The graph below shows the relationship between maternal r2vuaw p,dct: ;nco9/age and the incidence of non-disjunction. What relationship is suggested by thw2 d:; o, avcnurtp9c/e data in the graph?

  Which stage of meiosis is represel+ :moquowceplj2gh1+u 2o+nbx -: 7 ented in the diagram below?

  The diagram below shows chromosomes during meiosisdq g4sw eq3w5an94* yq.


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 whic3fhk r 43d3gqrr1s8uxvb*xfe;rm 7 4 uh would be present in the nucleus of a cell as a result of x 7;uhxb4v fr34*dfkrme 18qr3 s g3ureach process?

  Which keyword is matched to the correct db*jug 6f22tnpefinition?

  Which statement(s) about mitosis is/are true:,o1lub(44 dc dda g3eqlfi+v?
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 hakkc4i (x-mqec 8t2( letter points to a cell in anaphase?

  During which stage of mitosis does the nuclear envelope brea ,lk-jsqs*5 /k gti;rmk down?

  Which one of the followu4 f*gpbr9hb.99 9yoebyx0c9gg4g luing transport proteins only carries out active transport?.bhfu9g 4*uyex9bc9gy lg 0g 9p4o9rb

  Which process does notns ap0t3 +gqrt(g0vii0ilx j5zk(-u; happen in the shoot apex?

  Which type/s of membrane transport do/does not require enerxvazuiey j877 8/oc,r gy expenditure?
I. Facilitated diffusion
II. Active transport
III. Osmosis

  The diagram below represents a cell with a diploid number oyn6-s2w;fblxx ow5 1 vf 4. Which stage of cell division is the cell currently undo1yn sxfbw;l62xvw 5-ergoing?

  The photomicrograph below shows a sl1z(a o/3 ,i,jehvmj root tip meristem. Which of the following sentences correctly defines a meristei13l (/mzejva,o ,jhsm?

  When does the random orientation of homologous chromosome ):tn , p*nsxyn4zgkmag nra;r7(8h2k pairs occur?

  Which process does not occur during j/yv60) uw zw2tjx; swmeiosis?

  If a cell with a diploid number of 36 c1e rip1wo6 c ,ga*wwe *,l)o3or w0neundergoes mitosis, how many chromosomes will be present in each daughter cell after cytokinesirg n ccoe,wlp w1**3 re1o0a6owi,)wes?

  The image shows a micn6 /qcfzx x*1vrograph of a cell.


What explains the appearance of the cell in the micrograph?

  Which statement(s) about homologous chromosomcl6ti, y5m tq+n0ml0 31pwtkmes 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 sy;m. so;j :4 vry mkwvs)8b/xpyndrome.

Which statement is not correct?

  In the cells of a horse (E. caballus) during prophase I of meiosis I theaihx )g70m.e 2 zxzl.gre are 6.lxag gzz)m0e2.h x 7i4 chromosomes. What is the haploid number of chromosomes?

  Which arrow is pointing to a chiq6j8t q*bo5 4wd 1cikqasma?

  The diagram below represents the structure of a shoot apical ioax3o.* - dxow.at, cc(gj; bmeristem. Which row in the table correctly identifies the processes occuring in the structuo g*(oxi-a;.. 3tjd o ,bxcwacres labeled in the diagram?

  How does meiosis promote xpoaren;38e6variation?

  Which of the following statements is/are correct for me5(e,9qq(vz amrkmpw;f ld g 79iosis?
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 che at+ xl)izg1kuw3 e9a-yik.0romosomes.


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 zitsw1t*ofm u525yw3d oi9l3x d 28m dfrom primary tumours as a result of the movement of cel m3io55xzusww9td l1*td8f 2od i23 myls?

  How many chiasmata are presentu4ci8al2jnu0t- s8bd l)d pz zcu;a18 in the diagram?

  Which statement is a swc -48d 0fe4zjob(c udimilarity between cytokinesis in animal and plant cells?

  Which stage of meiosis isbmo ;5iov( /pk1toy ;s matched to the correct description?

  Which statement(s) are true of menr z5meok/+zus /b;,fsa ;h8 siosis 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 an oocyte after the first m/ kt pgtv 26drwi3)7aueiotic division. This results in the formation rvwigtd /)u73pa 6k t2of one large cell and one small cell. What is the fate of the large cell?

  Which row correctly describes diploid and haploid cellsy s iuwbi7n1x24f( wd) in humans?

  The following table sho9m 1kbc3s qo6hws the diploid chromosome number of a range of species.


Which of these statements is correct?

  What conclusion can be drawn from the karyogram be9vt eevxx.1t6mgp 2 usdh0zv qb .n17xyc5m,(low?

  Which of the following processes is characteristic of the meiotic 7qm .ocru*/p hand not the mitotic cell cycp ./hurcm o7q*le?

