The graph below shows the relationship between maternal age ln+lpkb dx551 and the incidence of non-disjunctiokd15 lbp+5 lxnn. What relationship is suggested by the data in the graph?

  Which stage of meiosis is represented in the diagram bqe6ddh qy84fz;rxf z.9,zdib (r:uq 1elow?

  The diagram below shows chromosomes during mepb:svb v3*: zbiosis.


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 bmx1 s ;ivh83,yquw:jnumber of alleles of a single gene which would be present in the nucleus of a mx3vi1jsh8 ,qby;u:w cell as a result of each process?

  Which keyword is matched to the correctgz p84x *nl;yo definition?

  Which statement(s) about mitosis is/are tr+ 3ym*n pc6uxbue?
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 a cell fd41t b)--ovpnmzl5 m in anaphase?

  During which stage of mi 4 oxtbzi8)jiq f513k0r ls)putosis does the nuclear envelope break down?

  Which one of the following transport proteins only cxg )p/2b yawi/st gz(2arries out active transport?2 a2tp zs(i/gxwybg)/

  Which process does not happ. 2 fgv7v;.a8jfdsjc,/zqxix-c bq3cnmmw )/en in the shoot apex?

  Which type/s of membrane tra kwkasy0*,/ 2,7vcwzqtb:i igt3htv t 6f wn6/nsport do/does 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 stage of cp+f 02iqpy6 sfell division is the cell currently un2f fsy0ip6 +qpdergoing?

  The photomicrograph below s me0d pjn+wwh 51wfy1:hows a root tip meristem. Which of the following sentences correctly defines a mh mywdnep w1+w:jf105eristem?

  When does the random orientation of homologouw9a:94gsddho o5nqv .s chromosome pairs occur?

  Which process does not occur during mei;p sr294xkpr y ysvww:*q8ri+ bo d;w-osis?

  If a cell with a diploid number of 36 undergoes mitosis, how many chromosomui:6kl1)fusw 45 p; amth /rkmes will be present in each daughtem hk ui r t/5l;kawum:p1)fs64r cell after cytokinesis?

  The image shows a micrograph of a cel.t5x/znkz/8 z6, q oqyx(wtxo l.


What explains the appearance of the cell in the micrograph?

  Which statement(s) about homologous chromosomes is/atl:- dr*s hf kpd tutx/(7-ii;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 individual with Down syndrome.jkf6j x pv+o9g wex07.

Which statement is not correct?

  In the cells of a horse (E. caballus) during prophase I ofz .*ibl/4um/mf0 p yfo meiosis I there are 64 chromosomes. What is the haploid number of ff/umo.lm*4 b i yz0p/chromosomes?

  Which arrow is pointing to a chiasmssqt j:+4302fl dch/eez: ae wa?

  The diagram below represents the structure of a shoot apical m.q:,tg gve2kk eristem. Which row in the table correctly ident2:g tq gek,v.kifies the processes occuring in the structures labeled in the diagram?

  How does meiosis promote vxj ju-oua21yki7.e vz)5pi/ojd 96o jariation?

  Which of the following statements is/are correct for meiosp2sh.xyj47 v5mspz3g2 k6 am ;lczm2pis?
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 chromosomes. 1: ecdzexwpg 5 kk8v2)t- igf*


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 primar8 k2rhn xfcj35y tumours as a result of the mo 5chf 8n3k2xrjvement of cells?

  How many chiasmata are present in the diag 65 kcfvtd-8x8g 2db be jao+r11k;uzuram?

  Which statement is a similarity between cytokinesis in animal and plant celbny0 z80cnd.i m u4z6mls?

  Which stage of meiosis is matched to the corrty+lbu 0s dt20ve+wrff./9wpect description?

  Which statement(s) are truegcy f yz/;jk4yd9h m14 of meiosis 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 ana pd3o6 (kt+te oocyte after the first meiotic division. This results in the formationpk+d3 t6o(ae t of one large cell and one small cell. What is the fate of the large cell?

  Which row correctly describes diploid and haploid w8xi6nlw7)o(nvra2t szxk4 9cells in humans?

  The following table shows the diploiphb bu nd1.3g9d chromosome number of a range of species.


Which of these statements is correct?

  What conclusion can be drawn froe/ta-nc:5 ki0. 6/p jpeks krpm the karyogram below?

  Which of the following processes is ch7 q0peclabkl n- 5 h(fa,vr9v1aracteristic of the meiotic and not the mitotic celvq7 ,a9(1v p0l5cr hkab-felnl cycle?

