The graph below shows the relationship between maternj6*jr7 zcw i3aal age and the incidence of non-disjunctiowac76*ri 3j jzn. What relationship is suggested by the data in the graph?

  Which stage of meiosis is reprj53:or5d kzwaq 3.f wzesented in the diagram below?

  The diagram below showsqizx+fd :gt ,k(wr8f4 chromosomes 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 states the number of alleles of a single gene whic6- 7t5x/o6ysj pot3omtns0jcg7sj-w -n /hxwh would be present in the n7tty-j67jsj -p gxs6hw/wo n0 o3o nx tms5/c-ucleus of a cell as a result of each process?

  Which keyword is matched to the correct definition?8p/b ;z95ei 9 *on6vj 0lfdrzhvf4xb o

  Which statement(s) about mitosis i,ok0wm6. vye, mnde8*sxmt* k3n*msu s/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 lette22 ng8en *tn 6dmi0rls1l 4mxbj:g4o nr points to a cell in anaphase?

  During which stage of mitosis doryw(y iaz6m 62es the nuclear envelope break down?

  Which one of the following transport proteins only c7q,ks5 juvzl0n2q6in:c1b n uarries out active transport?b2 z6n: u1jqiknlsu07 c5q v,n

  Which process does not happenckm)f; * jwrx:ug -l0w in the shoot apex?

  Which type/s of membrane transport do/doeb oqp5 vk:e-a6(p1x6mrwn.m hs not require energy expenditure?
I. Facilitated diffusion
II. Active transport
III. Osmosis

  The diagram below represe0 d2i g+x*yufznts a cell with a diploid number of 4. Which stage of cell division is the cell currently u2fgzu*+0 ixydndergoing?

  The photomicrograph below shows a root tip meristem. Which of the follozrmbh-4,7 hb:7i ey lowing senten- lb 4h:hye,zm7b 7roices correctly defines a meristem?

  When does the random orientati75to)0x *ajdehdqd5 f:w o0xv on of homologous chromosome pairs occur?

  Which process does not occ+ jtub kqoba9ah 590(aur during meiosis?

  If a cell with a diploid number of 36 undergoes mitosis, how many chromoso xp *kzbwyour 7b9g)o 98qds;:mes will be present in each daughter cell after cytp9o7yk swb8 )ugzx* roq bd:;9okinesis?

  The image shows a mi1 ma/u -bmu 4)d -ucuetw;,4xh9nu cgoi3:iaucrograph of a cell.


What explains the appearance of the cell in the micrograph?

  Which statement(s) about ho9q4 pl72iqm domologous 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 individual with Du sw)npt4e v;ue-- ek8own syndrome.

Which statement is not correct?

  In the cells of a horse (E. caballus) during prophase I of meiosis I there are 9*3htt, cehv5cnoh.s 64 chromosomes. What is the hapl*vtseo9hc, t3hh. 5n coid number of chromosomes?

  Which arrow is pointing to a chiasma?;ol-/5ib2z cdubu y 4f* nol(i

  The diagram below represents the struct f:ajuvx-/jc8q ) ouk)r6arx7ure of a shoot apical meristem. Which row in the table correctly identifies the p)x:vk6 8 c rxraquoa/-juj)7f rocesses occuring in the structures labeled in the diagram?

  How does meiosis promote vafyeao3szbiy1g4 uxkszp(b7 76.* ; pxriation?

  Which of the following statements is/are correct for meiosis?dc;e+xjjg 58o
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 chro;ox+xpk4n xs1n lsj44mosomes.


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 ,u4 agx3ugiyu fr;2 /kkw/*oytumours from primary tumours as o g/xy;2kkrf/g,u*uya 4 3iwu a result of the movement of cells?

  How many chiasmata are present i wzrr4(3 okfng1oktd/f( nj 1/n the diagram?

  Which statement is a similarity betwe79z176p+hn zjryy lk ven cytokinesis in animal and plant cells?

  Which stage of meiosis is matched tosn( i)w uqt.w i8r6tq3p2x8a a the correct description?

  Which statement(s) are true of meiosis I but not m.8ttz0hbh(3r-ftxg w 8cs t.seiosis 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 thnued; l za3rf2u+ .i54 a9psjb:r2w(5bnbv ole first meiotic division. This results in the format r .;d2i2(:l4eznn3slur jaf59uw b+bopv ab5ion of one large cell and one small cell. What is the fate of the large cell?

  Which row correctly describes diploid and qo: 9g-icb wz6haploid cells in humans?

  The following table shows the diploid chromosome number of a range o3f0ko2aea( u bf species.


Which of these statements is correct?

  What conclusion can be drawn from the karyogram2 , up6aua yf9hux;ks- below?

  Which of the following processes is characteristic of the meiotic and no0ss5 uxxx ,dd tyt12l7t the mitotic cell c7x0t x5s ,uldtsdx 21yycle?

