The graph below showzfn9* lf17wd v4o( m7y1x gg,4hyphgc s the relationship between maternal age and the incidence of non-disjunction. Ww y 9hhg1*yx1(vlg4opfcf n7g47z, dm hat relationship is suggested by the data in the graph?

  Which stage of meiosis is represented ihuowa6 m./c:rxxiniz1y z 3 w,,7 mi/d lzf*+jn the diagram below?

  The diagram below shows chromosomes duri 5*pa n0lxg5u tyw.:hwng 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 numb/ywm2by9pdqvw -*khg j ,p 9q9er of alleles of a single gene which would be present in thehgpmdwqyj,p/99qk w-v92 y b* nucleus of a cell as a result of each process?

  Which keyword is matched to the correco ccxy..g/v 4 gy7r2xvt definition?

  Which statement(s) about mitosiscr1vpoqkd /xw x t6f, :lt5+m0 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 z,spzq6lal-kjra)47 /sp da8 points to a cell in anaphase?

  During which stage of mitosis does r9tm nvf/d)k5h8q p4i the nuclear envelope break down?

  Which one of the follow, 5x,v na0dlpqmf0 jj)dha(oka4-y4ving transport proteins only carries out active transport?4,v0a yx -4v0n fomlqp)a, d5dah(kjj

  Which process does not happennl, .1r3ogwgtki1el3 grrr j7)1r ri : in the shoot apex?

  Which type/s of membrane transport do/does not rew h, m5sy,-lag)y qob9quire 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 ue eeq-f a7azg*y45:x cell division is the cellzeey xf4:ug7-a5 aeq* currently undergoing?

  The photomicrograph below shows a s0xq1gi vi)ci i(4nc8z,m rb26p ybb*root tip meristem. Which of the following sentences correctly defin(nb r, v2m 1sibygi 4q* 6cpiz8c0xb)ies a meristem?

  When does the random orientation of homologous chromos0rd m8lxwv1+y 3+drzsome pairs occur?

  Which process does not occ47 pow z urz::hmmzp,-x(ys 2eur during meiosis?

  If a cell with a diploid number yo8vml1 y/ 4j-nfx,v)ol sn-lof 36 undergoes mitosis, how many chromosomes will be present in ey8l f) /l4vmonyn- x- js1,lovach daughter cell after cytokinesis?

  The image shows a micrograph or0w q5l7disy cp0ak )p0c+d*s f a cell.


What explains the appearance of the cell in the micrograph?

  Which statement(s) about homologous chromosomes ism2; c xbsko nte3g5fe/ g46-,swg0gax/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 -a+53ifaf5.fpo-o m6nqcp kp with Down syndrome.

Which statement is not correct?

  In the cells of a ho swn 6zm-x7ovlr6c it0ap/ 5)krse (E. caballus) during prophase I of meiosis I there are 64 6 -c5m7wkr)6 l s o/tnp0ixvazchromosomes. What is the haploid number of chromosomes?

  Which arrow is pointinfllx:(/ 7fxsug to a chiasma?

  The diagram below represents the structure of a shoot ap.v +uby6lz nn23e kxf3ical meristem. Which row in the table correctly identifies the processes occuring in the structures labeled in th+3xen6.zfk 2blnu vy3 e diagram?

  How does meiosis projef5h5++kb g6dz q + sqqxly+67adc n4 rb5/anmote variation?

  Which of the following statements iskl:mh* 9qa9o4hj c;ol/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* xo.+u :.8xtbbuu+c lnrxr 9io 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 form) (3koc,azkcp8,n kbvma:cq4 ation of secondary tumours from primary tumours as a result of th oavq )kcp(43nz8cak,b ,c:m ke movement of cells?

  How many chiasmata are present in v9ajxcg,s u/es;:x q. the diagram?

  Which statement is a similarity between cytokinesis in animal and pxwbll6)+lx5suucls3 u -, xgp29: ienlant cells?

  Which stage of meiosis is k*mq,et4x o 3/,oqdlnk(ro 3zmatched to the correct description?

  Which statement(s) are true of meis j((7i)n9e ukr(la bbosis 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 oocyte after the first meiotqqrudgv3a 9mx,s82+g nn )-loic division. This results in x )mu9d l-3s,g8 navo2nqgq+r the formation of one large cell and one small cell. What is the fate of the large cell?

  Which row correctly describes dipl o+ckkimj: spai1 ao kd1*54mo/k,s3toid and haploid cells in humans?

  The following table shows the diploidbfa;e7v m z:hm,8ahx v.4jc)k chromosome number of a range of species.


Which of these statements is correct?

  What conclusion can be drawn gmrs(abi 8xpv ss8007from the karyogram below?

  Which of the following processes is characteristic of the meiotiml1ze;15o5xn2kf i orc and not the mitotic cel1e ; 52rzkoixmf1 n5oll cycle?

