The graph below shows the relationship between maternal age and the incidxbsg/q6)o5fx v* ur )ience of non-disjunction. Wha5 uqi6xvo/f s))xb *rgt relationship is suggested by the data in the graph?

  Which stage of meiosis is represented in the gpgk n39sz;v6 diagram below?

  The diagram below shows chromosomes duribd ;gzmoo6( ,ing 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 alleles9wcl -s5 kaw(w 7wz)gg of a single gene which would be present in tgg9 k w(w-cazl7 w5)swhe nucleus of a cell as a result of each process?

  Which keyword is matched to the correct definitio7ni(qd * .ljwlfmlq+v cz+ 57zn?

  Which statement(s) about mitpy0ml3y mr h973ktk 0kosis 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 p4fv8uks me+3 fx/*tjuoints to a cell in anaphase?

  During which stage of mitos(* 0a7yfxjr n7a ; 9k ifg8t6xvcqkato --xtu3is does the nuclear envelope break down?

  Which one of the following transport proteins only carri zl tunstdv;mv;3;+5hes out active transport?+uzsld;h; ;v v3ttmn5

  Which process does not happ1 y*va3qq.b2p h7 lrfwen in the shoot apex?

  Which type/s of membrane transport do/does not require enesw /0aah3hv8qrgy expenditure?
I. Facilitated diffusion
II. Active transport
III. Osmosis

  The diagram below represents a cell with a diploid number of 4. Which st 6yg *yyndz(8x+e2b c0j,x adcage of cell division is the cell currently unde2ed+ zndcxy8ayb(,x6* gjy0 c rgoing?

  The photomicrograph below shows a gd yh-if* x4,dmfz1; fed tr3p-7y2iuroot tip meristem. Which of the following sentences correctly xe;h -2yf3 frt,i*4d1p7m-gz dud ifydefines a meristem?

  When does the random orientation of homologous chrowt 0oxc:o 9w4zxf8r 6smosome pairs occur?

  Which process does nol6 a5kdcq2o +ot occur during meiosis?

  If a cell with a diploid number of 3:zjh l2w1 udu;ciz /i.9h(jl u6 undergoes mitosis, how many chromosomes will be presentzw:hu1.j(ih;lu 2zl i /ju 9cd in each daughter cell after cytokinesis?

  The image shows a micrograph of a celb) mjqu w:ilo 7ad1d,4je, fq5s;myf6 l.


What explains the appearance of the cell in the micrograph?

  Which statement(s) about homologous chromosomes is/are not true? 5xkyy50ezq ei 1 ooa;6
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 syb,*io,fx3a f5 s k9tbzndrome.

Which statement is not correct?

  In the cells of a horse (E. caballus) during prophase I of meiosis Ie*u we)3jg:a x there are 64 chromosomes. Whae:x ) ug3j*aewt is the haploid number of chromosomes?

  Which arrow is pointing to i c rnq;9 do:pv9izb*:a chiasma?

  The diagram below represents the structure of k:/+-9jca+mzxaiq2+ph )oh ee i/b z ua shoot apical meristem. Which row in the tabb q-m/e /+ j+oi p9xehzah)a+:cuiz2kle correctly identifies the processes occuring in the structures labeled in the diagram?

  How does meiosis promote vari,bdcpet h ea/ e-h2x-jm6vc+/ ation?

  Which of the following statements is/are correctq/,- ti ;l pdb;da)ra.xd 9tg+bf( qmh 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 r9 ; cq-f4hy24 uqw 0:pbebit1ekcb xpsy1h2( 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 seconi44/n /dw)ek6xfkka ekw0h,t dary tumours from primary tumours as a re0t,fkk4 ein6)k/whdwxe k a/4sult of the movement of cells?

  How many chiasmata are present in th5wfc izzil.5 m.+m bch2.v)ve e diagram?

  Which statement is a similarity between cytokinesis in animal and plant ckt, ;p1bn99: uvhrgy nells?

  Which stage of meiosis is matche.msoe2g;;*dh znj k2zd to the correct description?

  Which statement(s) are true of meiosis I but v:q9w9tj4y we)-q;(csf kgic 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 meiotic division. This result/en. hvwok8srh6 b 90js in the formation of one large cell and one small cell. What is the fater.8hvh9j osb 0nk/we6 of the large cell?

  Which row correctly describes diploiddyatlixl1r o4k :w4 6w;c:u0q and haploid cells in humans?

  The following table shows the diploid chromosome number of a raqs,o71h*k:6ze b akepnge of species.


Which of these statements is correct?

  What conclusion can be drawn from the karyogram bli/q/yih op g20:;zsbelow?

  Which of the following processes is characteristic of the meiotic and not ther+x gbtez9b9 )dq.) uinjtp23 mitotic celld)ip b ug993tz qjetbrx) n.+2 cycle?