  The diagram represents a bud with a shoot apical mern fi myo7 0n9gqlr+f1+istem.

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 rkt9(ran s-gu0 ow shows the correk-9au(tsnr g 0ct chromosome number for different cell types and cell division stages?.

  At the end of which phase of meiosis I does pd a2w:yj t8gb*9u8 )qhk3wu,w4qmtzcrossing over occur, and what is the outcome of crosm2 8wbt:wz 4 ,pk3gu a)utyhj d8w9q*qsing over?

  Which of the following statements does not describe a step i1tmqlz 5 fb2 a6eyzu0+n the sodium-potassium pump cycle inquz2lz0bm1+ y 6et af5 the neuronal cells?

  Which row in the table below is o ytk be)0nz/q dyq.j7ia +n*.true of meiosis?

Membrane transport is important fhbeafxw,d 08- or allowing particles to move across the cell mehd0axe wb f,-8mbrane and respond to changes 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. l sar1bko.64vm; wrz/

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 co a dur:(n7pni7ncentrations of different cyclins during the cell cycle. Which cyclin is involved in prepiu dpr( n:7a7naring for DNA replication?

The diagram below shows chromosomes duriz27 qzbjz*m+wlr3 eo*ng 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 tq 6cifb+sk3q1o5uw( xhe separation of homologous chromosomes?

  The mitotic index of throat tissues taken72k0n1rrg hsi from 4 different patients is shown below. Which patient is most likely to have cancerous ts72r0gr kni 1hhroat tissue?

1.Draw a labelled diagram to repre2d .e34suv4biln6d4tfxoh (m sent 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 karyotype. .h grygk m2. hxun8* el,9svg2bj /g1b


What is the abnormality in this karyotype and its cause?

The graph below shows the relative amount of DNA in one cell during one complet;9n bhio hcy5a2m61sd3gjhs7e cell cycle. Each letter nh yd27c6h31 io5j;sh sgbm9 arepresents 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 fy0gq:rxa(v u9t,8 zmmale cat that is homozygous for brown, long hair and vfxzur 09t(a:qgm,8y a female cat that has black, short hair.


Which of the offspring has a recombinant genotype?

1.Outline how polygenic tou5*/dp5 hoatraits 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 of non-sis+uu sjvq750ldx 2nnf8ter chromatids shown in the diagju vflx 8d20uqsnn7+5ram below?

  The photomicrograph shows a pollen grain from L. can;tap:j w56h tkdidum (Lily). Which stage of meiosis is shown?h5:ptk 6tjaw ;

1.Outline the events1 jy49o3jxzhl p.cuo. which would lead to an individual being born with Down syndrome, which is1j4o zhx3oc9. . ljupy characterised by the presence of 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 meascomf, n+8gow*kk3n8 suring plant growth. A study was conducted on white oo8 ns*3nkm8gk w+foc,nions (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 waysko1al xom a5tb368zc , in which cells can divide. The diagrams below show two cells from an 685c,ob1xla3ktz moa 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 expre+jj 9my. n(gec (knn8gssion 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 sr 5,/wh+tiu q:gwin5 ohow a cell, with a diploid number of 8, in different stages of meiosis. Which row correctly names each stage? q:go5hn,w+5/ r iituw

  The micrographs show four phases of meiosis I in a plant. In what ordevuwx6m 27gmy3+0 wtcur do thesev7ytxw3 2 wm+ uug6c0m phases occur?

Mitochondria are resp 6triaay- ,9bionsible for 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 suggested that, in some eukaryotic organisms, inheritance patterns of mtD6r ay,btiai9 -NA 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 difazusc t(fz+b3mm k1j*(*po+nferent stages of the cell cycle in four samples o*ktz jz uf1* ( mcp++3sbaomn(f lung tissue from four patients. Which tissue has the lowest mitotic index?

  The diagram shows the dominant cyclin/Cn1x/f lc zwhguk1 .d+uvl4+9m DK complexes at different time points in the cell91dnl 1zw4ufkm +x cl.hvu+/g cycle. Which cyclin/CDK complex activates DNA replication machinery?

  Studies have shown that genes such as Cyclin Dependent Kinase 3 (CDKN3) areqh9zxc3t3bal0qv f ; ee0-h o9 highly overet9;q9qb0azee h l3 30oxhcv -fxpressed 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 )d nfht*)( szkvow+t1 E the highest during the cell cycle ?