The graph below shows the relationship between maternal agb weh66kb5 l.re and the incidence of non-disjunction.5 l6be r.w6bkh What relationship is suggested by the data in the graph?

  Which stage of meiosis is represented in the diagram below? qi 4(km;-ie e6:yuitt,xpfe+ ln+nq )

  The diagram below shows chromosomrnc6 okz360mi es 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 of tqh of,,8s 8och7g5 gbnn:cd;g 8k)jf a single gene which would be present i58qcoo c h,t8 bfhg, 8)nsk gfgd7:n;jn the nucleus of a cell as a result of each process?

  Which keyword is matched to the correct definition?c0 a wpp8nh5*n

  Which statement(s) about mitosis ;+5sgvqs*wfh 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 lettluytxj;fd9 .q50av 3oer points to a cell in anaphase?

  During which stage of mitosk59i t7j;xspu is does the nuclear envelope break down?

  Which one of the following transport proteins only cartzd8c5b94xxjo5l ii1di.z e1ries out active transport?dlxzi15 cd 419z o.x85t iejib

  Which process does not happen in the shoot ng(m8;dj 2n d4bc qeg8apex?

  Which type/s of membrane transport do/does2fu 3bzh)*h2 vah4ncz 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 stage of c)d 2lzq6ya)gf n2sjoa1(hb j/ell division jqs (d fa6l)2/)ha2 y bzjgn1ois the cell currently undergoing?

  The photomicrograph below shows a root tip meristem. Which of 1k;bnqt lyzb0c0tj ,3k+ ir t-the following sentences correctly defines a meristem? z3- c1+tjbyl qbkn00trkt,;i

  When does the random td f. vm8b-wgnw qbjo+6p;;47t.8/t xsq kz dlorientation of homologous chromosome pairs occur?

  Which process does not occsup 4c:v 8 z7jfui3z0our during meiosis?

  If a cell with a diploid number of 36 undergoes mitosis, how ma5g ) nku3sp)h8(r zeoany chromosomes will be present in each daughter cell after cyu op()e5g kz )r3s8hnatokinesis?

  The image shows a micrograph o)r0yt 8xfta5 df::has bkx n,,f a cell.


What explains the appearance of the cell in the micrograph?

  Which statement(s) about homologous chromosomes is/are not t6 ()3oj0xhy, ykulhxg rue?
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 Down syxhhmwo-ow)(ji1u 7g6l gl4 ,qndrome.

Which statement is not correct?

  In the cells of a horse zuee 7 3 z/zipqf+7m8lbz+e b)(E. caballus) during prophase I of meiosis I there are 64 chromosomes. What is the haploid number of chromoezbp im f7uqe+ /z3+ )7belzz8somes?

  Which arrow is pointc; 5v4nz0sh+jjiw a8lfgf1 a*ing to a chiasma?

  The diagram below represents the structure of a shoo7g*aiui a72crju0 ( not apical meristem. Which row in the table correctly idengou77ru0*2a(iijcn a tifies the processes occuring in the structures labeled in the diagram?

  How does meiosis promote v -hme)l jbb.mxnu,y2x9x,2 kuariation?

  Which of the following statementr:/n zok/e( ies 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 two homologous chromosomes.xi c6bdsutk*:qf,rhtp 2+3vb 9n6 y4xd xo n89


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 d .* pe +ydxz t/2n8(k o87oerdhsp/piof secondary tumours from primary tumours as a res+hed o(8p*edd 8xrpnkpyt 7iz.o//2sult of the movement of cells?

  How many chiasmata are present in the diagra u3q7,bg p2bpgs,y3b cm?

  Which statement is a similarity between cytokinesis in animal and px r.l gfln:-mav9s1f2lant cells?

  Which stage of meiosis is matched to the correct descrip-ql2x4qe gf/rn uj;z1tion?

  Which statement(s) are true of meiosis I bu:xjxmkr. bal(j0o3z u9 e8*xst 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. Thit .rk0lilo 7gxy o2me6r+x63bs results in the formation of one large cell and one small3iktmx b yex6gl6 2o orl70r+. cell. What is the fate of the large cell?

  Which row correctly describes diploid and haploid u (cqjkj3m:v,cells in humans?

  The following table shows the diploid chromosome n9 q j v0y8z,b,zdnlf/uumber of a range of species.


Which of these statements is correct?

  What conclusion can be draweg0wd18.ng a6zcolz/ n from the karyogram below?

  Which of the following processes is characteristic of the meiotic and no fg:2i41tdzeft the mitotic cell dt2igz14: f efcycle?

  The diagram represents a bud with a shoot apical meristem.fbg3cr g 7vr+ajg* x42

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 (Ptba6ex7fzlj1(u; z * qan troglodytes) is 48. Which row shows the co t6u;e1*( zxjzla7fq brrect chromosome number for different cell types and cell division stages?.

