The graph below shows tc - )br cvaus7*9*miszhe relationship between maternal age and the incidence of non-disjunction. What relationship is uzb-am s9cv r)* i*7cssuggested by the data in the graph?

  Which stage of meiosis is represe mf g8:-to9wsgnted in the diagram below?

  The diagram below show6 ai8 (xry+sek-cpkq)s 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 of a single o(a/hy-po6-h 8w son igene which would be present in the nucleus of p oyw-6sh/oo a(hn-i 8a cell as a result of each process?

  Which keyword is matched to the correct definitiogg 3n0k wg.* sahqzk-(n?

  Which statement(s) about mitosis )c4lz+ zdrr7v 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, whix+i+hd xriqh(;+)dxp ch letter points to a cell in anaphase?

  During which stage of mitosis does the nucle(2g-pf zhowxi)pm-)6h3k a;gnuz g6d ar envelope break down?

  Which one of the following transport proteins only carrie+tn7/a*sm n p zstjr7,qufy18w0o8mw s out active transport?8u*p z+wno/qm1 7asyfsw rn j87t 0mt,

  Which process does not hap e+k b;qzv 9 o3yif/d/,xgwm0ppen in the shoot apex?

  Which type/s of membrane transport do/wgix; 3 lra(1om2f,q1l4s 8wuo7 yfizdoes 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 siwxkih,*3nf ) tage of cell division is the cell currentlyx3hf*k iin ),w undergoing?

  The photomicrograph below shows a root tip meristem. Which of the followingfu 9l4h zu-4 w)i7x+yg*nvnsb sentences correctly defines aun+l4* i)x9hw- z f4uybvgns7 meristem?

  When does the random tq)nw6c luah ft3-i**orientation of homologous chromosome pairs occur?

  Which process does not occur during 0 le3z*s rki)7 odabqtq) v0x7sxi k..meiosis?

  If a cell with a diploid number of 36 urrc5oeb pr.u*qc dc-0/ is* 6cndergoes mitosis, how many chromosomes will be present in each daughter cell after cytokice0r-cb.pqc* / c*id orsu5r 6nesis?

  The image shows a micrograu. q.fwi:wgkm y*4mg)xu sh :6-ci3 ygph of a cell.


What explains the appearance of the cell in the micrograph?

  Which statement(s) about homologous chromosomes is8m, htfr *9heq/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 Down syndrome. . ;8v,zr )b*0owxhgzwywbg9o

Which statement is not correct?

  In the cells of a horse (E. caballus) during prophase I rq x5euz u eg,+zva 2/t*2usrjb-uh35 of meiosis I there are 64 chr / rvet*2b355xu+- ujzq s,ur zgah2euomosomes. What is the haploid number of chromosomes?

  Which arrow is pointinujilwd)z72 52 adk de7g to a chiasma?

  The diagram below represents the structure of a shoot abl8dnj( .b0hrs x1s (dpical meristem. Which row in the table correctly identifies the processes occuring in the structures labeled in the di(r8 db l nxdj.(b0hs1sagram?

  How does meiosis promote variatippp/b iy (p6:eon?

  Which of the following s qyt90vgpm./ 0)s4*kllciukitatements 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 tw c)lp8.z 7jrzho 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 rg2.30 h6ykd dlg50ggbk + to0(qxpfyformation of secondary tumours from primary tumours as a result of the movement of cells?kgp3 gg. d x0lbf(+20t0kydyrho5q g6

  How many chiasmata are present in the dqe3-: j23qu7d8oexu oov mcksvg1 8y+iagram?

  Which statement is a simikr ea.c5p3v2vt2w dw -larity between cytokinesis in animal and plant cells?

  Which stage of meiosis is matched to the correct desc p u.1y8k ,bu:py3vlh*wii+ rlription?

  Which statement(s) are true ox3la9 wit ttj9xv1),ef meiosis I but 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 oocylxiee/oto+33:n + + lyjk-srbte after the first meiotic division. This results in the formation of one large cell and one small cell. yb:3e - +toxej 3orlik ++/nslWhat is the fate of the large cell?

  Which row correctly describes diploid and hap /b:dtijo4)k n jlcd2*loid cells in humans?

  The following table shows the diploid chromosome number of a ra , eh7te:3vfsnnge of species.


Which of these statements is correct?

  What conclusion can bk /ma5ge4p1abe drawn from the karyogram below?

  Which of the following processes is charagkpd w:8 7wm3u --melhcteristic of the meiotic and not the mitotic cell cycl:eg 7pm-wmh8k -ld 3wue?

