The graph below shows the relationship between maternal age and the incide2y(ev 6k,b tb(to s3tjnce of non-disjunction. What relationship is 3st 6yev j2bb((ktto ,suggested by the data in the graph?

  Which stage of meiosis is represented in the diagram b psg46ocj( o mnd60q3t+1ug dpelow?

  The diagram below shows;w ) *kdwvr/yapz: .fj 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 of alleles of a sin*m3k,+ckfjhpvp u9 m5 gle gene which would be present in the nucleus of a cellkh5u 9m, mp *+ckpjv3f as a result of each process?

  Which keyword is matched to the correct definitiwf o3:. vygh r,)si9rpon?

  Which statement(s) about mitou9 jo44lb e +:p/hfrzqsis 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-t 5xygs* rhy) in anaphase?

  During which stage of + p0srr c8bn+w(hzsa0mitosis does the nuclear envelope break down?

  Which one of the following transport proteins onusg kw; v169gnly carries out active transport?96gnvw sk g1;u

  Which process does noo pg s2+8;pf+6s/(0gtrrj ctj ) or7 antjj6gat happen in the shoot apex?

  Which type/s of membrane transport do/does not require energy exn.lc4hf1wk k/,l 5qfxpenditure?
I. Facilitated diffusion
II. Active transport
III. Osmosis

  The diagram below represents a cell with a diploid number of 4. Which stage of cypr 3k p,kt.q,iwsloe1-h 8c9ell division is the cell curre p3okyqh-lc,its p9k w81,.rently undergoing?

  The photomicrograph below shows a root tip meristem. Whd/k7e- rz;ltuich of the following sentences correctly d etu-7 rl;k/dzefines a meristem?

  When does the random orientation of h r.aee)b5 v) e/hfcvh+omologous chromosome pairs occur?

  Which process does not occur duri.35h)4;prul ry53yhx ca xd/ev0h irtng meiosis?

  If a cell with a diploid number of 36 u84sepb mu;/oveh sp6 3ndergoes mitosis, how many chromosomes will be present in each daughter cell after hepuo3m 6s8v ; 4e/bpscytokinesis?

  The image shows a microgra8t2sejua nr434mys 6r ph of a cell.


What explains the appearance of the cell in the micrograph?

  Which statement(s) about homologous chromosomes is/are not true0(6ks) ,slu4xt cgsiu ?
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 individu4 u)jwt(2p uolal with Down syndrome.

Which statement is not correct?

  In the cells of a horse (E. caballus) during prophase I of meiosis I ther1.s,h,l)f - 7rpgvzlky/v ,k 9sfkuof e are 64 chromosomes. What is the hapl 7kkllsk1 h). fuoy,v -fgf/9rs,pz,void number of chromosomes?

  Which arrow is pointing to a chd-+utc6/ i,ldo*m 5qpv /ywk riasma?

  The diagram below represents the structure of a shoot apical aed5q( yi/utt5 oit,inc)9h6 meristem. Which row in the table correctly identifies the processes occurin5 i)9(ieht5 a 6 uotncqti,/dyg in the structures labeled in the diagram?

  How does meiosis promote varia*l x6y.z lqu/)qcg vv(tion?

  Which of the following m,) vvz* oj:*9 ih-3kwbhtcv cstatements 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 gaxk *v mp*+ ir8aq84isdmetes produced 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 s:jxrb7qhypm86 t,x+ zecondary tumours from primary tumours as a result of the movement of cells? rtmhjzb,6xxp+ 8q :7y

  How many chiasmata arey pjr5dwg zd-.c,q( w9zvon21 present in the diagram?

  Which statement is a similarity between cytve9c3 2cqk6vqokinesis in animal and plant cells?

  Which stage of meiosis is matched to the cog2kz3gv2. .pxp yhxn0rrect description?

  Which statement(s) are true of meiosis .bbesf1v/af(5r ox*k 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 resum(ed7gh/1 8(lomszca lts in ths(emgah8cdo(/l1zm 7e formation of one large cell and one small cell. What is the fate of the large cell?

  Which row correctly describes diploid and haploid cells in9r6bu ( fasvc5/gf6ke humans?

  The following table shows the diploid chromosome number of a uw wn2ojq9r ;pt m3a28fd g,(irange of species.


Which of these statements is correct?

  What conclusion can be drawn from theecd yz94;b kddod, 23q karyogram below?

  Which of the following processes is characteristic of ticje*;ad y 9j6he meiotic and not the mitotic cela*idy;cjj e 96l cycle?

  The diagram represents a bud with a shoot apical merisuo m, gz: ka)21;anicqtem.

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 row shows zy2eys 4foyo bi ,+0-qh 2*t,znj;yokthe correct chromosome number z ooy0 2+ neb;ks4y2,oyyifzht ,*-qjfor different cell types and cell division stages?.

