The graph below shows the relationship between maternal age and t:c na0a:y+ aj02x azi2iuw ne;he incidence of non-disjunction. Whnaicw:i 0aj;20 2e y:x+uazan at relationship is suggested by the data in the graph?

  Which stage of meiosis is va3o/quvm/ m*w(5xdw represented in the diagram below?

  The diagram below shows chromosomes duriz exuf.lu*qiyi9v 2-.ng 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 tyhz -/-ld 2mvm.-jqas he number of alleles of a single gene which would be azh.jl-q2 dv /-y-ms mpresent in the nucleus of a cell as a result of each process?

  Which keyword is matched to the correct definitior:guyr y b68tur+/)l sn?

  Which statement(s) aboutzea1 nud zg+(g/q,h*m /wwg u, mitosis 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 awp p9f /,ptrcs5v*b 3e r3aiert;m0r2 cell in anaphase?

  During which stage of mitosis does the nuclhtll -3 u6quf1ri-c) lear envelope break down?

  Which one of the following transport proteins only carries out active transpor nwfy(-(rr3 )plctm+: pyekt6t?-mr 6t r(ty p ce3)+wply(kf:n

  Which process does not happel. ( /5nzk*d my5 ;pt 1sxofunb.efzu*n in the shoot apex?

  Which type/s of membrane transport do/does not req1v dewf(u96e9kpb6wauire energy expenditure?
I. Facilitated diffusion
II. Active transport
III. Osmosis

  The diagram below represenhtnn 7 ejiolbs/4 gel8n/*, m4ts a cell with a diploid number of 4. Which stage of cell division is the cell currently undegjh8 otlbn,nl/i*/s4mn74e e rgoing?

  The photomicrograph below shows a root tip meristem. a6h/o;vxib7x Which of the following sentences correctl;iv/x7 xobh6 ay defines a meristem?

  When does the random orientation of homologous chromosome pairs .-t2njnp/rk,nqbfb .8omkq -0 cx0w ooccur?

  Which process does not occ,bkzg 9/ 2ypif4p wwu9ur during meiosis?

  If a cell with a diploid nqd 9d/7kz1wja umber of 36 undergoes mitosis, how many chromosomes will be present in each daughter cell after cytokin dkzw9da1q /7jesis?

  The image shows a micrograph of a cell. l9u;yctg3au1


What explains the appearance of the cell in the micrograph?

  Which statement(s) about h.os rfy 16iqal rj-r(9omologous 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 individuawe 6gpm9h4kg on ,h+0al with Down syndrome.

Which statement is not correct?

  In the cells of a horse (E.nm y9u0h 1g78cui;rabjhy/05se bw 2f caballus) during prophase I of meiosis I there are 64 chromosomes. What is the haploid number of hgshfn25 a8 rub1 em0icyy;bwuj709 /chromosomes?

  Which arrow is pointing jkd h r9h+59 c,) w7b/ gs*maabmhe;onto a chiasma?

  The diagram below represents the structure of a shoot apical meristem.7qq ,zde 5l8z4ohp5ns4v+jxx Which row in the table d8 nh4esz5xpxv4,q 5 z7+oql jcorrectly identifies the processes occuring in the structures labeled in the diagram?

  How does meiosis promsyjv ay:f4v0v*n/3vic.pn * kote variation?

  Which of the following statements is/are correct ansee,hc t4(w;tvl0xf-49 fn 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 xh03ti 3l gzh.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:.xuuv;n e mt. the formation of secondary tumours from primary tumours as a result of the movement of cells?v;u nt..mxeu :

  How many chiasmata are present in th)a5pizh/ 2bp g 1z(adfe diagram?

  Which statement is a similarity between cytokinesis ing6pk72hx8idu +ik r .pio( yfpv96z:s animal and plant cells?

  Which stage of meiosis is matched to the c ny-oqe/j 55aaorrect description?

  Which statement(s) are true of meiosis I but not me9gl-bnl3 crfvu0c1b 3 iosis 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 division5 b3zc9 7g/sn yzmc0ryyt6b+n. This results in the formation of one large cell and one small cellr0+nbyzt n bgz39c6m/c5y7 sy. What is the fate of the large cell?

  Which row correctly describes diploid and haploid cells in humans?a,1o ;gmdyu+pf;qsiiov 29u8

  The following table shows the di:.) zlz1*xbe83 u6v (zj1 )9zddnvnpdilf g fxploid chromosome number of a range of species.


Which of these statements is correct?

  What conclusion can be drawnxa7ui )/kaj + cmbk3gkv(/x .m from the karyogram below?

  Which of the following ;wv kv;kh1 /kfprocesses is characteristic of the meiotic and not the mitotic cellw1kk vk/;;f vh cycle?

