The graph below shows the rjlus 11h) nd1eelationship between maternal age and the incidence of non-disjunction. What relationship is sus1el11 d)nujhggested by the data in the graph?

  Which stage of meiosis is represented ixihzol03 j0d. i(o gs(n the diagram below?

  The diagram below showwk4eqo)pi 6h suz3 8;is chromosomes 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 numb (-a(83y3gjd zto 6ub)r1xzqnzhkud5 er of alleles of a single gene which would be present in the nucluj1xgzkd3b)8q(3a zh d(5-uoz6 y nrteus of a cell as a result of each process?

  Which keyword is matched to the correct def.vk gr 3*pk-v-y *r*uz1or5l7ya qmg9ocoha0 inition?

  Which statement(s) about mitosu,pu;.1 ) zuyriyuo) sis 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 letty:l b8xxyvc5* er points to a cell in anaphase?

  During which stage of mitosis does toc4yqsl e48yik:32 xa he nuclear envelope break down?

  Which one of the following transport proteins only carries ozrlyj 7r5 mq d7fwvf-2t*8c(aut active transport?8z 2 vwc7r-*a fd(qrmt7 fjl5y

  Which process does not happen in the shoot ap./-:r p)icivs 7blp ng zh21vuex?

  Which type/s of membrane transport do/does not require energy expendituinr0b4 )34fdj (k89at uvt ljare?
I. Facilitated diffusion
II. Active transport
III. Osmosis

  The diagram below repu6 qj gg4zd 9vih( i:8-g2bwmvresents a cell with a diploid number of 4. Which stage of cell division is the cell currentl i2uzb(d q-gw4g9 8 vm:6ijvghy undergoing?

  The photomicrograph below shows a root tip meristemq+v lobbp f,h/8- rx/j. Which of the following sentences correctly defin/r,/lhpf +v- 8qbjo bxes a meristem?

  When does the random orientation of homologous chwe3vyhz.2k h e i+:ls6romosome pairs occur?

  Which process does not occu8q4j lim)5 vtvr during meiosis?

  If a cell with a diploid number of 36 undergoes mitosis, how many chromosomecgd w1l /k-;sys will be present in each daughter cell after cytokinesiswky/sc;ld1g- ?

  The image shows a micrograph of a wd 0n u3.9cdngcell.


What explains the appearance of the cell in the micrograph?

  Which statement(s) about homologous chromosomes is/are not 3jferp) , ,ez2adi(fe 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 u06e - :,wztuh;9(x 4vnw ywqetya8vy individual with Down syndrome.

Which statement is not correct?

  In the cells of a horse (E. caballus) during prophase I of mxbmbhn6p5t*ve 8i*h t; bte ;(eiosis I there are 64 chromosomes. What is; vhme5p * etb*8b(b;intthx6 the haploid number of chromosomes?

  Which arrow is pointing to a chiasm 54) 9r/dougv do yms94gqi:hua?

  The diagram below represents the structure of a shoot apical meristem. Which row skvya(/ rb1;u6 sj 5glk5 ;jmyh3l4ez in the table correctly identifies the processes occuring in the structures labeled in the diagram? ;zej3 bv aj lgs1 my(u6;5yl4rk/hs k5

  How does meiosis pro b)1:fcsb;pls x6no 6vmote variation?

  Which of the following sasksg: +nwa9yql )a0 mry0 ,s/tatements 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 homolog- :ccrlpj6f-h qd 1kc,ous 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 formatfntba bt -soj/797 8qlion of secondary tumours from primary tumours as a result ofln7bbf-qt8 oja7/ts9 the movement of cells?

  How many chiasmata are pr*fj3iyd2e ayf(yk *t1 esent in the diagram?

  Which statement is a similarity between cytokinesis in avywmm1 9efc+c,3e hs+nimal and plant cells?

  Which stage of meiosis is feglzzw66x- +8l /(b- leenxomatched to the correct description?

  Which statement(s) are trumey q(0hiotw t/3 .mj7e of meiosis 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. This re mhw f mrf/70ur2(c0dzsults in the formation of one large cell and one smalld2m0u(/mrf z7w0fh cr cell. What is the fate of the large cell?

  Which row correctly describes diploid and+lfu** tcws 0y haploid cells in humans?

  The following table shows the diploid chromosome number of a range of sry qd5f (5*o5/ndvc9f)kmora pecies.


Which of these statements is correct?

  What conclusion can be drawn frdbufe- ,fnx+2f+vlk6 l90xkj vx1 ze )om the karyogram below?

  Which of the following processes is characteristic of the t/rg27zphu d 2meiotic and not the mitotic hz2rg dp2/ t7ucell cycle?

