The graph below shows the relationship between mr8) 6 xukm wl5j8.drym3e h+ w:nkhip3--ickm aternal age and the incidence of non-disjunction. What relationship is suggested by the data in thip5nu) -kxw3 r-w6ke+jm hcm:ikyrlm8h 83.de graph?

  Which stage of meiosis is represented in the diagwrufc7pq.- 0 qram below?

  The diagram below shows chromjkn p 4cvt:gzj(a7b p19oki3hb-e ;v*osomes 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 would:s/njqq;x) dlp ;g00lpd 9xt f be prep:x0 t;jd xsq9 dg;/ )nfp0lqlsent in the nucleus of a cell as a result of each process?

  Which keyword is matched to the correct definij ba2k) 9f(hmxtion?

  Which statement(s) about mib9v ( ly/er ajqv:yaooz9m7 ;*tosis 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, wh6q4:(scn5 o/ezpkqkr1zgtb + ich letter points to a cell in anaphase?

  During which stage of mitosis does the nuclear envelfm1m .3i;*hrte1l ivrope break down?

  Which one of the following transport proteins only carries out active lq;slkz-dk/ed/ (fb ,,tzga8 transport?el l z (g,q,z/;fbd/ka -ds8tk

  Which process does not happen in the shook01kf+ z*h0uge)1bnf uek jy -t apex?

  Which type/s of membrane transport do/does not require energy mkt(f0nro 4re.3d*glv 5uz s mdbg73(expenditure?
I. Facilitated diffusion
II. Active transport
III. Osmosis

  The diagram below represents a cell with a diploid number of 4. Which stage of 73hbwi)qse a, d:lsy+cell division is the cell currently undergos 3de7 i,yw+slaq):hbing?

  The photomicrograph below shofm*; ogake0 t9ji./+felkh *zws a root tip meristem. Which of the following sentences correctly defines a meristemejhtk.+ gomf9k izf**0;/ela?

  When does the random orientation of spii ez-(z( o8l6r6gr-zj5bnhomologous chromosome pairs occur?

  Which process does not occur during meiosiso;+wj7jff +tb?

  If a cell with a diploid number of 36 undergoes mitosis,wbp ,w-dm.r 3sdhj* woh6 /rw, how many chromosomes wil/ bjwhwp.,dh,6wdor w* r3s- ml be present in each daughter cell after cytokinesis?

  The image shows a mic2oxy wqq: x2z;s ob(e9rograph of a cell.


What explains the appearance of the cell in the micrograph?

  Which statement(s) about homologous chromosomes is/are notgkj61fe75 z :nwbv e4f 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 wit:36r1vz k+zfd hw rm6dh Down syndrome.

Which statement is not correct?

  In the cells of a horse (E. caballus) during prophase I of meiosis I there a+uw*7 .(b cpe proe2bgre 64 chromosomes. What i ue7ocbb w*r+2pp eg(.s the haploid number of chromosomes?

  Which arrow is pointi v+ hpwu/kb4);qil rzw2;7rzing to a chiasma?

  The diagram below represents the struwgg)d6o*3j074tmj6r g uyasv cture of a shoot apical meristem. Which row in the table correctly identifies the processes occuring in the stjygu6)w g3 0sjgmv6* dt r74aoructures labeled in the diagram?

  How does meiosis pro,ak+lu q72fd jmote variation?

  Which of the following statements iu u8m g. t.;sbdor(s)as/are correct 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 homwafa+:) (i+sj t2crt 8e6mrkmologous 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 secondary tumours from primary tumwmjnyifot fb :+iw/syu4932; ours as a result of the movement of cellsu3w4y/ 9 ;2yftsm +j:wfobiin ?

  How many chiasmata are present in the 9 mqnyylw)9m2agqf.(apw) r0 diagram?

  Which statement is a similariz 4 7)e13dfzg. fp8ajyxf+lci ty between cytokinesis in animal and plant cells?

  Which stage of meiosis is matched to 3 y5a;ax 6svx;.wyg ukthe correct description?

  Which statement(s) are true of meiosis I ii. -rtc x0bo0.-.dftvfdu+f*i,y wfgh5an* 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:r lmdjnjwtppr, -:ppts,+,+. This results in the formation of one large cell and one small cell. tp,:w+:t -j nppp mrs ,jrl,d+What is the fate of the large cell?

  Which row correctly describes diploid and haploid cells in humansin0tge2+zcrw h* :m-p ?

  The following table shows the diploid chromosome num 7lg8b hxz2j8bber of a range of species.


Which of these statements is correct?

  What conclusion can be drawn from the kardw ujgbv*mzy/3c p0u:nm6xohji .30 q lr:a /7yogram below?

  Which of the following processes is characteristic of the meiotic and not t s np,*ws49lt od. y/0ifjd8g17yfd hphe mitotic cell cycle?p s dnoy*7y9/ d18gjpi.,lw 4f 0shfdt

  The diagram represen:n)ckbo u+t/ r ai)pe6ts a bud with 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 chimpanzeemm7a) cm2x.ka (Pan troglodytes) is 48. Which row shows the correct chromosome number for different cell types and cell divkxa mac7 m2m).ision stages?.

