The graph below shows the relationship between matern1l8zi 1mwdja4etuy 8 6-:qlnlal age and the incidence of non-disjunction. What relationship is suggested by the data in th4 nld1lmi-w z:eylut 88qa6 1je graph?

  Which stage of meiosis is represented i+odx 2zy8x+- ifkak-gn the diagram below?

  The diagram below shows chromosomes during meiodq7 mv15g4yhs:rf;kl sis.


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 si, :3y mvilue+k+fo xg2ob 1*yingle gene which would be present in the nucleus of x,m+ 3 oie2f+*ly 1obiug :yvka cell as a result of each process?

  Which keyword is matchedsvmy 7uxm,jlo4;68 gs to the correct definition?

  Which statement(s) about mitos g3 ,jtp2e+ou 6wd z-j:;3rakijlbc4wis 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,q- ef + tlsmy2/pa/ko to a cell in anaphase?

  During which stage of mitosis does the nuclear eng977l(z kv znjvelope break down?

  Which one of the following transport proteins only carries out active transport5iqb7o t/x/y;qc; kri:; jp on?;pqnri ; ckjqy/o:iox7t;5 / b

  Which process does not happen in the shoot apet7qg;,cx c dg5x?

  Which type/s of membrane tkq.iv0sv9 1wj )h/ gqvransport do/does not require energy expenditure?
I. Facilitated diffusion
II. Active transport
III. Osmosis

  The diagram below represents a cell with a diploije3v:8) /ln ra7/cz)ev9xh ckh 6tbpwd number of 4. Which stage of cell division is the /)6r3:bze xc9 v awlh7jcn h/et8pk)vcell currently undergoing?

  The photomicrograph below shows a root tipm-3lqyi/ pmf,q h3 lv+kl16zg meristem. Which of the following sentences coqllq3z mfkm+gh i, 16-p/v3 lyrrectly defines a meristem?

  When does the random ori3 6 .oxemcx4kxbp9- fsdbt v/9entation of homologous chromosome pairs occur?

  Which process does not occur during meiosis?sshxae ds a2l** y+u8-

  If a cell with a diploid number of 36 undergoes mitosis, hoe zmg (qz +x0tegsrq v;5p;p4/w many chromosomes will be pg(t5e/;+vz; rqpe m0gs z4qxpresent in each daughter cell after cytokinesis?

  The image shows a micrograph of a b10v to(h/be;qz69ulb;ss 2gz; w uodcell.


What explains the appearance of the cell in the micrograph?

  Which statement(s) about hooy k vw3,z.csca-6 vqhx2 ,nr2mologous chromosomes 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 a,ez8udn8 k 5gtgdvu0 +n individual with Down syndrome.

Which statement is not correct?

  In the cells of a horse (E. caballus) during prophase I of meiosis I there art /l waii5(ck*e 64 chromosomes. What is the haploid number owa i cl/k(5t*if chromosomes?

  Which arrow is pointing5:npbv: fh e ;yg(nv3g to a chiasma?

  The diagram below represents the structure of a shoot aa ypba/i4 ,7x9f0 hgvepical meristem. Which row in the table correctly identif9fpya ix0e/,hv74a g bies the processes occuring in the structures labeled in the diagram?

  How does meiosis promfxhvbx ,9 6o2iote variation?

  Which of the following statement owa5rrr94fnw1-c+q i08lf szs 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 from two *s5(x7x . cdta k um,wbe1ewc7homologous 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 s(3sg7 9r,vvrsois n5cecondary tumours from primary tumours as a result of the mo5gc 7vs9rnir 3sos,v( vement of cells?

  How many chiasmata are pr30o) qb/xx8as g3 ldzbl )jx1desent in the diagram?

  Which statement is a similarity between ceknub+( 4gnj85pe kx.ytokinesis in animal and plant cells?

  Which stage of meiosis i* wp+ 3/o,ueusn7ppahs matched to the correct description?

  Which statement(s) are truf0v c;n:19m1 nbzixnjwni*5pe of meiosis 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 an9bq 2pc*ulfo . oocyte after the first meiotic division. This results in the formation of one lf2qbpu.lo c 9*arge cell and one small cell. What is the fate of the large cell?

  Which row correctly describes diploid and haploidy bsxz:21sjnji6+/ 2gi /ibvz cells in humans?

  The following table shows the diploid chromosome number of a range of spef / m80ywvb6i:t j8lkmcies.


Which of these statements is correct?

  What conclusion can be drawn from the unfzrz*3 :+ck5pe/g*kea c(bkaryogram below?

  Which of the followinwrx9* *u9j dminb2 od2g processes is characteristic of the meiotic and not the mitotic cell cycle2 o9jd9 m2*uxbwidn* r?

