The graph below shows the relationship between maternal age and the incidence o(9kfytu : 0( .7sabmucqccbf: f non-disjunction. What relationship is suggested by the d(fcqaky97 :ct( cb:umu.fb0s ata in the graph?

  Which stage of meiosis is2 ml74 1jnzwox represented in the diagram below?

  The diagram below shows chromosomes during meiosisj9 -efbru7 +fpvhve04.


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 singlegq jv(am rv3+l ra563s gene which would be present in the nucleus of a cell as a result of eavsvql( j3gm+3ra 65 rach process?

  Which keyword is matched to the34,wv la)m c/8e yqurs correct definition?

  Which statement(s) about mkps0. mucb;i:hcq0 +a q e7*y wlk4xz6itosis 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 letn6rz a:yjt7zs g,e)o*ter points to a cell in anaphase?

  During which stage of mitosis does the nnr) v bm:w69l:lx7 tcvuclear envelope break down?

  Which one of the folr ur *3b:mszj*lowing transport proteins only carries out active transport? brs:m*jr*3 uz

  Which process does not happen in the shoot apn-zrfvt (fhl7l /e*-6y9mxfi ex?

  Which type/s of membrane transport do/g;t2ismbs7eof 2tbvvp3(u-uh)p5.zdoes not require energy expenditure?
I. Facilitated diffusion
II. Active transport
III. Osmosis

  The diagram below represents a cell with a diploid number o3 +ma uc:jsun9f 4. Which stage of cell div j:csuu+an3m9 ision is the cell currently undergoing?

  The photomicrograph below shows a root tip meriste*wk/h 5vzdne;k4 )pv am. Which of the following sentk)ezvdan4khwv5p ;*/ ences correctly defines a meristem?

  When does the random orientation of homologous chromosome pairs ol 3 z8,(7 znqrre;.ovxhu7mqp1wd-t dccur?

  Which process does not occur durin .srh-/;.vu5 fmdi nox 8iuei+g meiosis?

  If a cell with a diploid number of 36 undergoes mitosis, how many chromosoqf.e)5e v7kiymes will be preseve)k5e fiy.7qnt in each daughter cell after cytokinesis?

  The image shows a midx d+ 5aff4v*pcrograph of a cell.


What explains the appearance of the cell in the micrograph?

  Which statement(s) about homologous chromosomes is9f 8iqh/u 2isj8syz :e3mrit1/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 Down syndro0w, i5jqi p:rij:5egp(1md leme.

Which statement is not correct?

  In the cells of a horse (E. caballus) during prophase I of v02kibi6* dan o)*crx meiosis I there are 64 chromosomes. What is the haploid number of chromosomes?o 0ck6*brdiiva* n 2x)

  Which arrow is pointing to a chiasma?l)cnwt,oy6 k)vo n/l- hodam5;v r(8t

  The diagram below represents the structure of a shoot apical mr6iw4z2 2ui jueristem. Which row in theiuj6izw2u r2 4 table correctly identifies the processes occuring in the structures labeled in the diagram?

  How does meiosis promy6 euewzb eq7: 88pmo/ote variation?

  Which of the following statements is/are corrbczsonc g 9;28ect for meiosis?
I. It is a reduction division
II. It involves random orientation
III. It produces genetically identical cells

  The diagram shows gametes producev0 unr)l1 mucgegrv3c(*lz-:.su q z5d 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 tumoursyf(( qs+zw0 bj as a result o0wybjfz( (+qs f the movement of cells?

  How many chiasmata are present in the diagr*w;r0bz9bnqxv*in+eenc5 sv:x* - wl o o,u0j am?

  Which statement is a similarity between cytokinesis j,cgjr6 2z43or i/gqyin animal and plant cells?

  Which stage of meiosis is matched to v97xzvwws8l ) the correct description?

  Which statement(s) are true of meiosis I but not meioszr k+- 9hd-gwqis 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 o8 e1m0 3ar 2-mjwc0a:vgdskuan oocyte after the first meiotic division. This results in the formation of one ovs e3cmw ga0ju 8da210m :rk-large cell and one small cell. What is the fate of the large cell?

  Which row correctly desy d6:)f i73aio-vs,pn kv7xrocribes diploid and haploid cells in humans?

  The following table shows the diploid chromos0dycw hl3 -9mhju 5ms*ome number of a range of species.


Which of these statements is correct?

  What conclusion can be drawn from the karyog7j1wxwhom:en : p7w hj: ydv04ram below?

  Which of the following o(g)kg af ,v,exdrjlo 39f.p4processes is characteristic of the meiotic and not the mitotic cell cg l3r. gj),pod k (ef4,xfavo9ycle?

  The diagram represents a bud with a shoot apical meristemk59bdm8mq)8rwcn c ,h.

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 troglodytl6bvry l-n w+jpy8: pkh,.aa0es) is 48. Which row shows the co 8 p-jwly:hy+bnpa 6lv,.0kra rrect chromosome number for different cell types and cell division stages?.

