The graph below shows the relationship between maternal age an::u jb: q3ah,u l+ntuoquw 2-nd the incidence of non-disjunction. What relationship is suggested: :o3:tq ubun uqhn-ljua 2,w+ by the data in the graph?

  Which stage of meiosis is repru5i)a6wh0 u) tuq*zqaesented in the diagram below?

  The diagram below showsz6 5 avcq d-s53dm2wrq 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 all*hffdlnl-8g :jf za-7eles of a single gene which would be present in the nuclefn z-fh7lgf :-dlja*8 us of a cell as a result of each process?

  Which keyword is matched to thek exir / 82e;;ku/ibxl correct definition?

  Which statement(s) about mitosi)uq3j90nqu;svujc(jss xv u63zsw(6 s 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 a cell in a:xh4tfzy-- v 2dcdn9inaphase?

  During which stage of mitosis does thecc crw+,c8 2ix nuclear envelope break down?

  Which one of the following transport )nrpsoziba6b2 p qz+tu61t)c2 :z,x i proteins only carries out active transport? zzpin ,r:1 qb)6ba6izxpout2 )st2 c+

  Which process does not happen in ty69wglnfd-8(c;ltb u he shoot apex?

  Which type/s of membrane transport dk)mxuei kp;0l nou7fby:* 7-go/does not require energy expenditure?
I. Facilitated diffusion
II. Active transport
III. Osmosis

  The diagram below represents qny kld)*0ekyvk) ,7aa cell with a diploid number of 4. Which stage of celyn, lkdv70 aky*kq))e l division is the cell currently undergoing?

  The photomicrograph below shows a root tip meristem. Which oftuwiyc+j/gb,r971 sc d6qn.aq:at3k the following sentences correctly defines a meristem?aq7dst 3q 1w+6/kitbny9:cr .cj, agu

  When does the random orientation of homologous chromosome pairs occur?cq hri s +sbt3a-0xqbyf9wv9 im6c*7+

  Which process does not occurco0bc(6hpdjw w- 6)kyh:s(vh during meiosis?

  If a cell with a diploid number of 36 undergoes mitosis, how many chromosomes wj4herdah, 8/ u: s5zesih4ehz:8 sujders5 a/,ll be present in each daughter cell after cytokinesis?

  The image shows a micrograph of au+g4 ft- oovx2n24fbxi9ry5u bt i8;h cell.


What explains the appearance of the cell in the micrograph?

  Which statement(s) about homologous chromoo gf* +f58z9 5imnc (qdpxfu(ksomes 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 indi*x w .3+ rmnhyk)juro:vidual with Down syndrome.

Which statement is not correct?

  In the cells of a horse (E. caballus) during prophase I of meiosis 9voho 69 v:apgI there are 64 chromosomes. What is the haploid num69o vpv:oah9gber of chromosomes?

  Which arrow is pointing to a 1 -tvc+gayei bov*p24)2vi(r0neesm chiasma?

  The diagram below represents the structure of a shoot apigd9*ny* mh-xi+ 0 w(np 2rjbnzcal meristem. Which row in the table correctly identifies the dwr (znmbp9y nij 0h* g*+2-nxprocesses occuring in the structures labeled in the diagram?

  How does meiosis promote variabdpz*q 6,gw 4 -qyul2rtion?

  Which of the following statements is/are correct for mec27 r8pvpzk gu(r+z9liosis?
I. It is a reduction division
II. It involves random orientation
III. It produces genetically identical cells

  The diagram shows gametes produceag2 0yddb( qr4,kju7 ed 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 tumou+vurf: (cr6ezrs from primary tumours as a v rr+uz:6e(fcresult of the movement of cells?

  How many chiasmata are present in,5u) 9qm*qytr1by gm v the diagram?

  Which statement is a similarity between cytokinesis dl z5pcw+.,m0d dw.ir in animal and plant cells?

  Which stage of meiosis is mh7etn9mf61rerr,8v.+ ke pdji r7n* a atched to the correct description?

  Which statement(s) a tkitcns;.i wq)w:v n:d;u,+ tre 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 t;axskg b3kc40 y). gjvhe first meiotic division. This results in the formation of one gkgx)3b ; j0yvc k4a.slarge cell and one small cell. What is the fate of the large cell?

  Which row correctly describes diploid and haploid cells in hum-+g+nhr (nvxs ans?

  The following table shows the diploid chromosome numbe2 -eiqazby(vy 9nwh69r of a range of species.


Which of these statements is correct?

  What conclusion can be drawn from the karyog.cv 33cs g (5wti.rjjdram below?

  Which of the following processes is characteri mf6xotdpv,9m2 ln5t* stic of the meiotic and not the mitotilmvftp 5 mo txn6*9d,2c cell cycle?

  The diagram represents a byn51 ja x6,ji 2+qxtewg,y3o lud 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 /yekk 4obj 8s/row shows the correct ch sjyeb4 ok/k/8romosome number for different cell types and cell division stages?.

