The graph below shows the relationship beuyt/ht.py7 edxelb4 -c++k /)lj u:xytween maternal age and the incidence of non-disjunction. What relationship is suggesh7eyt.l pe)xj:+yt ld+/ buc-/kyx4 uted by the data in the graph?

  Which stage of meiosis is represented in the diagram4 ;; cikh0,nvi)cwv lk below?

  The diagram below shows chromosomes dur)9 /bha pewoot5q8*eh 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 allel,.xn qtja;l2lyiej*llc / u ,1-abk4les of a single gene which would be present in the nucleus of a cell as a reae.n,*l ,-2 bt1jjuxalk cl q/ill;y4sult of each process?

  Which keyword is matched to the correct definition;o4fts)rq*z kp, d sk+?

  Which statement(s) about mifnaiu75yb r 2)tosis 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 pt0 g.p5jg6z:mjpd k aiw3apm)fh, q.6oints to a cell in anaphase?

  During which stage of mitosis does the nuclear envelopz9gpbv3eo:she1, i a9. ,ddbxe break down?

  Which one of the following transport proteins only carries out a f(jpe.oe;e3s8g u9ie ctive transport?ejf;8 e3sep(9i o .geu

  Which process does not z5 e9 qf lfrqb;;u::syhappen in the shoot apex?

  Which type/s of membrane transport do/doe4ql09+6h)e 3z)objosuy runy s not require energy expenditure?
I. Facilitated diffusion
II. Active transport
III. Osmosis

  The diagram below represents a cell with a diploid number of 4. Which staeam.:etj ;usvxof,(4)br ue7x9 gck, w3pch5ge of cev em.7fs9ux(cjbaw pe)3h xtg;4,e,5 :ok curll division is the cell currently undergoing?

  The photomicrograph below shows a root tip merer, kf qwsw,c3c5i(zr8 ,tc( kistem. Which of the following sente 8skwt ,irk r(,3q(,5cecczw fnces correctly defines a meristem?

  When does the random orientation of homologous chro,a4o5d w4hc)lg oime: mosome pairs occur?

  Which process does not occur during meiosis?h;b v6: ts3fta

  If a cell with a diploid number of 36 undergoes mitosis, h; gur e fupl ce1-wdl.8m) 9b3q7a:ysoa: .beaow many chromosomes will be present in each daughter cell after cytoy.3a lu -l:fb)dp1u om8c ;ae:esea 7 wbr.9gqkinesis?

  The image shows a micrograph of a zbi; phs b3t:f/;7xsmcell.


What explains the appearance of the cell in the micrograph?

  Which statement(s) awt+h+g5i teze 6zy1 +cbout homologous 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 with Downh7h,o) le5c ;8bsqmknuyb) j* syndrome.

Which statement is not correct?

  In the cells of a horse (E. caballus) during propgjbndtr2;n2z sw( 7n (hase I of meiosis I there are 64 chromosomes. What is the haploid z ndbn7t2;gw 2(rn( sjnumber of chromosomes?

  Which arrow is pointing +v4zhbqg9ig xsu 0w1.to a chiasma?

  The diagram below represents the strucaspw8n24 zu5hture of a shoot apical meristem. Which row in the table correctl4u2zhw n8p5sa y identifies the processes occuring in the structures labeled in the diagram?

  How does meiosis promote variat ,3i x00moicbx*a 1vj.io 8lytion?

  Which of the following statements is/are correct for meios*2e g e grzkvbn.9y0p;is?
I. It is a reduction division
II. It involves random orientation
III. It produces genetically identical cells

  The diagram shows gametes produced from two hbc:p6 9 ingcl93n:fgjomologous 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 thew04v wau)pdh 3 formation of secondary tumours from primary tumours as a result of the movem hawv0)pd4w u3ent of cells?

  How many chiasmata ar8 bhpwvyz/ r(-y8u6 vuz ;,tqme present in the diagram?

  Which statement is a similarity between cytokinesis in zses*d ++8ynmymv68 manimal and plant cells?

  Which stage of meiosis is matched to the corre0 pk1.n2im xtc2o5yea ct description?

  Which statement(s) are true of meiosis I but u8:x e+e 7vjxznot 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 results izno3r :38.n6u pgnrmyn the formation of one large cell and one small cell. What is the fr68rnugzmn33 y: .pnoate of the large cell?

  Which row correctly describes diploid and haploid ch z-pnhrr7.b2c, -2 v) yr8s ,qgdggrgells in humans?

  The following table shows the diploid chromosome number of a ra y0-w3,apuq fynge of species.


Which of these statements is correct?

  What conclusion can be drawn from tb3(1,au y9iw7yoc /4pog4ad*ohlq jbhe karyogram below?

  Which of the following processes is characteristic of the m a9hx( ro2sbah4u8i/reiotic and not the mitotic o2ara849/h sbr xi(hu cell cycle?