  The diagram represents a bud with a shoot apical merist;39*d yw oxanyem.

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 o1xm eq5nk9a3if the chimpanzee (Pan troglodytes) is 48. Which row shows the c9q3nekia x1 m5orrect chromosome number for different cell types and cell division stages?.

  At the end of which phase of meiosis I doeswc)+l8etjh304y b cin crossing over occur, and what is the outcome yw83t+ 40ibhelnc )jc of crossing over?

  Which of the following statements does not describe a step in the sodium-potass)8pbg+sqip g 3bne1y 8ium pump cycle in the neuro1ep) ps 8y3bn8i+ggbq nal cells?

  Which row in the table j 1lge8a t 89u:y cfold0.v 5y9cshrh0below is true of meiosis?

Membrane transport is important fosp6 43dk wcj12ji uzg+r allowing particles to move across the cell me zu2 kg6jdji 4wcps3+1mbrane and respond to changes 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 lc0hlzm76f)2 zt iqz(4n swf4is regulated 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 different cyclins duringpd)glh3camd1r f:2 -f the cell cycle. Which cyclin is involved in prepaa3d:f c h gm-d)1lf2rpring for DNA replication?

The diagram below shows chvmr2oljh.k,j (m*f1 q ycp62promosomes 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 i87eo*kz1csi e 3zgea(nvolves the separation of homologous chromosomes?

  The mitotic index of throat tissues taken from 4 different(o6on,mv x.gg patients is shown below. Which patient is most likely to have cancerous thng 6mog.(vxo ,roat tissue?

1.Draw a labelled di2e y ua+k,d;k5p)xt1ots, 1 mnrxxj:tagram to 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 hxo93 3g f,jrg.g( xx2ai wq/tmuman karyotype.


What is the abnormality in this karyotype and its cause?

The graph below shows the relative 3wlcn;7gb:pu lb yr: /amount of DNA in one cell during one complete cell cycle. Each letter represents one stanlc3 /:ul gpw7:y r;bbge 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 tha:g;z;4gtr93r gy ok yot is homozygous for brown, long htz grg;9o okgy; y4:r3air and a female cat that has black, short hair.


Which of the offspring has a recombinant genotype?

1.Outline how polygenic traits can s6fo6mr r wq)q2how a normal 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 crossi/ xpwe+l6g v,tng over of non-sister chromatids shown in the diagram be6l+xtgpewv/ , low?

  The photomicrograph shows a pollen grain taxese /l)*h1, h4a d30qq oihfrom L. candidum (Lily). Which stage of meioe*1dh lih/0x4 e,oq)qt3ashasis is shown?

1.Outline the events which would leady1ao5kfy2-h f to an individual being born with Down syndrome, which is characterised by the presence of t-f5k2yoh f ay1hree copies of chromosome 21.

2.Explain how meiosis increases variation.

3.Outline the stages of meiosis.

The mitotic index is an indir.msi(8ncmi 8od7fl c: ect way of measuring plant growth. A study was conducted on white onions (Alliui so(8:nl 7ccm ifdm.8m 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 which clchd10po k/ j3ells can divide. The diagrams below show two cells from an organism with a diploid number (2n) of 0opc1 hdj3l/k 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 /f8d8tf2u erha2p *v yvio:(win 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 of 8, in differem7qmfq(c6cy6q m /dn 7nt stages of meiosis. Which row correctly names each 6 d(nmqfmc y6mq7c/q7stage?

  The micrographs show four phases of meiosis I in a plant.9pz6rhb:avd .dfr5d 4 h*rld: In what order do these ldvfh.z*d:rr6d 5ab dpr 49 :hphases occur?

Mitochondria are responsible for supplyxpsju5 .ro1f;.igprn3aytxbp7 w *5 5ing 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 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 yea p3pt;.nwsf51y7ju5b gra.xoxi5pr*st 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 stagehr uq6i tbj9t*.2dyzf(dc/kp5x .g0y s of the cell cycle in four samples of lung tissue from four patients. Which tissue ha0(9rdy2 kfijut x65g/ hd. bt.cqy pz*s the lowest mitotic index?

  The diagram shows the dominant cyclin/CDK complexes at different g2go-.hw +mdd time points in tod .-+mg2dgwhhe cell cycle. Which cyclin/CDK complex activates DNA replication machinery?

  Studies have shown that genes suc p*r4(3oluc qgh as Cyclin Dependent Kinase 3 (CDKN3) are highly overexpressed in(q u rpl4cog3* 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 h *:0od5emj yjlighest during the cell cycle ?