The graph below shows the relationship b2,ka7awwqgff cl h(2, etween maternal age and the incidence of non-disjunction. What w7lhfckafa g2,(2,q wrelationship is suggested by the data in the graph?

  Which stage of meiosis is represented in the dii f,9.. v ka3cscln2vud a(oj2agram below?

  The diagram below shows chromosomes during rmq7iul-w+n/ 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 nug1y meq,-n,iil7lw*yh5 elg /mber of alleles of a single gene which would be present in the nucleus of a cell as a lmyge, *7e,i5lnqi1l/-gyh w result of each process?

  Which keyword is matched to the correcx r2b7pgocs;c +4,iyet definition?

  Which statement(s) about mitosis is/are truqe2db (6ws5w8fpi 0w ze?
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 anaphase?:sb; jyc*e wh6

  During which stage of m2pl f820upkxditosis does the nuclear envelope break down?

  Which one of the following transport proteins only carries out achs brk0x p0iu5 koqnx+((ex8, tive transport?pur5 xnqhxe x,0( s08 ki+(bok

  Which process does not happen in the shoot ap plzg:6g ;(xowex?

  Which type/s of membrasjihh (6-d c2uy4*vlv2)g sa vne transport 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 stagm7*t((w i9qdig forx/ e of cell division is the cell currently undergoi(ti(* mxrwoi7q 9fd/g ng?

  The photomicrograph below shows a wnd grbl4s0:k73vpf. root tip meristem. Which of the following sentences correctly defines a meristksdgw4 nr37fp: .b0 lvem?

  When does the random orientation of homologous 5izjfp,yuzm0 3j1) nrchromosome pairs occur?

  Which process does not occux8)/kmukuy n;5n g2ihu 1vr ;fr during meiosis?

  If a cell with a diploid number of 36 undergoes mitosi;jhfcn .uwo eu+oi y(u.hy/ 2b h7m(i+s, how many chromosomes will be present in e. + ibch(y+f;w e(2jhnuiy./moh7uu oach daughter cell after cytokinesis?

  The image shows a microg vh lyc9t:r (vf5 7gs0adc9ef2raph of a cell.


What explains the appearance of the cell in the micrograph?

  Which statement(s) about homologoog s:faj9nha1y/ 4eum cesn1b 3) ot.(us 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 with Down joe khpv8iy5h 1n */puevu 0d1c*-vi;syndrome.

Which statement is not correct?

  In the cells of a horse (E. cab91mqrt5 pbop; wnw4 x5allus) during prophase I of meiosis I there are 64 chq94 ; owbwm5 xntp15prromosomes. What is the haploid number of chromosomes?

  Which arrow is pointing to ;+ fbp ltz6/hma chiasma?

  The diagram below represents the 8eey.j ( ha,dustructure of a shoot apical meristem. Which row in the table correctly identifies the processes occuring in t ej .huy8a,(edhe structures labeled in the diagram?

  How does meiosis promotc8,fx2g(s* r)fgf. sldr q j9ke variation?

  Which of the following statements is/are corr3 n)d0bs v,ms bd, twjn b8e/c*9*sbloect 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 e -o h;rr0 v25h6p1 m3bv+epmkh4fuvichromosomes.


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 /u*cg +nhj 1av *9k*j)r sfzogdb1v,dsecondary tumours from primary tumours as a result of the movement of c1*1v)c*g*vjz srdb/dj ugkf+,anh9 oells?

  How many chiasmata are present in the diagramrgxn1dc 4;5fc?

  Which statement is a similarity between cytokinesis in animal and plant c e5n ;dmpx2u8dells?

  Which stage of meiosis is matched to the corr7kvl cpt2 9d5sect description?

  Which statement(s) are true of meiosis I but not meisdn f l+yow(;+sxa n3g,3x 2tgosis 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 division0vz0 maw+x; xs. This results in the formation of one large cmw;zx0vx a0+s ell and one small cell. What is the fate of the large cell?

  Which row correctly describes diploid and haploid cells in humans?25cd xs0*q;o +ci 6)q)bfymx sj64v. splits g

  The following table )ivxv/qu gk:8 shows the diploid chromosome number of a range of species.


Which of these statements is correct?

  What conclusion can be drawn from the karyogram 7p:hx8 k lh,qeq3sua; below?

  Which of the following processes utcasj*pg* w//lqan7lb, +b0* eoe(k azn64qis characteristic of the meiotic and not the mitotic cell cycl,ea/cn6 * lk qj p tqs70ban4zew(ab**g u+/ole?

