The graph below shows the relationship between maternal age an,t0tk vs)oh*ff 1wf )ud the incidence of non-disjunction. What relationu1ff0 v osw t)*f,kt)hship is suggested by the data in the graph?

  Which stage of meiosis is r n8gkq f2zecj(5+ lj1-cxo8xe epresented in the diagram below?

  The diagram below shows chromosied/d dn(2)pz;ojb 4 80dawvqhu,oh1 omes 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 single gene which woulzbc9/.bj6y hgr2 j ba0d be present in the nucleus of a cell as a/bb.9za6jr0 2jyg bhc result of each process?

  Which keyword is matched to the c0vuip679qtgli(p hxv( dlw39sck5 p 7orrect definition?

  Which statement(s) a6e o:mu(7n;z d-5vyfxiow;zq bout mitosis 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 cewhid y 0tj57p u19hn/p) t4p nz2-ofowll in anaphase?

  During which stage of mi (7v7(joc+ q8a jbv4pwpnu3 vytosis does the nuclear envelope break down?

  Which one of the following transpo /15mg1k v clf+.lmnj mg-.xhwrt proteins only carries out active transport? h1/gm..ll1vk m c 5wf+ng-jxm

  Which process does not happen in the sj3.n8fwakl)e is 6xp5 hoot apex?

  Which type/s of membrane transport do/does not require energy exsv.-juc8gf5 ependiture?
I. Facilitated diffusion
II. Active transport
III. Osmosis

  The diagram below represents a cell wit3 t6ebdsk.h7 zq )ywbem*; t/hh a diploid number of 4. Which stage of cell division is the cell cut6ymw* bh h 3s/t;zdkqb.)e 7errently undergoing?

  The photomicrograph below shows a rg kud n2)th1yuc/s2,boot tip meristem. Which of the following sentences correctcybthug,k1 / 2d 2)nusly defines a meristem?

  When does the random orientation o s. uy6kiai3 t;1wgpv7f homologous chromosome pairs occur?

  Which process does not occur during meiosordoy*7 tbb3+y nc 71vis?

  If a cell with a diploid number of 36 undergoes mitosis, how many chromosomes wi79uh;.inmg mu ll be present in each daughmg i9unm;hu7. ter cell after cytokinesis?

  The image shows a micrograph ojnfe 9x7p,zg -f a cell.


What explains the appearance of the cell in the micrograph?

  Which statement(s) about homologous chromosomesqc 9lb9df cda(e3j *l0 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 indiu5xv--kmjq7 r/xu w* pq.vp) qvidual with Down syndrome.

Which statement is not correct?

  In the cells of a horse (E. caballus) during pro )ks4(ss+ yqsmx(w7lhphase I of meiosis I there are 64 chromosomes. What is the haplo4qss(xmw) hk7 ( ls+syid number of chromosomes?

  Which arrow is pointing to a chi 1rgv/k8b vt5s:1puftiun93 e asma?

  The diagram below represents the structure of a shy(qi + fs./iq7l epax(oot apical meristem. Which row in the table colq afp/y+iie 7.( (qxsrrectly identifies the processes occuring in the structures labeled in the diagram?

  How does meiosis promotewjgs +0) ees:kypk e)-a 2tv0s variation?

  Which of the following statements is/are c7xkh5/ )hnmz7a:ed vb orrect 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 chro*f +d ;x usif+-:cfxqlmosomes.


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 describesw9w*idplj 0e; the formation of secondary tumours from primary tumours as a result of the movement *ji ; wlp9ewd0of cells?

  How many chiasmata are present in the diagarn/13ef-qsd 0h/iux.c )tvuram?

  Which statement is a similarity between cytokinesis in animal and plant cells?wl tdycw8 )(.f

  Which stage of meiosis ntj2p oq ms:/bs u*i9/is matched to the correct description?

  Which statement(s) are true of mx zqs*38/qs cbeiosis 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 me l1uo*;n6 my bxq)5hvhq5 7zcpiotic division. This results in the formation of onenb l z1v6pxc7 oy5mhh5*)q u;q large cell and one small cell. What is the fate of the large cell?

  Which row correctly describes diploi4.lpbwwyynfq:+5qj) v7lm t ;. pib2tr,+zexd and haploid cells in humans?

  The following table shows the diplo98 jjy6xx:ju jid chromosome number of a range of species.


Which of these statements is correct?

  What conclusion can be drawn from the karyogram 5yk57w8f anj:yj)ol l below?

  Which of the following proces7jrs aad +w )po 5vzui*zt88(wses is characteristic of the meiotic and not the mitotic cell cyp *wzt5r (i7)uz8 s vd+aj8aowcle?

  The diagram represents a bud with a shoot apical meristde)2s en7edeu z3 qz tjd+323um3hx/ vem.

