1 kcqeqrig;or meiosis?
I. It is a reduction division
II. It involves random orientation
III. It produces genetically identical cells

  The diagram shows gadgt) vw/ /ic4mmetes produced 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 tumour. qibzknyl y;;,n6 jdyd0*:pss from primary tumours as a qypjd0n; ,z.d nb l:yy*i;ks6 result of the movement of cells?

  How many chiasmata are present in the d6r5 :uhys pb0jiagram?

  Which statement is a similarity between cytokinesis in animal and u1 h+pcp i-,fus fx+q4 d+p9ebplant cells?

  Which stage of meiosis is matched to the correct descriptacr5b8+ws;i-iwgcqu 0suz 3, ion?

  Which statement(s) are true of meiosis I but not meiosis II2ixlx,) blk l 5pnw)+f?
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 meiotic9.ye/.t;qpn.kywez) vhd-lw division. This results in the formation of one large cell and one small cell. What is the fa .;9h.tew.eyp )/wqyvnkl d-zte of the large cell?

  Which row correctly describes dm z 41-.a9byf :badlto +l;lxeiploid and haploid cells in humans?

  The following table shows the diploid chr6bu0wwjjq 5q+ omosome number of a range of species.


Which of these statements is correct?

  What conclusion can be drawn frommp-/2;uglgddg+4 b+3hl z gja the karyogram below?

  Which of the following processes is characteristic of the meiotic and g9iu (vpfag )8not the mitotic cellvp f8gg9i( )ua cycle?

  The diagram represents a bud with a shoot apical meristemryi7(mhz7) chso0t0 j .

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 (P8.lan 8x* dmvoan troglodytes) is 48. Which row shows the correct chromonoxa8*dl. vm8 some number for different cell types and cell division stages?.

  At the end of which phase of meiosis I does crossing over occur, and what is tk,2x fk b tml*yi71v4uhe outcome of crosmxuk ,1t 4ibvf72*k ylsing over?

  Which of the following statements does not des afo .4l:tjey2cribe a step in the sodium-potassium pump cycle in the neuronal cel aofj4 t2yl.:els?

  Which row in the table below is true of meios4j( lg fspfn:b6n+s mn1k:n:wis?

Membrane transport is important for allowing particles to move across the cell mv6x8g(3rd2st - xkxdap7lc i*embrane and respond to changes in the chemical compodkx7- x*6csvp(8ad3r li x2tg sition 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 i+ya z)0p9 gub j/ p3ydenusw4:g+imy-n 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 dy3 uq6w9a+ sml1ckl/(ppbq v 7uring the cell cycle. Which cyclin is involved in preparing pvk3+9q / wbyl(c7plsaum1 6qfor DNA replication?

The diagram below shows chromosome hjadq 0iy/w25s 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 hootvhb u*(i ,y/0m q-uqmologous chromosomes?

  The mitotic index of throat tissues ta zyu-n;qv.s59ieq . bhken from 4 different patients is shown below. Which patient is most likely to have cancerous . ; . siqnz-hq5vuyb9ethroat tissue?

1.Draw a labelled diagram to represent the process of crossi*gv6ze* y 8m(r -e41omepqoavng over.

2.Compare and contrast random orientation and crossing over.

3.Outline the stages of meiosis.

  The image shows an abnormal human karyotyqus my-2ml1 ::v*eyzrpe.


What is the abnormality in this karyotype and its cause?

The graph below shows the relative amount of DNAt g- fb(2yisc l221lu4vx0xcv in one cell during one complete cell cycle. Each lucxg4t2ix l0c2sfv(yvl12b- etter 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 au 1(/t,sgeso a cross between a male cat that is homozygous for brown, long hair and a female cat that has black,os sg(uta/e,1 short hair.


Which of the offspring has a recombinant genotype?

1.Outline how polygenic traits can show a normal distribution. 8eut1lhbge q*nfa8*4

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 over of non-sister chromzz;wo)u)1bt kepb)ln8u 8m7jatids shown in tmwuko j8bunt) l18) z);pebz7 he diagram below?

  The photomicrograph shows a pollen grain from L. ce : ,y7liom2dyx-u;y sandidum (Lily). Which stage of meiosis ium-d yosy;l,e2 yi7:xs shown?

1.Outline the events which would lead to an individual being bor8jvn (u2km) x* ps5alkn with Down syndroka jmulv*n8 k(xs)2 5pme, 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 indirect way of measuring plant growth. A study wasiiva(xb:fm0o 3ad f;5a /a /aq conducted on white onions (Allium cepa), under controlled conditions in a lab, to investigate the effect of soildm ;:axia50f /i a(f3ao q/abv 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 yx9j byk70y(,koyajx8h0+g x two ways in which cells can divide. The diagrams below show two ceh+(g9bjxx0k oxk y8yy 07ajy,lls from 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 gene expression in stem growthij f)b6 fn8ji2.

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 different siiib3 3amma;w+*cc8 gtages of meiosis. Which row correctly na3gi+ic 8a3 bmi*;amwcmes each stage?

  The micrographs show four phxt*xv99w o, pqases of meiosis I in a plant. In what order do these phases occur?9v ,xpqto*9 xw

Mitochondria are responsible for supplying metabolic en yvbezinpzs.y3 98 *9aergy 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* .3 eiay8pyz 9vszbn9 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 d62 zhee2xoh*q8l 3qjk 4b2ftqifferent stages of the cell cycle in four samples of lung tissue from four patients. Which tissue has the lowest j x3q28ketqh2 hzfoqebl64* 2mitotic index?

  The diagram shows thejaxfy(s oxdfnul61 mtw):7 b ;s6wp 1,xuro.2 dominant cyclin/CDK complexes at different time points in the cell cycle. Whicdlx1y2xau7 n6 w).wbpo1:s ;r 6tsumxf, j(ofh cyclin/CDK complex activates DNA replication machinery?

  Studies have shown that genes such as Cyclin Dependen;rlfz2uuf0 um6:1rgxtu;g 4 qt Kinase 3 (CDKN3) are highly overexpressed in cervical tu6qfutf 21gxuug;: rz 4r0lum;mours.


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.pwu2 d3ss7 yb cell cycle ?