The graph below shows the relationship between maternal :*e(-z8hht igr(belj age and the incidence of non-disjunction. What relationship is suggested by the data inlj8 t-e(i* :zgr (bheh the graph?

  Which stage of meiosis is represented in the mc2-khw pexg m6(mz ,0diagram below?

  The diagram below shows chromosom63ey qjelt9x ;es 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 s-l 6vy.mlgl*h tates the number of alleles of a single gene which would be present in the nucleus of a celv* h y.6glml-ll as a result of each process?

  Which keyword is matched to theffwhbf4 urt- plqz 9:.c:-5se correct definition?

  Which statement(s) about mitosis is/)b+ krgzo06y tm(9lt bare 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 j6v/2s1i k y8dapr7*ycg7 udfletter points to a cell in anaphase?

  During which stage of mitosis does the nuclear envelo/nq3s9 6fdsz-l vsh4j pe break down?

  Which one of the following j4gb)(g1czmctransport proteins only carries out active transport?1bg) j z4(ccmg

  Which process does not happen a,lo6mt1 +u6qt u 8r97djbk7ss1 reiwin the shoot apex?

  Which type/s of membrane transport do/does not require energy;upvh 2ic /bsb0cm1.qxy; (oinsv, . r expenditure?
I. Facilitated diffusion
II. Active transport
III. Osmosis

  The diagram below represents a cell with a diploid number of 4. Which stbhi5 09e v11ybhjh1zqhv2b,jage of cell division is the cell c5,i hv0he bq921 bvjb1hzy1jh urrently undergoing?

  The photomicrograph below shows a root tip meristem. Which of the followzpv0 7ity)t5 k nus5ft o29skf72lug .ing sentences correctly defines a meristem? s ug uz nvsf tk5)2l0t72.f5okti9py7

  When does the random orientation of hob6ngdgdx -ljj :w3c r-p/,r 2omologous chromosome pairs occur?

  Which process does not occurc9khtvyza/s1daxphq9+,. z1vj+yt4s -a ic8 during meiosis?

  If a cell with a diploid number of 36 undergoes mitosis, how many chromosomes,7-iavdi7ylk k)r c1y will be present in each daughter cell after cytova dyy7k 7kc1),-iirlkinesis?

  The image shows a micrograph of auk() 3lq:hmjweat *c .qmp6z + cell.


What explains the appearance of the cell in the micrograph?

  Which statement(s) about homologous chro3r/kxjyoqlcc 4-sbpr/q4 y ;i k8xq59mosomes 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 individual,a q48b39las. jyey kc with Down syndrome.

Which statement is not correct?

  In the cells of a horse (E. caballus) during prophase I of meiosis Ink 1aa 8je0-ty there are 64 chromoj a 1a0yent-8ksomes. What is the haploid number of chromosomes?

  Which arrow is pointing to a chiasma?-8c j ,agr.m)zmu(ka g

  The diagram below represents thed;hod88u6 avwcwfgx/bj3 8a 9 structure of a shoot apical meristem. Which row in the table correct/ 38g8fw6xdo8duh9 acwj;ba vly identifies the processes occuring in the structures labeled in the diagram?

  How does meiosis prom+qv*ks1 )f sb/ ijtj hrnm7(,rote variation?

  Which of the following statements is/are cofdk oxmg9.3vmp v1 p*7rrect 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 homologojm)fmli z/.e:0xf: fj,ze; bsus 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 tktq9d;l 98r+q t0qubx2bo m,humours from primary tumours as a result of the movement of ce,m+qu;9lkb tq9xrob 0 t 2qd8hlls?

  How many chiasmata are presen aq+j17osr wo.t in the diagram?

  Which statement is a similarity between cytokinesis in animal l+gykl8 /ghrrp1+7rvand plant cells?

  Which stage of meiosis is matchnw,76yjrlt7 qed to the correct description?

  Which statement(s) are true of mei m) cq-,ixf fx ewc1*0-:dlcguosis 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 oocytrcgw+ qcs . -8bo:nl.qe after the first meiotic division. This results in the formation of one large cell and one small cell. What is the f8 clqw- o.bns .g:q+rcate of the large cell?

  Which row correctly describes diploid, v j7rzu4)nih; au2e1g q4lok and haploid cells in humans?

  The following table showsd1xk,ti5 dak )k9pk1gm:k k z7 the diploid chromosome number of a range of species.


Which of these statements is correct?

  What conclusion can be drawn from sp2u * zt,*gkjiwz1x1the karyogram below?

  Which of the following processes is characteristic /y,s w/z-o7 bwjv;xzo of the meiotic and not the mitotic cell o;oj w-x,y/w 7/bvzz scycle?