  At the end of which phase of meiosis I does crossing over occur, and wha lcl8o 65)q6jxvn- thvt is the outcome of crossing ov6)vt lj86vo5n x-qlc her?

  Which of the following statements does8ws: jgu*4xo h not describe a step in the sodium-potassium pump cycle in thho*4xu8js: wge neuronal cells?

  Which row in the table below isxsfs36 oh v71hti5voi9 is *r4 true of meiosis?

Membrane transport is i7x+7a qu3mlj jmportant for allowing particles to move across the cell membrane and respond to ch77+ mjx aqul3janges 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 re9pw tap+v e7/a+kbyfo j4v.b,gulated 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 dogvkng3/ 6d 8sifferent cyclins during the cell cycle. Which cyclin is involved in preparing fodn6s8 g/o3kvg r DNA replication?

The diagram below shows cva4*;d7 4brucrsarg yj( b9/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 separation of hog,u5cz z n p;;cym(624co fozmmologous chromosomes?

  The mitotic index of throat tissues taken from 4 different path03 xf *ywg+schwf;8x ients is shown below. Which patient is most likely to havef;0w sfy x+3w g*hhcx8 cancerous throat tissue?

1.Draw a labelled diagram to represent the process of crom: :f z1*aeagevx okhe.o + a9g2/tpi(ssing over.

2.Compare and contrast random orientation and crossing over.

3.Outline the stages of meiosis.

  The image shows an abnuyyc a8wd)m(-ormal human karyotype.


What is the abnormality in this karyotype and its cause?

The graph below shows the relative amount of DNA in one cell d;g9u ofk6z d-nuring one complete cell cycle. Each letter represents one stage of the cell cycouf9kz;-gd n 6le.


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 cq+(wr23tf ldun23 e xac-(ib is homozygous for brown,q-nl ar 23x(3 wc(tcduie+f2b long hair and a female cat that has black, short hair.


Which of the offspring has a recombinant genotype?

1.Outline how polygenic traits can show a nor1bf0c r)hm;te mal 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 crossing over of non-sister chromatids s r0eird q tb,+bc4 2nkmug/9l.yt.bc -hown in the diagra,.b ut9cl4gi-qbr ycd/ 2km b e.+r0tnm below?

  The photomicrograph shows 2-(vhcm, c--)s79a1 ovgtbek3rbjqnw pz;o ba pollen grain from L. candidum (Lily). Which stage of meiosis igc k e7)(on1; bm,rvvpw - 2czjbh3qst-bo-9as shown?

1.Outline the events which would lead to aikkuajfz q*-)xj/q,w/ca 5 y)+qm3 sln individual being born with Down syndrome, which is characterised by the presence of threes5qya* i kq+-/c 3x/ jj)),m lzuwfkaq copies of chromosome 21.

2.Explain how meiosis increases variation.

3.Outline the stages of meiosis.

The mitotic index is anizvxj0+ 9+jm/eb 0pj d indirect way of measuring plant growth. A study was conducted on white onions (Allium cepa), under controlled conditions in a lab, to investigate the effect of soil pH on th0j ejj90m+ v+b /zxidpe 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 iry2hn 1(;ww 3e hjfu1hn which cells can divide. The diagrams below show two cells from an organism with a dipjwe32( h1hu yrfw1;hnloid 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 gen xne6sc*3e5l2 i-jxehe 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 diploid number w ocjvba66zc: g63y -sof 8, in different stages of meiosis. Which row correctly names ejbv yz c:o66-scgw 3a6ach stage?

  The micrographs show four phases of meiosis I in a plant. In what order dougpw *gb:h4bdi(ofq 5y4a1 tye477mp these f77 : p(ia4gdt5q1mbgy op4yu* bh 4ewphases occur?

Mitochondria are responsible for s6 wwpjc/ 0x7ynupplying metabolic energy in eukaryotic cells. In most eukaryotes, which reproduce by sexual reproduction, mitochondrial DNA (mtDNA) is inherited from onlyy j0xw c67pwn/ 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 dizeb lh v/63c2 pk7xi s4r(.kfrob,5vpfferent stages of the cell cycle in four samples of lung tissue from four patients. Which tckveh3.i5 p kz6sorx/b27 ,lfp r(4vbissue has the lowest mitotic index?

  The diagram shows the dominant cyclin/n9x(kb7gk mx3ujxkm g)0 fl-)CDK complexes at different time points in the cell cycle. Which cycgm xkk 0-klu f3m(n9gbj7)x) xlin/CDK complex activates DNA replication machinery?

  Studies have shown thaq4n 869x vo:c s;kklpzmi0mz7 t genes such as Cyclin Dependent Kinase 3 (CDKN3) are highly overexpressed in cervical t6sl0z mi v;cnxzkp:7m984o q kumours.


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 4td r wtpo,n .1 u,ryi20epk0xhighest during the cell cycle ?