  The diagram represents a bud with a fq2l; 2wh1rsev ,utz: v u52qkshoot 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 row shows t9 v o.,oxjy3zd8v-or6 i kkx4ihe correct chromosome number for different ce. k3xyzx-orik4io8j9d , vv6oll types and cell division stages?.

  At the end of which phase of8l1;kg ; kzrz( bbtc;q meiosis I does crossing over occur, and what is the outcome of crossing z(z;bq 18;gt ;lkbckrover?

  Which of the following statements does not describe a step in the so c/3xm;uu4 7dgiz llz7dium-potassium pump cycle in4mduc;3l7ux / gil7zz the neuronal cells?

  Which row in the table below i*x,,/m15yvf 0s5zuj5j qnuli ymcuv4s true of meiosis?

Membrane transport is important for allowing particles to move across the cellx8(46pp;k e)ek7ru, pudu im v membrane and respond to changes in the chemical composition of the extracellularr,k i6 7mek(u 4 8xvep;puu)pd 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 rb px43uvb:tsw 9 394elc5ipop/h /rndegulated 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 c z9gp; :* prhsc5sh877 tatvtvoncentrations of different cyclins during the cell cycle. Which cyclis hpat 5: s;p77hrgz vt8c*9tvn is involved in preparing for DNA replication?

The diagram below shows chromosomtq tnj1zt5p .6es 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 thc.omjo 8oi1y/j2o 1ybb(igt 8e separation of homologous chromosomes?

  The mitotic index of throat tissu-kb9iznyanr8fp8af 9 gbs uv;1q-:ek202 vgjes taken from 4 different patients is shown below. Which patient is most likely to have cancerous zqab9gnkv- e :rnp1 afif0bgs88j22 y;uv-9k throat tissue?

1.Draw a labelled diagram to represent the process of crossing ov4)yvzr /.dpws rq+4mh, aoa9 ier.

2.Compare and contrast random orientation and crossing over.

3.Outline the stages of meiosis.

  The image shows an abnormal human karyotype. h 3p9f7m eo*rvpl-/vc


What is the abnormality in this karyotype and its cause?

The graph below shows the relative amount of DNA in one cell during one5sd th;c(q-jh complete cell cycle. Each letter represents one stage of the cell cyc(sjc;htq-h 5d le.


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 sho;ex:zw/y3pxx ws a cross between a male cat that is homozygous for brown, long hair and a female cat that has black, x pwx:3zeyx/;short hair.


Which of the offspring has a recombinant genotype?

1.Outline how polygenic traits can shf( (whp )o0 no4ytor4iwuzq7+ow 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 n.n2,98i edvg g1mk(jyw wh0kof non-sister chromatids shown in the diagram below? , g98h2ingww0ne dvkj1(mk y.

  The photomicrograph shows a p *wtiv qw9wy4f-9g q.gollen grain from L. candidum (Lily). Which stage of meiosis is shown?.yw*q-wv qit9w gf4g9

1.Outline the events which would lead to an individual beinc hbc1n;o)s+i eg10h0 wu4jz ;exfbz; g born with Down syndrome, which is char)ezj;n iuh+0cws g4hcbx 0f1b ;1eo; zacterised 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 rlqifo, ( 4nbr-m,qpw31 ty ;zway of measuring plant growth. A study was conducted on white onion ,qo i43t,mrbz ;-wfynql1pr( s (Allium cepa), under controlled 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 whichzljr ++h87me l cells can divide. The diagrams below show two cells from an ormrj7l+helz8 + ganism 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 of5k,h- + l0jn)rc .3pnsyy ixqn gene expression 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 cell, with a diploid number of 8, in different sz u202gil59oms bd7bixxl.; jtages of meiosis. Which row correctly nax2l 2ib z;sio5 09m.bd7guxjlmes each stage?

  The micrographs show four phases of meiosis I in a plakrm .+xmv0b2 :d/v* ;m-qmncoouhxt 4nt. In what order do these phases occuromrvuqt40hc/ 2;m mv*x x nk:-dm o.+b?

Mitochondria are responsible for supplying metabolibt792ivj o- pyc 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 reproduction between two dif b97- ovytijp2ferent 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 r4gxe1f6.4rl co w,j0v 07eze5zhgnols in different stages of the cell cycle in four samples of lung tissue from four patients. Which tissue has the loxh05g7 r1ge0.jznc4r lfev,6ozw4 e owest mitotic index?

  The diagram shows the dominant cyclin/CDK c2,mrc owvj,ouk;lt+;c0wfwj .ic4y7 omplexes at different time points in the cell cycle. Which cyclin/CDK complex ac 4k;wijrf7oc. + t mujw,v2o;cw0ly,ctivates DNA replication machinery?

  Studies have shown thaf1,5tbv. f ksit genes such as Cyclin Dependent Kinase 3 (CDKN3) are highly overexpressed in cervicik ,5.bvf sft1al 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 y . *yaqjef91n1 mux3(qc1oraof cyclin E the highest during the cell cycle ?