The graph below shows the relationship between maternal age and the incidej hxzy 2+*mhr5ubl0o- nce of non-disjunction. What relationship is suggested by the data in the grazhlymj+ 5 hb*u-0ro x2ph?

  Which stage of meiosis is repres/**en, ae 7efv;ffixu)i gjk*ented in the diagram below?

  The diagram below shows chromosomrx.nnw9z5k dif:2g 7-urr g* res 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 aar 6/vpqf h)8rlleles of a single gene which would be present in the nucleus of a cell as a result of each processprf)rh6a /v q8?

  Which keyword is matched to the correct definitizxi)uxq; w,s7on?

  Which statement(s) about mitosis il 0 zyv*;xcq(a/2bgqls/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 t3kz sb9hz:7opo a cell in anaphase?

  During which stage of mitosis does the nuclear en*2t 93gdwhv uzpnm)q8velope break down?

  Which one of the following transport proteins only ca2 1 xohwk2o s9t.ze1ynv*7fs grries out active transport?x1s kzh21vys o7 o 9nw.etgf2*

  Which process does not happen in the shoot apeoe g-iq vsdo 8 z:9p/fsl538gbx?

  Which type/s of membrane transport do/does g:)fvlmka 2gt mxr-0) not require energy expenditure?
I. Facilitated diffusion
II. Active transport
III. Osmosis

  The diagram below representse3px -q n)8uqe a cell with a diploid number of 4. Which stage of cell divisqp-u3n qxee)8ion is the cell currently undergoing?

  The photomicrograph below shows a e9m04sfcqm sgb5h d x.2j)l-e root tip meristem. Which of the following sentences correctly defin bel0xs2mg qj)hd4ec9 fs-.m 5es a meristem?

  When does the random orientation of homologous chromoq:g atg. 6.7 luxaqgtha.r..psome pairs occur?

  Which process does not oc* gm-xvk*ewl468 rz rlcur during meiosis?

  If a cell with a diploid number of 36 undergoes mu)(xek+;2hxv xm jx5 qitosis, how many chromosomes will be pre;m)xh vux52x qkxj+e( sent in each daughter cell after cytokinesis?

  The image shows a micrograph of a ce(d4w szk/ks9 ,3g,trmy egc hwt0z/)hll.


What explains the appearance of the cell in the micrograph?

  Which statement(s) about homologous cub8jl ;7 sekf7hromosomes 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 individu2y: 2-tpc lyjf -hds5hal with Down syndrome.

Which statement is not correct?

  In the cells of a horse (E. caballus) during prophase I of meiosis I thes3vidn j7sa;j 5x(c bf 6g rb6;vd1p6tre are 64 chromosomes. What is thet ba7b5v v6fx3s;6jjr6n;d d(sp1cig haploid number of chromosomes?

  Which arrow is pointing to a chiasm5- h,*mlpvja p,p nep7a?

  The diagram below represents the structure of a shoot apical meristem. lh0a1uekxr47)y nu ) *ldxo/mWhich row in the table correctly identifies the processes occuring in the structure*0xnrayelm7u )1hdux/)ok l 4s labeled in the diagram?

  How does meiosis promote v4cps+gwz wd t mw)02.variation?

  Which of the following statements is/are cor5st3+fbhb)x dtl4u q 6rect for meiosis?
I. It is a reduction division
II. It involves random orientation
III. It produces genetically identical cells

  The diagram shows gametes produced fromcj4hl2 yuf ,e3 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 se: mdlzp g iy2:d)6of6scondary tumours from primary tumours as a result of the movement of cel 2i)ys l6d::gfom6p dzls?

  How many chiasmata are present in thek pvpd* ;cpemf 6gsa*ecs5t5o:w+z.- diagram?

  Which statement is a similarity between cytokinesis in animal and plant ce zjrzn+,9 zj5c(ivyq5 lls?

  Which stage of meiosis is match7r-. edzg(tw ubil v62ed to the correct description?

  Which statement(s) are true of mei,1:mz,kmxjp z:lie)f osis 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 ooc )zbqx/jje.aj 1vxo65 yte after the first meiotic division. This results in the formation o zjj ) .jebxxaqv/56o1f one large cell and one small cell. What is the fate of the large cell?

  Which row correctly describes di)6)az, -un6 d gruyqkgploid and haploid cells in humans?

  The following table shows the diploid chromosome number of a range oe 8v/xomz-v7yf species.


Which of these statements is correct?

  What conclusion can be drawn from the karyograin3p(ko8dmx5oeb:b 9dz qa1 9m below?

  Which of the following processes is characteristic of the meiotic and not)uo2ncs3n np ) the mitc2)3n nopsun)otic cell cycle?

