The graph below shows theg:1p7r)6syr 3dgr r (1rshirs relationship between maternal age and the incidence of non-disjunction. What relationship is s1rs7g srrr(yp3s r) 6rgi:d1huggested by the data in the graph?

  Which stage of meiosis is represented in the diagram h)h dxlbmbwr 8fp:fu ngk 7k)ar 6e731jm /-3sbelow?

  The diagram below shows chromosomes 4pqlczwd *07o8 sjp9ok 2g:giduring 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 ct a;-ufnam08gene which would be present in mtf n;0cu -8aathe nucleus of a cell as a result of each process?

  Which keyword is matched to the 7jinyk:me t t ,0i y0lzy96he7correct definition?

  Which statement(s) about mitosib q(, +w rh8gph(lv)jrs 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 le2/3vsrz*illu :))vkyv 2p 5zkwpul3ntter points to a cell in anaphase?

  During which stage of mitosis does the nuclear envelope break down?4okpj,4jv-bg.c a c .z8cle ro1ay ;h9

  Which one of the following transport proteins only carries out active transpors;oyhc w*znw5:jfag)w2i+ x* q h-4 mft?hw+c*2h s jn-fz;45wfg)*my qaxi o w:

  Which process does not happen in the shoot apyxt(8jw 8/ kfnex?

  Which type/s of membrane transport do/does not require energy expenditurzoi:gb5/ .jsj:-iv jte?
I. Facilitated diffusion
II. Active transport
III. Osmosis

  The diagram below represents a cell with a diploid numb x6:n9wls66;)lovfoz e qo)/o *xkmbuer of 4. Which stage of cell division im*so9 ull6/ ):)x; 66veoofz nbxokwq s the cell currently undergoing?

  The photomicrograph below shows a root tip meristem. Which of the 8ptq4kirdji437r8 lbfollowing sentenrl pijrki4 qd387 t8b4ces correctly defines a meristem?

  When does the random orientation of homologous chrom/ly/*x9wrl k hosome pairs occur?

  Which process does not occur during meiosis etwrq+j +q52owbwe b0s:-jh/ ?

  If a cell with a diploid number of 36 und(bve4d*bs**wnx ynvqh0--7eri ezf :ergoes mitosis, how many chromosomes will be present in each daugz7-e *(x4nwebv*yhnebs* fqi v-r:d 0hter cell after cytokinesis?

  The image shows a micrograly7c9 f1ze85yvz6 frcph of a cell.


What explains the appearance of the cell in the micrograph?

  Which statement(s) about homoli ( d79jjmu nxexdlr4ur)8+vr9 e j8*cogous chromosomes 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 individufc/x6tg0b5 s(fnu, k1 sxyza3o (zyidl ,l0q;al with Down syndrome.

Which statement is not correct?

  In the cells of a horse (E. caballus) during prophase I of meiosis I therwelxq*7(1le9f cjdz :e are 64 chromosomes. What is tew9 djc :e(l1*x7q lzfhe haploid number of chromosomes?

  Which arrow is point gloyq g+38wg(/h- sibing to a chiasma?

  The diagram below reprjlx71 s:onns ,.fc0q resents the structure of a shoot apical meristem. Which row in the table correctxqc1n:,l0 s sjrnf7. oly identifies the processes occuring in the structures labeled in the diagram?

  How does meiosis promote variatqxu*a9t;gbg7du* yg;,k e 1 z -hti3qbion?

  Which of the following statements is/are correct for me0tg e 22 /.elss4d *szucqga+ziosis?
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 chv +d p3bv 9*da+6y+j ueju5tmvromosomes.


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 foxsrvcj8u+:z*- 1fmzo re( s /jx v-5rzrmation of secondary tumours from primary tumours as a result *jz+/ vzz-esrsrf1crx5vuo:-j( mx 8 of the movement of cells?

  How many chiasmata are f;h t q3+p4 b3on,iy.bnsl.anpresent in the diagram?

  Which statement is a similarity between cytokinesis in animal and plant cn u z-ux/vex1am0v 65oells?

  Which stage of meiosis is matched to the correct descriptionl82,guza ry7gm/q(ha ?

  Which statement(s) are true of meiosisc1ctz6 5yzw ,; ssc+)*nsipms 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. Thi eq5-rod)w k*os results in the formation of one large5eq-)* oko rdw cell and one small cell. What is the fate of the large cell?

  Which row correctly describes diploid and haploid cells in humar-0x*sjkk4hhhern 1oq;sd6 z r) o51kns?

  The following table shows the diploid chromosome number of a ran ,ubo0qxdu93b ge of species.


Which of these statements is correct?

  What conclusion can be drawn from the karyogram belowp(qv /sris b j+n7a-o4?

