The graph below shows the relationship m b00 +bt7ugqgt6vqdgt1 :z( hbetween maternal age and the incidence of non-disjunction. What relationship is suggested by the data in the:gq+dt 0 zgqg ttu0(v 761mbhb graph?

  Which stage of meiosis is represented in the diagram bell7x/ cx2v7x)tmrurw( ow?

  The diagram below shows chromosomes during meiosis cs s9/6hs:wq x(iut6;rm0rrs .


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 s62b+l:t.) xu aaf q0vuq)wnmhtates the number of alleles of a single gene which would be present infbxalut + ahn)2q.wvq) :u0m6 the nucleus of a cell as a result of each process?

  Which keyword is matched to the correct defini7ep+h,d u,i xwtion?

  Which statement(s) about mitosis is/are trquhzqa: gn ms(u-s ;4ww tin-13en)6rue?
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 tofl9 4h,arnhsx-)fp/z a cell in anaphase?

  During which stage of mitosis does the nuclear envelope jgz.jji7s 3m 1/ls8 xhbreak down?

  Which one of the following transport proteins only carries out activwzlw kw p.y61ugx: 5-ce transport?: uwwzp -6c5 wgkxy1l.

  Which process does not happen in thdj125mu v6l p tmeu2x+e shoot apex?

  Which type/s of membrane transport do/does not require energy expendirp( ma.sq v.7ja64okoture?
I. Facilitated diffusion
II. Active transport
III. Osmosis

  The diagram below represents a cell with a diploid number of 4. Which sta c;b(twy*js2*wy s5 bbge of cell divisionjs;b (wbbyyws c*2*5t is the cell currently undergoing?

  The photomicrograph below shows a root tip meristem. Whichpl ns5kzt *uddc1v 6:6 of the following sentences correctly defines a meristd6 n zkt:udvs5cl6*1pem?

  When does the random orientation of homologous chr c5/vi- b1oakjomosome pairs occur?

  Which process does not occur during mj;l8erj;wd2 g gwtq-1 eiosis?

  If a cell with a diploid number of 36 undergoes mitosis, fu6elfb i(0 -ihow many chromosomes will be present in each daughter cell a0 u6bfe f-lii(fter cytokinesis?

  The image shows a micrewbt.xz+ gxdb -/ytd ga(57 wylf02u1ograph of a cell.


What explains the appearance of the cell in the micrograph?

  Which statement(s) about homologous chromosi i8ndyh:2 :0rq7bn9 fwqij9y kg9+flomes 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 indik/o2wbv. - ii7 v+zvcxvidual with Down syndrome.

Which statement is not correct?

  In the cells of a horse (E. caballus) during prophase I;io j r)gu3ye7 of meiosis I there are 64 chromosomes. Whau)gj7 eyoi3r;t is the haploid number of chromosomes?

  Which arrow is pointing to aw2 exsyj6( et-qbo ;*y chiasma?

  The diagram below reprv8gkr5my bk q h) 7(pd(,(qddoesents the structure of a shoot apical meristem. Which row in the table correctly identifies the processes occurinq yp(k57m 8 d dhqko(v,b)(rgdg in the structures labeled in the diagram?

  How does meiosis promotvja4zuqkn 0hlt8r5-9kp, 8g4 mh ) 7yhu m(ckce variation?

  Which of the following statements is/are correc- uuhto/7)- udalr6ypt 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 hor 0sk7ek4 gfeuf(,zj3 mologous 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 secon*jw82 pg9xaw udary tumours from primary tumours as a result ofwu2gax9p*j 8w the movement of cells?

  How many chiasmata are presegir0 n ar6(u tqoj1q6ea 7zlv.65mrb/nt in the diagram?

  Which statement is a simn m0zwfzms/:f)u ;*kbilarity between cytokinesis in animal and plant cells?

  Which stage of meiosis is matched to the correct descre8ka og+tx(gqn0(.cription?

  Which statement(s) are true of meiosis I but not mh*6/feeq nem9eiosis 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 fei2.dvo x peb8en4q04 irst meiotic division. This results in the formation of one large cell and one small cell. What is the fate of the larebio.240x vd4epn8 eq ge cell?

  Which row correctly describes diploid and haploid cells in hue+xt)kv/ pu y:y.fe3dmans?

  The following table shows the diploid chromosome number of a r( qas uv, imk5foz:0,xange of species.


Which of these statements is correct?

  What conclusion can be drawn f2)3phxx o lul4)qljk3p/d/:m5vhah lrom the karyogram below?

  Which of the following processes is characteristic of ozlzm5 g vaq-+ vqwg*3r3+g)athe meiotic and not the mitotic cell cyrv5)3a*alqm3o +z v-+qgwg g zcle?