  At the end of which phase of meiosis I does crossing over occur, and wha,hmr.e/5uhe n:g0c*vv d4j hb t is the outcome of crossing oven,hmj h v/cru4h0dv5bge*e: . r?

  Which of the following sts;qar3hepah xv44x6 :xbvk4 0atements does not describe a step in the sodium-potassium pump cycle ib40ka ;p4vxa6 rhv4eq:h3xx sn the neuronal cells?

  Which row in the table below is true ofqe0hix 1r1 o/iu;pxg9 meiosis?

Membrane transport is important for allowing particles to move across the vp49h9da29ebz x( 7c /l,gi ocwkjd1e cell membrane and respond to changes in the chemical composition of the extracellular fl hdzxpee92/locj1c7(a,w g4 9db ki9 vuid.

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 o2d30 x)o bixqc8q6g8v bh 57w/0gzlf hs qw/acells.

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 con:oxsykic ..h+w(ae s8centrations of different cyclins during the cell cycle. Which cyclin is involved in preparingw .s .o+(y xcaeksh:8i for DNA replication?

The diagram below shows chromos fq3t:; ew;wlx6qg))th; idksomes 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 chr 7z; :laitxj/eomosomes?

  The mitotic index of throat tissues taken from 4 different patients is showng0n(m -, c 20ssnen3b hept,qu below. Whi3t( -s0pbc,,me eh n 02usqngnch patient is most likely to have cancerous throat tissue?

1.Draw a labelled diagram to represent the process of crou0n:i )di9byxp -u o;kssing over.

2.Compare and contrast random orientation and crossing over.

3.Outline the stages of meiosis.

  The image shows an a8t 6wj ohs u+jv b4xto8pcp765bnormal human karyotype.


What is the abnormality in this karyotype and its cause?

The graph below shows the relative amount of DNA 23n-r8ziobd jin one cell during one complete cell cycle. Each letter represents one stag3no diz -8bjr2e 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 adr9b;d)ah) m*e6)xc-nihdi h male cat that is homozygous for brown, lodir)6d9h)imh; hc - ad*xneb)ng hair and a female cat that has black, short hair.


Which of the offspring has a recombinant genotype?

1.Outline how polygenic traits can show a noq1 irlf ;t3 1/3 s-n:cfraxevermal 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 chromatid djmh2p;i9: tcs shown in t:;di h9pjcm2t he diagram below?

  The photomicrograph shows a pollen grain frombudzo l2)3 ,3awf1 c1ljr2y io L. candidum (Lily). Which stage of meiosis is shol ,o fc1y3a j b2lo3)12driwuzwn?

1.Outline the events which would lead to an individual being born with Down dzk*vps)a2kcons(/,:jkk/+b k + ekq syndrome, whiko)cseks(kd:2,/ k n++k/bq ajk*pvzch is characterised 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 gr54,,1zuw:nerza m o xbowth. A study was conducted on white onions (Allium cepa), under controlled conditionszer4,unza,1o x w b5:m 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 ta9+fne s jj2 5c1cey3hwo ways in which cells can divide. The diagrams below show two cells from an organism with a diploid95eysjjah12 fnc c+ 3e 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 xi 72b- xz5,ijy pg+ceexpression 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, wirt d 9q +jecvvil/s:j*)x+ t6uth a diploid number of 8, in different stages of meiosis. Which row correctly names each stag6r) +ux:*iq vvdj+sj e/9l ttce?

  The micrographs show fortiwhj03 d.:1 tkb5 wjur phases of meiosis I in a plant. In what order do these phases occur? ir0.1d kjjw:5 3tbht w

Mitochondria are responsible for supplying metabolic energy in tfup hpzz/83ye;nu .ozt) )a,eukaryotic cells. In most eukaryotes, which reproduce by sexual reproduction, mitochondrial DNA (mtDNA) is inherited from only one of the parents: the motherp/h;fn zzy)u p,.att3)e 8uoz 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 different stages of tcafz.;g lg- v/0co 0rbhe cell cycle in four samples of lung tissue from four patients. Which tissue has the lowecfgg/0zr b0avo. c-;lst mitotic index?

  The diagram shows the domin-8 -dl1fj5fyce.fu,vm wvs o-ant cyclin/CDK complexes at different time points in the cell cycle. Which cyclin/CDK complex activates DNA replication machinef5u.ov,fsy vd-e-1fm lj 8 -cwry?

  Studies have shown that genes such as Cyclin Dependent Kinase 3 (CDKN3) are f 2d o;bydw1u(w,m6 cwhighly overexpressed iwwd bu21cfw,od y( ;6mn 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 ob :l7w 3uod*3 otgqv/-e q1i8mb7jwnnf cyclin E the highest during the cell cycle ?