The graph below shows the relationship betwefh(0 mupp en67en maternal age and the incidence of non-disjunction. What relationship is suggested by the data in the grap76hu(n0f mppeh?

  Which stage of meiosis is represented in the diagram +qspeo*yv+-;ci7jbun6 ) ucu below?

  The diagram below shows chromosomes during menxd;4t2o-5zyr pv l b6iosis.


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 allj7)udj1 nyzoy,t 3oypd7y90l d z0c ;jeles of a single gene which would be present in the nucleus of a cell as a result of each procej z1d 9y,0t;nou)jo7z 7d 3yjpc0ydlyss?

  Which keyword is matched to th qrc 7oi/ b+ci((hli;ke correct definition?

  Which statement(s) about mittly. g33jhsxcv y m*8 e)-h9wgosis 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 gy+-ssku m(qv sj1 1e7a cell in anaphase?

  During which stage of mitosis do*6ghangr svkq;-0) zyes the nuclear envelope break down?

  Which one of the following transport protei+0jgj j/;4s) xdzsp xjns only carries out active transport?; dj+j)sx xj4zg/sj0p

  Which process does not ha x271dyfvvy0v ppen in the shoot apex?

  Which type/s of membrane trang/wmnbt i4n1e -(b* g7rv+p cfsport do/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. Which stage of:b58 -t thvqla fiz9/n cell division is the cell currenlv 8f5q za-b:it t9nh/tly undergoing?

  The photomicrograph below shows a root tip meri2/uptv d.sl, nstem. Which of the following sentences correctly defines a meristem?2n.l d,ust v/p

  When does the random orientation of homologous chromosomuiy 4qmc: -c0xvya5 2me pairs occur?

  Which process does nobg( v.w 3)dmdl w3 eied cmt21e)tl9g5o-w*ezt occur during meiosis?

  If a cell with a diploid number of 36 undergoes mitosis, how many chromosotqb3t2gd,n (ik qy 8i6mes will be present in each dau qnqb32gdik yi6, (8ttghter cell after cytokinesis?

  The image shows a micrl-nhc-wqxp +/a,gwvv fs4h4gh -9/fcograph of a cell.


What explains the appearance of the cell in the micrograph?

  Which statement(s) about homologous chromosouz+qh/m ss2q(oza wcl9hx . 48mes 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 indivimyj:.8fw6 l74bjor .nhv a l,pdual with Down syndrome.

Which statement is not correct?

  In the cells of a horse (E. caballus) during prophase I of meiosis I there aresvo, ufyx/rxr ;o 330e 64 chromosomes. What is the haploid number of chromosomes?r3f exo3xuo0ry, ;s/ v

  Which arrow is pointing to a chiasrz 8/. cflv/2 -n1ll1 dzhj 5yndx7bcfma?

  The diagram below represents the structure of q egu;cza0.8c a shoot apical meristem. Which row in the table correctly identifies the processes occuring in the stc au;8e.0gzqcructures labeled in the diagram?

  How does meiosis promote varyi 0fp :dv7gnu7g+hk, iation?

  Which of the following statements is/are correct for m5;gms bz8 ho3ieiosis?
I. It is a reduction division
II. It involves random orientation
III. It produces genetically identical cells

  The diagram shows gametes produced ad8 p(-zxa3 p-+aarl sfrom 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 r/epxz -w3 a/;fngwa9 formation of secondary tumours from primary tumours as a resw/3fe arx;w9- nz pa/gult of the movement of cells?

  How many chiasmata are present in the diagram :eftx*v+3jsy?

  Which statement is a similarity between cytokinesis in animal aj34197gs yfs/elcxe3 3z wfcind plant cells?

  Which stage of meiosis is matched to the correct descripai9, rmu020y-x rpboetion?

  Which statement(s) are true of meiosis I but not mei dfyn2rwcj 13tb6 ufwt 4w069sosis 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 dibwn :fz8e6j)6on 7b swvision. This results in the forms :ewf6)6b z87nbjnowation of one large cell and one small cell. What is the fate of the large cell?

  Which row correctly describes diploirq928-ha ghs-1 ;d zjyoru- pid and haploid cells in humans?

  The following table shows the diploid chromosome numberce o +34.bm8g5snj-i jnuwcc / of a range of species.


Which of these statements is correct?

  What conclusion can be drawzct: ib ymr2+8n from the karyogram below?

  Which of the following processes is characteristic of the meiotic an(.i/(+2i in pij wammnd not the mitotic c/i+jnwp2 (i mmn(ai.iell cycle?

