The graph below shows the relationship between maternal -zazt958-:usn dm qvg age and the incidence of non-ddsuzq m t n58gv-9-:zaisjunction. What relationship is suggested by the data in the graph?

  Which stage of meiosis is represente n4k-nhef9,rld in the diagram below?

  The diagram below shows ch, h l45fhp;t7k(ibj muromosomes 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+ndxb4.2ci 9e qrx pm-3;tq oheles of a single gene which would be presp 9xmcx. b3oiqrtd2;e +nqh4-ent in the nucleus of a cell as a result of each process?

  Which keyword is matched to the correct defi:tn:l54i2lll d rsm p1nition?

  Which statement(s) about mitosis 9b 2lk xzg7es(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 xc7 m v) 4z+rd/2d :gbm h+*+izb3+ofshxfi hzcell in anaphase?

  During which stage of mitosis doesj(lt-unwdnxy3u32qa : 2mir 0dewb.6 the nuclear envelope break down?

  Which one of the following transport proteins only carries e-6zo1fmq5c,s2ot ky9 z s2nxout active transport?o2s zt k5c91s-6zyoxn2m qe, f

  Which process does not hapxgh6 c a.yi/0n*b zo(gpen in the shoot apex?

  Which type/s of membrane transpor8ko3oilu8zh t5f (e/rt do/does not require energy expenditure?
I. Facilitated diffusion
II. Active transport
III. Osmosis

  The diagram below represents a cell d5+21ud wq nacwith a diploid number of 4. Which stage of cell division is the cell currew1+u5dq c2dan ntly undergoing?

  The photomicrograph below shows a rood.cpcq,b(3j psfvy 4,t tip meristem. Which of the following sentences cop4byqvs jp.,(cf3 c,d rrectly defines a meristem?

  When does the random orientation of homologous chromosome pa.cj -igb4m.f cr7uz0j9 c)hpy5 xf :sqirs occur?

  Which process does not occur during meio no ,j4f)(p ws1 vd1 ql5-5gciqfix5ddsis?

  If a cell with a diploid number of 36 x w(rvp2:jur.undergoes mitosis, how many chromosomes will be present in each daughter cell after cytokinesisjpr2x.( ur wv:?

  The image shows a micrograph of a cell. qf4e8tjuiz da 1cu4/-ve 1s( e


What explains the appearance of the cell in the micrograph?

  Which statement(s) about homologous chromosomes is/are not txbxplc is .v xu+dnnc*(3:l() rue?
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 hl f;7js:s/-;wyscr e6, hdhfDown syndrome.

Which statement is not correct?

  In the cells of a horse (E. caballus) during prophasw3 q/ 5 jeaawy()2nsqae I of meiosis I there are 64 chromosomes. Whataeqyw)/n3j(a5 s aq 2w is the haploid number of chromosomes?

  Which arrow is pointing to fz(yu n+ut)p: a chiasma?

  The diagram below represents thmy xz(9/) 27 dnfn 4syf0cmzqse structure of a shoot apical meristem. Which row in the table correctly identifies the processe0zdcf/2 qm s nx7n4fz)myy(s9s occuring in the structures labeled in the diagram?

  How does meiosis promote var 5a5ms rt6pos;iation?

  Which of the following statements is/are correct for meiosk )3w*aeo3/zfmrd1+o fbzz,u mxc e*0is?
I. It is a reduction division
II. It involves random orientation
III. It produces genetically identical cells

  The diagram shows gametes 39rq;v5jox z cproduced 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 * ) gr polx36e750fthzv dglx2secondary tumours from primary tumours as a result of the movement 3 pv lgox5tle7fr)*x60gz hd2 of cells?

  How many chiasmata are 875zhx3x5r2yorrlah:nu 6 ijpresent in the diagram?

  Which statement is a similarity,ug f6 4eqtuz j2+;yr,myb6tz between cytokinesis in animal and plant cells?

  Which stage of meiosis is matched to the correct descriptnt53 b0cyt5t iion?

  Which statement(s) are true of meiosis I but not mu5q1wrgdcke0g )m-z ;eiosis 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 ,2a,tve cmjt o7f,w7ameiotic division. This results in the formation of one large cell and one small cell. fe2 7tva oc wam,,,jt7What is the fate of the large cell?

  Which row correctly describes diploid and haploid cells in humansa7jn kuy q ),+himmqp-m 3p92h?

  The following table shows the diploid chromosome number of a range 4mqpy4 meno:nb, o j8,3ioiu5of species.


Which of these statements is correct?

  What conclusion can be drawm aoqu/wn 84dyo;((v ln from the karyogram below?

  Which of the following processes is characteristic of the meiotic and not thej1rv p:eb h(b2s2ues pn1b 50s mitotis1e( 2nbb 2 ushv1pb0sj er5p:c cell cycle?