  Which of the following processes is characteristic of the meiotiy8 p9ucoyfx) i./pd c2c and not the mitotic cell cycle?d/)ycxi8c9 2 pfy.upo

  The diagram represents a bmhkmsc /5j))ujm bcj *)5gx(qud 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 chimpanzee (Pipg* v4zsl ,li ipfah2h.-,x 0an troglodytes) is 48. Which row shows the correct ch-a x sz24lil0 p.i*fp v,,highromosome number for different cell types and cell division stages?.

  At the end of which phase of meiosis I ;fw2emnu71z;zgnb c3 does crossing over occur, and what is the outcome of crossing overbuwn;fcm1z;23 gne7z ?

  Which of the following statements doesz3 rh yo9kyy2fvsv4d9zy0gg8 o/mz2+ not describe a step in the sodium-potassium zg9g/k02 zso8 d2yyhv4o+mfv y 9rzy3pump cycle in the neuronal cells?

  Which row in the tableopq.7pug k*r 6 below is true of meiosis?

Membrane transport is important for allowing particles to movepkfc0q bcnwm.rl7 *( l7u(dx; across the cell membrane and respond to changenxld (7. kcl( fw7r*u;qbmpc0s 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 regula( d7kuii:yq.t ted 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 showsy 0f 7aka3rn*vs/4b,mzwke-d the concentrations of different cyclins during the cell cycle. Which cyclin is involve /r0wb y knzf m,es-vk*7d43aad in preparing for DNA replication?

The diagram below sh ,t5wq7tg;( z ub8c -aqq2kxzyows chromosomes 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 chromosom k1b*hu7ymd.d es?

  The mitotic index of throat tissues taken from 4 dc. k-esxh0+kk03( bj y ijm,efifferent patients is shown below. Which patient is most likel( k mb3yec-e0sixhk.+,0jj kfy to have cancerous throat tissue?

1.Draw a labelled diagram to represent the process of crossing o(kreo+ il 53rlver.

2.Compare and contrast random orientation and crossing over.

3.Outline the stages of meiosis.

  The image shows an abnormal human kargyy j1;c 0e5mwyotype.


What is the abnormality in this karyotype and its cause?

The graph below shows the relative amount of DNA in one cell during one 16u*lwgejx1 g ioq82s h*fpt yg-ue (1complete cellg q1 t8 fu6u-gj(1 12wxp*e*eoyighsl cycle. 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 between kz 97 j1i6 p sytxy5db*n8krdfbu w0+/a male cat that is homozygous for brown, long hair and0jn yzf p5*1sbr+yk6 wi8bu79 tdd/xk 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 distribution.s -ox3(zd :ukf jjp-k5

2.Outline the differences and similarities between homologous chromosomes.

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

  Which gamete can result from th8h4e ra /1agj5*zlp xke crossing over of non-sister chromatids shown in the diagram bel kxgale 41z5jha/ *p8row?

  The photomicrograph shows a pollen ghgi0 y3 zf+bbw9wv3 ) 5jrvy2crain from L. candidum (Lily). Which stage of meiosis is showf5cv9)hiw by+y j2zgvr3 3b0wn?

1.Outline the events which would lead to an individual being born - q50k d0(ujkko *hs asv4zp+wwith Down syndrome, which ipqkjwsz0+ *kkua - v(05 sohd4s 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 growth. w ug/ wz: *,bl(qrmyy2A study was conducted on white onions (Allium cepa), under controlled conditions in a lab, to investigate tl z 2: (ubyy,/*grwmwqhe 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 ways in which celld6 th*/fk8i hps can divide. The diagrams below show two cells from an organism with k*t86hi/p dhf 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 eum :em56ywxzk 2fm,)u xpression 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 different sta,4n.8yv-guc z-q y -gltm4tdr ges of mey,t8ty-z - gnvc l-4ugqm4r d.iosis. Which row correctly names each stage?

  The micrographs show four phases of meiosis I in a plant. In wh8orovi o *+m,hat order do thesemo h 8v+*oio,r phases occur?

Mitochondria are responsible for supplying metc((2l .a udm7 hjc5b7lxet)w tabolic energy 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 parenclaxt.e7bd (w ) l7c5m2utj(h ts. 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 nu +qy(mk8lq9zumber of cells in different stages of the cell cycle in four samples of lung tissue from four patients. Which tissue has the lowest mitotic inq l8+9 uzkyqm(dex?

  The diagram shows the dominant cyclin/CDK complexes at different time poinwl,pvi9.( vnt ts in the cell cycle. Which cyclin/CDK complex activates DNA tp9l,n.wvi(vreplication machinery?

  Studies have shown that genes such as Cyclin Dependent Ky o9rxvt.kn+e 1 f5;a0y,w ym1bfwv8finase 3 (CDKN3) are highly overexpytx fw wvfv,b01 k8 .f+y 5;ay1re9onmressed 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 oe; f0o(pyis .)dg v1oaf cyclin E the highest during the cell cycle ?