The graph below shows the r/9tuz.w ue g;relationship between maternal age and the incidence of non-disjunction. What relationship is suggeste. /;gr uu9wtzed by the data in the graph?

  Which stage of meiosis is represented in th1vbi hjw5b6 q6vv)exg/n,; lig*z7x te diagram below?

  The diagram below shows chromosomes during me0 (:dkyesd4hr- kztj2iosis.


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 tl3)3al5en u y24 juau4h ivt/qhe number of alleles of a single gene which would be present in the nucleus of a cell as a result i 32/ u4h3 yju5tq lv4unae)laof each process?

  Which keyword is matched to the correct hpg col+98v( iz rqgi;+t1;,3pzzyp hdefinition?

  Which statement(s) about mitz; :i rin2htn1gl6ms (osis 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 lettd,e/wh x ji6ii0 i)(2 e p,dyncsf7/fber points to a cell in anaphase?

  During which stage of mitosis does the nuclear env7jodqx7 0yjg ,i.dpl;afj7w / elope break down?

  Which one of the follbw;bs p6ub7:j . fn:kfowing transport proteins only carries out active transport?;.6s :buwb f:bjfn 7pk

  Which process does not happen in the shoot apex,g ycv,f)ubsd - -tqu.?

  Which type/s of membrane transport do/do q0u) 3qajss4aes 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 stage opwa9 lg*h 8g8kf cell division is the cell currentlwl8 ag 9h*kp8gy undergoing?

  The photomicrograph below shows a root tip meristem)hzwnxli)x wx9 e8;m5. Which of the following sentences m5wx9whi8) )exn ;lzxcorrectly defines a meristem?

  When does the random orientation of homologous chromosomog-6-8c0+ o7by5yh af q:0 t +6qbytqltik jkie pairs occur?

  Which process does not occur during mp- yv0e dt2;z u0q)dqzeiosis?

  If a cell with a diploid number of 36 und *k*8rnxui lt4im/mj *v 8-plqsn)ui .ergoes mitosis, how many chromosomes will be present in each daughter cell after cytokineul) imq/l j4.sr xutvn-nmi*p*88*i ksis?

  The image shows a micrograph of3k ,jdyg 0bju7 a cell.


What explains the appearance of the cell in the micrograph?

  Which statement(s) about homologous chromosomes is/are not true? tj)hm*f 5(nxy
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 w:8dd4j(gmq 60r jgbez ith Down syndrome.

Which statement is not correct?

  In the cells of a horse (E. caballus) during prophase I of meiosis 7k s:b7e;rhkd4 ix4dq I there are 64 chromosomes. What is the haploid number of chromosomes74hse:k d ;d7kqri b4x?

  Which arrow is pointing t5t(dx jxn ;*edpgu1s8 o a chiasma?

  The diagram below represents the structure of a shoot apica8x cdaj i2-b(1ipojb;l meristem. Which row in the table correctly identifies the processes occuring in thb8o -xjiijp(1;b 2cdae structures labeled in the diagram?

  How does meiosis promote vary3c7+up1+7 4zwtebzew b8utxhe:r 5c iation?

  Which of the following statelhfn hm i;6xi :a)1n0mments 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 ;qq5i8aqwhl ) 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 tum -j .dbg+kpws 22lgn ghf65il6u9sli5 ours from primary tumours as a result of the moveg il+pl2bhg 5f9k26sd65.n w usi-jlg ment of cells?

  How many chiasmata are presenta. z .qczj1ssk* crn7, in the diagram?

  Which statement is a similarity between cytokinesismrl+w1h)z2xh7 -sq5ilimp2 k in animal and plant cells?

  Which stage of meiosis is matched to the correct descrijc6g - ebn2pm*ption?

  Which statement(s) are true of ) xa cr8.60z yz)dbgxomeiosis 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 division. -v aqad6g22ih39b94r 1y j fp;uesqj nThis results in the formation of one large cell and one small cell. What is the fate of the large fg y ;1qj6-q32aniur 49ve9spj 2d hbacell?

  Which row correctly describes diploid anpyc ;yh0m ycr yvu/t7lgh55:/d haploid cells in humans?

  The following table shows the diploid chromosome number of a rang2j 0 -h c2gcp:jaqckg.e of species.


Which of these statements is correct?

  What conclusion can be drawn from the karyogram b2 +c ubk 3z1ilmnyhy,)f-u/yhelow?

  Which of the following processes is characteri:p.w5he j g/*b(bsq btstic of the meiotic and not the mitotic ce*/psth bj bw bq.(5ge:ll cycle?

  The diagram represents a bud with a shoot apical meris1ny lcsv+m66zjh ro 6+tem.