  The diagram represents a bud with a shoot apical meristem7k,rqqtb mv*3 /v8cvq.

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 ocved0/ x*zk q-f the chimpanzee (Pan troglodytes) is 48. Which row shows the correct chromosome number for diffe/x-vkde z*q0crent cell types and cell division stages?.

  At the end of which phase of meiosis I7 l rgv/aahkdj c-opk36: ifuq1ry302 does crossing over occur, and what is the outcg/ 3 d-6p7ul:aoak c qik20jr3 yrvh1fome of crossing over?

  Which of the following s:k5b os8dkkumz5r9i9n2. v nltatements does not describe a step in the sodium-potassium pkdnznl 9r89v s.2 :b o55uikkmump cycle in the neuronal cells?

  Which row in the table belo5rk 2hhp eskn5k- j1;ow is true of meiosis?

Membrane transport i rz-v2*, vzlv,8jb04v ltqlg us important for allowing particles to move across the cell membrane and respond to chlvrzvj 0-l t8vz,q,*ug4vlb2 anges in the chemical 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 in eu.*22:s 7bjvpylp9)bzg ctasz +;vg, f*j qecells.

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 different cyclins during the cellp.rh7c 2rnigt/cvq,7ng8r g* cycle. Which cyclin is involved in preparing for DNA replicatiop72,ggg ht r7q/ 8cncr.nr* ivn?

The diagram below shows chromosomes during meiosd k 6gkb6h8y rcw+8*eris.

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 hoy f6htf*0xam7,i,gy l mologous chromosomes?

  The mitotic index of throakq(ebo3tsa,;5c /h k gt tissues taken from 4 different patients is shown below. Which patient is most likely to havea/k(5;tsbe3c o q,kg h cancerous throat tissue?

1.Draw a labelled diagram to represent z- kpp,aw,:lothe process of crossing over.

2.Compare and contrast random orientation and crossing over.

3.Outline the stages of meiosis.

  The image shows an abnormal human karyotyp-d w7uk0xt6q re.


What is the abnormality in this karyotype and its cause?

The graph below shows the relati4) ) aq)vsde:8j lh1m8lhzwu xve amount of DNA in one cell during one complete cell cycle. Each l)8ls 4hzjha1 8v:u xe dw)ql)metter 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 xh - vbh1ti+,fhomozygous for brown, long hair and a female cat that has black, shortx1v,+hth -fi b hair.


Which of the offspring has a recombinant genotype?

1.Outline how polygenic traits can show a nofgxqrnul hdn6 h,a53u09 c b8/rmal 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 o9; xxgp x8lcp)f non-sister chromatids shown in the diagram belox)9xx p gpc;l8w?

  The photomicrograph shows a pollen grain from L. candid(kb*l: s2zfak-w r7bcum (Lily). Which stage of meios b rzsfcb :2lk7-w*ka(is is shown?

1.Outline the events which would lead to an individual beigpa5bu)3rmw 6 o+q(u ing born with Down syndrome, which is characterised by the presence of three copiu +umw ipbq3)(rao 56ges 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 gz (l,buv144;xdiew3kq 5gjh2emm u h)rowth. A study was conducted on white onions (Allium cepa), under controlled conditions in a lab, to investigate the effect of soil pH on the mitotic index of the rox3mkbeqj5)u, zhwl42(i4umeg1vh d ;ots.


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 diasm);tw:g ,r3yx eps.xgrams below show two cells from an organism with xx3tps srw; ,:m. )gyea 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 expressiov9x:x. bpg.jk n 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 sl- kl9xdgpuayj ;z*15tages of meiosi;1zga*5lujykx-pl 9 ds. Which row correctly names each stage?

  The micrographs show four phases of mt/xvjzru o988eiosis I in a plant. In what order do these phases occ9x/8zr8uotv j ur?

Mitochondria are responsible for supplying metaboilwb+6g6 kye( ar(b e*lic 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 bebreb6alyekw*6 (+ g(itween 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 nu t lihq(,)t0g/z(o g. s)s:kqg1ecjwbmber of cells in different stages of the cell cycle in four samples of lung tissue from four patients. Which tissue has thhq)1),itoj ((sb:kz gw.c elg/sg0qt e lowest mitotic index?

  The diagram shows the ygbs0 ty3,/fgdominant cyclin/CDK complexes at different time points in the cell cycle. Which cyclin/CDK complsgf y,bt 30y/gex activates DNA replication machinery?

  Studies have shown thatv c)sm)m4 xp2q genes such as Cyclin Dependent Kinase 3 (CDKN3) are highly overexpressed in cervical tumm 4m xq)p)vsc2ours.


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/mjac y3s0):/ .5 rletk 2o;evtio xzb of cyclin E the highest during the cell cycle ?