The graph below shows the relationship between maternal age and the incidencw-i.ox +q3yi ve of non-disjunction. What rei-wxq. oyi 3+vlationship is suggested by the data in the graph?

  Which stage of meiosis invkaom(: lwkk72hry/m s6.:u+ny0f zs represented in the diagram below?

  The diagram below shows chromosomes daug795p th;o suring 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 whi(j6dy*uqj* ; aynw8h och would be ph(; 6way j* u8jdnoy*qresent in the nucleus of a cell as a result of each process?

  Which keyword is matched to the correct definition?p/t-ut;r p0iur * k9zj

  Which statement(s) about v9s4 /e61negyrwdn n2 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, whi ;m,j/b02 mjsubcnx -bch letter points to a cell in anaphase?

  During which stage of mitosis does the nub0( aj9n,:u-yqwl mnk sc; on2clear envelope break down?

  Which one of the following transport proteins t cna s/hor5j,i9 fu-4only carries out active transport?/u4jafr9,o cts nh-i5

  Which process does not happen in the shook;y s /zxji81ot apex?

  Which type/s of membrane transport do/does not require energy expendwm3.t xdj m2p ;tsxvfx-i.4 9miture?
I. Facilitated diffusion
II. Active transport
III. Osmosis

  The diagram below represents a cell with a diploid number of 4. Wh zxe246 q,y7lgkxt54/qhqlh nich stage of cell n z,4tlh2q4ge y6h qk75lq/xx division is the cell currently undergoing?

  The photomicrograph below shows a root tip meristem. Which of 3 2ldpnb2uqo 3--wjwe7 tt6m4waqy6 i the following sentences correctly defines a meristem? 4qw3t6tp -y7loi- 2e an2u3 6mbwdj qw

  When does the random orientation of homologous chromosz(rw)s 3 r-nk(3tfjlzome pairs occur?

  Which process does notzzng l rsh ndt/.1* 6iha3a03q occur during meiosis?

  If a cell with a diploid number of 36 unde0u9er/ jlu2a5qsi 1 oergoes mitosis, how many chromosomes wi 1e9ou0al/i q5ju2resll be present in each daughter cell after cytokinesis?

  The image shows a microgr cw: w:cp1kvb+aph of a cell.


What explains the appearance of the cell in the micrograph?

  Which statement(s) about homologous chromosomes i 4xoytlr-h xx.24ys j.s/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 individr:q1ao7ucai+n2ko u s;w+ky+ual with Down syndrome.

Which statement is not correct?

  In the cells of a horse (E. caballus) during prophase I of meiosis I thy6cakio6 e( h,pe1e+q ere are 64 chromosomes. What is theio e(y1p6ckeq,e6h+ a haploid number of chromosomes?

  Which arrow is pointing to adoet.(,guzj z o7,)eb(eh /c dl ,ud;y chiasma?

  The diagram below represents the s (pdk,kn 7jlcy*gd.0jtructure of a shoot apical meristem. Which row in the table correctly identifies the processes occuring in the structures labeled in the diagrgd0 c,jl pk(. kjd7ny*am?

  How does meiosis promote variationzch+d-fyr;hsgf*g l 9)l) o -epm:i p.?

  Which of the following statements is/are corre3 yfm1; zw9mptq0gi v/ct 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 chromosx0 gp:fyx+/ipvo; pj )omes.


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 seco .-id.lw bvq7 xq2soa+ndary tumours from primary tumours as a result of the mbwxoqs7i l2-q.d.+av ovement of cells?

  How many chiasmata are present in the diagr,/ l49 f.veved-rj*xi akb-mvj,o, ooam?

  Which statement is a similar(xhex +c3yaspv t+94tity between cytokinesis in animal and plant cells?

  Which stage of meiosis is matched to the correez qfal9 3w4d((qcet- tn7gb9ct description?

  Which statement(s) are true of meiosis I but notoqi 2 ss8w3(ot 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 meiotic division. :f*/zk as*jfe 7yqxn; This results in the formation of one large cell and one small cell. What is thee*a /fzsx:7qyfn *k j; fate of the large cell?

  Which row correctly describn1 u.av2v,az ktirp e*+;7h rbes diploid and haploid cells in humans?

  The following table shows the diploid x )-u3ef8s z6 uthf0ixchromosome number of a range of species.


Which of these statements is correct?

  What conclusion can be drawn from the karyogram below:aqmafqn xb)u .o n; vqrr3s7-5j+qs8?

  Which of the following processes is characteristic of the meiotic and not tc4b umwin2:(g) iky k)xe v,w:xw 7zgr*)2wul he mii)7 w*bcuez42wign)(r 2xkwwg)x k mlu:y:v,totic cell cycle?