  The diagram represents a bud with a shoot apics9ug g j/4dltrnx4-o +al 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 of the chimpanzee (t0m + e8/trvpuPan troglodytes) is 48. Which row shows the correct chromosome v8m/+ 0eturptnumber for different cell types and cell division stages?.

  At the end of which phase of meiosis I does crossing over occcnw93 nk: beb7gx n10nur, and what is the outcome of crnxc 0n1b3: wnkg7ebn9ossing over?

  Which of the following statements .*ugvlo7 s an:6o,hxogg, u1hzv 18qbdoes not describe a step in the sodium-potassiuug7.o,gaolubv11 86hh vx*o sng :qz,m pump cycle in the neuronal cells?

  Which row in the table below is tru5j2x.. ftbw3p(o h4uiak.oi z e of meiosis?

Membrane transport is9+z1slafx: d o important for allowing particles to move across the cell membrane and respond to changes in the chemical compl19z o+a dfsx:osition 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 regur 15edejjsa kil,8 f-:52cax gr,h0oflated 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 shof0dzu2f 9+ fjlws the concentrations of different cyclins during the cell cycle. Which cycli jflf9d0f2+uzn is involved in preparing for DNA replication?

The diagram below shows chromosomes during meiosis8v ,g7kyehcysuasv. -5lge(u:r33ca2 h x lp3.

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 i :*w ul0rbhcp) zjgce0r4l6o1nvolves the separation of homologous chromosomes?

  The mitotic index of throat tissuessf y;c707(b )w .5jcvbqbm luq 6fihp) taken from 4 different patients is shown below. Which patief6(5)b7ylw;cb m i. cufhq7bp0v jqs)nt is most likely to have cancerous throat tissue?

1.Draw a labelled diagk,jqq7w aka5 *ram 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 human karyotyk4*;qbuo .w dkpe.


What is the abnormality in this karyotype and its cause?

The graph below shows the rela4wjf:kb t mfp+b0i(u6tive amount of DNA in one cell during one complete cell cycle. Each letter represents one stage of the cw4b+ (u6 mp0tfi f:bjkell 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 homng 03gadl zvk7uxx8uh x(n7(8ozygous for brown, long hair and a female cat that has blah770( auk 3dgnn xzxv xl8(u8gck, short hair.


Which of the offspring has a recombinant genotype?

1.Outline how polygenic trad /se4-gah+lvits 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 rpt0* - q7ftrecrossing over of non-sister chromatids shown in the diagrtef 7r r0q*-tpam below?

  The photomicrograph shows a poll,)c gw3l z9d7)fe wc*kxyf h*wen grain from L. candidum (Lily). Which stage of meiosis ix lf)39*ww wzhcg*)de,f 7 cyks shown?

1.Outline the events which would lead to an individual being born with Downxdsuvqq u: by z8 w24le;q-/0b syndrome, which is characterised by the presence of three copies of chromosome 21.8bq zq:l 0 2u -edws4y/vqbx;u

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 w7dzy6 7r2t;gmbdev6 - xuy2roas conducted on white onions (Allium cep7b67ru-vxry dz26mg;2oyed ta), 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 wh9i j/i no8+mmcich cells can divide. The diagrams below show two cells from an organism with a diploid mji8c/no9+im 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 st 1cw -z2o:ktolem growth.

2.Outline how growth is controlled in the shoot apex of plants.

3.Explain the process and applications of micropropagation.

  The diagrams below showo7.n.t l)irlj a cell, with a diploid number of 8, in different stages oflitnl7 j.or. ) meiosis. Which row correctly names each stage?

  The micrographs show four phases of meiosis I in a plant. In wh 2:z zzr+ji q3a)mkz,e 6vcyv/at order do these pha az/:6c 2qz)iver ym,zv+kj z3ses occur?

Mitochondria are responsible for supplying metabolic energy in eukarycidp r *z-na 3(l;fw2votic 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 *fdp2(awc; nr-iv3lzfrom 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 of the cell;4 unv*miof1n8lu)h a qe.w 2k cycle in four sew)nmquu 2f4 la ikhn1o v.*;8amples of lung tissue from four patients. Which tissue has the lowest mitotic index?

  The diagram shows the do(gtmph l2 oy0iw:ra4 ,minant cyclin/CDK complexes at different time points in the cell cy,ot2yw4(0i hrm:gapl cle. Which cyclin/CDK complex activates DNA replication machinery?

  Studies have shown that u+9 enj*ouyzo43)2mhik5v h*oiaa8 lgenes such as Cyclin Dependent Kinase 3 (CDKN3) are highly overexpressed +y moijav *o8zk524 3an uui*)elho9h 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 cyclin E t+wdcpi-f jl 7*il6zm;-vdi o:rx *i0the highest during the cell cycle ?