The graph below shows the relationship b kh3r2i mdfvr7 j1r0v*etween maternal age and the incidence of non-disjunction. What relationship is suggested by r0j7irvm*dh1 r3f2k vthe data in the graph?

  Which stage of meiosi1/q,jz mxwojqp4 (3pfh.;jz vs is represented in the diagram below?

  The diagram below shows chrfi * . v i:vlm e;h8dvtvd-*zr7f8p+ynomosomes 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 **nyr9(4 uzpook /dbsa single gene which would be present in the nucleus of a cell as *ds/r*bnu4(kp9 yozo a result of each process?

  Which keyword is matched to the correct definitmvagdr2 b;s;1 0f/ zzoion?

  Which statement(s) about mitosis oml38/8fd,jb v,p y7thq uuj3is/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 belobcs. re4n.:;xvr) wg.:fam xl1s ic4 dk1-lmfw, which letter points to a cell in anaphase?

  During which stage of mitosid9 :asmb-jx/9cb)5e ee txp9ts does the nuclear envelope break down?

  Which one of the following transport proteins only8py f+( eiqe.m t 7.zn9ihp6thj4keoh7-e5ze carries out active transport?j+ z-tn9m .e674( ife8qokeeph7zhte5 ph.yi

  Which process does not happen in the shoot apmt+mujsk .np0ie+d;dx nu5.d 2e ,r8vex?

  Which type/s of membrane transport do/does not req;x:tk utx2/so uire energy expenditure?
I. Facilitated diffusion
II. Active transport
III. Osmosis

  The diagram below represents a cell with a dipj06 )js xxo)jeloid number of 4. Which stage of cell division is the )xx j0)j6oejscell currently undergoing?

  The photomicrograph blm2:j)6be1gl06yl, slt :i bf+fjyqw elow shows a root tip meristem. Which of the following sentences corr6felb0slwi6:qmbyft1 j j),l g l:+2 yectly defines a meristem?

  When does the random orientation of )ps vmb8 o.1e7udd u35o5fxy nhomologous chromosome pairs occur?

  Which process does not occur during meiosis?b u jg3j 88gqkuf7k4(a

  If a cell with a diploid number of 36 u iob5 h,zae;0zv+(kl6l2 ,a7dt d wkrdndergoes mitosis, how many chromosomes will be present in each daughter cel a5rhoddke+ t6a wdkiz l;b (v7,0z,l2l after cytokinesis?

  The image shows a microgg63n4duye :usraph of a cell.


What explains the appearance of the cell in the micrograph?

  Which statement(s) about homologous chromosomes is/a*;nqu1c.w q nore 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 w c fqh5pod/g0f2bc: *yh 2csr-ith Down syndrome.

Which statement is not correct?

  In the cells of a horse (E. caballus)25 - swk n /zx4uuq8cikss9dv5 during prophase I of meiosis I there are 64 chromosomes. What is the haploid number of chromosom 2zw usss94cdu5 8vq-/xik 5knes?

  Which arrow is pointing to a rdl1ey;ar-jyy)e aws: dd )dwc2)h0mu1) : vlchiasma?

  The diagram below represents the structure oh+2c6 7vemthrm 74uo7ev8ape f a shoot apical meristem. Which row in the table correctly identifies theh aeet678h ue vro 4+2m7vcmp7 processes occuring in the structures labeled in the diagram?

  How does meiosis promote vld x7*nol1ig 7ariation?

  Which of the following statements is/are 6 0yhh,fmyy k)correct 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 tw1d ow;tqoi2*: f .hnyil82o nco homologous 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 primary tumot63h/xnmh q8.9b8nso6 4 0 jrvjmxe kours as a result of the movement of c648/o tbxhm8 .k nvjnq0s9xj6 o3rm ehells?

  How many chiasmata are present in g / +vnqh9f3ikime83jz x*vl7the diagram?

  Which statement is a similarity between cytokinesisy.puej, oeda/2oxq)mr4vl 29c g6 7rw in animal and plant cells?

  Which stage of meiosis is matched t(tql7 g, utp.mfrx 5zonn x q+1d(s,;go the correct description?

  Which statement(s) are true of meiosis I but 8uu sub5 dvep zjv 97rua7-j59not 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 firs sb a):n36cry1jgc1 aoml)-cct meiotic division. This results in the formation of one large cell and one small cell. What is the fate of thea6l:-) rn3)oc1cg b1yjccsa m large cell?

  Which row correctly describes diploid an ;+yo qjm -twsgc h-z:g/8yi1gd haploid cells in humans?

  The following table shows the diploid chromosome number of a raww qa2kb9(qfdbbc ,e / ipgr3e-o6 4n/nge of species.


Which of these statements is correct?

  What conclusion can be do 9lb5qwxkg1aue up e9f/8s e 4 io*c9d1mvv)2rawn from the karyogram below?