  At the end of which phase of meiosis I does crossing ovehvn6 by (6x7p2bff2ey9e t1jwr occur, and what is the outchff6t ne17y(y 2jpb2v6 x9 ebwome of crossing over?

  Which of the following statements does not describe a step in the sodium-pota 5wynkix ;gq;7vzl-9e ssium pump cycle in the n-yg7v 5;ewxn9zk q il;euronal cells?

  Which row in the table below is tr u0qzm 8(o*ysw;(wquvue of meiosis?

Membrane transport is important for allowing particq tv7 +mvt0bsd9orkv /iaa0.r0m cu +8les to move across the cell membrane and respond to c+ u +rv0a rvcbmq9t00 78dasi.ovt /kmhanges 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 in1+ m kg-qvz;cnfiwi:w 45ea7 n 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 concentrations of different cyclins during the cell r7t5p(n;l(slp g5mmsxo w m/+n jc;g- cycle. Which cyclin is involved in preparing for DNA replics;(p n5ljnmxpst(o-grm 7w ; clgm5+/ation?

The diagram below shows chromosomes during meiosis. ycu2mwb.t5 (7x8y mmw

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 chromosomes?hueibx3kp.x* p89 f8c

  The mitotic index of throat tissues takenc28p- rzms 66yd ,toug from 4 different patients is shown below. Whicm6o, 2y6drps -zctg 8uh patient is most likely to have cancerous throat tissue?

1.Draw a labelled diagram to represent the prr38gy +s8eujs r)6gh2 bh+cnzocess of crossing over.

2.Compare and contrast random orientation and crossing over.

3.Outline the stages of meiosis.

  The image shows an abnormau bpqy wi3z).vtt)(x+l human karyotype.


What is the abnormality in this karyotype and its cause?

The graph below shows the relative amount of DNA in one cell during oneta ,eo;vc*51mif7z/ 2yrbylo complete cell cycle. Each letter represents one stage of the c7 /ocflmoi1byayz t*5 ,v2e;rell 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 cwb4j8jq 7er+* d b9oydatp,f3 at that is homozygous for brown, l q9+y3epfbd bj*, rwo4t87dajong hair and a female cat that has black, short hair.


Which of the offspring has a recombinant genotype?

1.Outline how polygeniwvmqq+qn5rd9n m-p, 1l-p-s rc traits 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 kh k lvx:-yl85fq-0mfvo0sr6 of non-sister chromatids shown in the diagram bv6l-kh okr05xfs q - vyfm0l:8elow?

  The photomicrograph shows a pollen grain j(m4 /s8 la+klxe wm8p+ckbi: from L. candidum (Lily). Which stage of meiosis is b48la+( mm/kc8 lsijxw+ek :pshown?

1.Outline the events which would lead to an individual being born wit oof/ufb(e1 p9h Down syndrome, which is characterised by the presenc9 (o /pboufef1e of three copies of chromosome 21.

2.Explain how meiosis increases variation.

3.Outline the stages of meiosis.

The mitotic index is an indirect wpvi3 d m4jwfsfg.7 .0i57 yfeway of measuring plant growth. A study was conducted on white onions (Allium cepa), under controllew.0 jg77w.fyd5 4pvmiesif3 fd 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 beloh jen bpdg0q) h;h1q7)w show two cells from an organism wit; gjehd7q0))nhbp1q hh 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 stem grkrupc8 fz5v35owth.

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 ceh kbha))9q (fill, with a diploid number of 8, in different stages of meiosis. Which row correctq khfiba)h9) (ly names each stage?

  The micrographs show four phases of meiosi7-;msdh pgbags xs6gp b(68r qv12h-z; u1zyus I in a plant. In what order do these phases occu hg-x2sgbubav;s6qzpz g -17pdr(u 18 ysh; m6r?

Mitochondria are responsibl uag u6js, w+*onb+9mce for supplying metabolic energy in eukaryotic cells. In most eukaryotes, which reproduce by sexual reproduction, mitochondrial DNA (mtDNA) is inherited from omn*, ja+uc g9w uo6+sbnly 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 iy u4,suxsmg,ou:hi8hc3 j6om7 b 5a6u n different stages of the cell cycle in fou3aos4:,u uxmhbg87u65hy jm6 ,csiu or samples of lung tissue from four patients. Which tissue has the lowest mitotic index?

  The diagram shows the dominant cyclin/CDK complexes at different ti,7 0mwpi5epqnu8idy 6xmi ; w:me points in the cell cycle. Which cyclin/CDK complex activates DNA replication machinery?w ne ixmdupiiy5m70;,:8wp6q

  Studies have shown that genes such as Cyclin Dependent Ki4u7sf ic-gg 4;hxv 9mvnase 3 (CDKN3) are highly overexf4u; 4-vcimggs 79 hvxpressed 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 ce5ea zmvu.;.u(/gmht yclin E the highest during the cell cycle ?