The graph below shows the relationship between materna 4j0+tq w qxq4 a3kk8j(*udsyql age and the incidence of non-disjunction. Whqkq s3 kxj t0q4*+q8wy(aud4 jat relationship is suggested by the data in the graph?

  Which stage of meiosis is represented in the s jy:i*9jtzbml.l1.l8 bw b1idiagram below?

  The diagram below shows chromosomesxl;q)/.r wt9a rq6ytg7ej c3 n 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 st :*inoc+f :,usmqvei(ates the number of alleles of a single gene which would be present in the nucleus ois(*u ei :qv +o,:fcmnf a cell as a result of each process?

  Which keyword is matched to the correct definition?b j/ 6n/3v:jumdfqp*,wnem6z qp) j1 m

  Which statement(s) about mitogggzi+ /goq6kb3uc66m 14)qqe)tri5g *bl hcsis 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 points to ax:fp):cz* za/0pmmo tj0je 0 u cell in anaphase?

  During which stage of mitosis dorbx vg4s *n.,/i6isz tes the nuclear envelope break down?

  Which one of the following transport proteins only carries oi 60m 7ilu c8:mpjco7ag nwj(p;/gc6lut active transport?icja u(8p/p6lnc0cw; mgilmj:7 7go 6

  Which process does notckj7/dox0ww 4) 5pg gl happen in the shoot apex?

  Which type/s of membrane transport do/does not require energy expenditure? :ks: yvri0skklm2f3q y1y, 0 w
I. Facilitated diffusion
II. Active transport
III. Osmosis

  The diagram below represents a cell with a diploid number of 4. Which stage ok (jcv etd :r)j;ivs7*f ceecvrj) :s(v7kj *;idt ll division is the cell currently undergoing?

  The photomicrograph below shows a 5 m2n0lvtq/o* 4 txhb0)hwpzeroot tip meristem. Which of the following sentences correctl0vheq4hz lt)2omwbp x*/05tn y defines a meristem?

  When does the random orientation of homologous cuax./omtvq-nz 88 +mgfd,0n bhromosome pairs occur?

  Which process does not occur during meiosis?*bqam, l d,3n eq:pwx(

  If a cell with a diploid number of 36 undergoes mit3 )v ulbfx29-hosa;b -aoje(losis, how many chromosomes wiu-ev;)lox 2(b9sh lf3 abo a-jll be present in each daughter cell after cytokinesis?

  The image shows a micrograph r t r56kdqu 7/.mwpe7r zh8t3dof a cell.


What explains the appearance of the cell in the micrograph?

  Which statement(s) about homologous chromosomes iznpi+st/c rgn6 si.: fs.-u7i 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 axd 4p :4f4qstqn individual with Down syndrome.

Which statement is not correct?

  In the cells of a horse (E. caballus) during pj jl 6g lx1ye-djs(w3sv(o22zrophase I of meiosis I there are 64 chromosomes. What is the haploid number of chromosome zd 2j3x-v(elw2 gy6soj1s(ljs?

  Which arrow is pointing to 2v gxx9jsn:3d a chiasma?

  The diagram below represents the structure of a shoot apical meristem. Wdi i w7j dk+mrl0)8f;7syb ut3hich row in the table co7y)wid3;dlmt ib jk0s +8fr u7rrectly identifies the processes occuring in the structures labeled in the diagram?

  How does meiosis promote variation?qh;( + bza5cfyc 4tno8

  Which of the followingwv0j6d:h8 *jctz./f 6mpxbo z statements is/are correct for meiosis?
I. It is a reduction division
II. It involves random orientation
III. It produces genetically identical cells

  The diagram shows gamet 94vxx1omk) 9/kvecwges produced from two 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 c 713itds1b9(oim1gjqrks9p tumours from primary tumours as a result tr(o1q3c1dspg b1i9j m7 ks9iof the movement of cells?

  How many chiasmata are cj*ua5d (zo.41v kyy bpresent in the diagram?

  Which statement is a simila ga ni9zh8h-5arity between cytokinesis in animal and plant cells?

  Which stage of meiosis is matched to thedcv) sks68 )nx correct description?

  Which statement(s) are tc thb/ a83)e+gpal9iyrue of meiosis 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 meiotic division. This res(f:biyvo7o+o0a ke0 ac5l4if ults in the formation of one large cell and one small cell. What is the fatee7coavy+ k 0fbol( 045:a fioi of the large cell?

  Which row correctly descre spvvps)-oxp2v k 2c :,b kd+3ky(2bvibes diploid and haploid cells in humans?

  The following table shows thee y;.-pq; *idmn( bukj diploid chromosome number of a range of species.


Which of these statements is correct?

  What conclusion can be drawn from the pq .zsvxm7y/kuokk ms9 *52g;karyogram below?

  Which of the following processes isx/7d xk yfmd;4n) vdd9g+z/nr characteristic of the meiotic and not the mitv+dnfd49 n/xm dk/ xy7 drzg);otic cell cycle?