  The diagram represents a bud with a shoot apical meri+j0pzptc pr/- stem.

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. Whichi5g ./j fz8i:m(8ktho8ndhtwm ljc;3 row shows the correct chromosome number for different cell types j.d (l3/ mgkttjw 88im8h5hn :ioz; fcand cell division stages?.

  At the end of which phase of meiosis I does crossing over occur, and what iad;va57w .r3+ei a8smkd,ibws the outcome of crossingari5s;a+v m3i d edbw.78wa ,k over?

  Which of the following statements does not desw( ,yv jeg ssw;f-)ae*0po ki5cribe a step in the sodium-potassium pump cycle in the neuronal cellswgy );5jpevkes, w*s 0ao(f-i ?

  Which row in the table below is true of mextf2b. l2cobz14 bt-kiosis?

Membrane transport is important for allowing 20umn6 ;chf:yzv csl6particles to move across the cell membrane and responfv m;2 :z6 0cnsu6chlyd 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 regulated i lbk6)zc;a8egq uld csj-u6,y. s.rb5n 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 t)/n,p nj dbt+whe concentrations of different cyclins during the cell cycle. Which cyclin is involved in prejdt/bp +n ),nwparing for DNA replication?

The diagram below shows chromosomes during meiosis. h85oncj( aen a)an,s,b-3vr9j s sjq,

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 invoz+yhptk )k,i3lves the separation of homologous chromosomes?

  The mitotic index of throat tissues taken from 4 difxp/ 3z x z/vpe3mt5x*tferent patients is shown below. Which patie/z xtxev3 5z3xm*ppt/nt is most likely to have cancerous throat tissue?

1.Draw a labelled diagram to re+( 5agileyj q;5md4x bku+t/jpresent 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 kj pfg1l 5)(9c8uahbexd pb5j o m2e6x+aryotype.


What is the abnormality in this karyotype and its cause?

The graph below shows the relative amount of DNA in one cell during one completetns c h*y8k c8m+fj, e45.luyc kt+48n cjcle.m,yy8cuh5fs * cell 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 homozygous for brxld.1n1 fgkcjkn90v:7/dz bd own, long hair and a female cat that has blk cnbz gdk.dndj10 vfx9 1/l:7ack, short hair.


Which of the offspring has a recombinant genotype?

1.Outline how polygenic traits ca4ir: 4is, 9uw; fkhtwdn 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 crossirh5uiv l d94vtk++3hr ng over of non-sister chromatids shown in the diagram below? l5rvh+ iu+ r3t vdh9k4

  The photomicrograph shows a pollen grain from L. canoccn79* k+utp+7uh9 bo lut aq rui;;8didum (Lily). Which stage oft 9o8h;uup* alu ukn9ir+bt o7 +;q7cc meiosis is shown?

1.Outline the events which would lead to an individual being born with/o99n rtn+th t5t *rpi Down syndrome, nh 5/oit9r9rtt*n + tpwhich is characterised 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 growth. A study was condoe7jpi 8r bv+ 5n9f,mhucted on white onions (eo 7iv,b+pnmfhr j 895Allium cepa), 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 which cells can divide. The diagrams b,ntu2 kn oo-l3elow show two cells from an organism with a diploid numbntu2kolon ,- 3er (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 x6+d4dy7 +mre (p2a2jnfe b6arqavb5mh t. 0pstem 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 sk35a;3uqj 4hmjm qd*ftages of meiosis. Which row correctly *qj u4fh ;akq3 35mjmdnames each stage?

  The micrographs show four phases o)00 v zngy(lhyf meiosis I in a plant. In what order do these ph n0lhgv z(yy0)ases occur?

Mitochondria are responsible for supplying metabolic energy in eukaht8 p (ye-mfeo8j v41iryotic 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 eukajet ofy8ve-4pm( 1h 8iryotic 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 num)s/t d5hrt):c j8m k7yyj y4bcber of cells in different stages of the cell cycle in four samples of lung tissue from four patien 4yr/cht)yj)jbk:8d m5cyst7ts. Which tissue has the lowest mitotic index?

  The diagram shows the dominant cyclin/CDK complexes at dia0hm8rbhk 8wkzj-vo, 351 rd nr zvr5:fferent time points in the cell cycle. 8 31n8hrd:r0,rzbvjrz-mkhkvw55 a oWhich cyclin/CDK complex activates DNA replication machinery?

  Studies have shown that genes such as Cyclin Depen :i :w71kma c9vbrtwd/dent Kinase 3 (CDKN3) are highly overexpressed in cervical tumoursv :w cwd7m9t r/kai1:b.


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 during the cell cycl2ewdu3vksyhrr n-i4; 7 ,y0o ee ?