The graph below shows the relationshi 29w+ ;y3sjqbeqv a7exp between maternal age and the incidence of non-disjunction. What relationshq;e yv72e+j 3ba9wqxsip is suggested by the data in the graph?

  Which stage of meiosis is represent8jsjx7 mi5tb, vki 00+1axvbsed in the diagram below?

  The diagram below shows chrj3+ (dkqxeem *rx34 +n)7qpw f,xpy.nvfe; huomosomes 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 gene whmp :2:iz(1nwznkmgg (ich would be present in the nucleus of a cell as a result of each(z:m : gnkzinwpg1m 2( process?

  Which keyword is matco)9+(y4zd7hh 3u ju ei/xxw0vhk* rkdhed to the correct definition?

  Which statement(s) about mitos)nu1/ ty7wl7+f inms zis 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 anan9p1 q /yit 4;nopwod(phase?

  During which stage of mitosis does the nuclq/q io- dxeeer14+86wjgxr ; tear envelope break down?

  Which one of the following transport proteins onm m4eweiv vk3e3j0(zl5d z,wvv7vp19ly carries out active transport? p4wvi3ev vez7( 0v9jme,1m3 vlzdkw 5

  Which process does notzodpn *keex/,9u 0/s8kshru; happen in the shoot apex?

  Which type/s of membrane transpkyc 2xogmxee30s* y0;8p tel5kb6y0 k ort do/does not require energy expenditure?
I. Facilitated diffusion
II. Active transport
III. Osmosis

  The diagram below represents a cell with a dipspp3 6cxj(le i:4 fmv8 lp/h*aloid number of 4. Which stage of cell division is the 4 ipe:fma6v/3cp jh l*( pxls8cell currently undergoing?

  The photomicrograph below shows a root tip meristem. Which of theva )9j .isk-lh following sentences correctly defines a merih.)v9ljasi k-stem?

  When does the random orientation of homologous chromosome pairsrn2 l4yxd+pi6 occur?

  Which process does not occurqyf jj)0ai u1o8/7a :k(ealjzx1)ov p during meiosis?

  If a cell with a diploid numbey8ht. m0x9h jor of 36 undergoes mitosis, how many chromosomes willmj h8 xo09.yht be present in each daughter cell after cytokinesis?

  The image shows a microgral+csg igxr)1ut u:/(vph of a cell.


What explains the appearance of the cell in the micrograph?

  Which statement(s) about homologous chromosomes is/are no8ud ztd7c6n0iqu ir2) t 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 l j725 8bkm5umzvrw *yia1v8 cwith Down syndrome.

Which statement is not correct?

  In the cells of a hori a5;fdg5szw*7kdp. xfr ;:jrse (E. caballus) during prophase I of meiosis I there are 64 chromosomes. What is the haploid number of chrom.w;:dk;7grj*5sr5xizda ffp osomes?

  Which arrow is pointing to a chiasma? e7;z8au4u fdbj v/d 4r

  The diagram below represents the structure +7d g.xk+i bnwof a shoot apical meristem. Which row in the table correctly identifies the processes occuring in the structur7.b+id xn+g kwes labeled in the diagram?

  How does meiosis promote var/ , k05uvt1 y hl5eezdisftt*8iation?

  Which of the following statements is/kmg)f*c6bmeke4d3n(m68j t qare 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 homologoud oh.47yi xk2qs 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 forf:0 qegmcna 9 oqf,(3iciq d(*mation of secondary tumours from primary tumours as a result of the mo(q, oce0g3q*aqcm( :id fn9ifvement of cells?

  How many chiasmata are present in the q/,2en1vm qchdiagram?

  Which statement is a similarity between cytokinesis in animarjm;z78 iqay7 l and plant cells?

  Which stage of meiosis is matched to thedbnbuf 9jl o(e9t/. x2 correct description?

  Which statement(s) are true of meiosis I but not meiosi-0szcgm(wik 2 s 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. Thfw kx+n;1ulyhb 6s i..mor02 fis results in the formation of one large cell and one small cell. What is the fa.l. ksiyffuxo b;60nwrh+ 2m1te of the large cell?

  Which row correctly de,(al-ci u)tg tscribes diploid and haploid cells in humans?

  The following table showe-tzuwnw4dj * 0b t2js,hs*t 3s the diploid chromosome number of a range of species.


Which of these statements is correct?

  What conclusion can be drawn from the j0m5-m4yt1. lvw5v+ a(pa qwd)urewf karyogram below?

  Which of the following processes is characteristic of the meiotic and not t j 2kyk2 ce6jexyq*h96he mitotic 6e9x j y6cyk*hejq 2k2cell cycle?

  The diagram represents a bud with tc ,osn/hf.quq;o7696q w sytpa r:3fa shoot apical meristem.