  The diagram represents a bud with a shoot az z5jcwk dx8+.kd/,z+gn q a,vyj1tw2pical 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. uf9 mct*v25 lbjmop, 5Which row shows the correct chromosomcv foml9,*j5mt52 u bpe number for different cell types and cell division stages?.

  At the end of which phase of meiosis I does crossing oveia (kbxje8 a y+(:lb6cr occur, and what is the outcab8c ie(baljy k:+6(x ome of crossing over?

  Which of the following statements d:p5 4 wd:uf vddosqh0za-h5p4oes not describe a step in the sodium-potassium pump cycle hvo4dspuw z- :qp 505dhad4 :fin the neuronal cells?

  Which row in the table below is trrivxe,;a 7s n-ue of meiosis?

Membrane transport is important for allowing particles a 0k3jka:zwb:k8 b-ncto move across the cell membrane and respond to changes in the ca8-3kkb:0j na:bwk zchemical 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 imvce ds:4 wsc;p1hump - 2c*c6s 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 cyclins during the cell wdx4h(.t0uv rcycle. Which cyclin is involved in preparing for DNA rh4x0(dw v.tureplication?

The diagram below shows chromv7c nq 4c sjis:9aad)1osomes 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 separation of +s(zny6 b my/shomologous chromosomes?

  The mitotic index of throat tissues taken from 4 different patients isf7e a7jj7 jyddg+.qc7 shown below. Which patient is most likely to have cancerouj ej7jqfcd 7d+ .ag77ys throat tissue?

1.Draw a labelled diagram to reprx qe575o tw0 9qu1gwzhp k51afesent the process of crossing over.

2.Compare and contrast random orientation and crossing over.

3.Outline the stages of meiosis.

  The image shows an abnv(w p8d 5pq 5oytqh;9q hle1k4ormal human karyotype.


What is the abnormality in this karyotype and its cause?

The graph below shows the r co3. +lfazr/en0f2n selative amount of DNA in one cell during one complete cell cycle. Each letter represn0s rcf + oe3f./zlan2ents 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 avnhzv 0a1;0ldar9 sf( ,bnhn5t0l,p+p wlmz1 cross between a male cat that is homozygous for brown, long hair and a female cat that has black, short halhp09bvm1a+z n,vatz;(0s 1n r0, nwldfplh 5ir.


Which of the offspring has a recombinant genotype?

1.Outline how polygenic traits can show a normal distribucocv4.gn5jsw v8x .wp)7ut ) ytion.

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 sh4r*1u: pbm9et tzi l,lown in ttt:zpr4u b9 llei*m, 1he diagram below?

  The photomicrograph shows a pollen grain from L. candidum (Lily). Whichuvb,;9jo-ynq6f 8d u i stage of mdu f o-uyvi9b8;n j,q6eiosis is shown?

1.Outline the events,h;, ozjewf3z j9 i(qizt ;,su which would lead to an individual being born with Down syndrome, which is characterised by the presence of three copies of ch9o zjhtf;; u,j i(i,3qsz,w zeromosome 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 wa4dpnswl+ys 80 s conducted on white onions 4 0s8wnlsdyp+ (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 are two ways in which cells can divide. 13gi bv icb;;ng81)*bj zu npg1,mvoqThe diagrams below show two cells from an organism witn iq;cg;1uv,*izbjb 1)3 pm1no vggb8h 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 gre3) uln)-dum a (7ifsiowth.

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 numbms3 kt6 :x;wgher of 8, in different stages of meiosis. Which row correctly names each stg 3;k:tshx wm6age?

  The micrographs show foyym uh9e;,)bv6u, aezp 3tlt,ur phases of meiosis I in a plant. In what order do these phases occuya 6,3t, vzm lpye;)teb,h9uur?

Mitochondria are respoxs e-wz- jphs 0+4z4kynsible 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 beepz4kejw zysh4s-x0-+n 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 difea *na9am :b42fcjr80dtmffn ** gme7ferent stages of the cell cycle in four sagf*d e jta9ef7mn20r4fam:a*c8nm b * mples of lung tissue from four patients. Which tissue has the lowest mitotic index?

  The diagram shows the dominant cwb b 2agj(ct2 67vs.6)qbxmng yclin/CDK complexes at different time points in the cell cycle. Whichsq()b g2nt27 bj6xmc b.w6gva cyclin/CDK complex activates DNA replication machinery?

  Studies have shown that genes such as Cx8ls lij9-aj;r *(fq eyclin Dependent Kinase 3 (CDKN3) are highly o(ei;f *s 8-xjllr9jaq verexpressed 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 te.d-h + xkawcz:4pgh:he cell cycle ?