The graph below shows the relationship between mh*o34o n+ck n3tyvth, aternal age and the incidence of non-disjuncti4,o*ytcn vn k3+o ht3hon. What relationship is suggested by the data in the graph?

  Which stage of meiosis is radcfj2 t:rh b7uq5j( hv q)x,0epresented in the diagram below?

  The diagram below shows chromosomsw um708tpql4 46ux d,f y+h+*ffgwve es 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 statez rr3 b4r-xm.ws the number of alleles of a single gene which would be present in the nucleus zrb.- 4mr3rxwof a cell as a result of each process?

  Which keyword is matched to the correct definitiono yp,wf(bt:i4q +1xaoi(sbp: ?

  Which statement(s) about mitosis is xt6l3k4b+ zb ytmry9(/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,z.ibqnm8k w7/o bf v q6,f,,owk7bprsks2--l which letter points to a cell in anaphase?

  During which stage ou-a1mx8, uu rgf mitosis does the nuclear envelope break down?

  Which one of the following transport proteins only carrihdbq aq,v(/q4es out active transport?q ,q(dq4 bav/h

  Which process does not happen in the shoot ad 8,g .x pg..c,g azfoizrn++qpex?

  Which type/s of membran((p4aeyoah k yz (:tf)e transport do/does not require energy expenditure?
I. Facilitated diffusion
II. Active transport
III. Osmosis

  The diagram below repres q;m8k/sbesz8ents a cell with a diploid number of 4. Which stage of cell division is the cell currentl;z e bq8s/8mksy undergoing?

  The photomicrograph below shopvxzxbur7 t,+01vzp6nb6xw1 ws a root tip meristem. Which of the following sentences correctly defineu6pn,xbb +10 xxwr p16tvvzz7s a meristem?

  When does the random orientation of homologous chromosome pairs occurskn bqnq65b7 n7 4/vmu?

  Which process does not occurrnl3l t) axbat/(a xoq92xn99 during meiosis?

  If a cell with a diploid number of 36 undergoes mbhanrb 58i nj72q 2xt 0-lyho)itosis, how many chromosomes will be present in each0j8n r5 bt2 lhiyb2ox7anh )-q daughter cell after cytokinesis?

  The image shows a micrograph of a cell.wxp9z t4c:ip lr*yg:84hgp v.


What explains the appearance of the cell in the micrograph?

  Which statement(s) about homologous chromosofp xiu/5vh0-) n3vy+xeon 3b omes 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 Dowv2 i:/chhb1sj(qfb2i )q2qr 6g p mv+in syndrome.

Which statement is not correct?

  In the cells of a horse (E. caballus) during prophase I o5; v;hp,z i4bbmf l6ngf meiosis I there are 64 chromosomes. What is the haploid numbz b f,h5n;4mlvpg6 i;ber of chromosomes?

  Which arrow is pointing to a chiasma?u66g :k c gno-kf.b*pb

  The diagram below represents the structure of a shoot apical meristem. Whice/lg k,r6 i-heh row in the table c,e6 r-e lk/ghiorrectly identifies the processes occuring in the structures labeled in the diagram?

  How does meiosis promote variat(q*geoh m)e.b ion?

  Which of the following statements is/are correchyurk lufhat6s,x8 f10 c8qj(i,( y o1t 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 homologous chromosomvq1 rcnhem*k dhc1:8. es.


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 formationf8. prlh+ sslsz-1w -x of secondary tumours from primary tumours as a result of thrxw-sfhs z+.l8sp -1le movement of cells?

  How many chiasmata are present in theipm5.mrh.d9jc) mk t: diagram?

  Which statement is a similarity between cymu j ef-8kn5x)tokinesis in animal and plant cells?

  Which stage of meiosis is matched to the correct descrip qbv6e:;1mbev +qf7cntion?

  Which statement(s) are true of meiosisu hb*2.;boi 1 usrp3wq 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 anj+;*yh-nux,ga9m36 xgnz v em oocyte after the first meiotic division. This results in the formation of one large cell a 9njg,z+63-* uxxnh mvymae;gnd one small cell. What is the fate of the large cell?

  Which row correctly describes diploid and haploid cel thun 0b8472sg qmc)*i ktns:dls in humans?

  The following table shows the dih7jceint 0,tsi+hjg;o (zu -. ploid chromosome number of a range of species.


Which of these statements is correct?

  What conclusion can be drawn from the karyogrfw3lis4y 7 +cu*fskl1am below?

  Which of the following processes is characteristic of the meiotic and novu ; 4*g7vbmgr*mgsz; t the mi7; mm sv*;4vb zrgg*ugtotic cell cycle?

  The diagram represents a bud with*q8/lre/dq1lkz;x *ymuma/n 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 rowpauag j8 vc3- v:y5p1n shows the correct chromosome number for different cpa -c 3a1jv5 y8vp:nguell types and cell division stages?.

