The graph below shows the relati*ez22ixc- gt2: /rkq wu:hsidfg(5 mj onship between maternal age and the incidence of non-disjunction. What qdg f zigcm:xw:*2kt5u2j -is/hr(2erelationship is suggested by the data in the graph?

  Which stage of meiosis i*qbx3dja 94xm9s yo; wsi1 p4is represented in the diagram below?

  The diagram below sh4heq*hk exsfd(srle0xo3o )c**4 fx:ows 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 number ovc6t )) lvpr/l,fvu *tf alleles of a single gene which would be present in the nucleus of a )uv) tl*cl,prv/6v ft cell as a result of each process?

  Which keyword is matched to the correct definitio (.u+xqu,r gimejl-i)b3b c8 zn?

  Which statement(s) about mitosi4 njzc4btr l+1s 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, wh i wnxb8.f ,edgk1ty0b fj1(q*r6wx8 uich letter points to a cell in anaphase?

  During which stage of mitosis doesxbhqcje h5 r;0dlz-xg49o5x6 the nuclear envelope break down?

  Which one of the followkxr6+qhf k/j24qnhm )ing transport proteins only carries out active transport?qh+xjk2/kfr4 mhqn) 6

  Which process does not hap6jc9f5eo-jvz 0 w4)cuo gpjp,pen in the shoot apex?

  Which type/s of membra/ knljn5 hb bk;;hlz0;ne transport do/does not require energy expenditure?
I. Facilitated diffusion
II. Active transport
III. Osmosis

  The diagram below represents a cell with a diploid nr ua;x* *a2hcaumber of 4. Which stage of cell division is the cell cu ar*a2xhu *ca;rrently undergoing?

  The photomicrograph below shows a root tip meristem. Whikxa3kt zsq.u 4f-ld:5ch of the following sente f4kud -z: s.5qaxl3tknces correctly defines a meristem?

  When does the random orientation of homologous chromosome pa7x9dt zjw2 oj)irs occur?

  Which process does not occur during x0usx7/ oo/qi9d)oho meiosis?

  If a cell with a diploid number of 36 undergoes mitohi8*8dqrn3p +zbd-u w sis, how many chromosomes will be present in each daughter cell after cytokines id8bh -nrwu*z 3+8qdpis?

  The image shows a microgr d bjrant-( nn;qn7(p4aph of a cell.


What explains the appearance of the cell in the micrograph?

  Which statement(s) about homologous chromosomes is/are ni rykx qkq/3 ei(ez*1b al:a,)ot 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 indivib9e lnx:6rywhcj*l m1 ut93 2.jb1ffidual with Down syndrome.

Which statement is not correct?

  In the cells of a horse (E. caballus)t gpa5yk84yl8 yh+q/t during prophase I of meiosis I there are 64 chromosomes. What is the haploid number of chromok/ a8p8ghy5qty+l 4tysomes?

  Which arrow is pointing to a chiasm ;c2pkirh6pjw4 +d2tl7t 9dn qa?

  The diagram below represen pk.wfcca8ohk2w ex9 h*601vb ts the structure of a shoot apical meristem. Which row in the table correctly identifies the processes occuring in the structures lab1 0ox *kwa2kc.fhpw9c6 ebv8h eled in the diagram?

  How does meiosis promoteno;z3un); hr q variation?

  Which of the following statements is/are correct f7zdwqve8bt /+ i xp 7j:vrm:l2or meiosis?
I. It is a reduction division
II. It involves random orientation
III. It produces genetically identical cells

  The diagram shows gametes producenlw*o3+ zcq 7ap- u8/ 6yjqkgjd 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 thhdlu4;1h,l q4kt 0ad rce au44e formation of secondary tumours from primary tumours as a result of the movement o10h4cah q4 l4l,ud adrke tu;4f cells?

  How many chiasmata are present inqz 5qjc:u1e xdsadct; vj;*vzt+ :m+, the diagram?

  Which statement is a similarity between cytokinesis in animal and plant ce z*9m kv xaaj5ng0/nya7rb2 (plls?

  Which stage of meiosis is matched to the correct descrtvt;d:0dtwgqa- vgz2vae( 07iption?

  Which statement(s) are true of mei. ;l(mixie)z*o6e pcu ,lvw- x (+vomcr7 u;syosis 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 afterk)w i7nduj/(rx)wu3r the first meiotic division. This results in the formation of one large cew)u(dx r nk)3u/w ij7rll and one small cell. What is the fate of the large cell?

  Which row correctly describes diploid and haplow q):5ziepe u55pgh-mid cells in humans?

  The following table shows the diploid chromosome number of a range of species. x: u: oa7a+fqc


Which of these statements is correct?

  What conclusion can be drawn from the 1tc ,hcnn+gu 1j*bn,mcotd(6karyogram below?

  Which of the following processes is characteristic of the meiotic and not the uol:dz8 d 09yttkvp-bo1 2*aymitotic celld ptz2b-t0d8: lkoa*vy y1ou9 cycle?

