The graph below shows the rep,,h5o*2df q*/xaqpgs;d zbhlationship between maternal age and the incidence of non-disjunction. What relationship is suggested **dz;fs p,hhx25q/,d pq bogaby the data in the graph?

  Which stage of meiosis is represented in th.d:vqx1 - n91bkdunz muaj8m :e diagram below?

  The diagram below sh:ywd- .kfhw zj h5wpq1 yo *)qj vzfyx*b)e02*ows chromosomes during 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 the number of alleles of a single gene /-roip3egq9*j jtym *which would be present in the nucleus of a cell aey-p *og*m jrt/9q3ijs a result of each process?

  Which keyword is matched to the c puwl -9b8kc./dv9 f)e hh(bkforrect definition?

  Which statement(s) about mitosis is/are trueuqjn 3 y ,u(tlbuj 1l(zbc*a6;?
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, whjpk4jb p(u)s kgl:87:dwv k7l ich letter points to a cell in anaphase?

  During which stage of mitosis does the mt6u v(i3sn09 xu yv(*ru 5lqunuclear envelope break down?

  Which one of the following trju -hea4pv: 8qansport proteins only carries out active transport?eq:pj8u -ah4v

  Which process does not happen 9 he*s)d 9 9t4nnzzx9z:sesii in the shoot apex?

  Which type/s of membrane trirbv6 ,u6gs )lansport do/does not require energy expenditure?
I. Facilitated diffusion
II. Active transport
III. Osmosis

  The diagram below represents a cell with a diploid n w+c j59f/+75ky9bc:elwhehf uj -v enumber of 4. Which stage of cell division is the cell currently underg :/l97uhw5y5cnb+e9ecfk vejhj+- w foing?

  The photomicrograph belowv curv l5b1 /eez:,7u+tmdym5 shows a root tip meristem. Which of the following sentences correctly define5myvduu5 t : v/rem7l+z,b c1es a meristem?

  When does the random orientation of homor xy(r g+wy1p7logous chromosome pairs occur?

  Which process does no;+q vs8ut/os8qhq2*;nb f nc gt occur during meiosis?

  If a cell with a diploid number of 36 undergoe(nw8j):xlsi1xz wa; h 9p bw7ms mitosis, how many chromosomes will be present in each daughter cell afzj h x(1 xlbpsa:;wwn79mw)i8ter cytokinesis?

  The image shows a microx 6a,y8( +j u sxymllmjs)pu(,bk)u0fgraph of a cell.


What explains the appearance of the cell in the micrograph?

  Which statement(s) ax1g-ot4f pv2jb qkuz-rt: 0e: bout homologous 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 individual wt6bl/vk (o0 cuith Down syndrome.

Which statement is not correct?

  In the cells of a horse (/wd6hh)1v gq-jfavpvlp:mma s: .09a E. caballus) during prophase I of meiosis I there are 64 chromosomes. What is the haplo0v.p :w1/-jas m: phfhaagd 9ql)6mvvid number of chromosomes?

  Which arrow is pointing to a chi/ nqy.s-.yed8l e( dlqasma?

  The diagram below represents the structure of a shood(fkf odo +o 2 ,mba:mm27cj9et apical meristem. Which row in the table correctly identifies the processesm2c d (7efo9jmdo: 2+ kbmao,f occuring in the structures labeled in the diagram?

  How does meiosis promote varifaj 1f 7+6evw)nchn,9-f bhftation?

  Which of the following statements-mp72d4/q srokr6.id8znkr x ;vc1wn 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 chro: b91mpqkun3c,i1 o/apfu8rxmosomes.


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 vjgn9oc xzvjm6p:z66tf l ,5nln4 l- .the formation of secondary tumours from primary tumours as a result of t,pvnlovzg czx .n- lmt j6649f6:n5jl he movement of cells?

  How many chiasmata are present in the di tecrx 7):3qfit+ bh-fagram?

  Which statement is a similarity between cytokinesis in anizv6v9eh c i ecfb6;yq2k/ i,+zmal and plant cells?

  Which stage of meiosiqt/k8l9neyx 4)u3)py vm 9 aag+qz(ois is matched to the correct description?

  Which statement(s) are iue1mi-* oh e3 mjm1k+true 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 an oocyte after the first meiotic divmznrqz*d,0 a7u :qq1kision. This results in the formation of one l a,dm :n1zqrq7qkz*0uarge cell and one small cell. What is the fate of the large cell?

  Which row correctly describes diploid and haploid cells i/ l8zlygrx(u/eodi (:n humans?

  The following table shows thet omgp +3nx1vux-;p-w diploid chromosome number of a range of species.


Which of these statements is correct?

  What conclusion can bju:ej62ang o: )+hu4h 2iu 2iw spjq7qe drawn from the karyogram below?

  Which of the following processes is characteristic of the meioticyf,vr w qch.0( and not the mitotic rqfy. v(,hc0w cell cycle?

