The graph below shows the relationship between maternal a;c3w,6oo)o1zo9pfd ys t; ev kge and the incidence of non-disjunction. What relationship v1e,y; f 3 w;o pzdk)oots9o6cis suggested by the data in the graph?

  Which stage of meiosis is represented in the diagrfe )nheam. g04am below?

  The diagram below shows chrom9vh :a 5qm5vero3d-i zosomes 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 allele:a1qthf vy 77caibj;vfek+:)h g ;cl-e; z9r es of a single gene which would be present in the nucleus of a cell as a result of eacveac1q fegh zt+ 79ai;l: j 7;-cbvyhk:)e;rfh process?

  Which keyword is match33jhh : eqy 1yuth3z)ted to the correct definition?

  Which statement(s) abouto p0c )1dddz7t 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 letraf2xnkxf4xu c n+fy -;93l2ater points to a cell in anaphase?

  During which stage of mitosis does the nuclear env;m*z geg p, l6/yk8a2hvkee s0elope break down?

  Which one of the followeye.54ko jctu:oifrwn-v 9 +5ing transport proteins only carries out active transport?ct.4oykju owre9 :5nf5+eiv -

  Which process does not happen in the shoot * je9 ut7gv1emwq vy:;apex?

  Which type/s of membrane transport do/does not - j j1zy:j3buv d8y,ea2c4m te9fr5gorequire energy expenditure?
I. Facilitated diffusion
II. Active transport
III. Osmosis

  The diagram below represents a cell with a diploid number of 4. Which sta;+8a*efff 6ghb/,r vnfhn(udge of cell division is the ce n( f;vf+6 gn*dhe/8ua,hbffrll currently undergoing?

  The photomicrograph below shows a root tipg (dp+v qcmy*gjvu2h +49r7hy meristem. Which of the following sentences correctly defi +dc4v9hm 7pggq * +2h(uvjryynes a meristem?

  When does the random oriq s2x hhm/hhnb2y;ww - +dm)6m:4glndentation of homologous chromosome pairs occur?

  Which process does not occur during meiosidfxhqa 4jm5) .s?

  If a cell with a diploid numbersd ;hw;23mui66+ch ah :brtx r of 36 undergoes mitosis, how many chromosomes will be present inhrui ;r 2csax;b h6d3wm: 6t+h each daughter cell after cytokinesis?

  The image shows a micrograph of a wy9 ci3dxh(4h cell.


What explains the appearance of the cell in the micrograph?

  Which statement(s) about homologgahj: p ( 4uxds(,kj.aous 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 c*y9;c mc56 p(y-tx2s3fyqqfe.v zp e with Down syndrome.

Which statement is not correct?

  In the cells of a horse (E. cabam b c6n+dfdu:hvuk2r5 zf v98.llus) during prophase I of meiosis I there are 64 chromosomes. What is the haploid number of nu9uh5d+kbv6r cfvm82 zfd. : chromosomes?

  Which arrow is pointin2) :ic1x cz.-dg tiubdg to a chiasma?

  The diagram below represents the structure;o7pac: stb o: of a shoot apical meristem. Which row in the table correctly identifies :otcbpo; 7s:athe processes occuring in the structures labeled in the diagram?

  How does meiosis proy3,3 tvzapy2 omote variation?

  Which of the following statements is/are correct d0v 2kzykwnii*66u(*s oxs,cfor 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 homologousvwm 4 xlr9(n7g +niis/ 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 of secondary tumours from prim,8e 3h7red ashzf;la0 pcy : )lc4k5bbary tumours as a res;8e5)k 3h7b 0lp,yh4:c zafbldecr asult of the movement of cells?

  How many chiasmata areegc.;zc u.kx5xk d+6u present in the diagram?

  Which statement is a similarity between cytokinesis in animak-s*w+rgbw . 5xhv2fll and plant cells?

  Which stage of meiosis is matchedg 7gsgm: 20cpj to the correct description?

  Which statement(s) are true of meiosis I but nfq,ym4 r:9pxuk2e 1 owot 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 firstg+1+qmi jzgq , meiotic division. This results in the formation of one large cell and one small cell. What is the fate of the large celgj1 q, zg++miql?

  Which row correctly describes diploid and haploid ce/dm+zh y qi4 rzw(;mr*lls in humans?

  The following table shows the diploid chromosome number oflep;r+ai/a(+lh e cjyz 2 .j/l a range of species.


Which of these statements is correct?

  What conclusion can be drawn from the karyq9y1sqn/po acle1 l7 5i4o nk0ogram below?

  Which of the following processes is chara* z+0ic4uuxi4pdox /zcteristic of the meiotic and not the mitotic cu0z4czo * +x/4ixiupdell cycle?