  At the end of which phase of meiosis I does crossing over occur,mf6 8jo hr)+a5bmdu ;a and what is the outcome of crossing o6armjhmfo5a) ;u+b8 dver?

  Which of the following statements does not describe a step in the svwym) ych5n 6i7k :;uxodium-potassium pump cycle in the neuronal cel m6 ;y5nhyxw cv7):ikuls?

  Which row in the table below is true o77puyb7sq, lk f meiosis?

Membrane transport is important for allowing particles to m vwn5ll3de5 ( 5vh0vxlove across the cell membrane and respond to changes in the chemical composition of the extracellular fluid.v 5we0lvl( 3nlvxd h55

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 mitosir4423g nchu ;tud3oxz -j ylpt/65dijuexb*4s 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 showsufa 0jbh +s+qp0tc :u5 the concentrations of different cyclins during the cell cycle. Which cyclin is involved in preparing for DNA replicat0 +fujs:h+pcbaq 50 ution?

The diagram below shows c 3uti2k)/( cnzm 70dddyk:d6d/fccg ahromosomes 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 homologous chromodrv-8 myy/ k3z1 k7vmzsomes?

  The mitotic index of throat tissues taken from 4 difnso;u3)lv,b.o2z p t.u318mggy yn rfferent patients is shown below. Which patient is most lik 3ontl ungs .my.r3; f,b1vg2 8youzp)ely to have cancerous throat tissue?

1.Draw a labelled diagram to represent the process of crossing gd2wv 4imm,fhay )pd9-tv, icl 8f9(4toq ic2over.

2.Compare and contrast random orientation and crossing over.

3.Outline the stages of meiosis.

  The image shows an abnormal hu dby ;8cb,k 1o9gtl+y opm6d3p4czz .oman karyotype.


What is the abnormality in this karyotype and its cause?

The graph below shows the relative amount of DNA in on:zb6ya qob:; ke cell during one complete cell cycle;b :kqb6zyo: a. Each letter 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 betweev -ealtwv(yn gx de743-0ao8yn a male cat that is homozygous for brown, long hair and a female cat that vx8ayd7y(a 3two0- g4nelve-has black, short hair.


Which of the offspring has a recombinant genotype?

1.Outline how polygenic traits can show a norm tp;q ars9k(z4al distribution.

2.Outline the differences and similarities between homologous chromosomes.

3.Explain why expected and observed Mendelian ratios may differ.

  Which gamete can resujf1/ : 26mfiia j4zcxqq9bo 9flt from the crossing over of non-sister chromatids shown in the diagram below?q mf:q1b949jozi 2fcaf 6i j/x

  The photomicrograph shows a pollen grain from L. candidum (2l 8e1 21iskf f 6/ibzixlcp:c2 5mxalLily). Which stage of meiosis isxi 61s8czflfx 22p1ica2/5e k il blm: shown?

1.Outline the events which would lead to an individual being born with Down syq+85q4 tep qg) 6rfqlpndrome, which is characterised by the presence of three copies of ch rl5qepq pf 68t)g4q+qromosome 21.

2.Explain how meiosis increases variation.

3.Outline the stages of meiosis.

The mitotic index is an indirect way of measuring p (paf-;/kh 54ondudg xs /sgh*lant growth. A study was conducted on white onions (Allium cepa), under controlled conditions in aa/4d/5o* g p gks;hn(-hufdxs 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 warko ;o:fmq+ v0zu.d9yc;+u;bne z we, ys in which cells can divide. The diagrams below show two cells from+;m 0r dezuu ;+.o fqyz;wkc9vn:,e bo 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 expressiswb;( c0 tp 68fne9q(yo:wtbi on 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 diploid numbed/ (d 12fnaxbor of 8, in different stages of meiosis. Which row corro n/dda1bf2 (xectly names each stage?

  The micrographs show four pha9nl (iset o52kv-m88wzbrc6 uses of meiosis I in a plant. In what order do these phase9 m-ce(rn5lovi bs 2u ktw868zs occur?

Mitochondria are responsible for supplying me2l;d7f(pi64 t ozboo ptabolic energy in eukaryotic cells. In most eukaryotes, which reproduce by sexual reproduction, mitochondrial DNA (mtDNA) iso7 t2oibz ;4 p(dl6fpo 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 difows(4eg1/6z.rkpfg9xb /q lrferent stages of the cell cycle in four samples of lung tissue from four patients. Which tissue has the lowest mitotic px4z6w9/kg/gr.be fsr 1lo (qindex?

  The diagram shows the dominant cyclin/CDK complexes at di;85oybg.)g z8qt4u-ve 3/kqoqwf ojj fferent time points in the cell cycle. Which cyclin/CDK complex activates DNA replication machinery?-5)k /b gvez 8qyf.t o3uj;qjg8qow o4

  Studies have shown that gen3 81re8r5maip:ma plees such as Cyclin Dependent Kinase 3 (CDKN3) are highly overexpressed 38iramlp rpa:1e e58min 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 the cell cycle yp7 qt nm ;/,n)sc4gij?