The graph below shows the relationship between maternal agelnszr3ue) .,s and the incidence of non-disjunction. What rez,s)lun .e3sr lationship is suggested by the data in the graph?

  Which stage of meiosis is representes 9c f;.mjb2a,oq-st bdv)tz5d in the diagram below?

  The diagram below shows chromosomes dur2d(85wldgjo z6lq 1xy55pea ding 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 singl93wc0 7(dszb ny/caw6zlues-b fg z))e gene which would be present in the nucleus of a cell as a result of each procw7z-sd z efl (/ab9sc gub6z0)wy3c n)ess?

  Which keyword is matched to the correct defiatj; l7dqutti lz1q.j2*7k y)nition?

  Which statement(s) about mitosis is/are true?.y*j*ykknn d 5s-ev .g
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?n h zp:)i31vrlsbhv35

  During which stage of mitosis does the nuclear envelope br .gc nt-w+*yobeak down?

  Which one of the following transport proteins only carries out active transport? ky1 het3-dz78wokh5 nk wt7zy-kh e 85nd3oh1

  Which process does not happen in theoy u/exjk98u2 shoot apex?

  Which type/s of membrane transport do/does not require energy expenditure?r ;2 ohwdez+5s:4lo vn
I. Facilitated diffusion
II. Active transport
III. Osmosis

  The diagram below represents a cell with a diploid number of 4. a m zs9 wo.8rukujb ;./cl72boWhich stage of cell divac8 7lozb9;m bj2r/sk .owuu. ision is the cell currently undergoing?

  The photomicrograph below shows a7ti1 0s qoaca: root tip meristem. Which of the following sentences correctly definess0oqa71cit:a a meristem?

  When does the random orientation of homologous chromos-twh3zi: e5d+dh sg8h ome pairs occur?

  Which process does noto,9bz o3js2lpj 5xg;z occur during meiosis?

  If a cell with a diploid number of 36 undergoes mitosis, how many chromosomes wiri7tl d ufg9u zm4d. g4ul 7ae315rri*ll 4l 1rtdu9 leuui7m45z*df 3r i.g7gra be present in each daughter cell after cytokinesis?

  The image shows a micrograph ;3u6az2hhtwu of a cell.


What explains the appearance of the cell in the micrograph?

  Which statement(s) about homologous chromosomes is/are(mk yvpzj)gn nt7c. -6 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 synd4m adf0 :g,:7edidue qem-wznxz4 z.(rome.

Which statement is not correct?

  In the cells of a horse (E. caballus)9vzvc5may1v + during prophase I of meiosis I there are 64 chromosomes. What is zvv v59cm+ay 1the haploid number of chromosomes?

  Which arrow is pointing to a chiasma? :kov e2g wf*u6

  The diagram below represents the structure of a shoot apicalw9gtp +m mzm4-oe 1/tqfj7c, 7o4fuey meristem. Which row in the table correctly ,7 + mg49o4fc7w/mteyjzto ef-m up1q identifies the processes occuring in the structures labeled in the diagram?

  How does meiosis promote variatizylm 9 mw n2:q-.myh9ton?

  Which of the following statements is/are correct for meiosis?) rm/,,sjl626 auwd+ bs ieccvtq+f )i
I. It is a reduction division
II. It involves random orientation
III. It produces genetically identical cells

  The diagram shows gametes produced from two homologouso60yi.y 9e+ay w nor3:7zeq xo 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 tuy 17x l jrcfvqkyi31+g4r4h9r mours as a result of the movement v4hq49x3jfkg+ lc y1rir7 yr1of cells?

  How many chiasmata are present in the diagd 3:7fd6duljce 0h *fgram?

  Which statement is a similarity bet;4(q d s;ppdnmween cytokinesis in animal and plant cells?

  Which stage of meiosis is matched to the correct descriptiowl: du f,i;/kvn?

  Which statement(s) are true of meiosis I but not meiosis Ip ryk9rwkhia21j:1gp:p ; u8pI?
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 jprr4zn 2tu4egt3k fh , o;:ej*3nyk/first meiotic division. This results in the formation of one large cell and one small cell. What is the fate of the large cell 3enkt:r3h o*pk2gjyjt,/4rne4f;uz ?

  Which row correctly describes diploid and haploid cells in hojba3 +(ad4p2mhsw y (q3c(oeumans?

  The following table shows the diploid chromosome nuwt2yx/y 6h a9rmber of a range of species.


Which of these statements is correct?

  What conclusion can be drawn from the karlqy)1:oke r)7w r1 nggyogram below?

  Which of the following processes is characteristic of the meiotic and not thk s:h4ggtg7e3 g)djm 5e mitotic cellg45hmjd t 73g sk)g:eg cycle?

