The graph below shows the relationship between maternal age aus0 fg l nqg9cifc*2)1nd the incidence of non-disjunction. What relationship is sugges9c1 )f*cfui2gsqn l 0gted by the data in the graph?

  Which stage of meiosis is repres7x+*yrla 9m i yf rpl-) 6yor.hhf75 xnknlk53ented in the diagram below?

  The diagram below shows chromosomes during meiosis. 9t ;hcur6u *bg4p8se l uzy5f)


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 whij(rn 2n29k ,gbtjcv)l;r9upjo +r.zb ch would be present in t nv+l j99;bop)g2r rucz.,krj jb (t2nhe nucleus of a cell as a result of each process?

  Which keyword is matched to the corre)pi1ut dkl 0)sct definition?

  Which statement(s) a-l eeeb7 k5hao/l38z c4olp,wbout 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 points to a cell in a5-j 1 8b-bh7j 7s0wcfe2 zbnd,zpvml anaphase?

  During which stage of mitosiskf mnb9;b/ ;pk does the nuclear envelope break down?

  Which one of the following transport proteins onl qrh1x*2v nuc6y carries out active transport?r*uq hv1x6n2c

  Which process does not happen in t pms tur:t0w4yr-f0a /he shoot apex?

  Which type/s of membrane transport do/does not require energizj6v4 a3d4sktx.kp )y expenditure?
I. Facilitated diffusion
II. Active transport
III. Osmosis

  The diagram below represents a cell with a diploid number of 4. W(bo 65q:het im q.,mfchich stage of cell division is the cell bm.qc,5(:o h6tqmif ecurrently undergoing?

  The photomicrograph ,fvgu,b9mphsjq50 q8ler3c m/1n8 yp below shows a root tip meristem. Which of the following sentences nvlsr5/ 8umh08mpeg, pf3cqqy,b1 9j correctly defines a meristem?

  When does the randomv ey9wtos0,6t /,bad f orientation of homologous chromosome pairs occur?

  Which process does not occur dur p4.)gcy-ji2x. u fbre5-d nrting meiosis?

  If a cell with a diploid number of 36 undergoes mitosis, ho(4 v0an +6g.-7z/9 fuc ulcvwjsfz jbqw many chromosomes will be present in each daughter cell af .(sbgu4 qv+c7u jj6vzcf-l0wzfa9 /nter cytokinesis?

  The image shows a microgrsns ycqe-)4.wq; 7nwc aph of a cell.


What explains the appearance of the cell in the micrograph?

  Which statement(s) about homologous chromosomes is/are not tr2col3bk z/zg )ue?
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.jdw/c h h38a4u

Which statement is not correct?

  In the cells of a horse (E. caballus) during prophase I of meiosi ssvr +1;xxm2zs I there are 64 chromosomes. What is the haploid number ors1xv2 m x+sz;f chromosomes?

  Which arrow is pointing to a chiasma? hodzho 7 dd0 ;-nwwwn3 e34bc2f71jco

  The diagram below represents the structure of a shoot apical meristem. Wh8.d3nv/oj 4gsxmzl1 a ich row in the tabz/dl3ma8.v4gj o nx1s le correctly identifies the processes occuring in the structures labeled in the diagram?

  How does meiosis promooq k;:ffghjin2cj9 gqcj.3 4+te variation?

  Which of the following staten; er08rxzl(plah .m*6hmln / ments 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 fro/upl0o3u7t o zm 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 tudu(fhpt a5-v;bv 8r8 zmours from primary tumours as a re btr-d(;fu88p v5azhvsult of the movement of cells?

  How many chiasmata are prklb a:w;a c yf1t/n,-pem2i)tesent in the diagram?

  Which statement is a similarity between65**s olpir nv cytokinesis in animal and plant cells?

  Which stage of meiosis is matc9sft()e ay+wo* x2h wkhed to the correct description?

  Which statement(s) are true of meiosijwr)pi .4r.zf g0by 1ls 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 ;u etdt-7od.h oocyte after the first meiotic division. This results in the formation of one large cell and one small cell. What is the fate of the large cell?d7oet; dhut-.

  Which row correctly descril6ko/ y h (bbyqrhb)*gus4+0k9 pt 0gmbes diploid and haploid cells in humans?

  The following table shows the diploid chrolyjuk d70o5l /mosome number of a range of species.


Which of these statements is correct?

  What conclusion can be drawn from the kar b, ,r7pxl,f4 greom2tyogram below?

  Which of the following processes is characteristic of the meiotic and notp.;p0w 9ehdh e4leny1 the mitotic c 4pyhedn ;h9.0 we1eplell cycle?

  The diagram represents a bud with a shoot apical objze94 t )4rnuo/ :bggtj;6j 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 troglodytep*.a71 x;cb jjosule6s) is 48. Which row shows the correct chromosome number for different cellol *p.ea1bjj u76xc; s types and cell division stages?.

