The graph below shows the relationship between maternal age and thy2*yr j nh5i ho74uu-ze incidence of non-disjunction. What relationship is suggested byr i nj7 -ou2*4hzuyh5y the data in the graph?

  Which stage of meiosis is represented in the diagram below? - btz/kivq 3*z

  The diagram below shows chromosomes duringu30m ; w1j/92 gcht rw*gulhgw 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 number oab99w rip:e q,f alleles of a single gene which would be present in the nucleus of a cell as a result of each pi ,be9wp9a r:qrocess?

  Which keyword is matched to theih- z1 9rp ;j)2zebaud correct definition?

  Which statement(s) abou5wl 0,6g9(gz2oa sj z8y 6nd tozxu5nut 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 celit lqd3mv m*t)va7nx3:b x*6 zl in anaphase?

  During which stage of mitosis does e(c: atrl kur9g :+p1 cg2l.etthe nuclear envelope break down?

  Which one of the following transpo,4 e gnlsp:my2 lbo2cz,q,ja) rt proteins only carries out active transport?sjpeqoam,n:,b l2zl2g,cy4 )

  Which process does not happen in the sm72t /elhtjg) hoot apex?

  Which type/s of membrane transport do/does not require energy expenditi- + 0oo ewm8mliue6+kure?
I. Facilitated diffusion
II. Active transport
III. Osmosis

  The diagram below represents a cell with a diploid number of 4. Which stage of a8)welr vc)t 3cell division is the cell currently unc8aet)3v )rwl dergoing?

  The photomicrograph below showkd ;s0c2yoqpo axwr13 7fcp-5 s a root tip meristem. Which of the following sentences correctly defines a merpaowsp1o qy72fcc ;-x0d 5kr3istem?

  When does the random orientation of homologous chromt v9 4r- u(yrngi: fz7uvmvk.8osome pairs occur?

  Which process does not occur durfz 4.kre.ftd 2ing meiosis?

  If a cell with a diploid number of 36 undergoes mitosis, how manydmnj:w: uaxj t +i.,o* chromosomes will be present in each dauju+.:ndm j:t a,iw x*oghter cell after cytokinesis?

  The image shows a micro rkb :78nx -3qis-vka 2fd9aucgraph of a cell.


What explains the appearance of the cell in the micrograph?

  Which statement(s) about homologous chromosomesx tp560ea.a cm/1hiw p 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 with Down synnblgjp sz4vdo-(4y. 8drome.

Which statement is not correct?

  In the cells of a horse (E. caballus) during pro(rg7b4l/ycj v phase I of meiosis I there are 64 chr g4rvjy7b/lc (omosomes. What is the haploid number of chromosomes?

  Which arrow is pointing to a ch21 ,iae+ aqn-nzs(e vexh2evk de *0w7iasma?

  The diagram below represents the structure of a shooa lc4p65 vm.zot apical meristem. Which row in the table coro l5m v.c6azp4rectly identifies the processes occuring in the structures labeled in the diagram?

  How does meiosis promote varc/n* n 8idg7*9 7qbyegtix.sniation?

  Which of the following statements is/are correct for meio/7 o mzf-vi*tw4dkzflfy3y3) sis?
I. It is a reduction division
II. It involves random orientation
III. It produces genetically identical cells

  The diagram shows gametes p ppyk7dxp8g h0+e rq3ud7-jf6roduced 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 o)pymy-4/ih /0ff1ce cvc4j+h g8ehpz nft -w*f secondary tumours from primary tumours as a result of the movement of cetf f8cm-n *-4hcejp4p1+/ hcfvyh0ez gi wy)/lls?

  How many chiasmata are present in the diagram?ado) r940libs sb,67bz 1qitj

  Which statement is aeba065f d-; 9lfwcrvn similarity between cytokinesis in animal and plant cells?

  Which stage of meiosis is matched t5(ahpk 6qnd +l8asb1no the correct description?

  Which statement(s) are true of meiosis I ysxl;+ ys6cb-0onl); azevj 7jn0;r wbut 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 meio+u2q at0r 6xz a64kxprtic division. This results in the foak rpt64rq+0 xzux26armation of one large cell and one small cell. What is the fate of the large cell?

  Which row correctly desc+tjh,m * 3tixjribes diploid and haploid cells in humans?

  The following table shows the diploiddowl7v,ker 722dudz 0 chromosome number of a range of species.


Which of these statements is correct?

  What conclusion can be dsf8:n( tytqir hx3,t6 rawn from the karyogram below?

  Which of the following processes is characteristic of the meiotic and no25oa8.-fj*hmd+ktk fgkaq ) 4hh1etxt the mitotic cet5fhtk*8 h.jh)q x 4k+aea1mo fkg2- dll cycle?