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 ofr2edun; e rielaj .1)lhjb4hz 61 +5ak the chimpanzee (Pan troglodytes) is 48. Which row shows the correct chromosome number for different cell types and cell division stage hz+ ;deh) jr451aeni612buk e.jll ars?.

  At the end of which phase of meiosis I does crossing over occur, and what is tv(5yn2w1s12klro r2mhw )ulo ;2uq azhe outcome of2l25wwozm11 (lso2yuu vahq r;rn) 2k crossing over?

  Which of the following statements does not describe a step in the sodium-1n4dsw vg3 jjk3hwf 98potassium pump cycle in the neuk h vj41983 gjsdww3fnronal cells?

  Which row in the table belo nswv 6ai/s86, msnwqdq53p/gw is true of meiosis?

Membrane transport is important for allowinqng;rka+z19r z ed, b:g particles to move across the cell membrane and respond to changes in the chemical com;k+qdrng, z9:r 1eza bposition 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 reug+x tdwae dfgxq )j:x+m.5pp7ip4* 5gulated 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 cioq4(- a perc:tc66mzr 6 p.hconcentrations of different cyclins during the cell cycle. Which cyclin is involved in preparing for DNA replication? t qcpc6-6e:hrpza64imo. cr (

The diagram below shows chromosomej+ *y2o2eojx js 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 homologous chromosome:a3v3 hd6qps is?

  The mitotic index of throa2i*;h qgl- /grvcz j3ut tissues taken from 4 different patients is shown below. Which patient is most likely to have cancerous throat tig;gc-h z3ql r2j*u/ vissue?

1.Draw a labelled diagram toz t2uwty -m v1acie052 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 abno*0kmjx y.utf /rmal human karyotype.


What is the abnormality in this karyotype and its cause?

The graph below shows the relo*zq5wxfr 3*jative amount of DNA in one cell during one complete c xrjzof**q 53well cycle. Each letter 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 a cross between a male cat that is homoz/l,xzq nq 2+/ t(hlxpiygous for brown, long hair an +xq2il,/zx /hp n(qtld a female cat that has black, short hair.


Which of the offspring has a recombinant genotype?

1.Outline how polygenic traioi,thg5 kru 5bm,tf/*ts can show 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 crossing over of non-sister chromatids shown i*4gj;o-2dzh jj rf :uln the diaj :f 4d;*uor- zjhlg2jgram below?

  The photomicrograph shows a pollen grain from L. candidum ip:ghg*( aq, a,w5jixo c4ly1 (Lily). Which stage of meiosis is shojl(ag,*iyc 4x5q:owgi 1 ahp,wn?

1.Outline the events which would lead to an individual being born with Down synd l/gy7(ai0h8q sknyb i4 k0.ljrome, which is characterised by the presence of threey igjy4k0iq(/h k7 las8bnl.0 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 stuuefns w8ihu f088jv +-dy was conducted on white onions (Allium cepanfvu88u-e8sw j+i f0h ), 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 ar6sxvalm;du+oo-f ) i((pc t6 q5cdb,i e two ways in which cells can divide. The diagrams below show two x+p5v6o,l( uosiac q) tmb cd-fd;6(icells 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 gt3uos:xosd a6:1 j4 k1vk s;jyrowth.

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 digms34cwhfv:2 ploid number of 8, in different stages of meiosis. Which row correctly names each stagsm 4w v3hg2fc:e?

  The micrographs show four phases of meiosis I in a plant. In whuu/,c 6 jnm /iv h;c0p,m1ntjbat order do these phases oc6 /u;v,mumj/0cc hnipbn,1 jtcur?

Mitochondria are responsible for supplying meta., soiize4,gc bolic energy in eukaryotic cells. In most eukaryotes, which reproduce by sexual reproduction, mitochondrial DNA (mtDNA) is inherited from only one of the parencg ,.ozei,is4 ts: 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 different stages o*+mzt.:eth:pwb - qupwy x+. qf the cell cycle in four samples of lunq qhwbwpt+*ue t .y-z:x :p+m.g tissue from four patients. Which tissue has the lowest mitotic index?

  The diagram shows the dominant cyclin/CDK comple: 4eaawui w)(exes at different time points in the cell cycle. Which cyclin/CDK complex activates DNA replication machinw(ia:4a )ew euery?

  Studies have shown that genes such as Cyclin c(1t5w v+nwj vufv- odo7zel)3q/:vvDependent Kinase 3 (CDKN3) are highly ove-vo+ n7j)q fov/vv5dw:zvw1l(3t euc rexpressed 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 cyclit.2hh2 yec3c/axhm/z5whx n 3n E the highest during the cell cycle ?