  The diagram represents a bud wi7i4(bpd7p1rm*) bhql(hw fqoth 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 c8+ynhl4sh e 6ahimpanzee (Pan troglodytes) is 48. Which row shows the correct chromosome number for different cell types s86n+e4h ahyl and cell division stages?.

  At the end of which phase of meiosis I does crossing over occur, and what is t8g8b ,pn*fib 8zwn,sohe outcome of crossing oveisz,8bn g8 *fw n8po,br?

  Which of the following statements does not deybz,m z*u;c4o5 7awy 2/kxhkvscribe a step in the sodium-potassium pump cycle in the neuronaky o ;yhb4z u7,52*zkw/a cmvxl cells?

  Which row in the table below is truez+:ktjx l78 5oe)m kzk of meiosis?

Membrane transport is imporo7fj u7m2v yx.jkkfm(x 0m( o4tant for allowing particles to move across the cell membrane and respond to chang0u(7 kmojfm4x (x fk.y7jmov2es 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 cells. qg;r 8x0rad0)hhlw5n oj glb.)dut11

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 concentb+ 6ih(ra 4adfrations of different cyclins during the cell cycle. Which cyclin is involved in preparing for DNA replicr(aif4a+ d6bh ation?

The diagram below shows chromosomes during meiosisltt*bme) js7 )e,+kz w.

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 ykwuli -eq9 52of homologous chromosomes?

  The mitotic index of throat tissues taken from 4 different patixx9zv ,sp 0*xpents is shown below. Which pati v9* psxzp0,xxent is most likely to have cancerous throat tissue?

1.Draw a labelled diagram to represent the process+zft j/f 5gkju*-7uxv d5slw; of crossing over.

2.Compare and contrast random orientation and crossing over.

3.Outline the stages of meiosis.

  The image shows an a: bmw.iq5f1n c-f 2raobnormal human karyotype.


What is the abnormality in this karyotype and its cause?

The graph below shows the relative amount of DNA in one cell l6: wibs(mn2dt+zc5e during one complete cell cycle. Each letter represente 5ztbl mwn+c(:si26ds 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 hovky)m fq+ f:2d* wxr2emozygous for brown, long xwevmqy+f*2d:f ) k2r hair and a female cat that has black, short hair.


Which of the offspring has a recombinant genotype?

1.Outline how polygenic traiou msu fnk19.e187ie gt1 d*sbq f6)ants can show 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 oq ) 3*tp;e1bf7bfwj(1sw6 x yr j) /hrw3phrnff non-sister chromatids shown in the diagraj ) fp b 3b; twq*1rehrwjf)f61ryh7n/wp(x3s m below?

  The photomicrograph shows a pollen grai3ck 0ot6y ),kjsjmwk0w5.ez 1pqsa vp). n-rfn from L. candidum (Lily). Which stage of meiosis is show .a 0ns mrkfps5,c-ew)1o)pj.v 0q3zjytkkw 6n?

1.Outline the events which would lead tov7-mj4,zide nz-szfj3v .w4s an individual being born with Down syndrome, which is characterised by the presence of three copies of chromosome 21 zfs7-en44- vsmz3wv.ijdz ,j.

2.Explain how meiosis increases variation.

3.Outline the stages of meiosis.

The mitotic index is an indirect way of measuring u/acq(,h z: xiplant growth. 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 ofx zhqu/c :(ia, 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 wj,f ) (-gcyc rvyqsy:,ays in which cells can divide. The diagrams below show two cells from gyyv,(f)jcrq,sc-: y 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 eomll/aabrx:*khj+z 3-r ,8rxxpression 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 4 xfg 7m. fhiyxgw/*,xxb-m6g cell, with a diploid number of 8, in different stages of meiosis. Which row correctlixfmywh4.g,m x x g6/f- bgx7*y names each stage?

  The micrographs show four phasjm)5hq+ p d*jies of meiosis I in a plant. In what order do these phases oj5m) qhpd+ ij*ccur?

Mitochondria are responsible fo1fnwbk 5t q7zk:d5(nt k4ppc 3 cu69ifr supplying 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 t6qndbnk c(u7tc 15p5 : pwf3f4zk9iksuggested 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 stage+vc( egze cdj(agapq ((+c/q-s of the cell cycle in four samples of lung tissue from four patients. Which tissue has the lowest a z q(c (jeqadgc-v((pc /+g+emitotic index?

  The diagram shows the dominant cyclin/CDK complexes at differentt trh9j 6u6l giuvkz cm8c.+(/ time points in the cell cycle. Wk(. ic/lm9 c z8t+tu jghvu6r6hich cyclin/CDK complex activates DNA replication machinery?

  Studies have shown that genes such as Cyclin Dependeqfl yd1nvruionzeg w4n2 /,) + i/7zl7nt Kinase 3 (CDKN3) are highly overexpressed in cervical tumo)7 unz7qoeir2/g zny v +1il4n,wl fd/urs.


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 duri+0 pwwa87wkcd ng the cell cycle ?