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 trog/ul+oxjc mi-o 57 gn9vl) v*fulodytes) is 48. Which row shows the correct chromosome number forolv -uig v9l5+fcnx om7)/* ju different cell types and cell division stages?.

  At the end of which phase of meiotu*6sr( wdm1(i6kff r sis I does crossing over occur, and what is the outcome or m(d(6*tk6i srw 1ffuf crossing over?

  Which of the following statements dol,ti0b vnt-pyv:6vlj 9syg * 7es not describe a step in the sodium-potassium pump cycle in the neuronalvpi- 7tv0 bgs,tl *9: njylvy6 cells?

  Which row in the table below is true;( ig 2l wkne;luz*tm9.(gxle qdw) +i of meiosis?

Membrane transport is important for allowing fo4bswv svr1iso h 7n./lu:;: particles to move across the cell membrane and respond to changes in the chemicah:n sfw voru: ;ob/il41v 7.ssl 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 is6d)8hgnqn813d nb3qpucc e z ; regulated 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,drxd .2 :bn:z uq9wzm the concentrations of different cyclins during the cell cycle. Which cyclin is involved in : .d2zxw 9qmn:rbu,zdpreparing for DNA replication?

The diagram below showg qd*3u-ko9.b *bq r8o/yavums chromosomes 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 separatiodu gy 1iz5x , h9yt52yvaov;m+n of homologous chromosomes?

  The mitotic index of throat tissues taken from 4 different patsq/qi8 vwllhd1 oqn: t(y 9h/(r+l,pe ients is shown bel:wt n hv/19y/lqel(+rlhqpqso,d 8(iow. Which patient is most likely to have cancerous throat tissue?

1.Draw a labelled diagram to represent the process of i5sp/d,(ch g m. b4dydcrossing over.

2.Compare and contrast random orientation and crossing over.

3.Outline the stages of meiosis.

  The image shows an abnormalep mr8yk j6/t, human karyotype.


What is the abnormality in this karyotype and its cause?

The graph below shows thu baezd,r5e o.bzkk r a7*/85ge relative amount of DNA in one cell during one complete ce 55.r,z/uo dgbbark8 z*kee7 all cycle. Each letter represents 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 homozyb /6 sqsb+xj 7k,sk0zigous for brown, long hair and a female cat that j k q/sib7skb0xz,+s6 has black, short hair.


Which of the offspring has a recombinant genotype?

1.Outline how polygenic traits can sho,:+akj1ufwb 0 gkag1+ogad /ow 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-sr ylc(u-(mcz5 zhb9 e-ister chromatids shown in the dia ze((y5-h bl9zc-rmu cgram below?

  The photomicrograph shows a pollen grain fjk-o ahh (r wqd8sp968rom L. candidum (Lily). Which stage of meis(hwpqj6kr8 o a h9-8dosis is shown?

1.Outline the events which would lead to an individual being born mk1*u*epw e5dp1ey(2; nly vbwith Down syndrome, which is characterised bp(ymuy1*enw5e 1d*ekl ;v2pby 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 indirect way of measuring plant growth. A study odhz- vjj 3 9k80h1 nwsnrfr-0wtzb,0was conducted on white onions (Allium cepa), under controlled conditions in a lab, to in-tvnhj, - 0hw z1n8fr3k0wbzor 9sjd0vestigate 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 cvp4k9 zyio0yzlxu4- ,.rah. u an divide. The diagrams below show two cells from an organism with a diploika-h uxyzz, u0vr ..oi9ly44 pd 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 expressio3)ef u a qz7r*-fhtpkgk 04-gkn 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, wm im( ,wi5m5ntith a diploid number of 8, in different stages of meiot m,i(mwm 55insis. Which row correctly names each stage?

  The micrographs show four phases of meiosis I in a plant. In what order do the-:5 vwts0 lvv .u.0m fivzj+fcse phaslt +5v.wmcvvvf-:i f juz .00ses occur?

Mitochondria are responsible for supplying metabolic energy in eukaryot,85o par+una mic 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 di8r +pom,aa5nufferent 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 nah/ql)du6 7+ sf/wo8:aded q different stages of the cell cycle in four samples of lung tissue from four patients. Which tissue has /:s f 76dw8qa/dnu o+q)edlhathe lowest mitotic index?

  The diagram shows the dominant e v; :p xkf(w5y16+guv4vol-s-s uortcyclin/CDK complexes at different time points in the cell cycle. Which cyclin/CDK o:trve- sslpf;4 ovvw(u kuyx-56 1 g+complex activates DNA replication machinery?

  Studies have shown that genes such as Cyclin Dependent Kinase 3 (CDKN3) are high.frh5+tv7j0xzxg( 8vf x sxi)r xx58jvzx g0.fi7v)(th+x fs ly 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 the cell h.m7ncuq89cat i)q5mcycle ?