  The diagram represents a bud with a sho-. vukw,mrg- bot 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 r;o 0k qeejj;)z3lmqk: ow shows the correct chromosome n e)3z:;kq e;kqo0l jjmumber for different cell types and cell division stages?.

  At the end of which phas30ap-s j: rqmle of meiosis I does crossing over occur, and what is the -qa msjlp3:r0 outcome of crossing over?

  Which of the following statements does not describe a stxyw9fz /,i6 pi/g2uffep in the sodium-potassium pump cycle in the n2pix/uyiw/, g9f6ff z euronal cells?

  Which row in the table below is d8tb a;ec*9 nf+2dg kdtrue of meiosis?

Membrane transport is important for all6jc23ak l b1+)ombpsc owing particles to move across the cell membrane and respond to changes in the chemical composition of the extracellula m31pcbal sobk2cj+)6r 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 celli:mq2 4jl (yhfvq-47mtu48u ww 9u urbs.

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 shj5j7woc/o 4ka ows the concentrations of different cyclins during the cell cycle. Which cyclin is inv4j kow/7o5jcaolved in preparing for DNA replication?

The diagram below shows nj57l9j 4+ bv )jhju82*lb hmfnej1sgchromosomes 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 fk -x0k,ujnm6 homologous chromosomes?

  The mitotic index of throat tissues taken from 4 different patients is shown bsg rss e*nk; 21gz0j1-ugrh1oelow. Whir kj;0s h usosg12zg*r1en1 -gch patient is most likely to have cancerous throat tissue?

1.Draw a labelled diagram to represent the process of cro 4ci-6mtmy .wpf )mq.jssing over.

2.Compare and contrast random orientation and crossing over.

3.Outline the stages of meiosis.

  The image shows an abnormal humanpb)un rdzqu 35p1 ndktf)4::h karyotype.


What is the abnormality in this karyotype and its cause?

The graph below shows the relative amount of D3z7 o*qd rm3opNA in one cell during one complete cell cycle. Each letter represents *3oo37zmprdq 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 f 4r2 nqfon3n dp,(se*w),nlcbetween a male cat that is homozygous for brown, long hair and a female cat that has blanne r(wno 4d2s,3q fnc*),p flck, short hair.


Which of the offspring has a recombinant genotype?

1.Outline how polygenic traits can show a normal n vtcyq8nz( pu+3 l:2/kp (zmodistribution.

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 crossin)uoj((nat v b2g over of non-sister chromatids shown in t2n )uo(ab (jvthe diagram below?

  The photomicrograph shows a pollen grain from L. candidum (Lily). v ,hv:dwp9cordno 7pudpb ;b(1g4 +ar78s-a lWhich stage of meiosis is shown? :u8pp,rrsa9pdb+(d lo v4h;dco17g a7b-nvw

1.Outline the events which would lead topgorq9yv 7wu*b/za8 u,x+s. 5 8gjpik an individual being born with Down syndro/zgbur p87*ukw, 8jg viqsa.yx5po9+me, which is 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 inf(hp3qm )qn0w)ptf8 bdirect way of measuring plant growth. A study was conducted on white onions (Allium cepa), under controlled conditions in a lab, to investigate the effect of soil pH on the mitotic h)pw8mtff03bnq) q( p 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 dian:qvj kcctxw/ /6/qhj-a( br(grams below show twot/(c :qbch wa xjj-6/kq (n/rv cells from 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 r9ud.xewkofm76g;x i tff0 32gene expression 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 diploid numo u7tu-vzz k9u+f3, naber of 8, in different stages of meiosis. Whi za,+ -zf tnu7u3ku9voch row correctly names each stage?

  The micrographs show four phases of meiosis I in a plant. In what order do theska3fl f j8/ z6eu+qzuao:+n 4ue phaseskz:f enouj flq6+z3 8 a+a4/uu occur?

Mitochondria are responsibl8fj72cab 5q 1n fjkm+2nx+gxgkbr c, (e 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 mtDNA found in hybrid cells, which are thnkk,q++jnc f r5fa82x2 gj(xbm7b1gce 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 different stages of the cell cycle wxvjfr:8mo(ja2 ;za6w.2nx n in four samples of lung tissue from four patients. Which tissue haz 2fan8nm6o jwxr ;xwa2 .(v:js the lowest mitotic index?

  The diagram shows the dominant cyclin/CDK complexes at differemlga4my) g3 c0nt time points in the cell cycle. Which cyclin/CDK complex activates DNA replication mac)0mcg glaym34 hinery?

  Studies have shown that genes such as Cyclin Dependent Kinase 3 (C+vt6j gp)6a uoDKN3) are highly overexpressed in cerv v) gutajo6+p6ical 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 oku aae,lsxxo) hb7.. 1,qg8scyclin E the highest during the cell cycle ?