The graph below shows the relationship between maternal age and the incidexcfc ;p38o//;vf xutunce of non-dcutxf o c pf;;/xv/8u3isjunction. What relationship is suggested by the data in the graph?

  Which stage of meiosis is represented in the diagram )xfxnqox pm f07; gu44below?

  The diagram below shows chromosomes duri e :49jeybmd(vkec b61ng 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 thfc9wz0z wwt+adh 0f )dqv88+b :h wu0he number of alleles of a single gene which would be present in the nucleus of a cell)0 +thwf8ww: 9vu dqw+dhbz 8z 0fach0 as a result of each process?

  Which keyword is matched to the correct definiti 1re1qr4 vryvu(mmj /)on?

  Which statement(s) about mitosis isijt6m hw0l+7o /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 lettha6 d0 3efubq(er points to a cell in anaphase?

  During which stage of mitosis does the nuclear envelop/ hq5 vtz(*rjre break down?

  Which one of the following trans8nfo-rz 4 ,h,nf xq-xkport proteins only carries out active transport?rq,-xfnoznxf -h, 48k

  Which process does not happenbv0(r/ d+k5s:fc4 wv d0fza by in the shoot apex?

  Which type/s of membrane transport do// 6sxef*4ss rv;s9blm(6evk a does not require energy expenditure?
I. Facilitated diffusion
II. Active transport
III. Osmosis

  The diagram below represents a cell with a diploid number of 4. Wh fj8, ktlhdq/cv+( f/qich stage of cell divisqc d(kjh/f8vq l+ft/ ,ion is the cell currently undergoing?

  The photomicrograph below shows a root tip meristem. Which of th uamk1b5 b..ihe following sentences correctly5b.hbm. u1ika defines a meristem?

  When does the random orientation of hkd9ohh,nt * gayg ;,t0oy.gw*omologous chromosome pairs occur?

  Which process does not occur during gh*he6dvitd e :t/.h2meiosis?

  If a cell with a diploid number of 36 undergoes mitosis, how many chromosom7p5 v;vqt8wq xes will be preseqqw7vvtp;8 x5 nt in each daughter cell after cytokinesis?

  The image shows a micrograph of a ce*-56dqeo3s8nr7jhl a4 unuib 1 qqb8qll.


What explains the appearance of the cell in the micrograph?

  Which statement(s) about homologous chromosomesy o(/yfwtldbgo69 k5 6 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 individual with Down syndrom yk)n-;9 bqjvnn 3jundnq3g**e.

Which statement is not correct?

  In the cells of a horse (E. caballus) during prophase I of meiosis I there areej - 8jktop5v: 64 chromosomes. What is the haploid number of chromosj58:-oevk tpjomes?

  Which arrow is pointing +ah4k5 t l jfqykd)j94to a chiasma?

  The diagram below representscnyp p6l-9,1+ns 8 llj 7j/o7mafbef a the structure of a shoot apical meristem. Which row in the ta fllnp9 ma+86f-j,bn/yc7slpo ea j1 7ble correctly identifies the processes occuring in the structures labeled in the diagram?

  How does meiosis prom e51wi al7fdiar q2y:;ote variation?

  Which of the following statements is/are correct for meiuop-,dpy +:6: md hiyaosis?
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 5mm5eqkb 1n :lz*r 0oakv80z echromosomes.


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 t6kdu8;lgh ) nw:jhm (83ryt lzumours from primary tumours as a result of the movementw) ymjhr(: t8klnldugh;z6 38 of cells?

  How many chiasmata are preseq ,*2rdg2 8d opow3krj3vt b mxjq5/0lnt in the diagram?

  Which statement is a immifm9ebx56k eont+r yjkqw(2+o++5hm k21 similarity between cytokinesis in animal and plant cells?

  Which stage of meiosis is matched to the peper 7* x):;. im*x kb2n:ms ;jhclvfcorrect description?

  Which statement(s) area(4 . brjjgw7f4x2wrqvlhp 32 true 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 results ir jrq )fr*6*mr9wp*t ecv76ix n the formationjfp irmt 9*q*676wrr cv exr*) of one large cell and one small cell. What is the fate of the large cell?

  Which row correctly describes dipd0x 5y:k0rbg3nncnovfu,k+ .loid and haploid cells in humans?

  The following table shows the diploid chromosome number of a range of species.rnhq.0 7ntr6i(mw5cg


Which of these statements is correct?

  What conclusion can be drawn from the kar lt*m+ft+ (kdeyogram below?

  Which of the following processes is characteristic of the meiotic y3so5 (g8qd2dvlwez6l ph/+sand not the mitotic ce+g /ld2(zpe3o5vswq6d yl sh8 ll cycle?

