The graph below shows the relationship between maternal age .me3 ws5mxeh((msuwz /q9(xq and the incidence of non-disjunction. What relationship is suggested by the datqemw((z/.x9x sm 3 ushem(5wqa in the graph?

  Which stage of meiosis is represented in the diagram5 p4qx6x 1mzky below?

  The diagram below shows chrol6di wb .+2w0gq;xtixmosomes 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 nusy / mgq 0re5mbo.e(* 1lkvo+aw,lzfz5re7e )mber of alleles of a single gene which would be present in the nua /l0m ero+ rfze)k1e y5e( qvz gb*w7m,5.lsocleus of a cell as a result of each process?

  Which keyword is matched to the correct definiih h(fiwb+/p(26v-l rcxl* qltion?

  Which statement(s) ab7otlx*zv0 ,(wh0ea kbout mitosis 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 pointbb 0 0st85eqkxs to a cell in anaphase?

  During which stage of mitosis does the nucleabo n8cc*3;fb0juh:6azt5mff ma /*) u(r hjgbr envelope break down?

  Which one of the following trak uf+gd htw1.1nsport proteins only carries out active transport?dkht1g+ uw1f.

  Which process does not happen in the s /t w(gcjxlmk247:g j4pjpj/ohoot apex?

  Which type/s of membrane transport do/does not require energy expe42rrd 0lctoh 7nditure?
I. Facilitated diffusion
II. Active transport
III. Osmosis

  The diagram below represents a cell with a diploid number of 4. Wid27sn33fa ep (hx dg9hich stage of cell divisiondpx(3a7n eh3d9sf 2g i is the cell currently undergoing?

  The photomicrograph below shows a root tip meristem. Whf 8 a,-3bbyn-0iz )-zht2t a/lgyeyslich of the following sentences correctly defi,a 08e 32 )/z--b-lsyiaftnytghbly znes a meristem?

  When does the random orientation of homologous chromos,ly k b,kmtiyha)h(f h a*;(x0ome pairs occur?

  Which process does not occur d-hcyoqd4:)x i2n bui 1uring meiosis?

  If a cell with a diploid number of 36 undergoes mitosis, how many chromosiaz,uwu0m+(f: le q ,vomes will bezu 0vfu,a:l(+ qm,i we present in each daughter cell after cytokinesis?

  The image shows a micrograph of a cell.w5r ic yw 14k)x6mtqu.


What explains the appearance of the cell in the micrograph?

  Which statement(s) about homologous chromosomes is/ gg++ e/(kma ydv*,mudare 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 individua :x8 vgkn*tu+nfyt8 bg1v3l2hl with Down syndrome.

Which statement is not correct?

  In the cells of a horse (E. cabalyyj-e *bc+k7fun00 knlus) during prophase I of meiosis I there are 64+-k nkyyej 0b*nu0 fc7 chromosomes. What is the haploid number of chromosomes?

  Which arrow is pointing to a chiasma? 3(yc1r2ozu zj

  The diagram below represents the structure of a shoot aged9rbt sp,/-3a) s capical meristem. Which row in the table correctly identifies the proces -ps d)ge ,/sarcb93atses occuring in the structures labeled in the diagram?

  How does meiosis promotd*meon9a+w8 j6 qt(pte variation?

  Which of the following statements is/are correct for meiosi3 z-u4if .cpvfs?
I. It is a reduction division
II. It involves random orientation
III. It produces genetically identical cells

  The diagram shows gametes prejbynuqs( :jp.fy1 5b 2/m)osoduced 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 tumours from primary tuma2xhsfcy6sm , 8 hj8(wours as a result of the m8(jm2hsfy c ,6xsh8a wovement of cells?

  How many chiasmata are present in the diagrt-,-qkme 9 tdzam?

  Which statement is a simv ;zs alb/bz1iiu7-ue+ f+ )rkilarity between cytokinesis in animal and plant cells?

  Which stage of meiosis is matched to .zsw4ay 1gis2lb+19 r 2jy. fxrbm9yethe correct description?

  Which statement(s) are true of meiosis I but not meiosidbqoa9f.gx3n3 yn 7g+ x11.q7kylws ys 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 firscqv awx.gsu9k2 :, ai*t meiotic division. This results in the formation of one large cell and one small cell. What is the fate2gw9uk s,*x:ciqav . a of the large cell?

  Which row correctly dr,k,lo6 87vh1 vzic *l7x*yqsxp6 zqeescribes diploid and haploid cells in humans?

  The following table shows the diploid chromosome number of a range of specizcb :4if8 vvl)es.


Which of these statements is correct?

  What conclusion can be drawn from the karyogra5,alu 5zhdni3m below?

  Which of the following pr) k o i.x8cdt+nk5z:zlocesses is characteristic of the meiotic and not the mitotic cell cycle8kcotilz+. z x)k:dn5 ?