  The diagram represents a bud h-d/lkn.o u2l 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 trogjwvundw ,w1.1eu .oe ft m7s()lodytes) is 48. Which row shows the .st.n (m1, we1jeuw7)f wduovcorrect chromosome number for different cell types and cell division stages?.

  At the end of which phase of meiosis I does crossing over occur, andz*0n/h.wegj9 ggad ;e8o dh;f what is the outh.d8d e; 0*wzh jg;/ofagge9 ncome of crossing over?

  Which of the following statements does not describe a step in the sodiu2,ddx lid:ruc:/n4)a tqdunby: i9 x,61aainm-potassit:i xc u,u,ldi n1)d9d x: aqbd4anya 6n:/ri2um pump cycle in the neuronal cells?

  Which row in the table below 34sgbvfzodr) (a iy)5is true of meiosis?

Membrane transport is important for allowing particles to move across the ce894)s axsng)2j qwvu ,tzig lbd9o/ 3zll membrane and respond to changes in the chemical composa9w jtz3v4li gqsd 8))zsn bu, /2xgo9ition 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 cek8qm;v4 3uaho lls.

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 7 pcxncr/ 2w ;soe(l3zduring the cell cycle. Which cyclizr/;ocew7pl snc2 (x3n is involved in preparing for DNA replication?

The diagram below shows chromosomes during meios 2bd sw:1kxvu9is.

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 meiosiww-.ihaw:hgk.xovv r h70ox pa ..26m s involves the separation of homologous chromosomes?

  The mitotic index of throat tissues taken from 4 different rhz3dsa )fklh0 n4l5/ patients is shown below. Whiclr5z n)s hl /3ad04hfkh patient is most likely to have cancerous throat tissue?

1.Draw a labelled diagram t2txiaa e p 28xx4y+p0go 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 huma: ,x*a py-2n ajqp6 .vn6klqvcn karyotype.


What is the abnormality in this karyotype and its cause?

The graph below shows the relative amount ofzy;1;urb6bhars c5: r DNA in one cell during one complete cell cycle. Each letter represents one stage of th5sz r ;r: bby6u;1crahe 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 homozygous for bro3z tn9 p8sqwe*wn, long hair and a female cat that has black, short hair.w*p9 s8znt3eq


Which of the offspring has a recombinant genotype?

1.Outline how polygenic traits zo h9p*;ypc.7h- mrx ocan 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 chromatids shown if * a4i (axwhc11gyp*9yvllf d)5qs+cn thfh+ y vis9a)(ly11g a d 5fcpx**4clqwe diagram below?

  The photomicrograph shows a pollen grain from L. c .0bs kt3yg*xrvz 9z4handidum (Lily). Which stage of meiosis i3 z0thb9sr g4.vz*y xks shown?

1.Outline the events which would lead to an individual being born with Down l:o w 6yzh,n)ogkt7,s syndrome, which is characterised by the presence of three co6hk nsgzy,:lw7, )ot opies of chromosome 21.

2.Explain how meiosis increases variation.

3.Outline the stages of meiosis.

The mitotic index is ayzjo:tj ig;-fs 0y(i3 n indirect way of measuring plant growth. A study was cond ;zj-3t yi0sjoi:f( gyucted 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 cells can divide. The d 7t4pm* u51pvquk u9mal i2at4iagrams below show two cells from an organism wittu4lauk 2i4* paup7m q 9v5mt1h 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 expresgl u,lb g*+wd-+kl)wssion 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 cell, with a di2wm h: p05 qji*ofnj7qploid number of 8, in different stages of meiosis. Which row correctly name2pqmwo n:07ij5* qj hfs each stage?

  The micrographs show four phases of meiosis Ifd(ru*c xh66h 9e0l gd in a plant. In what order do these phases of6e(dx u rdl*90h6hc gccur?

Mitochondria are responsible for supplying metabolic energy in eukaryotic cell*ix 1a syz)6/k slezt1s. 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 DNz/*l6sytieak 1)z1s xA 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 ines4m wr j2u2a42zru/j different stages of the cell cycle in four samples of lung tissue fwmu2 u aer/2z424jrjsrom four patients. Which tissue has the lowest mitotic index?

  The diagram shows the dominant cyclin/CDK complexes at differg*ml+v:e b27 j n6mo: cy3c)b xfykq3aent time points in the cell cycle. Which cyclin/CDK complex activates DNA repleom7 xq ) :ny*:6cc2jly3bm vbaf+k3gication machinery?

  Studies have shown that genes such as Cyclin Dependent Kinase 3 (CDKN3 gc/ nnqa u)18axg33yi) are highly overexpressed in caui cqg 1n3ay38 x)/ngervical 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 highestb5aa 0sg-gw5auho oud o,j045 during the cell cycle ?