  The diagram represents afvo0d+pz;z6ymc;0mi 4wed5mp h : mq7 bud 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 twcilycjt n0z)o5l qn;mh+*m/y- n :s 3he chimpanzee (Pan troglodytes) is 48. Which row shows the correct chromos 0nsy)-;c :*njtwl5omimhz3 yl/qc n +ome number for different cell types and cell division stages?.

  At the end of which phase of meiosis I doesni2h6 x oe3jsp).cg+ u crossing over occur, and what is the outcn+gp . 6e3iuso) 2jxhcome of crossing over?

  Which of the following statemp ekz6hpuqj/ /prz-42ents does not describe a step in the sodium-potassium pump cycle in the neurona p2z k//e -jzpqu4r6phl cells?

  Which row in the table below is true (gl 9csffk -;zienyg/g (6f.cl*b3 am of meiosis?

Membrane transport is irfe na;x6 /zj:,5w6 g+rslrs kmportant for allowing particles to move across the cell membrane and r5 sag r,nsrwjr6; z:ex/f +6klespond to changes in 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 2;w /pfldys( yis 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 the concentrations of different cy2qbqt r:bdtgx5 5 fnuz;*) 5tjclins during the cell cycle. Which cyclin is involved in preparing for DNA replication? u;zgt2d q :tr5nfj*x bqb55)t

The diagram below shows chromosomes during meiosig(a mk1 bk . (2layr9tec,pg4rs.

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 homologous chroou t9 /b*s,tcemosomes?

  The mitotic index of throat tissues taken fg:0tgtvm kyh/a( cd 5.rom 4 different patients is shown below. Which patient is mo ckgg(0t5md:th/ y. avst likely to have cancerous throat tissue?

1.Draw a labelled diagram to represh + ce-+brmw;qj/sk.aent the 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 karyotype. f68goo;e m(nke3t* nt


What is the abnormality in this karyotype and its cause?

The graph below shows g k hu; e m7:y36u-uesoq8qo+lthe relative amount of DNA in one cell during one complete cell cycle. Each letter 7uo qsm y;kelquh36egu-o:8+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 ma: rr1* d/q cw2lnwxko o70j1eile cat that is homozygous for brown, long hair and a female cat that has black, show1cwro kxjl2 : r7oden/ 0*q1irt hair.


Which of the offspring has a recombinant genotype?

1.Outline how polygenic traits can show a normal uck h8)7p(m j;ssof. fdistribution.

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 of5syuqn8y 7 n)j non-sister chromatids shown in the diagram jy)7unqy5 8 snbelow?

  The photomicrograph shows a pollen grain from L. candidum (Lily cct;)l3olhv dycl: j,f2t-ck-6i5,wk h ,mwt). Which stage of meiosis ltikc,:cl-5,otf, ;h6l w twm yk3hjd-vc2 )c is shown?

1.Outline the events which would lead to an individual being bcp1w*2 ztvavglq sl,7j4 hu-) orn with Down syndrome, which is characterised by the presence of thresgzlv 7vachul q4)21*tw-p j,e 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 stu np(vspsuq9vv0ggh0 ad /,.+e9ljh /fdy was conducted on white onivugvhg+s9 (ep9n/0 . h ,vlqf ajpd0/sons (Allium cepa), under controlled conditions in a lab, to investigate 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 arvr6+.2 x22zwznpd rxr(wuphl52 o 4vm e two ways in which cells can divide. The diagrams below show two cells from an organism withxx26rov nm25lz dr(vhp.z+wr u2 w4p2 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 exprn17x6u e-m/,l2nzw) g crik ugession 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 /w3ai ir;x8zkdiploid number of 8, in different stages of meiosis. Which row i;wz3i8 /xkarcorrectly names each stage?

  The micrographs show four phases of meiosis I o0-(ddf. k oeyc hc(q9j) fvz6in a plant. In what order do these phases occurf9zh6 -(q)(oevdjdc.yo k0c f?

Mitochondria are responsibr73omp uuum;6 le 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 the result of sexual reproduction between two different yeast species, could be influenced by the parent’u;6uro mm7p 3us 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 cel;lrs i1 toe;2nls in different stages of the cell cycle in four sampleoet1 ;nl; is2rs of lung tissue from four patients. Which tissue has the lowest mitotic index?

  The diagram shows the dominant cyclin/CDK complexes aulk.1- vqi hf1s3i- p1f4h;mn5pnu hbe8s6dvt different time points in the cell cycle. Which cyclin/CDK complex acts5sdb qi4 pivu1 ;3f n-hm1hk u1e6l- fnv8p.hivates DNA replication machinery?

  Studies have shown that genes such as Cyclin Dependent Kinase 3 (CDKN3) are 534/xmy1bpsj /xg;ew4shfoqhighly oxsms q yx 5p3 1b/;ehoj4w/fg4verexpressed 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 cyc tl1h09riigz: an ma.+-gd4fjlin E the highest during the cell cycle ?