The graph below shows the rela dy4 ahe5,vp;itionship between maternal age and the incidence of non-disjunction. What relationship is suggestedivehyp;4a 5,d by the data in the graph?

  Which stage of meiosis is repryddlx omt +.m4 r312zfob km3t*vpc/-esented in the diagram below?

  The diagram below shows chromosomes during meiosis.s2nr6u cxi6 (nrcao07


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 gpidh8v 5c 5.fzene which would be present in t vd8h5f.c5zpihe nucleus of a cell as a result of each process?

  Which keyword is matched to the correct definition?mmoffy.1dknw . 5n:a5

  Which statement(s) about mitosis is/are tru- chl 1 30-z7nedpxosie?
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 ce s879m.hp5zngijp h/qll in anaphase?

  During which stage of mitosis does the nuclear envelope break down?w/t,mi-i5 ovjt iz)w8j58frz

  Which one of the follz;r7ybv r )(mvj9nd7 qowing transport proteins only carries out active transport?;zv7n d rbq vyjm)(r97

  Which process does not happen in the v3pel*i 0meqn.qagvrz6 r :11shoot apex?

  Which type/s of membrane transport do/does not requi8mv c ag 7bh(cv:wg.d4re energy expenditure?
I. Facilitated diffusion
II. Active transport
III. Osmosis

  The diagram below represents a cell with a diploid number o0ttuf:wd1,np f 4. Which stage of cell division is thpwnu ,dtt0: f1e cell currently undergoing?

  The photomicrograph below shows a root tip meristem. Whicjf( jmv5o 8*jmh of the following sentences corrf5vo m(mjjj 8*ectly defines a meristem?

  When does the random ocf vyw63eh-s6p/ 5zvjrientation of homologous chromosome pairs occur?

  Which process does not occur during meiosi/ +iad;j2wlq jm,8opt90 99 o vgumnehs?

  If a cell with a diplwedgvur:z,uh tqw 0v4 *y.7v /oid number of 36 undergoes mitosis, how many chromosomes will be present in each daughter cell after cytokinve04:. r/gq7y,wwdtuhu v zv *esis?

  The image shows a microgxz+rfr ;a;k) g.o0bwlaxb1 nt i 1.;flraph of a cell.


What explains the appearance of the cell in the micrograph?

  Which statement(s) about homo5lrjy.we ,z 5ilogous 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 an i q 41)emnid u:y 3*29hqip9(exb eagaundividual with Down syndrome.

Which statement is not correct?

  In the cells of a horse (E. caballuspbd(vzq 74-.gnyx7 d 7 png3pz) during prophase I of meiosis I there are 64 chromosomes. What is the haploid number of chrgzg.bp77 yn4nv qddp( 7p z-3xomosomes?

  Which arrow is pointing to a chiasmau*hw 87fto7iq0(a o pz?

  The diagram below represents tp;d1n8;s p vjk (ctx+bhe structure of a shoot apical meristem. Which row in the table correctly identifies the processes occuring in the structd t+s(cnpb8pv;1j; xkures labeled in the diagram?

  How does meiosis prom c9uk8nt ogem18up9od d, p:s3ote variation?

  Which of the following statements is/are rig ty-,sx8av3 h.:yj 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 homologous c 8.tp lso1wui6hromosomes.


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 tumours from primarji;c j og:8m-a*p 6ipcy tumours as a res agc- m:j;oi6pi p8*cjult of the movement of cells?

  How many chiasmata are present in the diagymx +7fzci,.,49 (rk4 ps c/rvizzl cjram?

  Which statement is a similarity between cy* c-daztq+ x; /z5xx.f-eq icttokinesis in animal and plant cells?

  Which stage of meiosis is matched to the correct descripr ciy0s22i8m4wev2jo tion?

  Which statement(s) are true of meiosis I but not mehyk8u- / 3bndwu/qkb cqx8y2 d0z 4s1iiosis 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 fi 1xblyd9mm/8 ;5ugirhsm 4f-orst meiotic division. This results in the formatioslhg1-m bx y4r9o5umf/8;mid n of one large cell and one small cell. What is the fate of the large cell?

  Which row correctly describes diploid and haploid cells in g)zj/tjn() bu humans?

  The following table shows the diploid chromosome number of a range of speciph a:2m yne(f5es.


Which of these statements is correct?

  What conclusion can be drawn from the karyogram below? im y na7m0w0ms9ll3-ykb t7-s

  Which of the following processes is c3 pegiok.rs- 5pseoj+ ;ih+*d haracteristic of the meiotic and not the mito-peo53 jr pshid .+g+e* ik;sotic cell cycle?