  The diagram represent 3tgtkx88h .nd746 -f asvoqbis a 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. 0wmw pm9ymh9( kp6( czWhich row shows the correct chromosome number for different cell types and cell division sw kw9mym c0(9m z6p(phtages?.

  At the end of which phase of meiosis I does crossyvg0sq3bx:r .mzc4od/bp .6jing over occur, and what is the outcome of cross.o/s3 x bp cjzq4rm6vb.g0:y ding over?

  Which of the following statements does not describe a st/urkl/q l ,bh8m h.9qpep in the sodium-potassium pump cycle in the neuronal cmrh/lb8plq./9 k h, uqells?

  Which row in the table below7 7a-24vssq(cb2x +fngt wc y:,uj1 u2geqkzs is true of meiosis?

Membrane transport is important for allowing particles to move across the-rdl+ ypkt 6;bro/0zr uwaxq;d7z++o, fl7jr cell membrane and respond to changes in the chemical composition o +;dlru-qwr77btjor,/da z ;l rkp 0x+y6f+zof 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+bf e;nf:t ;wdh3eyu+ted 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 shows the concentrations of different cyclins during the cell pu1qm+t 8:bxkfemq27 cycle. Which cyclib1:qq7k2uemx+fm t 8 pn is involved in preparing for DNA replication?

The diagram below shows chroaaekkpe316+z1a4z.9m j* hl v dmz c1omosomes during 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 involvw2vl digrz:-ycc 2.b 3es the separation of homologous chromosomes?

  The mitotic index of throat ti6jx/; jk0z8b kri ofye4od+4bssues taken from 4 different patients is shown below. Which patient is most likely4;jbb yrj ok i+d/84 xkoze06f to have cancerous throat tissue?

1.Draw a labelled diagepm 8( f1mkkh3ram to 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 karyotyphchixpf: ,6 wm92li1 ye.


What is the abnormality in this karyotype and its cause?

The graph below shows the relative amouks zv44.em /hent of DNA in one cell during one complete cell cycle. Each letter represe4.esh kzm/v e4nts 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 alapfo/ gdd*/glza 77 9 cross between a male cat that is homozygous for brown, long hair and a female *d g lfl/a77dpgzo/9acat that has black, short hair.


Which of the offspring has a recombinant genotype?

1.Outline how polygenv4.ev v8 msb2k3t1vpi ic 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 of non-sister chromo zmb2i8d ,+ )*wfdzxaf ph7u6atids shown in t28a,fozf*iw x6md+ud pzbh ) 7he diagram below?

  The photomicrograph shows a pollen grain from L.*pq4x- y wlqjgl4ntr )1md ):e candidum (Lily). Which stage of meiosis is show*lxj :wp )qrtmng4lq41edy )-n?

1.Outline the events which would lead u; c;g5zb kg uh2-kbn5to an individual being born with Down syndrome, which is characterised by the presence of threebunc- k;b 25;5khguz g copies of chromosome 21.

2.Explain how meiosis increases variation.

3.Outline the stages of meiosis.

The mitotic index is an i; fw g.r0:5vhonqwu/np a r,l6ndirect way of measuring plant growth. A study was conducted on white onions (Allium cepa), under controlled conditions in rn506gp / o:l;nuah.q,wfr wv 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 dip8q4; kwt l:bfvide. The diagrams below show two cells b;kqf p8l:4twfrom 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 in am 0y cp-po;b6 m*mf7zstem 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 different sta yh varr1qwi6512d.3s vmx(8 y7x 1sow7 larciges of meiosis. Which row 1xri6xh a3q1c.riro(v5w7 71 m yys2vl wads8correctly names each stage?

  The micrographs show four phases of meiosis I in a plant.mrhlng l-o7-.h b)/wy In what order do these phases hmro)w h ygl.- -/nbl7occur?

Mitochondria are responsible for supplying metabolic energy i aoi)h 9ch cnsd:kt,ap00 w+4pn 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 mtDNA found in hybrid cells, which are the result of sexual reproduction between two different yeast species, could be influenced by the parent’,00p4 kow:c9tphhs iac+ad)ns 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 *; ,o1tscr x ckeby/a6cell cycle in four samples of lung tissue from four patients. Which tissue has the o ba6k,e*c 1 xytrc/;slowest mitotic index?

  The diagram shows the dominant cyclin/CDK complexes at different time point- zlf pqm40uiw-s 1cq: g45jhks in the cell cycle. Which cyclin/CDK complex activates DNA replication machine 4mkf-js-0q1 g4hlc :qpwu5 izry?

  Studies have shown that genes su7f9- ixn 0jwiycc4l) g( ef/oech as Cyclin Dependent Kinase 3 (CDKN3) are highly overexpressed in cervical tumours0 ii9fng)4fc(o l /j wxcy7-ee.


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 duringezw0fo jhw(rokg, e)h0** -vr the cell cycle ?