The graph below shows theqbd0-:s o:h+5y;pyg qr0ep m a relationship between maternal age and the incidence of non-disjunction. What r+0y;0pgq:- bp5 a hsreqyd:o melationship is suggested by the data in the graph?

  Which stage of meiosis is represented in the diagram below?: yuh +1wgrh+u(q;niy

  The diagram below shows chromosomes during meios n )u0ho5ofd4jis.


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 which wouldm;qjn 9uk; cv(1 7m/u*fiihkb be present in the nuclu7n;q i cmmk1uvf i(9 hkbj/*;eus of a cell as a result of each process?

  Which keyword is matched to t(iap rmk18r2p-kl *en he correct definition?

  Which statement(s) about mitosdeah. pft.kyd;s1yx2b:65 ekis 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 to7 v. id:4uk9uor hhb/x a cell in anaphase?

  During which stage of mitosis d(b5i3no6g no i+tlid/ oes the nuclear envelope break down?

  Which one of the following transpyw/eke t ,0ey6 c2qw ep:g83r vvt(z0sort proteins only carries out active transport? gte kt(ec8z02/e:ypyv rewsw 36v0,q

  Which process does not happen i hif4 ls(bmpd(h:1i-wn the shoot apex?

  Which type/s of membrane transpov o4ktf9ye16tj , bz7nrt do/does not require energy expenditure?
I. Facilitated diffusion
II. Active transport
III. Osmosis

  The diagram below represents a cell with 7eriykr:tq63: bbpy2 a diploid number of 4. Which stage of cell division is the cell currently undergo:yq63kyberb7 2: ptr iing?

  The photomicrograph below shows a root tip mert fh :.6t ktxl2:bhth-istem. Which of the following sentences correctly defines a merist6htl:httf.t-:kxh b 2 em?

  When does the random orientation of hon,81:bckfqv 9p y dd:umologous chromosome pairs occur?

  Which process does not occur during meio:.wg j 7zqego4sis?

  If a cell with a diploid number of i4 6b4m1vht9 2xwjdmuz)g eg/ 36 undergoes mitosis, how many chromosomes will be present in each daughter cell after cytokinesibgx ezvwjm)4 i g4/hdu296t1ms?

  The image shows a microgvga93f3t r1 h6 naxd4xraph of a cell.


What explains the appearance of the cell in the micrograph?

  Which statement(s) about homologous chromosomes is/al j2k:lths0mvksp(,5 gh3ll )re 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 ind*v oqscjz:d(g jn6ga1b074 jsividual with Down syndrome.

Which statement is not correct?

  In the cells of a horse (E. caballus) during 6iq1f. 501l mucfdfzhr3 q(gz;kn 2xo prophase I of meiosis I there are 64 chromosoqcqlhikz5 ( f g0fnz6fuxr;1231md.omes. What is the haploid number of chromosomes?

  Which arrow is pointing to a c0y*vyl: mt)hthiasma?

  The diagram below represents the structure of a shoodiml7d)ra :g*s/ly 2ht apical meristem. Which row in r yld:i 7sgl*)2m/dahthe table correctly identifies the processes occuring in the structures labeled in the diagram?

  How does meiosis promote vari2;p3daz k +98xbkti0/m s ea4g uiyr3k8xz0puation?

  Which of the following stu)kr.*i it7uka4ev g:atements 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 gametes produced from two homologous chromoaf.s1v3 dt6auf bbm6 1somes.


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 fromb i0e xyu:3f/m primary tumours as a result of the movemem:xei0buf/y 3nt of cells?

  How many chiasmata a8cgua z5 u)o(wre present in the diagram?

  Which statement is a similarity between cytokinesis in animal and plant cevyg47 wai i+ )o7e*wxdl/wmj1 lls?

  Which stage of meiosis is matched to the correct descri8dn lsd -kf qrh2kldh12 0m,8rption?

  Which statement(s) are true of meiosis I but not meiosis5tsd9lsn )v 9w 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 afte;;d y:-foewxnkj1 oe 6r the first meiotic division. This results in the formation of one large cell and one small cell. What is the fate of the large -1yde;w6:nfoxo ; je kcell?

  Which row correctly describes dipln(j4vvv,x9 r1 d6zfjx5, -szhfc4 q ptoid and haploid cells in humans?

  The following table shows the diploid chromoso2/ ab *;7ujjrq2 z3lnc5sqr hfme number of a range of species.


Which of these statements is correct?

  What conclusion can be drawn from the k/hty)aiu0cg 4 .dm4kp aryogram below?

  Which of the following processes is characbf o9w)nc6y otd*c +o/e;sg4+ xib4m jteristic of the meiotic and not the mitotic celldg fn4+yebo+ mo94)oc w;/ts *xc6 bji cycle?