  The diagram represents a bud with a f,t+s9 dye)w95nrok m 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)w4csnuln q2 tllgh; *6 1oq*-d is 48. Which row shows the correct chromosome g1;lws*2h-t 6o*qnu4 lqcndlnumber for different cell types and cell division stages?.

  At the end of which phase of meiosis I does crossing over occur, andke* n0(bb7uy k what is the outcome ofbn0k7( ubyke* crossing over?

  Which of the following statements does not7wfr r9/f2kf wjd dm0nez:t9y9 b) 0wc describe a step in the sodium-potassiudkj0d :n7w) wf f9wrzy09t crbe9f2/ mm pump cycle in the neuronal cells?

  Which row in the table below is truergle6diys4 70 of meiosis?

Membrane transport is important for allowing particles to mo,o p*n l3gp+nqaw)az8ve across the cell membrzoaq+ng pw8l, pn 3)a*ane 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 re (i6xm chr6h+y0rm0w pgulated 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 concenv sxxr(22xr(4 cqqp2.rg 1pbcfr ;6wttrations of different cyclins during the cell cyr16r gpq2xr(ptf42 .r wsbxcxv (;cq2cle. Which cyclin is involved in preparing for DNA replication?

The diagram below shwb ( 8p)yaibn2w9r5roows 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 meiosism;bhrd:;ad e; o1ms )h involves the separation of homologous chromosomes?

  The mitotic index of throat tissues taken from 4 differen 1 /ov0wzlt ztu(p66)fe5au/aoz k4n bt patients is shown below. Which patient is mos0 l z(66t op/e5 unozvba/4)1uakf wztt likely to have cancerous throat tissue?

1.Draw a labelled diagram t2.:plixgus :izp h w2j86jtvh22u 2mxo represent 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 huma74w5 c;uli s gbxu2)lkn karyotype.


What is the abnormality in this karyotype and its cause?

The graph below shows the ir7 1kuco5gg 9fpd8:vrelative amount of DNA in one cell during one complete cell :u pri7c9 gd5fv8kog 1cycle. 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 male6w: bww-nx/jv ,vxv.h cat that is homozygous for brown, lonx.v6-j:,wwhw v/ nbx vg hair and a female cat that has black, short hair.


Which of the offspring has a recombinant genotype?

1.Outline how polygeni7rmqi kgxp,;8c 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 over of non-sistp7qklb)gwkp b,33s:yer chromatids shown in the diagram bel 3gs ,p wkkpy7q3b):lbow?

  The photomicrograph shows 5qqd06)nrcjwvwl89 iqp oc3 ; a pollen grain from L. candidum (Lily). Which stage of meiosis is shr viw 6qqo c 80p59qdc3njwl);own?

1.Outline the events which would lead to an int+eeok1+o m,ui z v14gdividual being born with Down syndrome, which is characterised by the present+4+1gmivko ue e,1ozce of three copies of chromosome 21.

2.Explain how meiosis increases variation.

3.Outline the stages of meiosis.

The mitotic index is aynto)lq,q 3z nw* .e:un indirect way of measuring plant growth. A study was conduct:yq*on tzu q.en,l3w)ed on white onions (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 cells can d v4wmxbo7 q(;sivide. The diagrams below show two cells from an organism with a diploid number (2n) xwq7 (sbvom;4 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 sfna)j0faw :fgyq rz:61p,eqm 5g, 2fqtem 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 stagesd7d/*c emu0nvyd2n q: of meiosis. Which row correc/ny d2:7uvm qcn0edd *tly names each stage?

  The micrographs show four phases of m,1ob 1 uu dwgriec4.v*eiosis I in a plant. In what order do these pha1v gc b1du4ei.*uw, roses occur?

Mitochondria are responsible for supplying q sc4cr+fg9p* metabolic energy in eukaryotic cells. In most eukaryotes, which rep49 c* spgr+qcfroduce 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 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 offaisk2 7 7zcm3 the cell cycle in four samples of lung tissue from four patients. Which tissue kcf3 z 7a7i2mshas the lowest mitotic index?

  The diagram shows the dominant *1 pq(*s f gb1wwctlq,cyclin/CDK complexes at different time points in the cgqcf*sw*11bl ,(wp t qell cycle. Which cyclin/CDK complex activates DNA replication machinery?

  Studies have shown tha/c j:3w :rsto*9ykxlrt genes such as Cyclin Dependent Kinase 3 (CDKN3) are highly ovek:9rl :s r*tw3joxcy/rexpressed in 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 cyclin E the highest during the cell cyyr;eoh d) +e3ifdqlqo+:g t*. cle ?