  The diagram represents a bud with a sh981jaskd h lr0 d75edpoot 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 troglodyti8(v;2y6sw / zfas ;ck bi(zpkes) is 48. Which row shows the correct chromosome number for different cell types and cell division stagesi;/(zw6 ckp;a sb( fis 82vzyk?.

  At the end of which phase of meiosis I does cros vthc:z -qq .i3ai7:old3fpk:sing over occur, and what is the outcome of crossing d: iafvq7kt:q .lo33h ip:zc- over?

  Which of the following statements does not describe a step in tok9 s2nir2 y.z s/p/pfhe sodium-potassium pump cycle in thef9 y.2//oskpi2np srz neuronal cells?

  Which row in the table below is true of meio/wyd:3 f5*- l:gtge + bggz9 e5pxtmrmsis?

Membrane transport is important for allowrvnped8 nx 0b+ *f/s-wing particles to move across the cell membrane and respond to changes in the chemical composition of the extracellular flui -bfpr *xsnnd8 ve+/w0d.

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 ro:*, czldom5 aegulated 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 le +ob5 7:s xt8z;rpamf e6o5. ztq;wcconcentrations of different cyclins during the cell cycle:;tba8+5x rs.emo;tqczzflp w7 6 5e o. Which cyclin is involved in preparing for DNA replication?

The diagram below shows chromosomes duriy 88m 15guevnz9j fvk)ng 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 /y*2roagr;8x u qn9hichromosomes?

  The mitotic index of throat tissues kfzsach-jmm.i +w6w,*58 emv taken from 4 different patients is shown below. Which patient is most likelw5. m+vcmz68,amfe k -*wihjsy to have cancerous throat tissue?

1.Draw a labelled diagram to represent the process of crok h, )dfgprrs7;l;hi3ssing over.

2.Compare and contrast random orientation and crossing over.

3.Outline the stages of meiosis.

  The image shows an abnormal human karyov.,pa - iuz1, xweunq7xw:w )htype.


What is the abnormality in this karyotype and its cause?

The graph below shows the relative amount alfu-unt 8h4y uj5 *h:of DNA in one cell during one complete ce4h:juu8uy ntfla*- 5 hll 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 crosshc9. bcsm1ry (a y4fq4 between a male cat that is homozygous for brown, long hair and a fcs 4 m9 r1.acy(bh4qyfemale cat that has black, short hair.


Which of the offspring has a recombinant genotype?

1.Outline how polygenic traits can show jztjfz,q+npx7w83 c) 7xz ib+ 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-sister cbsoj2 :+6ig*qwf l-a qhromatids shown in the diagram beloqw* 2bs-gfl:q6+o ji aw?

  The photomicrograph shows a pollen grains km7v up3*gbyz56(yp from L. candidum (Lily). Which stage of meiosis is(k zs6p5y *gp7ubvy3m shown?

1.Outline the events whichyyeak) z2 mgqz)/-+iz would lead to an individual being born with Down syndrome, whie -g/qm+ky)azzyz 2)ich 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 anmhhqx0s9ms h-f :0x,l indirect way of measuring plant growth. A study was conducted on white onions (Allium cepa), under controlled conditions in a lab, to investigate thxh 9h0sl0h: fmsqxm-,e 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 digpb r eu52:9bxx: kp.*l e4zehvide. The diagrams below show two cells from an organi5ex. pxb:e g9lzhuerbpk :24*sm 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 2op(nhqi xfypv )+ kc93,mj q+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 nut5d ozk v2,n,4:lqz vomber of 8, in different stages of meiosis. Which row correctl ,tvon25:z d,4vqlko zy names each stage?

  The micrographs show four phases of meiosis I in a plant. In wcb 4-*g 00c a;fyr17zvlaqsg rhat order do these phasfz va04gr b7* rs0;a g1qlycc-es occur?

Mitochondria are responsible for supplying metabolic energy in eukaryotic cempn+ . zkt;ky*lls. In most eukaryotes, which reproduce by sexual reproduction, mitochondrial DNA (mtDNA) is inherited from only on*mn.p z+ k;ykte 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 4au,)41hxipy- h 8h5ro pfqw xof the cell cycle in four samples of lung tissue from four patients. Which tissue has the lo u4o)4x xfih ,r15-qah pyhw8pwest mitotic index?

  The diagram shows the dominant cyclin/Cd.n . x27r wy nw+o;-bpk 3kgntbnha;,DK complexes at different time points in the ceayx;t2 nd.h;b,n.+n k7 prgn3o-bkw wll cycle. Which cyclin/CDK complex activates DNA replication machinery?

  Studies have shown that genes such as Cyclinu(mp)(e(kv3n pc3 nnp Dependent Kinase 3 (CDKN3) are highly overexpressed in cervica 3pknv 3ne(c(upp()n ml 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 hizp.wfl t5t)1q(c0un0o agqe l/k)*xaghest during the cell cycle ?