The graph below shows the relationship between maternal age 2sxn ,;6tq+ke wlo3wj and the incidence of non-disjunction. What relationship is suggested by the dataj,n+q; wt62elow 3skx in the graph?

  Which stage of meiosis iedqejr2 5d(- ds represented in the diagram below?

  The diagram below shows chromosomes during meiosiucyu2 + f8gdfpl+b85 ns.


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 sin nz)vs5r3qr0(r 6higpm3:as* q mnjk5gle gene which would be pres5g srnqriaj* (5 vhk q)s 63rp0:mmz3nent in the nucleus of a cell as a result of each process?

  Which keyword is matched to the correct definitioz btg a si93+-nhtg9a+n?

  Which statement(s) about mi3z 259-e: qboncfsbyrtosis 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 belouscoh8r17t* wc rjuqt 7k47+ nw, which letter points to a cell in anaphase?

  During which stage of mitosis doeabj 0w1 w-nx ggk5:8zef t993(pdnbyes the nuclear envelope break down?

  Which one of the following transport proteins only carries 8msi5lajx 7 mf f91s9yout active transport?am 8fl j1 ix99yf7sms5

  Which process does not happeq*ojp - mxyr3/ cj*spm)d1q*b n in the shoot apex?

  Which type/s of membrane transport do/does not require energy ex6(,n nkgb3 ozxpenditure?
I. Facilitated diffusion
II. Active transport
III. Osmosis

  The diagram below represents a cell with a di17dum 3vs qrr 8enz2p0iy45 fxploid number of 4. Which stage of cell divyq 72rn4sf1vi d5 3mr8ex0 zupision is the cell currently undergoing?

  The photomicrograph below sho0icyvy)h h7;y ws a root tip meristem. Which of the following sentences correctly def hy7y0hvy)c ;iines a meristem?

  When does the random orientation of homologous chromobgepl5ya-);qa( .;zl e *csv osome pairs occur?

  Which process does not occur during meiokpbs5lz6vv 3,, jwgm3 sis?

  If a cell with a diploid number of 36 undergoes mitosis, how many chromosoj3 (okmfb-c7p w 8nc(dmes will be present in each daughter cell after cyj7wfpdno (mk-c( 3bc8 tokinesis?

  The image shows a micrograph of a cell. 3x4 -d l)ne epgk*u1sa


What explains the appearance of the cell in the micrograph?

  Which statement(s) about homologous chromosomes is/:e)xx)ugm g8s,n 7dk mare 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 individua 8v9**zb4pjkw3 jt z2um-eiiyl with Down syndrome.

Which statement is not correct?

  In the cells of a horse (E. caballus) during prophase I of meiosis Iu x4s utu.1m)z there are 64 chromosomes. What i. mxu ts1zu)u4s the haploid number of chromosomes?

  Which arrow is pointing to a orp (z)xx r3:zh .yl7gchiasma?

  The diagram below represents the struct mw)fry* ouaho9.9vv -ure of a shoot apical meristem. Which row in the table correctly identifies the processes occuring in theuv rwyh)vaomf *o99- . structures labeled in the diagram?

  How does meiosis promh3qhqq9iey/ s) y:zqk+5ub ; kote variation?

  Which of the following stykb* ghcx4+qu+, ;ia8zc pdw5atements 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 1o d9pdxvc v-9produced 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 tumours from primary h(jng3w.nb64jemjg3ftnfa 0f j+) i9 tumours as a result of the movement of 43jbnah(3wjf+j f06fge m.itn n ) jg9cells?

  How many chiasmata are present in the di )y0dm c1fm.mlvix*3rj.)wvm6r 7hk bagram?

  Which statement is a similarity between cytokinesis in animal and plant ceex(ht g -rso7hmd x 10-a5,;bmj5fblllls?

  Which stage of meiosis is matched to 9itpj:t,d unmk6j7qcct.7 y* 7 /mki lthe correct description?

  Which statement(s) are true of :retpp:fy+ihu ;bn6ve )w+; umeiosis 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 meiot8 ty1c22d*bq8fz,uwdtfk 4 b4imo 3ikic division. This results in the formation of one large cell and one small cell. What is the fi w8qdu3zf ,k bbmtd4k 8 21iyfc42ot*ate of the large cell?

  Which row correctly describes diploid and hay,uiszb6k h ;:ploid cells in humans?

  The following table sf8hk k03*bjcj hows the diploid chromosome number of a range of species.


Which of these statements is correct?

  What conclusion can be drawn from the duyv3 qxg/;, nkaryogram below?

  Which of the following processes is characteristic of;7dw* .zm0b4g 5au fg posf4gf the meiotic and not the mit 4pwu4f0bgs5dg mo. f fza7*;gotic cell cycle?