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 mo 8nb3c+mve/6zfz 9wn k8 u(2zmr7vzthe chimpanzee (Pan troglodytes) is 48. Which row shows the correct chromosome number fornmbz ve3 n9z82rm7f(km wc/o uz68+zv different cell types and cell division stages?.

  At the end of which phase of meiosis I does crossing over occur, and what bk, :5hi-wtco is the outcome of crossini bow 5:hc-kt,g over?

  Which of the following statements does not describhn-bai* sfnu ,1)j c*6vkjg a8e a step in the sodium-potassium pump cy,n) *nvc1hbiuka j*8js-6agfcle in the neuronal cells?

  Which row in the table below is trywsv+nvnm0q vna2-)t/xh4y ( ue of meiosis?

Membrane transport is important for allowing particbdeu47bht7sr0a0 k h,les to move across the cell membrane and respond to chang, hs 0bkt0 dauhr747bees in 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 cel;8m nj2lhy vr8lid1if b ya7*x 3yp(x-ls.

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 ckr5mhiz4ws( th nc+ : kt1f0 npy.m+5kell cycle. Which cyclin is involved in pr tnm+zk(0t1. m + hcw5isyp :fk4hkr5neparing for DNA replication?

The diagram below shows chromosomes*m2nms zb0e 1 kym;4aixt f-0q 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 separation9trrdt3g;, x j of homologous chromosomes?

  The mitotic index of ;ogs txajzv (,)e;1tn throat tissues taken from 4 different patients is shown below. Which patient is most likely to have cjt;)(gotev1 sz an,;x ancerous throat tissue?

1.Draw a labelled diagram to represent the process of crossin*w;tz2a5 byzk g over.

2.Compare and contrast random orientation and crossing over.

3.Outline the stages of meiosis.

  The image shows an abnormal human karyotype. /yuj q(t(rhj/


What is the abnormality in this karyotype and its cause?

The graph below shows the relative amount of DNA in one cell dfk 2.ltb ov:r5uring one complete cell cycle. Each letter represents one stage of the c .k2rbfot 5:lvell 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 between5me d7n39be nmi xeh0( j6w,mg a male cat that is homozygous for brown, long hair and a female cat that has black, short hair09h,j5exm 7mdwieng 6m n(e 3b.


Which of the offspring has a recombinant genotype?

1.Outline how polygel- 01z(ac etdanic traits can show a normal 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 chromatids shown dl4pp uo1as6gd-) )eoin dpp))-go6aso1de4lu the diagram below?

  The photomicrograph shows a pollen grain from L. candidum (Lily)i0 chxiu.* rlj .yb1sty p/1p-. Which stage of meiosis is shb/jxt0y* iy-hlu.1p cis1. rpown?

1.Outline the events which would lead to an individual bei hcw*mrinj 9y wv1,z-8ng born with Down syndrome, which is characterised by the presence of three copies of z18cw,v- n9jiryw *mhchromosome 21.

2.Explain how meiosis increases variation.

3.Outline the stages of meiosis.

The mitotic index is an indirect way owt jnaxaik(:(rcgb/ m ;5o 9a(e,o: maf measuring plant growth. A study was conducted on white onions (Alliumea9(:ao r(jx w5aocna;:igm /(,tbmk 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 ktm vr(j04sf5two ways in which cells can divide. The diagrams below show two mrfsjvkt04( 5cells from 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 ,x7p j p6bcig0expression 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 number of 8, in differedj wsl7s;6 ypo7q: ol3m.u3pmnt stages of meiosis. Which y:m7w suoml;.j37 odqspp3 6lrow correctly names each stage?

  The micrographs show four phases of meiosis 6eg5vwn )em:)xjw y:xI in a plant. In what order do these w:xyx n) )g e5vm:we6jphases occur?

Mitochondria are responsible for supplying metabolic energy in eukymows xfb40-l;m0q ,iiu7y) qaryotic 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 suggested that, in some eukaryotic organisms, inheritance patterns of mtD iq wy f0om-7lyb)x0,4;sm uqiNA 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 f*vhzakr9h 59sz a10mcycle in four samples of lung tissue from four patients. Which tissue has90az*vrak9z shm51 fh the lowest mitotic index?

  The diagram shows the cpd ckoad-02,dominant cyclin/CDK complexes at different time points in the cell cycle. ,c0dkc 2-pdoaWhich cyclin/CDK complex activates DNA replication machinery?

  Studies have shown that genes such as Cycil 5bnwh6ra645 eac1s lin Dependent Kinase 3 (CDKN3) are highly overexpressed in cervical tumour w sb4ca1e6inl arh565s.


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 cy.3.ume5y z ve -y/ 6ml7/zv3qndnq itlcle ?