  The diagram represents a bud withyr:vbe0 xo p+og6zm2 . 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. Which row sh nfi;zzd9z9/8l d- ugdows the correct chromosome number for different cell typi/ zd8 nu;flzg9-9z ddes and cell division stages?.

  At the end of which v8jk71c1yb2y m /jnj3,nlsgcphase of meiosis I does crossing over occur, and what is the outcom cj1nsj372c,/yj nv1y8b k glme of crossing over?

  Which of the following statements does not describe a step in the sodi* iwoj0afe cao (h5h84um-potassium pump cioa*8 0fjc4e (5oahwhycle in the neuronal cells?

  Which row in the table below is true ofql, r9y)kb + d8;ue(se96kht, prjajr meiosis?

Membrane transport is important for allowing particles8mon 2s)fcedst-+ q +v to move across the cell membrane and respond to changes in the chemical composse)m2 dqsvct++-n8 of ition 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 regulatedyhtsca 7.sk7 p3n .*0hww8td gbp*r/r 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 co 66 j;ko4gemytncentrations of different cyclins during the cell cycle. Which cyclin is involved in preparing for DNA replimjt yog4;6e6 kcation?

The diagram below shows chromf xnda 86m4s ; e2z-sfy8yed/rosomes 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 separatio 0sni is5o-+cdn of homologous chromosomes?

  The mitotic index of throat tissues taken from 4 different patiep b6 tna2uaj3 kn5s61pnts is shown below. Which patient is mo2p3jn1uas5 bp6 t6 knast likely to have cancerous throat tissue?

1.Draw a labelled diagram to represent thek2g dnp5 *jxmu(+pro, (n76p 9cptzwm process of crossing over.

2.Compare and contrast random orientation and crossing over.

3.Outline the stages of meiosis.

  The image shows an abnormal human karyotypo;-r9 rebn1nzy ;d w(be.


What is the abnormality in this karyotype and its cause?

The graph below shows the ret3 l4t4m ;dzzdlative amount of DNA in one cell during one complete cell cycle. Each letter rep 3zmtzt4d4;dlresents 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 homozygop8 zm/(v ts-yaus for brown, long hair and a female cat that has black, short haat/p- 8(zvm ysir.


Which of the offspring has a recombinant genotype?

1.Outline how polygeniffgo5-ww3 gk 2 y3k:bwc traits can 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-so)o+uf 9l7nwp ister chromatids shown in the diagram belo)fw+9 lpn 7uoow?

  The photomicrograph shows a pollen grain from L. candidum (Lilsqz1 dg;rwcvs/b(*ih y4p1 b- y). Which stage of meiosis is showns/1bp*4cw bqrgvzhy;i- d s (1?

1.Outline the events which would lead to an individual bei)69 lnbc o* +phlap45bd ttkt3ng born with Down syndrome, which is charach) b b3 tkla94po56t+lt*n pdcterised 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 indirect way odt +h02s9i -rdmfkh6xcsi z/-f measuring plant growth. A study was conducted on white onions (Allium cepa), under controlled conditions in a lab, to investigate96k m+fdc2h zts ri-id0-xsh/ 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 di5abnv+ 2 l:bju4(yxa eagrams below show two c4 +blja: (u2e x5vyabnells 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 gene expresd ,y(x.m )7m(lju54fppf ;m hqi*cly gsion 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 showfjakdy1v1fs4.7 kt8lnj n 6m, a cell, with a diploid number of 8, in different stages of meiosis. Which row correctly names ekjs fvk 8,lm1d6fnn.j74a1ytach stage?

  The micrographs show four phases of meiosis I in a plant. In wpowf r)rr+x0rvhsj7fm0 7;7a hat order do these phsh 7x7+o 7rwr0v;frmrf 0j ap)ases occur?

Mitochondria are responsible rv 88yabo 7-ycqpt,l9for supplying metabolic energy in eukaryotic cells. In most eukaryotes, which reproduce by sexual reproduction, mitochondrial DNA (mt8trlpa , yvb8o-9cq7y DNA) 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 number of cells in differedyahzu;o/ +n4mh;q bo53tm2zkl 3.zr nt stages of the cell cycle in four samples of lung tissue from four patien kt/3uzlhhq2n;y3z5.rb m ooa zmd +;4ts. Which tissue has the lowest mitotic index?

  The diagram shows the dominant cyclin/CDK complexes atqr6*3 60j l.xn ibfinlfmqsd o52tu8 9 different time points in the cell cycle. Which cyclin/CDK dj32 .of xlmt6nbqlsfn69* ui qr08i5complex activates DNA replication machinery?

  Studies have shown that genes such as Cyclin Dependent Kinase 3 (CDKN3) are 5sz13c3 :ooazidoc a)highl 5ica:dz oszo33oc )a1y 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 cyclin6dgk 3ia 7jk:s E the highest during the cell cycle ?