  The diagram represents a bud with a sbn3a 5j 7mnfl6vpbu 56hoot 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 troglodytesaesghj j18q.r i9o4 0: jkvkgz+b59cd) is 48. Which row shows the correct chromosome number for different cell t +sh1 b 90:dgjakcvz8qo 95e4ikrg jj.ypes and cell division stages?.

  At the end of which phase of meiosis I does crossod*- pf pm.1tk cu vujm,51lh/ing over occur, and what is the out/5k.h*pjtvf-m 1c1l o, umpu dcome of crossing over?

  Which of the following statements does not des r8icblhgb.k8j-wel u;.q* 3acribe a step in the sodium-potassium pump cycle in the neurona lr;bwkigequ8-.c83 al*jh .bl cells?

  Which row in the table bjzsfb; ; (kkj1elow is true of meiosis?

Membrane transport is important for allowing particles to move across 69yn- :gpcg*m ffgss) the cell membrane and respond to changes in the chemical composit*)fgp sgm s6n:fyg c-9ion 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 regula f(xdw-+) qlift:v u)jc 2kv p9uw20mated 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 showty:yex5r y ii918 *nm9 zaq4mss the concentrations of different cyclins during the cell cycle. m y m19ieysry8t95i*:x a4qnzWhich cyclin is involved in preparing for DNA replication?

The diagram below shows chromosomes dxnm3*jcr;rq9a; pgw5 ;czu m6 uring 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 ch) *go r t+2kf/3oiayw+lmll y0romosomes?

  The mitotic index of throat tissues taken from 4 different patient 0t0 akhl:hoh)0md ;as2*qjh vs is shown below. Which patient is most likely to have cancerous throat tih; 0j:ola hhmvtsqk0)0 *2dhassue?

1.Draw a labelled diagram tocu cor x /mq8oihp*7bye-5uxyg68,n2 represent the 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 ka1tsn1e)v-e d xryotype.


What is the abnormality in this karyotype and its cause?

The graph below shows the relative amount of DNA in one cel;xf40r va pht2 (7wylfk*.bsp l during one complete cell cycle. Each l(27x4*kt p.0favsfw ;rbypl hetter 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 isn-6 uc*ebn sm,,sxsq(tjr54 t homozygous for brown, long hair and a female cat that has blauscb45xmtes,s-j* ,nn6q r(t ck, short hair.


Which of the offspring has a recombinant genotype?

1.Outline how polygenic traits can show a norma;arxde /v(+wu9x/jnyq*:v a ol 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 chromatids shown /hbzo:1y(v 57lfi iooyuh, 1 zin the diagram below? :1holihu /1 fzo y (iz5ybo7,v

  The photomicrograph shows a pollen grain from L. candidum (Limphvh6kv /k lyle*m88h + u:i2ly). Which stage of meiosis is shev mm8v l/h8+26pih kuk*hl :yown?

1.Outline the events which would lead to an individual bei5 r8wws k(r1npng born with Down syndrome, which is characterised by the presence ofsr81 wr5n(wpk 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 plant grptjkgia);z 2a :os1k/owth. A study was conducted on whk/tg1)p kzai:sj2 ;a oite onions (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 cnef0se+ue: 8i up3f7gkqh2 3 in which cells can divide. The diagrams below show 82qf 73hkecf3eeng 0:u+puistwo cells from an organism 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 inem*d .vy9h5fs*h/j mt 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 nhq5k: ylvc l3x, 4wd,uumber of 8, in different stages of meiosis. Which row coh 5,wc:dxlqkv4 y, u3lrrectly names each stage?

  The micrographs show four phases of meiosis I in2h*75s xle)fmz,g1 q dvoif8q a plant. In what order do these phases occuvm 2h *i)8sf,ef71qdl zqg5xor?

Mitochondria are responsible for supplying metabolic energy in euka. z.voadv(ovjzte 9*yh (. f)k 9ud8psryotic cells. In most eukaryotes, which reproduce by sexual reproduction, mitochondrial DNA (mtDNA) is inherited from only one of the parents: the mother in tkvo (ta v 9.e9szj* ov)..z(py8dfduhhe 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 aaz-tn q umz rl920m,g 0.gn *:9fwdypin different stages of the cell cycle in four samples of lung tnqzn,a* :lwa09f0z2 prg.m ugdtm-y 9issue from four patients. Which tissue has the lowest mitotic index?

  The diagram shows the (k5sgd6 a buds 07.bnldominant cyclin/CDK complexes at different time points in the cell cycle. Which cyclin/CDK complex activa6lb ds.ua(gs5bk 7 dn0tes DNA replication machinery?

  Studies have shown that genes such as Cyclin Dependent Kinase 3 f ved 1y15q9j/ uhtuy/(CDKN3) are highly overexpressed in cervical v9 fu 1deqtyhjy/u15/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 concentrationy6xf/ p3r80togax) ez g.bwiqnan5u od-78b, of cyclin E the highest during the cell cycle ?