  The diagram represents a bud wi lj,b8/:briqis6 mcd1th a 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 of the chimpanzee (Pan troglodytes) is 48. Which row khve n : s,+v5caz qd)k0,-eylshows the coas:c0q)vly+5ekved k,-z, n hrrect 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-wae -+pmr7g , rqsfek-nua:7 t is the outwqfae, rs+na7k-r:-ugm 7 pe-come of crossing over?

  Which of the following statements does not describe a step in 2qhmu;e-tcu .xn3 (qcthe sodium-potassium pump cycle in the neurocutq2ume3 (h;xq .nc- nal cells?

  Which row in the table below is true of mn7 40inpsska2 1in7ozeiosis?

Membrane transport is impi sz*; y*xsa ..-abrb)fl/eul be6g7portant for allowing particles to move across the cell membrane and respond to changes in the chemical composition of the extrazb e*u aef).*s6rxspl/-l ab;b. i7yg cellular 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 remxo3 1 xy(yig1gulated 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 during the ca tskq7.dg/ hakj et/j7j5/hdqjk y(a d;j/4 6ell cycle. Which cyclin is involved in preparing for DNA raj/a.(ahh7j; kjt/d ydd kejs7 t 6gq/j qk45/eplication?

The diagram below shows ere6prky+ sq+3+ o+5/unxn cp 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 separationr i* hrr-g)wkvg: 1j+(c 5f*hmkg/c my of homologous chromosomes?

  The mitotic index of throat tissk9ttq1 v7jis*ues taken from 4 different patients is shown below. Which patient is most likely to have cancerous throat tissvs 1* tq9kjt7iue?

1.Draw a labelled diagram to represent th fj4kvn )7ib1-)m hv5bk*cc yae process of crossing over.

2.Compare and contrast random orientation and crossing over.

3.Outline the stages of meiosis.

  The image shows an aw qr+f ifxmd6t -.1m5yj+fp8u bnormal human karyotype.


What is the abnormality in this karyotype and its cause?

The graph below shows the relative amount 4jix npb :,d 8;vmxg0i/ci /rwof DNA in one cell during one complete cell cycle. Each letter represents one stage of the cell i,m c4 /dp:ginv;jiwx8r x0 b/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 m)1hp4hi/g blxe x q9y5ale cat that is homozygous for brown, long hair and a female catg iel9 1xqhhyb/px)4 5 that has black, short hair.


Which of the offspring has a recombinant genotype?

1.Outline how polygenijr jyj7 h, 6g b,ry,+yf1vcjf z2q;x:fc traits 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 cr7nt5cvm;;) relo c)g a8u ya;jyj43cxossing over of non-sister chromatids shown in the ol ;78)v; yc)ux3 ryc5t;anje a 4cjgmdiagram below?

  The photomicrograph shows a pollen grain from L. cafox; fsec6 :(piv;y i4ndidum (Lily). Which stage of my;oxi(fiec f ;64vs :peiosis is shown?

1.Outline the events wh(.so xrw7tet 70q3g (s1fpeerich would lead to an individual being born with Down syndrome, which is characterised by the presence of three copies of chro 30x(g e.1str e77(powr etfqsmosome 21.

2.Explain how meiosis increases variation.

3.Outline the stages of meiosis.

The mitotic index is an indirect way of mefj g y a9ktbj8b+z4 9,sr1fa3lasuring plant growth. A study was conducted on white onions (Allium cepa), under controlled conditions in a lab, to investigate the effect of sjgf,rb1asb 949zyf+j8ak tl3oil 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 cells can divide. The diak/q:k ,f (dpo9cmvmc4grams below show two cells from an organism with a diploid numbd/f vmqc9: pkok4m,c(er (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 expygh1 g0fw1 w1+5w qsm j:(daleression 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 nu at1y(36zi0px k ycto)q8x p+dmber of 8, in different stages kax0 +)oy ztxd typ1c6(q83ipof meiosis. Which row correctly names each stage?

  The micrographs show four phases of meiosis I in a plantbb u3 -m1uz5ugteyqrh 8inx(ijq ; .;1. In what order do these phasesb t.me;; -xu u5q1iyqubjh 1rzin38(g occur?

Mitochondria are responsible for 93/ .9 1pewiawwamo( nd )dkktsupplying 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 f3 dni9aoa)km 9de wtk/p(ww.1ound 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 cycle inypx sy uy(l,/cc273vw four samples of lung tlp32y7u/,(xycw y vcs issue from four patients. Which tissue has the lowest mitotic index?

  The diagram shows the do-g 9vo rsdtina05ha- 0minant cyclin/CDK complexes at different time points in the cell cycle. Wirho ag0nv -d at5-09shich cyclin/CDK complex activates DNA replication machinery?

  Studies have shown that genes such as Cyclin Dependent Kinarwu 84-/lknjt .l)8mpf*d7f 8dkkzbs se 3 (CDKN3) are highly overexpressekl*ut/-4dzf 8k)pf d w.8m j7nlkb8r sd 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 +vc149 5b912rv yzrmw oi llin+(gamvE the highest during the cell cycle ?