The graph below shows the relationship between maternal age and the incidkz*mh4 sj9 0tpence of non-disjunction. What relationship j4pt9*k zsmh 0is suggested by the data in the graph?

  Which stage of meiosis is represented in the diagra1 o m7xk1jjvc3m below?

  The diagram below shows chromosomes during meiosi3zx;vdm)p*(k2gn(x2do oz kz s.


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 jgqjowq7uw .ksbn)fg c. ,vplpxp +z0+2 s,2 *single gene which would be pres0xo,qzf .jcws pj2s g .n+bpw7,plkvg)u*q+2ent in the nucleus of a cell as a result of each process?

  Which keyword is matched to the twm+ ;.z ppuz7:dk gt+correct definition?

  Which statement(s) about m9e3v)++to0 b5qb q*kum zrwdmitosis 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 cell i5 r0 wq0hplzq0r hh 4yi4wc9bnw32j4h:m)lpyn anaphase?

  During which stage of pvl,.2whe /2zoy/qq mmitosis does the nuclear envelope break down?

  Which one of the following transpofze9zc,d*zq3 rt proteins only carries out active transport?9 ,c*qdez 3zzf

  Which process does not happen in 7;en qym 7xckc)0,xssthe shoot apex?

  Which type/s of membrane trawdih wz fw6e/z1isk1hx p7 (,/nsport do/does not require energy expenditure?
I. Facilitated diffusion
II. Active transport
III. Osmosis

  The diagram below represents a cell wi3-):jlgchl8ics-xu -h gt0 d sth a diploid number of 4. Which stage of cell division is the cell currentl3:xigl8lc -0hu -t s-s cjdg)hy undergoing?

  The photomicrograph beopja v d3;01mwf y2fj2low shows a root tip meristem. Which of the following sentences correctly def jpy;2dafov 23 01jfmwines a meristem?

  When does the random orientation of homologous chromosome ikqu6v9 3*yj tpydn 2; kn6x2rpairs occur?

  Which process does not occur during meio3opxsc- r9- x rki++z9vc3r aksis?

  If a cell with a diploid number of 36 undergoes mitosis,szl l .)ib+ 8jzf7 y 0alvkx/menn7o+2 how many chromosomes will be present in each daughter cell after cytokinesno i vmn+x7lzj )fk/b.zals y72+8le0 is?

  The image shows a micrograph of a cell.yu44 /ekrxch + *q/rvfsn:a u,


What explains the appearance of the cell in the micrograph?

  Which statement(s) about homologous chromosomes is/are not trut0wl1p:mct d5 pz:t5w e?
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 indg,im 6*x0rxg5 jgk,2mekmyk*-ye +cfividual with Down syndrome.

Which statement is not correct?

  In the cells of a horse (E. caballus) during prophase I of meiosis I there are (zzr0nfkh+ mlac0 87d 64 chromosomes. Whaz0d(ac + 8nrhfzk7 ml0t is the haploid number of chromosomes?

  Which arrow is pointin vtb)5/cy+qc 57ohuzag to a chiasma?

  The diagram below represents the structure of a shoot 0j r-hrk65vyu9vcq0 nm lw2-t apical meristem. Which row in the tabhu v00 65ny9r m2wcjvq-rt lk-le correctly identifies the processes occuring in the structures labeled in the diagram?

  How does meiosis promote variation?3d a2;knx otxihk t2)en4 bm-,

  Which of the following statements is/are correct forpfx)fj p7) 2-3ujsyki 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 hoz p wu5u0l5.dymologous 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 ofbeu,7y;f vfv0 secondary tumours from primary tumours as a resul0; ve u,7vfbfyt of the movement of cells?

  How many chiasmata are pre3ehbu pwvmn9o9zt: y 0i 4:ssa5pww 4,sent in the diagram?

  Which statement is a similarity between cytokinesis in anima* nd u r*u1v/itued; (q)dr(hcl and plant cells?

  Which stage of meiosis is matched to the k6tqwg (b mk6*; cmb9scorrect description?

  Which statement(s) are true of meiosis I but not mei co2kn87ckk,o osis 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 meiotic ( gfvul(4 ous3k, p3dtdivision. This results in the formation of one large to,fu (v3 pgudl4k3(s cell and one small cell. What is the fate of the large cell?

  Which row correctly describes diploid and haploid cells i;weq/ 7lp58q,hlr mkt/c 2nld n humans?

  The following table shows the diploid chromosome number of a range of specieqd(- y01):q qujb4ij uyyc tc+s.


Which of these statements is correct?

  What conclusion can be drawn from the karyogu4qye-v 1a+z(7lzwn rram below?

  Which of the following processes is characteristic o ) 4hyambv::uof the meiotic and not the mitotic cell c4 mv:aoy h)bu:ycle?