  The diagram represents a bud with a shoot apica 0 g.(zip ace5ewe v9t8s,0vqil 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 (y: ,nnvovpc7bxvqa:5f8;n c : Pan troglodytes) is 48. Which row shows the correct chromosome number for different cell types and cell divac5:vqv ; fn7nov px,:nb:cy8ision stages?.

  At the end of which phase of meiosis I does crossing over occur, and what is t krf8s6cxlw(4 he outwx8k64 s c(lfrcome of crossing over?

  Which of the following statements does not descr60 x-vphwcn5:bvj6 5ihkgwe2ibe a step in the sodium-potassium pump cycle in the neuronal cells? j6n:kv5ipw w26hvgb 50exh- c

  Which row in the table be7 xfo3ve msani1 q1 nt ko01aiz*394mnlow is true of meiosis?

Membrane transport i iiya 153/zx 1dsjez7zs important for allowing particles to move across the cell membrane and respond to changes in the chemicaj5zi3s1 z7/exa1zi dyl 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 regulated iqbs */0rikh*i)gi sia39)zb vn 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 concentraq4 +l o c1vsb:)ljen2ations of different cyclins during the cell cycle. Which cyclin i1olle :qn)v4+s 2bacjs involved in preparing for DNA replication?

The diagram below shows chromosomes during meiosis1l ffhvpxg4::.

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 g emz5d).mo1nf+ ;donof homologous chromosomes?

  The mitotic index of throat tissues taken fr 88db; ev*dg-lnjqdp s08ar9iom 4 different patients is shown below. Which patient is most likely to havbn i9rlj dd8g0s;-q evd 8ap*8e cancerous throat tissue?

1.Draw a labelled diagram to represent the process of crossingqk la/;q b0;jg over.

2.Compare and contrast random orientation and crossing over.

3.Outline the stages of meiosis.

  The image shows an abnormal human kar l pj7rdxcn2,nr6)pf +yotype.


What is the abnormality in this karyotype and its cause?

The graph below shows the relat/u6wbd(g w 9nw( q;hqoive amount of DNA in one cell during one complete cell cycle. qduwwq/ b wh6(9ogn (;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 thnthr zmwm8mo48 mw.36at is homozygous for brown, long hair and a female cat that has black, shortwmmm6h r8m8twn. 3o 4z hair.


Which of the offspring has a recombinant genotype?

1.Outline how polygenic traits can show a 2ggtt; eu:g2 0t+a ; qgfm0kuw je/7trnormal 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-sisteg-tkv6yn2 kmu:z hx fh;k81-yr chromatids shown in the diagkh -k1v ty:2h-zkufygnm6x; 8 ram below?

  The photomicrograph shows a pollen grain from L. candidum (Lily). Wv/kxlb 7-s) ipz4tt-mhich stage of meiosis is showx7 bk p/v zt--i4ltms)n?

1.Outline the events which would lead to an individual being born with Down synd2h0i fzmab*6orome, which is characa *o26mzi0fbhterised 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 s +33 n4h;r(a cso6wpobkcyy2plant growth. A study was conducted on white onions (Allium cepa), under cops2y cb;hc46r on+wos y3k3a (ntrolled 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 diagrams below4: 6x1gcm1gq hjuxj h2 show two cells from an organism wu cxm2 1j:hg 16gxhj4qith 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 ste s(ysezbmrxa :).2 zu1i6m(rv m 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 n7 t7wx,dgf)syyhyws)4rv -3 ag)k fg8umber of 8, in different stages of meiosis. Which row correctly namw,gyr 7s4)ffyt -g3wy8 k)g ds)xvh7a es each stage?

  The micrographs show four phases of meiosis I in a plant. In what order do thesexog0:w)4 zcfu phases ofg: ux o)cw40zccur?

Mitochondria are responsible for supplying metabolic energy inh.f zfat/jp/- eukaryotic cells. In most eukaryotes, which reproduce by sexual reproduction, mitochondrial DNA (mtDNA) is inherifj ph//ft. za-ted 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 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 ce;ooxz 8-po; bjll cycle in four samples of lung tissue from four patienoo;-bpz 8x;ojts. Which tissue has the lowest mitotic index?

  The diagram shows the dc69k ibbwbyef17qy,8 ominant cyclin/CDK complexes at different time points in the cell cycle. e81cbyfb, y9 iq7 bk6wWhich cyclin/CDK complex activates DNA replication machinery?

  Studies have shown that genes such as Cyclin Dependenttd9jd ;+8cp x xz/g*bmmy)u6z Kinase 3 (CDKN3) are highly overexpressed in cervical tumours. cd8;mymx t +6 gx/dz9ujp) *bz


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 cyclicvh2jdo(tptko9az 4e:5nz(1i9ti m8bc0 nr*n E the highest during the cell cycle ?