  The diagram represents a bud with a shoot apical meristem.p*:ga(vfg p. r

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. Whichyxh41qn mg;* +kg,xur row shows the correc4*hxu1 g,r+ q y;mngxkt chromosome number for different cell types and cell division stages?.

  At the end of which phase of meiosis I does crossing over occun/.f; d nvz5vbr, and what is the out5vz /d;nfn .bvcome of crossing over?

  Which of the following stj z2 d*t1r8ov- vjc,diatements does not describe a step in the sodium-potassium pump cycle in the neuro o, vj-81ji2tr vddz*cnal cells?

  Which row in the table below ike8* wy*i)lm/5 sv0 kis9d lkys true of meiosis?

Membrane transport is important for allowing particles to move across the cell *k /sy:+z6gomp3nmop50xqrl membrane and respond to changes isxy0p: rko/n+ 3plgo5mz mq 6*n 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 is regulated in cells.+ ya8wkng5qjt ipp (e2wvj0g 1g.nm:8

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 durzb+wl) l gxmb 9:-yd(iua6( uking the cell cycle. Which cyclin is involved dy6 z lua)9mbi+luw:g-(xk ( bin preparing for DNA replication?

The diagram below shows chr54n /nvixtqd. ns ;am5 j2ykr*omosomes 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 invol4 fw p4 u bu0sggi i:j/y47k6t.nlxk+fves the separation of homologous chromosomes?

  The mitotic index of throk-f5-ix. ougw at tissues taken from 4 different patients is shown below. Which patient is mo-i5.gwuf-o xk st likely to have cancerous throat tissue?

1.Draw a labelled diad(),xlad40 berem fw -gram to represent the process of crossing over.

2.Compare and contrast random orientation and crossing over.

3.Outline the stages of meiosis.

  The image shows an abnormalxhqsj7p,e( 96w b26d1gkis k j human karyotype.


What is the abnormality in this karyotype and its cause?

The graph below shows the relative amount of DNA in one cel,d232+ cf lxu,vd wxrzuz3(jn l during one complete cell cycle. Each letter represents one stag xn3f2w j3(,dc zux,+2lu dvrze 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 po95k3e3 r59 sbzqz dgyl-e(ss nr6f(cat that is homozygous for brown, long hair and r(3(delroqsfz59-9sz5n s3b 6gk ypea female cat that has black, short hair.


Which of the offspring has a recombinant genotype?

1.Outline how polygenic traits can show a normal distrib-viug o 3x3tqyc7+y*ke6o cwq6 a /dh,ution.

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 omqx.6 hfmdb6 s.jc o06ver of non-sister chromatids shown in the diagr s6bfm60x6.h c.qdojm am below?

  The photomicrograph shows a pollen grain from L. candidum (Lily). W /+h7y) p0w idceed7oahich stage of meiosis is sh )odi/ah+c7eye wd70pown?

1.Outline the events which would lexegg)0xo, v3/k2uf.2h u , sm-xfsrzkad to an individual being born with Down syndrome, which is characterised by the presence of three copies gsmhz.2)xf3v xu/r,o0fx2 se,kk -ug 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 was / 6uf( sm zjb5s;9f,m l.kpsxjj5e0erconducted on white onions (Allium cepa), under controlled conditions in a lab, 6xp9ems /j,ffl;jmj .b ez ks05r(su5 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 qj0l/fhgqi4/h v(twb 75 k7vmtwo ways in which cells can divide. The diagrams below show two cells from an organism with a diq k lgtwhb507 /h/i47f(vmvq jploid 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 expreo;j d lioaq.gqc3l:t / lu*9;18 bjxxgssion 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 showp6rkz*x2vr2 ; 1.zzbv5de:o pobmxh 8 a cell, with a diploid number of 8, in different stages of meiosis. Which row correctly nambp;bvo o2.:r2z5e18*xxdk6zrpmzhves each stage?

  The micrographs show four phases of meiosis I in a plant. In:5-atbht3j;mlmce :e what order do these phases occur?h:eb:m3ct; t -jl5mea

Mitochondria are responsible for supplying metabolic ez0 40wo5 jdiiwnergy 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 wi iw5wdjo00 z4hich 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 cyldn.0zk: ) uz,z53(hjdw wvqle(8hi tcle in four samples of lung tissue from four patients. Whizjn:eld3t. q hdv0l8w iz,5uk( w(z h)ch tissue has the lowest mitotic index?

  The diagram shows the dominant cyclik)b q+65a(rjqke) b gzn/CDK complexes at different time points in the cell cycle. Which cyclin/CDK complex activates DNA rej qaz(bkb)5)g+q kr 6eplication machinery?

  Studies have shown that ge2q)+*rp01z mzex iauqmr1 .x ynes such as Cyclin Dependent Kinase 3 (CDKN3) are highly overexpressex qae.rr1zuzpm y2 x1i+) qm0*d 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 concentrationumta)-gly z, ; of cyclin E the highest during the cell cycle ?