  The diagram represents a bud with a shoot apical meris ndb(n*j v:eqt4m r-:etem.

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) ig86r q:pptcs:, x :ned v15jots 48. Which row shows the correct chromosome number for different cell types rn p s1egj5p8t6dc :o xtv::q,and cell division stages?.

  At the end of which phase of meiosis I does crossq:88kk ms 8ii-og vy1hing over occur, and what is the outcome of crossing q-81ysm o: i hikgk88vover?

  Which of the following statements does not describe aisgg,z / 1- uilahx8b) step in the sodium-potassium pump cycle in the neuronbsi1-)a/hgl,u g iz8xal cells?

  Which row in the table below is true oa i-8okr n3x9vf meiosis?

Membrane transport is important for ally*uvx ehgr1pm /1w)4xowing particles to move across the cell membrane and respond to changes in the chemical composition of the extracellular fle1pr1x4w/xv m)yg u *huid.

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 regulatedjr1tbm jq*om iu*y; 0. 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 concentrations of different cyclins ovz9/lc p+tc4 during the cell cycle. Whiptol+z/ vcc4 9ch cyclin is involved in preparing for DNA replication?

The diagram below shows chromosomj a3w:2cl* ew v2gje8oes 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 sei(+1 .d gjyw6dkmsca :paration of homologous chromosomes?

  The mitotic index of throat tissues taken from 4 different patients is s,lv( e eivs c(df1tgaji.2s0 2hown below. Which patient is most likely to have cancerous throat1eie(.vs figdca0s,j2 vt l2( tissue?

1.Draw a labelled diagre+ 2b.l,lb alvxiy n1:am to 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 abnormald*8i aa8j(gkh human karyotype.


What is the abnormality in this karyotype and its cause?

The graph below shows the relative amount of a41oc qmz/sfc +ob1h3fho2 h 1DNA in one cell during one complete ce+1cz3 hbmh o1h q14 of2/cfsaoll 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 bet)yly1z,rwwsq7j p /7h ween a male cat that is homozygous for brown, long hair and a fem 71 qw)yrhs,lz7 j/ypwale cat that has black, short hair.


Which of the offspring has a recombinant genotype?

1.Outline how polygenic traits can show a normal distribtwr 8 ts49p5o*w jl)eiution.

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 chromatids shown inim3qr +v6u)x a the diagram below? ia6m)v3 xu+rq

  The photomicrograph shows a pollen grain from L. candidum (Lily). Whicw(kwvj(xtmm ,s 97 .fah stage of meiosis 7a,(mws .xj wmk9fv( tis shown?

1.Outline the events whw,vumo -qoote215 4cmich would lead to an individual being born with Down syndrome, which is characterioo,c muq 2e v5tm4-w1osed 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/0p2cr j nfp:n ,av( skqki2 ub6qu)t5 indirect way of measuring plant growth. A study was conducted on white onions (Allium cepa), under controlled conditions in a lab, to inve2bu kp)6:5cnv,(jqs0ak /tinqr u f2pstigate 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,eq2ow ea*az)g*wcs pa1y 8) ph0zl3lxm 1b6x below show two cells from an organism61p1,a 2ew 8 *pl zy 3*csgbax0lah)oqezm)xw 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 stem growth 3ez- z3hsjf lgbk,d0/.

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 jok4bm0g -,li n ;r-4sfuh7rrstages of meiosis. Which row correctly nmrril b0sfnjo ,4kr- h7-g4u;ames each stage?

  The micrographs show four phases of meiosis I in a ap .kp.eydw+p k;ybko*8o4a 2fssx 81plant. In what order do these phases ap+ky8xfs*w kde . p;oy1 o 284spkab.occur?

Mitochondria are responsible for supplying metabork no4y*jm i 9nxo86d1lic energy in eukaryotic 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, inheritance patterns of mtDNA found in hybrid cells, which are the result of sexual reproductii*y84k o1rondm6 j 9nxon 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 c( h-5gmo pyn*jell cycle in four samples of lung tissue from four patients. Which tissue has yo jp mhng5*-(the lowest mitotic index?

  The diagram shows the dominant cyclin/CDK to+o6;wjo-q dcomplexes at different time points in the cell cycle. Which cyclin/CDK complex activates DNA replication machinery? 6+q d -ojow;ot

  Studies have shown tnt;i)a*obzi cb0a hxu i)15v 96 a7(waq1usk xhat genes such as Cyclin Dependent Kinase 3 (CDKN3) are highly overexpressed in cervical tumoursos *k6nw)51ih (a bxvqa 7icia0b)uz ux1a;t9.


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 cy 5i.v7mysyi ,ecle ?