  The diagram represents a bud with a shoot apical meristempo0a7lc wen :4.

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 row showu :x eq j8yz; y6vd96sdkyd8vz;g,c+ rs the correct ch8; ezd8cr+vyv6;dx6y9s u yd:,kzgqjromosome number for different cell types and cell division stages?.

  At the end of which phase of meiosis I does crossing over occur, and14lml 8jqw3+wmr9qu7 q qv5rz what is the outcome of crossing ove9zqm7w4 3q5jwqmru+18qlrlv r?

  Which of the following statements d7p: o v(+sgrgloes not describe a step in the sodium-potassium pump cycle in the neuronal ce rps7vl +go:g(lls?

  Which row in the table below is true of 6,,+n)xeanh6y/xptnl br ,uq meiosis?

Membrane transport is important for allowing particles to move across the cetp/75ofggw-t c 8v;edb1b2( zmd w6upll membrane and respond to changes inzubpfbw15g d7 mg/v pew(d6 t o2-8ct; 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 6njppfh9zy/h+ -y t4cregulated 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 differep* tyg khdk1 )mh gfn:+e26b*mnt cyclins during the cell cycle. Which cyclin is involved in preparg h2np 1g*tmhk:*ykdm +b6e)fing for DNA replication?

The diagram below shows chromosom :+ p.;40. cnidite- jthxyrimes 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 homologous65n(z c9azuoi6 m b1kr chromosomes?

  The mitotic index of throat tissues taken from 4 different patien xgmv:p l5-p8its is shown below. Whichm 8:xi pvgp5l- patient is most likely to have cancerous throat tissue?

1.Draw a labelled diagramxz b(8paa-6qn3gv ow2 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 abnormlvb5r,apagy- r4 r:6 u; jlypv)j3o2a al human karyotype.


What is the abnormality in this karyotype and its cause?

The graph below shows the rela/*eqz)xadryh4fwio j3g + 77p tive amount of DNA in one cell during one complete cell cycle. Each letter re /*3 xw)7fyhagio4pje7dqz +rpresents 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 male cat that is homozygovf 4p .fej;)tvus for brown, long hair and a female cat that .ptf; evf4jv) has black, short hair.


Which of the offspring has a recombinant genotype?

1.Outline how polygenic traits can show a n1iv7ld (wk -xkormal 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 crcs9 24pvxs;wbossing over of non-sister chromatids shown inx s24;vsbpc9w the diagram below?

  The photomicrograph shows a pollen grain from L. candidum (Lily). Which stage of0 hdizq -u,w2i m0 q2ziid u-w,heiosis is shown?

1.Outline the events which would auw0 /.cppjb+lead to an individual being born with Down syndrome, which is characterised by the presence of three co ba0+uc/.wjp ppies of chromosome 21.

2.Explain how meiosis increases variation.

3.Outline the stages of meiosis.

The mitotic index is an indirect way of measuring plant growth. A study wv( b i: **q y5d4idt/ z4cy*fszlpd1wsas conducted on white onions (Allium cepa), under controlled conditions in a lab, to inve/:zi (14wsdt *y*5ycfd s*ldq b4 vzipstigate 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 cmw t 4()ujb9zua+4g l9v1aknt an divide. The diagrams below show two cells from an or 41v9tt(4ag9uk lm+az j nbw)uganism 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 expressi.,-h pq fm/1e kd3hz z56euqamon 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 celm8 2cjuusn,g8 *9soou l, with a diploid number of 8, in different stages of meiosis. Which row correc goj,uos*8u 9u 2smnc8tly names each stage?

  The micrographs show four phta(ky5-2 rzb cases of meiosis I in a plant. In what order do these phasey 2kt-(5ab zrcs occur?

Mitochondria are respons9 ytof tv5ewq6 g0k v+,8y9k0y75nm)cps sqftible for supplying metabolic energy in eukaryotic cells. In most eukaryotes, which reproduce by sexual reproductt e+q0f t n5yvpk906 ,ov7y9wc)gyk5s8ms qtfion, 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’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 nujk7 28k* pqrdtw+pb lp9jn.0 tmber of cells in different stages of the cell cycle in four samples of lung tissue from four patients. Which tissue has 9pj2lq .rk7*nt d8pwkp+t0j bthe lowest mitotic index?

  The diagram shows the dominant cyclin/CDK complexes at dif24b6k-k wkrxhm9 :lvqferent time points in the cell cycle. Which cyclin/CDK complex activates DNA rrwmx9hv6 kkkq42 lb:-eplication machinery?

  Studies have shown that genes such as Czds /x +0 ye,0u b22 yo;kzv(i0.qcudtt ymz;syclin Dependent Kinase 3 (CDKN3) are highly overexpressed in cervical t2ybi zzckut0e ;mxt+z0d 2/ (, ;vy.dusq s0oyumours.


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 the cell cycle ? 06mbwoy(rw; n