  The diagram represents a bud with a shoot ap * n1ka)w3vkerg*tn+uye ky ;()5 +iefe r0gouical 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) isdwc z 6qdjb-/vt9;, pl 48. Which row shows the correct chromosome number for di d -l6jwp/z;,tvdc9bqfferent cell types and cell division stages?.

  At the end of which phase of meiosis I doe+/aw* u 76) ( ahbu0gbw9rvdjna9 mxqes crossing over occur, and what is the outcome of crossihumd9ra ga)u7+ x6bq/*v0 9wwa neb(jng over?

  Which of the following statemensd )ypw3 3no(.qglx+qts does not describe a step in the sodium-potassium pump cycle in the qsoy3.+ pnqxlw3 )d(gneuronal cells?

  Which row in the table below is true of mepo pv51mb s ckuw8y*62iosis?

Membrane transport is important for allowing particles to movb57;3i4 we:2ztdd vp7 kp bbjme across the cell membrane and respond to changes in the chemical composition of the extracell e7: 5jk7w3;d2m pibvbdt zbp4ular 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 spwxnv3xjr:eg :,)v ws .;y 0sregulated 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 concentration 3 vxir .btilj0hr+(agfy.0.i+gd n-bs of different cyclins during the cell cycle. Which cyclin is involvegx.br+ 0tb hvn g(0-+fji iy.3drl. iad in preparing for DNA replication?

The diagram below shows chromosomes dx/ 0je3dqh od-f;ob t,:iyzo y+jww;mn85qe / uring 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 chromosomes4*d-(rrdwfzh ?

  The mitotic index of throat tissu v6db;/b pm)vge 5nqw(es taken from 4 different patients is shown below. Which patient is most likely to have eqng6w pm5()/ ;vd bbvcancerous throat tissue?

1.Draw a labelled diagram to represent the process of crossing-m.qkvgr9 v dy.s. ;rs over.

2.Compare and contrast random orientation and crossing over.

3.Outline the stages of meiosis.

  The image shows an abnormal hqc0cii3pr8 c k l4-*vh gara-)uman karyotype.


What is the abnormality in this karyotype and its cause?

The graph below shows the relative amount of Dilx7 a0d aw././zpf9bv ivjk3NA in one cell during one complete cell cycle. Each letter represa9 lz fkwv.dj70i3i.x/a pb v/ents 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 male cat that is homw kv* k0oym3*pozygous for brown, long hair and a female cat that has *kpwmvo 3k0y* black, short hair.


Which of the offspring has a recombinant genotype?

1.Outline how polygenic traits can show a normal distzbdfcfn8 wa (1d22i 9lribution.

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 ovei*vb:supjm: ,;f:3 y gijd3 hjr of non-sister chromatids shown in the diagramyb f:jj3:gujh3:;d ,ms vpi* i below?

  The photomicrograph shows a pollen grain from L8ec5nb tu8v-o. candidum (Lily). Which stage of me 5u8oe8bcntv- iosis is shown?

1.Outline the events which would lead to an individual being born with Dowx9 ;qlnb :mvard-p/s*a i2j*kn syndr2-slmn9:xiva*qbpdrja; k/ * ome, which is characterised 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 grow q:z4 s;fgse/lth. A study was conducted on white onions (Allium cepa), under controlled conditions in a lab, to investigate the effect of sg:qlz e ;sf4/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: 02 9lpxq*.ibyljl5 6wynmgr divide. The diagrams below show two c p6wm*b rygj lx 9ll5q2:niy.0ells 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 stem growthh:4 j3p70gum e:m hbjn.

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, ilv;aro;)ks2 81 bx btfn different stages of meiosis. Which roftklx 2a;ov)1sb;b 8rw correctly names each stage?

  The micrographs show four phases of meiosis I in a plant. In what order do tp:g4zq,p61vhxm x 2o t1xn9m/icxg* bhese phaseg2qhz16 pm9 : xigo*tx1xpn bm4c,xv /s occur?

Mitochondria are responsible for supplzv; a aag1n5z9ying metabolic 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 1aav5a gn9zz;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 in dt +dgjcvd2c2k-ld *+ four samples of lung tissue from four patients. Which tissue has t 22d +dkcjd-v*tclgd +he lowest mitotic index?

  The diagram shows the dominant c54 yl 3rseq/wlbg-*vg yclin/CDK complexes at different time points in the cell cycle. Which cyclin/CDK complex activates DNA replication macqg4*srelg v- wb /5yl3hinery?

  Studies have shown that genes svfdob k*6n as mx;057nmgx j7,uch as Cyclin Dependent Kinase 3 (CDKN3) are highkm,xmn7o6 7*f5 0xjb;nags vd ly overexpressed 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 h)j c +/ lea9o mo1;brtjzg5y7E the highest during the cell cycle ?