  The diagram represents a bud q hyw-q.b)r;2y:tkb e 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.g1j t5k; p3p9 ivtvc*a Which row shows the correct chromosome numjpt 1va93 c vip;kt5*gber for different cell types and cell division stages?.

  At the end of which phase of meiosis I doawpwg a/b. a23es crossing over occur, and what is the outcoaagapwb.w 3 2/me of crossing over?

  Which of the following so( 4qa g pv*x:4x,orlo9cpj0htatements does not describe a step in the sodium-potassium pump cycle in the neuro0oxxrj(*vcp 4g4p ,qa o l:o9hnal cells?

  Which row in the table below is g0d2(uvw 8hgltrue of meiosis?

Membrane transport is important fojxj 6pl)knr:5r allowing particles to move across the cell membrane and respond to changes in the chemical composition 5kj):pn6rjlxof 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 regulat2 nm*.4t7/;ckxzbo7 j q2xnje vkj7jjic r2w0ed 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 different cyclins bp ob gh 3:im xd7*u0.lm:pqo6during the cell cycle. Which cyclin is involved in preparing for DNAbu 03::p7b.h d6qiomloxmg p* replication?

The diagram below shows chromosomes during meiosiu5jf69np. wphh w:uu)s.

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 *zo/psl 4 n3rz3j g8fahomologous chromosomes?

  The mitotic index of throat tissues taken from 4 different patiebik1m i/ 9j- )+f 98zfimbhftfnts is shown below. Which bfmf-j+zki/i ) 8 f9tmbh19fipatient is most likely to have cancerous throat tissue?

1.Draw a labelled diagram to represent the process of crossing ovej5:, qtly owp/r.

2.Compare and contrast random orientation and crossing over.

3.Outline the stages of meiosis.

  The image shows an abnormal huma0ketsyd e*d6co0,l4 u n karyotype.


What is the abnormality in this karyotype and its cause?

The graph below shows the relative amount of DNA indyu )04h/xs9e,yds b p one cell during one complete cell cycle. Each letter represents one stage of the cell cycle.eyu bhsysd/d) 9x ,p04


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 betw 7rz4kj -zp(cfeen a male cat that is homozygous for brown, cf4p z j-7krz(long hair and a female cat that has black, short hair.


Which of the offspring has a recombinant genotype?

1.Outline how polygenic traits a 7zqk/3d s7lw8ld scm (pu8r5can 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 shb59mgs(jg rr( own in the dias5g9j(mg(rr b gram below?

  The photomicrograph shows a pollen grain from L. candidum (Lily). Which stagepd-e xy. (f and0d3z:d of meio.n:0ap -dx3(yd fdd ezsis is shown?

1.Outline the events which would lead to an individual being born wib-i4kq)td5nr ,g zpr ,th Down syndrome, which is characterised by the presegki b5- rrd ptnq,,)z4nce 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 v s2uetbnetov0l0j965 sq11wstudy was conducted on white onions (Allium cepa), under controlled conditions in a lab, to investigate thee 2s01nul6w1qvo90s5v b ttje 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 diagrams below sjl chxa)n5)u k7/s5nb how two cells from an organi 7u/)s)kjx hnn a5bc5lsm 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 expression in steoms irpa(nw80sav26 s ha76a 3m 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 number of 8, c (wq63*x u.zpee1 okrin different stages of meiosis. Which 6 z1(prk*uxq e.3 wcoerow correctly names each stage?

  The micrographs show four phases of meiosisi 5ba/k8) qvuo I in a plant. In what order do these phaseskq/i8 a)ov5ub occur?

Mitochondria are responsible for supplying metabolic energy in eukaryotic cedx7.h1xa bb0 mlls. 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 whibxbxam0 h 1d7.ch 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 in different stages of the cell cycle in fou,rh,k3d .7eyoedl cz8 r samples of lung tissue from four patients. Which tissue has the8el. c3ezdod ,rk 7h,y lowest mitotic index?

  The diagram shows the dominant cy*n 2dwur n.m3glux8ux5mp tvw 58i):l zxw4-mclin/CDK complexes at different time points in the cell cycle. z u- 4wwl 3iuug) v:x8n.x5mnt*xlwmp5r 2dm8Which cyclin/CDK complex activates DNA replication machinery?

  Studies have shown that genes such as Cyclin Depen9h4ccw9o f ,a)l*t syswip98g dent Kinase 3 (CDKN3) are highly overgsa 98* lccwhy49,)p9o fstiwexpressed 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 cy(dvpki0/ pxc c vh:3z/cle ?