  The diagram represents a bud whh df97(rwic(ouy, n(ith a 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 trogk bd()trli1*pl -r:fy lodytes) is 48. Which row shows the correct chromosome number for different cell typkfy 1rtbrdi* pll(): -es and cell division stages?.

  At the end of which phase of meiosis 6: xs lmb 5pe+ym3j:wkI does crossing over occur, and what is the oewy:xm5km36 j: lbsp+utcome of crossing over?

  Which of the following statements does not describe a stee+1xbt 1ey aj)p in the sodium-potassium puj)yx+t1b e1ea mp cycle in the neuronal cells?

  Which row in the table below is ikym0wr 279yyo:he 4jtrue of meiosis?

Membrane transport is important for allowingb) qi :wu3nq oqp//cl+ particles to move across the cell membrane and respond to changes in the chemical composition of the +nu p/c/obql: 3)iwqqextracellular 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 i2oafvr q:a) fw.bx(/ regulated 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 sh +li8pdwua)5 tows the concentrations of different cyclins during the cell cycle. Which cyclinl p+ta u8w)i5d is involved in preparing for DNA replication?

The diagram below shows cin+ l (fq()fvchwwr2 7hromosomes 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 inb.c9c7k;l be7 7agq ywy5*v;6 tyel olvolves the separation of homologous chromosomes?

  The mitotic index of throat tissues taken from 4 different patients ismnm *d+zhnl8 / shown below. Which patient is most likely to have cancer zml8 /nmd*nh+ous throat tissue?

1.Draw a labelled diagram to represery/9 -y7sv ti ;gco:(4of cgcjnt 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 kar 2tc ,opqjxwt f5)(.wyaj01czyotype.


What is the abnormality in this karyotype and its cause?

The graph below shows the relative amount of DNA i5 +a9cjqw4h ,as+r-q0y jy tni 4xr(obn one cell during one complete cell cycle. Each5ab(jj oa 9,++hscqqwxy4r0 t4r-ni y 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 malsq3mo+to y2c 5*wp3 lae cat that is homozygous for brown, long hair and a female cat tm3+25cpao*3tqosy w l hat has black, short hair.


Which of the offspring has a recombinant genotype?

1.Outline how polygenic ,vs 9pa -zvmw*tegw-9 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 /p7iuu7lde8n;n i 1f bover of non-sister chromatids shown in the d1u877e/lni f ;dbup niiagram below?

  The photomicrograph shows a pollen gqqm kuu3;.6cg 2v6oq r7qa4i hrain from L. candidum (Lily). Which stage of meiosis is si.uq3g 7c4rquq a6 62m khvq;ohown?

1.Outline the events which would lead to an indivf 3h(f-t wk0yridual being born with Down syndrome, which is characterised by the presence3rfkh f(- 0ywt of three copies of chromosome 21.

2.Explain how meiosis increases variation.

3.Outline the stages of meiosis.

The mitotic index is an indirect wayt.4gw:zcd1cz j e j6kwrr0.s1 of measuring plant growth. A study was conducted on white onions (Allium cepa), under controlled conditions in a lab, to investigate the effect of soil pH on the w je:gr sk10d jzrw6.41 c.ztcmitotic 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 di.r 0eb dhi(b5gagrams below show two cells from an organism with a diploid number (2n) r0i( d5.bgbh eof 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 uu3*giaja ggq3h/gum.d 8(9v 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, wi gbp 6;f w6h2b5ynfcie /;c:qfth a diploid number of 8, in different stages of meiosis. Which row correctly names each stage? fpb fic6 g c:w62eb;nh;q/5fy

  The micrographs show four phases of meiosis I s 2ez)hmz7fuefz g*b,k/a;x2ol+ lz4in a plant. In what order do these phases occur? xf ;k24 m7 )l+g2lz/ ,ezuazz*hbo sef

Mitochondria are responsible for supplying metabolic energy in eukaryotic f(*(9z4qouwyb dze f8cells. 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 ubofw9z 8z4dq ((*fyeboth 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 of the cell cycle 3)r e4hr *cnx 0bw fbb7c9h:dlin four samples of lung tissue from fd*bcl hnbbrwr )h907cf:4e 3xour patients. Which tissue has the lowest mitotic index?

  The diagram shows the dominant cyclin/CDK comple,tr*lyl,m g9ap; a3qzum - )fuxes at different time points in the cell cycle. Which cyclin/CDK complex activq, my)p fmgu;-larz3la *,9utates DNA replication machinery?

  Studies have shown that genes such as Cyclfz) m f:zja(0qin Dependent Kinase 3 (CDKN3) are highly 0zfj( a:m)q zfoverexpressed 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;2j3 7hvhl .y px+lqfn cell cycle ?