  At the end of which phase of meiosis I does crossing over occur, and what is thsn5jr vbrr.b:p 1o+) he outcome of crossirbh n)rjv.s1 br:o 5+png over?

  Which of the following statements does not describe a step in c.vg++yz.t5kcd h 519qfav7 uzcw+pt the sodium-potassium pump. f.vp1d+5c7hz gt9zcv kwca+q5t y+u cycle in the neuronal cells?

  Which row in the table below is true of meio ;-ximqb4 b-am yui2r(sis?

Membrane transport is imv /r9eam4u8ukk k -4efportant for allowing particles to move across the cell membrane and respond to changes in the chemical composition of the e-9 /ve uufa4k4mk8e rkxtracellular 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 regulat,35jm0kj weewq:tyi5ed 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 cey5unjaqj.h959b3 zx 3t6j /i h ywpmb1ll cycle. Which cyclin is involved in preparing for DN/.3xq9yh5ujpa yji wbz693nbhtm5 1jA replication?

The diagram below shows chromdee7.xy 5kiv sq542amsi3f rvp51e0gosomes 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 inve9ar(,dnskt: rr5 3bu olves the separation of homologous chromosomes?

  The mitotic index of throat tissx:5(3sj/ lfeps k* g) b4jjaxeues taken from 4 different patients is shown below. Whichfjx ajls*3x :g5eksb /(e4 )pj patient is most likely to have cancerous throat tissue?

1.Draw a labelled diagram to represent the plq+)5;1fodv3vt - kjdid*kzs/qu3hc rocess of crossing over.

2.Compare and contrast random orientation and crossing over.

3.Outline the stages of meiosis.

  The image shows an abnormal human kar-vwxx(.3i +l tfgy 1nxyotype.


What is the abnormality in this karyotype and its cause?

The graph below shows the relative amount of DNA in one cell during one c9;mket/p: aocomplete cell cycle. Each letter represents one stage of kc 9m /e;:otpathe 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 ty1;y- e:wekm between a male cat that is homozygous for brown, long hair and e:ym1ky-tw;e a female cat that has black, short hair.


Which of the offspring has a recombinant genotype?

1.Outline how polygenic traits can show a normal th n mh:4 j3a)js8cja)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 shos l vfn e l+rq+;yf5py7quf-x7u :u/k1wn in the diagn+ff1 ll u; ep/ xqy :577sfukuy-+vrqram below?

  The photomicrograph shows a pollen grain from L. candidum (Lily oe3 qtqx8qii6/znv/yh8d45n). Which stage of qiet8zx/5 y3nodh4 8n/6q viq meiosis is shown?

1.Outline the events xv+ :bnlru)z c4 r..kwwhich would lead to an individual being born with Down syndrome, which is characterised by the.ulxzr4+c n.bk):w v r presence of three copies of chromosome 21.

2.Explain how meiosis increases variation.

3.Outline the stages of meiosis.

The mitotic index is an (cbt-i8l0 q joindirect way of measuring plant growth. A study was conducted on white onions (Allium cepa), under controlled conditions in a lab, to investigate the effect of soil pH on the mitotic index of the rootc0ibjo -l(q 8ts.


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 cellsxff7s:dfm -b 9 can divide. The diagrams below show two cells from amf:s 9-bfd7 fxn 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 exrmv/qn5 5 3 47frga, tq9ukdwmpression 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 cellaw5sr2n)r,6s.qwfe kwu wq.3 , with a diploid number of 8, in different stages of meiosis. Which row correctly namesfa.rnw w3qu)ew,5wk2s rqs . 6 each stage?

  The micrographs show four phases of meiosis I in a plant. In what order do thesiyky5257 wli 0:w chafe phases oc5ch :yil20 wyfik7w5acur?

Mitochondria are responsible for supplying metabolic enerxnk4.vp8wm m t;m d7h;gy 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 been suggested that, in some eukaryotic organisms, inheritance patterns of mtDNA found in hybrid cells, which are the result of sexual reproduction between tw mh.8 pm;xd;m7kv4nt wo 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 numbeblv3 ao6d .wi0 kt+;bcr of cells in different stages of the cell cycle in four samples of lung tissue from four patients. Which tissue has the lo;.vdai0+kb o6 3t wbclwest mitotic index?

  The diagram shows the dominant cyclin/CDK complexes a p4kcjc.3n:l gc3a j99slax7et different time points in the cell cycle. Which cyclin/CDK complex activates DNA replicasl9x79 jcpa3l3 a :gkcen .jc4tion machinery?

  Studies have shown that genes such as Cyclin Dependent Kinase 3 (CDKN3) ari,cw0:oonivtt.*ultca5 f2 9e high 0*ctlfw 2taoicnt95,v iu :o.ly overexpressed 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 the(i ,zk);f3qf imh3oh qo;2tla cell cycle ?