  Which of the following proa ja6/x7nq s(bmeq*) kb9dc)r cesses is characteristic of the meiotic and not the mitotic) b)/sna9 djbqqkecrmx76*(a cell cycle?

  The diagram represents a bud with a shoot apical me0 w.x3v rj(qzpristem.

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) iedzc3aa1yjwtah3 gw 9,6 *9pbs 48. Which row shows the correct wja9 ,39*6wpay g 3 cd1ehaztbchromosome number for different cell types and cell division stages?.

  At the end of which phase of meiosis 8 x,8)+sjbxhtx 8 khjgI does crossing over occur, and what is the outcome of crtk)+ s8x xh,xj 8hjg8bossing over?

  Which of the following statements does not describe a step in the sodium-potau59 c.nf 8mvbz9ujm 4bssium pump cycle in the neuronal cmvbzm54n u8cbj. u9f 9ells?

  Which row in the table below is true z shc9sg-,+dr of meiosis?

Membrane transport is impo h1cjf 5dqofl+mns810 dmk1e*; drd 1drtant for allowing particles to move across the cell membrane and respond to changes in the chemd 18*qfme 1d 1ls;dn 5mcd10 +ohkfrdjical composition of the extracellular 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 r ohax ,g2n(mn1egulated 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 con vwr9;stbg4q )(9ayce centrations of different cyclins during the cell cycle. Which cyclin is involved in prepa y99bcge4aq vs ;w)t(rring for DNA replication?

The diagram below shows chromosomes during meiosis.h7vp(98u*frrpc fe6 t

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 th9 y5wfe66 *rxv4kjaade separation of homologous chromosomes?

  The mitotic index of throat tissues taken from 4 different patients iy)a0k )ov0fggs shown below. Which patient is most likely to have c0)gg vf0yak) oancerous throat tissue?

1.Draw a labelled diagram to represent the process or+ lhe p f4jnw3h;*mo6f crossing over.

2.Compare and contrast random orientation and crossing over.

3.Outline the stages of meiosis.

  The image shows an acq i3dbq3lbd 5ia(d:9 bnormal human karyotype.


What is the abnormality in this karyotype and its cause?

The graph below shows the relative amount of DNA in one cell during one complqsupd.v a-:) c9 t.r9mui td7sete ceis9.rvt-:uq. cptmdau d97 s) ll 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 between a male cat that is homozygous for 6o3z)z8l; pl.seo ymb2gwo5 vbrown, long hair and a fe ow;)zls563ovmlz gbp . 2oy8emale cat that has black, short hair.


Which of the offspring has a recombinant genotype?

1.Outline how polygenic traits can e6ecmv4am f3 8show 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 6g t3imj ,2psi9tz; qsof non-sister chromatids shown in the dz96 j gt;, siptim32sqiagram below?

  The photomicrograph show.vp+lm ohk6/ es a pollen grain from L. candidum (Lily). Which stage of meiosis is o h.6+vpkml e/shown?

1.Outline the events which would lead to an individual being born with Down sy4 v9e lsnm(-g3yubtci(3ar/y- fd2f xndrome, which is characterisedefg2b- y93n cs l/i- (mu( yxrd34vtaf 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 meap-pxqq8u: / xe o6sh 9qjc+nf3suring plant growth. A study was conducted on white onions (Allium cepa), under control3 j-9p /h:qx+q feun8pcqs o6xled 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 cell-v; xuu4akr 74zaf gk2s can divide. The diagrams below show two cells from an organr7k a4 afk2vuu;4gz- xism 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 iq+f f9vu, :eud)8 mspfn 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, with a diploid n;d 0vpc;0i*xc 2k bt e0xwl4xl9w gyl3umber of 8, in different stages of meiosis. Which rowx 39lylcx xp;gk0tdl *icb0vw ;0 2we4 correctly names each stage?

  The micrographs show four phases of meiosis I in a plant. In what order do td 9v9h dgbefpx30z6o4hese phases occurb9d4f3 9gv6o e0x dpzh?

Mitochondria are responsible for supplying melly9m 2 xc36cutabolic 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 eukary3lyluc mx269 cotic 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 cel;6p76t jjz 54 dyfrx0g1mk ;fvbq8pzjls in different stages of the cell cycle in four samples of lung t1g;rtpk dxjvmpz;jzq8j 5 y6f f6b407issue from four patients. Which tissue has the lowest mitotic index?

  The diagram shows thecs6 qqo :ex2+2v3adx o dominant cyclin/CDK complexes at different time points in the cell cycle. Whioqe 2c o:+savx62 dxq3ch cyclin/CDK complex activates DNA replication machinery?

  Studies have shown that genes such a elvq:cj :pplw7 fo,81s Cyclin Dependent Kinase 3 (CDKN3) are highly overexpressed in cervicqc1:fepo ,lp 78ljw v:al 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 th,q6cp3kxj 8xcf3ee-ue cell cycle ?