The graph below showl w;mj3rlo;1looo76al4zt a 8s the relationship between maternal age and the incidence of non-disjunction. What relationship is sug8al4 o6r ol; oa;wl7 3oz1jltmgested by the data in the graph?

  Which stage of meiosisk.p.8o a ir901pjpx py is represented in the diagram below?

  The diagram below shows chromosomes during meio an )8mlb)qah5 izo5vnwuwh+3-1 nu;usis.


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 alleles of a single gene which wok(oxwn yt/u*2*k0 vbpuld be presen*t kxkwy*(u/2pvb0 no t in the nucleus of a cell as a result of each process?

  Which keyword is matched to the cor/s -xw40cli snrect definition?

  Which statement(s) about mitosiyzc 0u9 8tskw7s 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 cell in anaqbjz 3vy, /s(aphase?

  During which stage of mitosis does the nuclear envelope brgl 4z42pxb+t eeak down?

  Which one of the following transport proteins only carries bhiu(crete i0/++,f 7*rr: 4xsgp+hxp nu(hsout active transport?ph *gsus nctiu7r4b ,e( rfe(+xr+ix/hh0p:+

  Which process does not haple8 a z-4rx)( zpgg+2zwvpq k2pen in the shoot apex?

  Which type/s of membrane transport do/does not require eney/3e )yyqq sd-2sf k;vrgy expenditure?
I. Facilitated diffusion
II. Active transport
III. Osmosis

  The diagram below represents a celp mnzjzbo++9hb m/ - ivs,38m9lvd sh0l with a diploid number of 4. Which stage of celzs/m9bldb8i p om0n hsj+9v- ,v 3hmz+l division is the cell currently undergoing?

  The photomicrograph below shows a rbnuqt)mwa fir-4g3x7 4x -g-woot tip meristem. Which of the following sentences correctly defines aa-3r-b4f4 mwxqgi-7g txnuw ) meristem?

  When does the random orientation of ho2j7o l 0v8m4aawtrjo8mologous chromosome pairs occur?

  Which process does not occur during mendh;ag7a-y) g+r a b)niosis?

  If a cell with a diplp0x)a kn-d u; k xsow9:a1rl,void number of 36 undergoes mitosis, how many chromosomes will be present in each daughter cell aks 0xax)al;9onvu -1pdk:r ,wfter cytokinesis?

  The image shows a mi7qan8jat t:dy s.i0,wcrograph of a cell.


What explains the appearance of the cell in the micrograph?

  Which statement(s) about homologous chromosomes is/am imrrfv9y54 b)v3(xwre 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 sy(dn29o cq4sbfndrome.

Which statement is not correct?

  In the cells of a horse (E. caballus) during prophase I of meiosis I there n-zqnk+d(;48vurzx b are 64 chromosz8xr -v 4(b+qunn;kdz omes. What is the haploid number of chromosomes?

  Which arrow is pointing to a chiasma?n5g intkmwqv x, 9a3)*j.u u6z

  The diagram below represents the structure of a shoot apical meristem. g4a i+pv5z4w ra52x+ny enc3i Which row in the table correctly identifies the processes occuring in the 2iir3avpa+nw+ 5n4 yg 5ze cx4structures labeled in the diagram?

  How does meiosis promote vari ./ -a qapo;y(ieap9jzd e/-juation?

  Which of the following st)jy e hli6,dwdns1b. )n18luf atements 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 gxh+ zkr:pbdn v 1)m)9j)rxg0*2x rpbproduced 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 secondary tumours from primary tumoucs3a g9xv,gj 8rs as a result of the3,9asj8gx gc v movement of cells?

  How many chiasmata are present in the dwco+6b9 xv7jxc)q .gdiagram?

  Which statement is a similarity between cytokinesis bhn7+m d k5us,sc)2 *5yg,4wxrgekh uin animal and plant cells?

  Which stage of meiosis is mathnm og)fra,)49qb kvera5d : .ched to the correct description?

  Which statement(s) are true of meiosis xk7c kn)slc(ccfj i ((t -,y-kI 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 meiov/v wz xynhz(y 2s25ld: 8ln7qtic division. This results in the formation of one large cell and one small cell. What is the fate of the large:qlh7v /z2y2zdn8 nx5y v ls(w cell?

  Which row correctly describes diploid and haploid cells in humh.id0 tt +6.y e(yrjusans?

  The following table shows the diploid chromo dkafd, i *5)b*fhg;thsome number of a range of species.


Which of these statements is correct?

  What conclusion can be drawn from the karyogram below5q-zqxnkbev*. h0 x 3e?

  Which of the following processes is characteristic of the meioticu(q1++ kyiuuv 2ag2lb and not the mitotic cellb uv2y1 aklqug 2(i++u cycle?

  The diagram represents a bud with a shoot apical merib-8l2vid+ okw stem.