  At the end of which phase of meiosis I does crossing ov. -kw ft ;cdmdm ncy:ef11ij*0er occur, and what is the outcome of crossing over-*icm: d 1 fm0tnecfwjk; 1d.y?

  Which of the following statements does not descc,pi esi/ ))ffribe a step in the sodium-potassium pump cycle in the neuronal cellsi/epif,)) f cs?

  Which row in the table belowl3m1 p n)hk 09pdkp+m8( cvhto is true of meiosis?

Membrane transport is important for allowing particles to move across the cel. *bla.ho :yuk tz0y-n06oe+adoz vhm g32h*c l mv-ahe h tkzm2 oogyh0l6d+uyc.0z3n*abo :*. embrane 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 is regul;t d 3v8qsl5.q*ayco4l i fj,xated 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 concentratioeeif5 whl) jbf8hxo3j,5 :+z yns of different cyclins during the cell cycle. Which 5,3fe eyl+ )fiwbjh:j85 xhozcyclin is involved in preparing for DNA replication?

The diagram below shows chromou8y+rz) -thm08xdtj msomes 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-guy3oqf) p w q )f77.kqhe(ir involves the separation of homologous chromosomes?

  The mitotic index of throat tissues taken from 4 differeuix:qdh 3x t)9mwb-i342pq ypnt patients is shown below. Which patiend9:yp)mx- qquwhtb3 4ix32ip t is most likely to have cancerous throat tissue?

1.Draw a labelled diagram to represent the proc)/e-twm l; dzuess of crossing over.

2.Compare and contrast random orientation and crossing over.

3.Outline the stages of meiosis.

  The image shows an abnormal+06rb v3fbytr human karyotype.


What is the abnormality in this karyotype and its cause?

The graph below shows the rn)l 7ftlaw1ue;r zqd ya89x4 1elative amount of DNA in one cell during one complete cell cycle. Each letter represents one stage of the cf) r7el twl1 qaa8;u1y49dnzxell 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 tha9ex+ xjhoy46ezo bjnj3 s*8 :tt is homozygous for brown, long hair and a femz*n4tj:+ xyeo3jejs8o9h 6xb ale cat that has black, short hair.


Which of the offspring has a recombinant genotype?

1.Outline how polygenic traits can show /o.aptenlf -y x/cyh03(tf y)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 resulk.zw0;y kq, pr*+qxt it from the crossing over of non-sister chromatids shown in the diagram belowkwq0r +t,*q yx izk;.p?

  The photomicrograph shows a pollen grve +9e2pw3*y lmnuw 5wain from L. candidum (Lily). Which stage of meioslp5+2n*e9mew3 y w vuwis is shown?

1.Outline the events which woue 0n*5 ar9dqgsqd,bitle3zf(e ue*1 9ld lead to an individual being born with Down syndrome, which is cha g1el 993eeidr5*(t saequ0*,fb zd nqracterised by the presence of three 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 growt 9dvs k5 w-kd*6.gisfch. A study was conducted on white onions (Allium cepa), under controlled conditions in a lab, to investigate the effect of soil pH on the mitotic index of thi 6 gkswds59.-vd* cfke 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 diagrams befc95ike37491yak isqgw azf01zv2 qm low show two cells from an organisq147ii5kz 3 ck0yqv9 z 2faa1w9emg fsm 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 express*i2x5d t y.ilkrzk5iu /i3,cvion 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 dipls c(2wqfe/ yw-oid number of 8, in different stages of meiosis. Which f ce/(ws2- qywrow correctly names each stage?

  The micrographs show four phases of meiosis I in a plant. In what order doqrpw v8c09 r2 (ly,oni these phases occur? , q0yl8rw o v(i2rcnp9

Mitochondria are responsible for sw .9d rjxydlw 9hbi ;djq+ 24v);aqh2dupplying 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 yeas ybq9wwj4diahx9qv;l) 2 h;dd.rjd+ 2t 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 dq-5u(bl hurc9 qm m+0lifferent stages of the cell cycle in four sampql (h+5uu0br -mc9mlqles of lung tissue from four patients. Which tissue has the lowest mitotic index?

  The diagram shows the dominant cyclin/CDK compldd9hglp/0*zuxuq3 2m0g( 8z6 c ldhdgexes at different time points in the cell cycle. Which cyclin/CDK complex activates DNA replication2(dmz gudgd/gudql*98hhcpx6l z3 00 machinery?

  Studies have shown that genes such as Cyclin Dependent Kinase 3 (CDKN3) arel4mo/did5w: j sfd0q; highly overexpressed in cervic54 omd;dj dl/ i0qs:wfal 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 highest l6 j eav)pg9+jp6js8vduring the cell cycle ?