  The diagram represenl zzmpt5aho c./u( l597m(0 ,k ksfszlts a bud with 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. Wh4i gz-m kfwh3p*(-(6 s)q+r: e+map aeaidccvich row shows the correct chromosome number for different cell types and cell division staz+c + qmiih*ca3r kaw)pfpva6(-d 4(-m:ees gges?.

  At the end of which phase of meiosis I doexr0(r g1zgwn 5s crossing over occur, and what is the outcome of crog r(5xn01z rwgssing over?

  Which of the following statements does not describe a ste8mlvf rofi ee d9oa3g2m )co:17g(7i np in the sodium-potassium pump cycle in theeo n :g3v)e o87f amg(c9fim7i odr2l1 neuronal cells?

  Which row in the table below isk vecls.i5:n7 true of meiosis?

Membrane transport is important for allowing particles to move across the cell m0j+-q scl(s :k6z zcpjkqc76iembrane and respond to changes in the chemical composition of the extracellular fj+q6s z 67: 0kcqlps-ki(z jccluid.

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 reggi- 1srt8a lifq5)5wo ulated 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 concent n:v( pm(o(icsphra 75rations of different cyclins during the cell cycle. Which cyclin is involved in preparing for DNA replicationn paormis 7:5c(( v(hp?

The diagram below shows chrogt*mun92b bq :mosomes 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 thbwlx*nu k895we separation of homologous chromosomes?

  The mitotic index of throat tissues taken from 4 different pyw; j)coj)-f gatients is shown below. Which patient is most likely to havgjcfy )j;wo-)e cancerous throat tissue?

1.Draw a labelled diagram to represent9ww+78bz (6q ingnhgz the process of crossing over.

2.Compare and contrast random orientation and crossing over.

3.Outline the stages of meiosis.

  The image shows an adgncbdpp1i bh4 3w9) 3mt2tf+bnormal human karyotype.


What is the abnormality in this karyotype and its cause?

The graph below shows th:,igv5;h js wx 0(8 itwgdsm:oe relative amount of DNA in one cell during one complete cell cycle. Each letter represents one stage of the cell xih5:wgv80jw(m;: ,ots gsd icycle.


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 homozygous 3cgz zkmw1m v( 9zu 3r6tsc5t*for brown, long hair and a female z6kt(3*3g zmmu1v9 z5rtscw ccat that has black, short hair.


Which of the offspring has a recombinant genotype?

1.Outline how polyge :kt7;hj s9.zrubcg: fnic 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 crossing oasv+lu vea(w4br/d/ry .n9 q(ver of non-sister chromatids shown in the diagram b./a v b(l uqr(w drs4ven/9ay+elow?

  The photomicrograph shows a pollen grain from L. candidum (Lily). Which sv-2pd ukdv -2+4t aipvtage of meios2d2p- vi +vapt-4dkvuis is shown?

1.Outline the events which would lead to an individual being born with Down sv0e7k ttrw a271 vvdi(yndrome, which is characterised by the presekd i0w(7t a1 vevr2vt7nce of three copies of chromosome 21.

2.Explain how meiosis increases variation.

3.Outline the stages of meiosis.

The mitotic index is an inmkx laub j9l7zg1soj3 2gx7 *7direct way of measuring plant growth. A study was conducted on white onions (Allium cepa), under 1gguak7*x3 2 zlljb oj797sxm 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 z3gnu id49 5o(jwv4jhtwo ways in which cells can divide. The diagrams below show two cells from aw4iv 34d uj(z5on g9jhn 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 exprescabgo a85 9*iasion 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 of 8, in different sth2qkee*i4vzz kx3a nwuo9w9a (-y *;no2inh1 ages of meiosis. Which row correctly name a(z 9 qi*2v3k-hw4n9ihe1yznuxawe oko;n*2s each stage?

  The micrographs show four phases of meiosis I in a pl i:fr pr)gy ykj,07ynccz uwiz:s33.4c d3lp8ant. In what order do thesedcg,l:i p3f .: 7zpc3zci)ruy483n jk0wyyrs phases occur?

Mitochondria are responsible for supplying metabolic energy in ee+t3r75uhrth :o q b y.tc;cg0ukaryotic 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 t;7rrut:y tg 5h03eoc+qc b h.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 ofpwj r(rng .ifz ,0o1s8 cells in different stages of the cell cycle in four samples of0ng1ws8jrri(. pf, zo lung tissue from four patients. Which tissue has the lowest mitotic index?

  The diagram shows the dominant cyclin/CDK comctq,rqjw)zrm5ig47 2y3h 8m r plexes at different time points in the cell cycle. Which cyclin/CDK complex activates DNA replication y,q mq mz 24ji8wt)rrgh7cr35machinery?

  Studies have shown that genes such as Cyclin Dependent Kinase 3 (CDKN3) zas v1y(+oz4eare highly overexpressed in cerzeyo 4a1zv+( svical 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 huim6( jsui7id157zie ighest during the cell cycle ?