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 chimpanzee8n vf0di k:xt0 (Pan troglodytes) is 48. Which row shows the correct chromosome number for different cell types and cell divisio:vf ktn8xd00in stages?.

  At the end of which phase of meiosis I do f5wc:t+ o 7hm;galp88hw jqe+es crossing over occur, and what is the outcome of crossing ove:ef8 a 5 jtw g;p+wchlomq8h+7r?

  Which of the following statement+ uxenglmrv 7tl2)4(h s does not describe a step in the sodium-potassium pum lm27()hxletvr4u+ gnp cycle in the neuronal cells?

  Which row in the table below is truhqfbse: 6b1 w ab*1/jne of meiosis?

Membrane transport is important for allowing particles to move acro(upw8))wfd f5f*lrr es8 +wu yss the cell membrane and respond to changes in the chemical composition o)fwdrf(rf5 8 8+lewy) puus* wf 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 +x6l0bu do/8pt 7gbov is 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 th8 fewzfo 2-,fre concentrations of different cyclins during the cell cycle. Which cyclin is involved in preparing for DNA replicat2f,o8wrz f-f eion?

The diagram below shows chromosomes during m uousz5x+ h7u*eiosis.

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 chroe :+vj8t x5klzmosomes?

  The mitotic index of throat lx7zbse)/ zk 96okau /tissues taken from 4 different patients is shown below. Which patientk ze /7)a/zko su9x6lb is most likely to have cancerous throat tissue?

1.Draw a labelled diagram to represent the process of cross/v ,uv.a/4fsldl 6i8k6 va umging over.

2.Compare and contrast random orientation and crossing over.

3.Outline the stages of meiosis.

  The image shows an abnormad/vn nw0ad 2:ln-+bijl human karyotype.


What is the abnormality in this karyotype and its cause?

The graph below shows the relative amount of DNq1, 7r t (o1hqkug,tdv3 k+meiA in one cell during one complete cell cycle. Each letter represents 3 vkrqdh ,1k,iu+ ogtt7m1 (qeone 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 homozygous f*bq)d5t 3cm0ehggh c 3or brown, long hair and a female cat that ha0c gc)teq b3 d5mghh*3s black, short hair.


Which of the offspring has a recombinant genotype?

1.Outline how polygenic traits can show a okke*b0s*xc 6normal 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 chro +k1c;sp c6iw hcm3nr9matids shown in ther3wc;pn 1 9imhck6cs + diagram below?

  The photomicrograph shows a pollen grain from L. candidum (Li 3lh36lxnr 0)t*snj sv +hwu,.tjgtp1 ly). Which stage of meiosis is jru h3jn nstt +)pg61wxtv0l * 3,ls.hshown?

1.Outline the events which would lead to an individual being born with Down s8qnvzl a8/ 2e+ sibqs2yndrome, which is char 2niqbvsq a+2l ze/88sacterised 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 of measuring plant growth. A study wasxv/;bsc.2 bo k conducted on white onions (Allium cepa), under controlled conditions in a lab, to investigate the effect of soil pH on theb/s.bvkxo;c 2 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 be:q-;ylu hlm8wvlbf rb+ 4c6x+d .evv0 low show two cells from anuxm 4 dre q+bwlhv-y; +0bvl6c8vlf.: 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 expression in stem grow;lqv3q pwh) )h *tc 3z/0o -ulbjov5msth.

2.Outline how growth is controlled in the shoot apex of plants.

3.Explain the process and applications of micropropagation.

  The diagrams below show ,:1eeqvn) 1-dlyu.;nray c+npwj j l ,a cell, with a diploid number of 8, in different stages oc.ljv na: 1nr u-dwqjp+yye1, ;)nl,ef meiosis. Which row correctly names each stage?

  The micrographs show four phases of meiosis I in a plant. In whav61k xwpic+,ac( ic f9t order do these p f6iv,9cpx+ acc(kw1ihases occur?

Mitochondria are responsible for supp yaklvnt;x,)3 lying 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,ynlv3k a;)xt 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 cevhz1 b2;9+ gvbo5p xuq wv:ab*lls in different stages of the cell cycle in four samples of lung tissue from four patients.5avzxg *uowbb;b1h2 p9 :qvv+ Which tissue has the lowest mitotic index?

  The diagram shows the dominant cyclin/CDK complexes at di5aa*xus5ixfyn (:0dai02d dq fferent time points in the cell cycle. Which cyclin/CDK complex activate aifxd2qid55d 0xu*nas(a0 y: s DNA replication machinery?

  Studies have shown that geness/0e+9ohag of1vb )nvcv*b3d such as Cyclin Dependent Kinase 3 (CDKN3) are highly overexpressed in cervical tu oe/n0)c3vf +sg dbb*1vh9avomours.


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 concentrationw5xjq ez lf/30)jn+ co of cyclin E the highest during the cell cycle ?