  The diagram represents a bud with a shoiae *+j:p-71)suy *u2n,ko yl dlidzlot 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),y8wxm97n vme ll t)zyh*2:ki is 48. Which row shows the correct chromosome number for differen8hwv2zimln9 : e*tmk x,y )yl7t cell types and cell division stages?.

  At the end of which phase of meiosis I does crossil oe;zhp+ p0akfl( b6kxn +*/yng over occur, and what is the outcome of crossink0 /blzx; en+ *+(p6yflaoh kpg over?

  Which of the following statements does not describe a step in thes.z3r,ii r; h q8o.eql sodium-potassium pump cycle in the neuronal celri, slreq;..q8hi 3z ols?

  Which row in the table below is true of meios0x32tc6ouyy 4u igll15u y1btis?

Membrane transport is im:* ;nqwtdwe gc8fk 1 je953zbxportant for allowing particles to move across the cell membrane and respond to changes in the chemgwn:ec *q3j;b5et8d9wx f1 zkical 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 in cel w tmh6y 5wpaxy:5c8h-ls.

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,9avz ;z gk (cni79nso concentrations of different cyclins during the cell cycle. Which cyclin is involved in preparing for DNA r,s ;o7v9kg(zn9a cnz ieplication?

The diagram below shows chromvx1d ne-ww0-kji5 z wf3f0pp9osomes 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 th t));b7cd0 t+l+v u tmow,kcyre separation of homologous chromosomes?

  The mitotic index of throat tissues taken from 4 differens .t wuw8p1ua1t patients is shown below. Which patient is most likely to havasu 8w.1 w1ptue cancerous throat tissue?

1.Draw a labelled diagram to represent the pro38 t.gdaa8 x0tl x ejct6umkrpp1i; 6*cess of crossing over.

2.Compare and contrast random orientation and crossing over.

3.Outline the stages of meiosis.

  The image shows an abnc)ie9.h 0q lttk-o*rqormal human karyotype.


What is the abnormality in this karyotype and its cause?

The graph below shows the ;r7atu +8oi tzjcy 7-lrelative amount of DNA in one cell during one complete cell cycle. Each letter represents oo tl;-c t8r7z +yjiau7ne 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 shm5cvmlrar a0ju+/ 5.ufga* s(y 7 8xotows a cross between a male cat that is homozygous for brown, long h7 */o+u5ammgr8s u0jt5y acal(.rfx vair and a female cat that has black, short hair.


Which of the offspring has a recombinant genotype?

1.Outline how polygenic traits can s8q4ieij-,3ifh l t xm8how 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 over of non-sister chromatidy -t1gtvsg u)*ml6 8hos shown in the diaov msg -gtyuh*6)1t8lgram below?

  The photomicrograph showe9a9j d rj-;jqrr ;2gyu0opnj 7: lrt/s a pollen grain from L. candidum (Lily). Which stage of meiosis u:9a2e0d orgjp;n7jqr 9ry r jlj-;t/is shown?

1.Outline the events which wouyu xgwn*ibx47r.y4nh92e p k4ld lead to an individual being born with Down syndrome, which is iyn9re4up.ny2*bgxx7h 4 w 4kcharacterised 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 cond0, llui0pqu+nt 1d4 o;7pgoimucted on white onions (Allium cepa), under ;pnqt u04l,oupi g oil +m1d07controlled 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 czk 2nf 5czvtl0h0 i+fqxjw9osn//(v 4an divide. The diagrams below show two900 lq4h( f+z/kf/jn 5nsvcvwto2 zix cells from an 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 expression in:kun ly;cu:q4 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 kc7t *o7ne)fsa diploid number of 8, in different stages of meiosis. Which row correctly cf7 )eo kn7s*tnames each stage?

  The micrographs show four phases of meiosis I in a plant. Ihars7u4 (llcxyw -gnw577 q kp. ,t4ugn what order do these phases occuur7 l(t p4, xk s4uwl5wagc.y nhgq7-7r?

Mitochondria are responsible for supplying metabolic energy in eukaryotic cells. ykeolh60kj:90ft 6gm In most eukaryotes, which reproduce by sexual reproduction, mitochondrial DNA (mtDNA) is inherited from only ofko0 096lmykeg6: jht ne 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 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 difn fmh( ;:at:nd(sf gc1ferent stages of the cell cycle in four samples of lung tissue from four patients. Which tissue has the lowest mitotic dafm;fthsg (n:c1( n: index?

  The diagram shows thrc* 9gdg(/nmw e dominant cyclin/CDK complexes at different time points in the cell cycle. Which cyclin/CDK complex activates DNAg (d /9c*mrwng replication machinery?

  Studies have shown that genes such as Cyclin Dependenu gv mmn8xg) h05gr*;st Kinase 3 (CDKN3) are highly overexpressed in cervical tumouxh nm8gsmvg *gur)50; rs.


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 durne(,kpb0 qvnjb :8bs,ing the cell cycle ?