  The diagram represents a bud with a shootgx.w+z+ im6ue 3y.tzi 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) is 48. Which cdf 1w, l,*fvhr8wcu0 row shows the correct chrof,l8h w0cfwrc 1du,*v mosome number for different cell types and cell division stages?.

  At the end of which phase oes2tyhhw4, i 0th*x2qf meiosis I does crossing over occur, and what is the 0t,2s*x 4hi qyhwe ht2outcome of crossing over?

  Which of the following statements does not describe a step in the sodium-potgr+ ;g gqzdw -p0xj)yr. 17 )evqxn,drassium pump cyclepdrwgn x rx0y) ); z 1,q7rgjqdv+eg-. in the neuronal cells?

  Which row in the table below is true ow5zwqr8ltkj686 1g rhf meiosis?

Membrane transport is important (wp t;y ;5o)krfc3 qjjw6m,rfu t(d9kfor allowing particles to move across the cell membrane and respond to changes in the chemical composition of the extracel p5j,u6(rt dr 3f9ytjw;(kqf mo) wc;klular 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 ip qs 7s*r 2qb, ynw7xenzi2*n0s 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 shows the concentrations of diff6z +a8 8 fryyu0moll5cerent cyclins during the cell cycle. Which lfao865c+uyyz 0l8rmcyclin is involved in preparing for DNA replication?

The diagram below shows chrom 2ys0 oqxzg-22oqb, yaosomes 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 separati1ki::vh7y.aw+ltwx mz vx;v5on of homologous chromosomes?

  The mitotic index of throat tissues taken from 4 di52c7kdzzv g mi ;:og.yfferent patients is shown below. Which patienk 52 g7yz;cmzodvgi.:t is most likely to have cancerous throat tissue?

1.Draw a labelled diagram to reps vh xj51sn;0qresent 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 humljmpw.k,1) c4oh hp-man karyotype.


What is the abnormality in this karyotype and its cause?

The graph below shows the relad4m nc(jsh0 tkpub-4*tive amount of DNA in one cell during one complete cell cycle. Each letter represents one stage of the cctdnp - * hbm4k0(u4jsell 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 betweena x0hasd-r/t+ d0 dv-y a male cat that is homozygous for brown, long hair and a female cat that has black, short xrd0d-ht-0s y/a+advhair.


Which of the offspring has a recombinant genotype?

1.Outline how polygenic traits can show a noq59.tr2 wz2icc-hffbng +. y ormal 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 1ti.yer0-gh ul+ t0w lh;iht. over of non-sister chromatids shown in the diagrawr0;hg -h+.1i uttie tllyh 0.m below?

  The photomicrograph shows a pollen graimq67 e2d1w zran from L. candidum (Lily). Which stage of meiosis is wd1 zq7amer26shown?

1.Outline the events which would lead to an individual being born with Down syndk99 v;xa9zozrru y40crome, which is characterised by the presence ofck9v0zx ruoay9;z 49r 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 growthy66yfe*-3d exk gaf4i . A study was conducted on white onions (Allium cepa), under contr aeyef4y d*i6gkf6-3 xolled 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 divide. The diagramss8ajmr;g -cm l/ 9xet5 below show two cells from an organism with a diploid number (2n) of 89cx8 -m5mrg ej;s lat/.


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 mjc h0bv 4)rm.in 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 .toyx .xr79tg rs;9s (gozvb( cell, with a diploid number of 8, in different stages of meiosis. Which row corr(7s 9b (tgy torsxo zx.9;vg.rectly names each stage?

  The micrographs show four fqaumz (6+y e-phases of meiosis I in a plant. In what order do these phases occa(u-ef yzm+6qur?

Mitochondria are responsible fhytj oux9((h.or supplying 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 con9uh tj((h.yxotrast 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 o7) au;qxyff7v9fz z jg5p(y6vf the cell cycle in four samples of lung tissue from four pa6gx77)j vff5va 9yfup;(y qz ztients. Which tissue has the lowest mitotic index?

  The diagram shows the dominant cyclin/CDK complexes at diffem diipd(e 2 q,k2 ;0hbs ong88lm,-ebtv2o9byrent time points in n2vy2g(dbm l, p8;isei8 km o2dbht9,qe o-b 0the cell cycle. Which cyclin/CDK complex activates DNA replication machinery?

  Studies have shown that genes such as Cyclin Dependent K,adh )q+nxqx+ fkoy1sw,;/nj inase 3 (CDKN3) are highly overexpressed in cervical tumours,hxxqs +a)kd1+j w ,n qfno;y/.


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 highestu.byh;- u5 qhj during the cell cycle ?