  At the end of which phase of meiosis I doen yb 3c0/v 4acne3a c,a 3jzcuv,xs3.bs crossing over occur, and what is the outcome of crossing oe,.cacz3 cns v,x33a 3cvnua/j4 bby0ver?

  Which of the following statements does not descri6t72 wk2t8 re u,mq pjh-0exvkbe a step in the sodium-potassium pump cytpeqtrh k2728 w-0m jk,ue6 xvcle in the neuronal cells?

  Which row in the table below xz qns :: 4vk. jgvfo+(4mkzx1is true of meiosis?

Membrane transport is impdd.a0,qz8f d zortant for allowing particles to move across the cell membrane and respond to chang,z. fzd8d qa0des 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 cellsf u;7/hp2+e-wu lh1ahzc9 og6 4y yat+ptj+dy.

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 t+o4mltb s( )zk9b4qk cx /u.edhe cell cycle. Which cyclince/ sqb4k9 t+ x) ubmz.o(lk4d is involved in preparing for DNA replication?

The diagram below shows chromo(vwhb( 4qe t4zm,o*by,l w7t dsomes 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 involves the separation of homologous chro*rt 36t2f c3u 0uuaojsmosomes?

  The mitotic index of thro-v 8ofs)iji5 ,l-a cai bksx7(jqh-8t at tissues taken from 4 different patients is shown below. Which patient is most likely to h-bo8fj)x (ij-7i5a ,t vsis lk cqh8a-ave cancerous throat tissue?

1.Draw a labelled diagram to representv q)nkz+ stz6/ n,/ts5emgz*pn-jyp 7 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 ka48tva gknepg+2 lhah-(9cq i ,ryotype.


What is the abnormality in this karyotype and its cause?

The graph below shows the relative amount of DNA in one cell during one complete4fr5r+t ktza hcm 8c24 cell cycle. Each letter represents o f8k+ca4htm54tz rcr2 ne 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 cr*ht5rblshc1j )s /r ) 6tytp9b;/t qeyoss between a male cat that is homozygous for brown, long hair and a female cat th /qr) hyhy1ptlts5b9s je*tr)t6 b;/cat has black, short hair.


Which of the offspring has a recombinant genotype?

1.Outline how polygenicria ( /oogxm,3u11pi :+r seyy 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 ofcotp .s g;n ncgd-l 7-sn+/a2iq7lzi9 non-sister chromatids shown in the diagram beloasqs d/;n7 ilp gint+l7n9z2c-c-g .ow?

  The photomicrograph shows a pollen grain from L. candidum (Lily). Whic ewnr tg j z608 +x ee,2k7nsw:xsga,znmx(j2(h stage of meiosis is shoxtxz(me kn0,j,7 +s2n: gwe(jxswrez6a ng8 2wn?

1.Outline the events which would lead o- shgq52pa5qep)k w( to an individual being born with Down syndrome, which is characterised by the presence ofkoe( qg5p5sp- 2ha)qw three copies of chromosome 21.

2.Explain how meiosis increases variation.

3.Outline the stages of meiosis.

The mitotic index is an indirm vo8 t g94oxcir1a;jvy9sjv wqg/a 567as)d/ect way of measuring plant growth. A study was conducte5s6sivw cav;g )rjd joa497m gxay9/v q o81t/d on white onions (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 ways in which celll8g e9- nhz2ge wo. q3y;s7t ormu7n.ls can divide. The diagrams below show two cells from an organism with a diploid number (2n) of 8.oeo-9tw3me l2h7. g r.gy 8uq; 7nsnlz


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 growthal+k/zj ptgm)z9pob 6q)hx 5 4.

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 sto2wo+*2eotlh ages of meiosis. Which row*e ooo 22t+lhw correctly names each stage?

  The micrographs show four phases of meiosis I in v8fpq iz4uoo q,v7f,28jz1dya plant. In what order do these phases occur?jpq qvzf,u8,i84o7zvod 1f2 y

Mitochondria are responsible for supplying metabolic eh yn7m/rf;oo4 nergy 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 mtDNA found in hybrid cells, which are the result of sexual reproduction between two different yea;y7f 4 rn/omhost 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 nuhqeq 74bhqcwhi4 f6z c65z-p1mber of cells in different stages of the cell cycle in four samples of lung tissue from four patients. Which tissue has the lowes zhq -w6 456qcpe4bzhcqi17hf t mitotic index?

  The diagram shows the dominant cyclil p/-i9*nz .jvbxg g8ln/CDK complexes at different time points in the cell cycle. Which cyclin/CDK complex activates DNA replication 8 /zig j x*vgbn-.p9llmachinery?

  Studies have shown that genes such as Cyclin Dependent Kinase 3 ehzi-x0y)r- y/ b/mbd(CDKN3) are highly )z- y/de xi/ r0ybhmb-overexpressed 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 themth 7+mwp*v5n cell cycle ?