  The diagram represents a xwnz-4s,ap r*bud with a shoot 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 lw.4gcu1n5vhnli; 5/ opa y;n row shows the correcw/oagp .51;;l hl5in y nnv4uct chromosome number for different cell types and cell division stages?.

  At the end of which phase of meiosis I does crossing over occur, and *;ojiq jd(-2)kd(paqzelfy5 what is the outcome of cro5*pe ji f) a; dq(2j(odylkq-zssing over?

  Which of the following statements does not describe a stwerls ch7z-ie/q gil r )tsc7;1/u .u/ep in the sodium-potassium pump cycle in the neuronal.ssu/izr;7lcruhq ) i /l7-ce1e tg/w cells?

  Which row in the table below is trubf jj,ci8t)5svc+q 6ne of meiosis?

Membrane transport is important for allowing particles to move across the cte(u v7pu3m,k- bgj z6ell membrane and respond to changes in the 3bpgtjuzu,(v6 ek 7-mchemical 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 cells. ;( xza 0m 7y02ct5e t7qqoltwo

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 diff6a(qku d g1y6serent cyclins during the cell cycle. Whi6gyu k 1(6dqasch cyclin is involved in preparing for DNA replication?

The diagram below shows chromosomes durt)dolb ( slv:1ing 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 ,17fc d2sul t87,2ql qzn cjkghomologous chromosomes?

  The mitotic index of throat tissues taken from 4 different patientab5-q04crqsb v-9-; k:ecjjmex - j zss is shown beloevj;mqs:0 qerj5 b9--jc s 4zk cx-a-bw. Which patient is most likely to have cancerous throat tissue?

1.Draw a labelled diagram to represent the process of crossing o b 9oc3uls4gd002avns ver.

2.Compare and contrast random orientation and crossing over.

3.Outline the stages of meiosis.

  The image shows an abnorser rtu3 b25(fmal human karyotype.


What is the abnormality in this karyotype and its cause?

The graph below shows the relative amounwk)z ) v-tjrxpf-7r+ nt of DNA in one cell during one complete cell cycle. Each letter represents one stage of the celrz tv--fwrxnj)pk7)+l 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 homozygous8 ayz -d5 wz8hq;wd)px for brown, long hair and 5y;q88xpdh-z wzwda )a female cat that has black, short hair.


Which of the offspring has a recombinant genotype?

1.Outline how polygenic traits can showbih0 +t6f-b, joyb9i0rd1yeq 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)eb.a avocbo5r by 260 the crossing over of non-sister chromatids shown in the diagram beb by.0c o2be)rv5aa6o low?

  The photomicrograph shows a pollen grain from L. candidum (Lily). Whicl5m wv8ba 8y8h qy1:muh stage of meiosis is8hl81yb qy aw:8m5muv shown?

1.Outline the events which would lead k +4jt8a l ,.sz7rgjaqto an individual being born with Down syndrome, which is characterised by ta4.zs,kl q 7jr8taj g+he presence of three copies of chromosome 21.

2.Explain how meiosis increases variation.

3.Outline the stages of meiosis.

The mitotic index is an indirecttkf(w*z2m*a ) p2 u*f.ppbv0m2xbdvl way of measuring plant growth. A study was conducted on white onions (Allium cepa), under controlledl*mbp*v)p2a 2z ( b.2*xufvwd0f mtpk 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 wayssp-wj; , 9 z/qgivu-cv wpr.m) in which cells can divide. The diagrams below show two cells from an organism with a dipl-jmugwr v.- ,c9iw p; vzqps)/oid 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 explfl- s 3nj09j awm)3kiression 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 different47m l5vwc4kzi ; m3rxi stages of meiosis. Which row correctly ikxvmlm4r w735i; c z4names each stage?

  The micrographs show four phases of tnp)z(e:(5hzb w-r(arqyo5( 2 jd qfj meiosis I in a plant. In what order do these (j j2az(qhq5be5f-n y trr)d:pw o(z( phases occur?

Mitochondria are responsible for sj;ob+l s4j)ohq:l2agupplying metabolic 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 eukaryja4q go) l+ j2;bh:lsootic 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 cell cycli1 rt)dck 9q5ze in four samples of lung tissue from four patients. Which tissueqz 5d t9irc1k) has the lowest mitotic index?

  The diagram shows the dominant cyclin/CDK complexes at differwgtd:sg+vuj q/g );vj/w9o8o ent time points in the cell cycle. togv98+ugq)sj /dw:v j ogw/;Which cyclin/CDK complex activates DNA replication machinery?

  Studies have shown that genes such as Cyclin Dependent Kinase 3 (CD3 o he4kwa;8rs5k: dlsKN3) are highly overexprd;a s4eo8 3w:5kkrhsl essed in cervical 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 hhvh )rmcq4w i.(.yd0the cell cycle ?