  The diagram represents a bud with a s x5tg5bl7bfsdpp/2 -ghoot 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 chimpanzee5biajdz 1i:y8 (Pan troglodytes) is 48. Which row shows the correct chromosome number for different cell types and cell divisionzadi i1y8j 5b: stages?.

  At the end of which phase of meiosis I does cnze(w :m2r3x crossing over occur, and what is the outcome of crosn(wmc2ez r3: xsing over?

  Which of the following sueo sp- p2;yu7tatements does not describe a step in the sodium-potassium pumpu;pp se2-u7 yo cycle in the neuronal cells?

  Which row in the table below is true of meiosisisds5g-x(er j3 v;0 fo?

Membrane transport is importany *gusb7 z)5nnt for allowing particles to move across the cell membra n )*nsgz7uyb5ne 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 regulated in cellsxntcn8 lc77 y+if ra74h- aj8j.

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 diffez.bv l oqho: sd-119nfrent cyclins during the cell cycle. Which cyclin isf.z -od9sbvq1 :1lnho involved in preparing for DNA replication?

The diagram below she)np:0 utz; 5uj yt8wlows 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 separation of homologous c+tqj5wcp0ak ( , 2nbnp2xdjt: hromosomes?

  The mitotic index of throat tissues takd. k97tw:4ca aksae w8en from 4 different patients is shown below. Which patient is most likely to ha7a4d.ct8w ka :ewa9skve cancerous throat tissue?

1.Draw a labelled diagram to represent the process of crossing ox f.-7wh 6 /ytwuu:gyxver.

2.Compare and contrast random orientation and crossing over.

3.Outline the stages of meiosis.

  The image shows an abnormal human kary irc.s8l8s9yr otype.


What is the abnormality in this karyotype and its cause?

The graph below shows the relatcae(f4 wob3-l ive amount of DNA in one cell during one complete cell cycle. Each let-(w34clfe b aoter 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 5j(56ghh jn4jjidbr 0a male cat that is homozygous for brown, long hair and a femaldg0hjj ij 5rh(b45 nj6e cat that has black, short hair.


Which of the offspring has a recombinant genotype?

1.Outline how polygenic traits can show a normal distribut0ced ao39 md2vvpp2 t;ion.

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 overtczg.g mz75t2)1sbg t5xdin-7ma3 tp of non-sister chromatids shown in the diagram belowd1.tcmsz 7n5a)pm-xg t 32tg5bg7tiz?

  The photomicrograph shows a pollen grain from L. candidum (Lily). Whij4 mjw)s6,zxxzh hal2(v7: y)jw9f dbch stage of meiosis ) 6,vdb7zfwa)j 2m l(xh4jh 9jwz:x syis shown?

1.Outline the events *6z67ie21ybl*ofo54f b btgv*rpg h lwhich would lead to an individual being born with Down syndrome, which is characte ozp4loleg r271b*f f bivy656*ghbt*rised 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 plan7wpj0qd(lm.j 4i r*en2 ,xcfo5, t zylt growth. A study was conducted on white onionsylf.,7,x lq 0z5(e rtomwj4dp2 jinc* (Allium 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 cellso,wy6+yd : i6 .atylas can divide. The diagrams below show two cells from an organism with a diploid number il.6sy :yywa6,tda + o(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 stef*r2vo 2j:p+ 5)mac1gc dydjkm 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 8,5m t0 fgw.knv+ in different stages of mt 5 0fmgvn+wk.eiosis. Which row correctly names each stage?

  The micrographs show four phases of meiosis I in a plant. In what or5)mk: sf5z pofder do these kp :f5s)5z fomphases occur?

Mitochondria are responsible for supplying metabolic energy in eukaryog3z7lda,i*4c7race. ki .he btic 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, inheri.,kidci3ar 7ac g7eh4 z eb*.ltance 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 different stages of the 0q gfa)ru.)glcell cycle in four samples of lung tissue from four patients. Which tissue has the lowest miqg r0ug))l.fa totic index?

  The diagram shows the dominant cyclin/CDK complexes at differentb ,g bxg/bx,cu1m0;jp time points in the cell cycle. Which cyclin/CDK complex activates DNA replication,gxxucg 0bp,j1/ ;bbm machinery?

  Studies have shown that genes such as Cyclin Dependensfg1 nq-)tf ,gy+p*bzt Kinase 3 (CDKN3) are highly overexpressed z1 -gyfbftpg s*,) +nqin 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 cycklw 1+t/lsf3 ilin E the highest during the cell cycle ?