The graph below shows the relationship between maternal age and t p - zaluj6s/wbv)b,k1i3fg5dhe incidence of non-disjunction. What relationship is suggested by the data in the graph-k)g 5 bv z/w lsb6,13apuidjf?

  Which stage of meiosis is represented in the g61;ohe n.(daznin+kdiagram below?

  The diagram below shows chromosomes during meiosn ykn: fqkd,,8is.


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 o-bt,kf ir3- 9c1yrtgsf alleles of a single gene which would be present in the nucleus of a cell as a 9gt- y1,c3sr tfkr-ibresult of each process?

  Which keyword is match qpd xi4zjhz4co*ukh2(4u1n l +/(bkged to the correct definition?

  Which statement(s) about m5,t ayts+xp y7itosis 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 letter0wfuqq5u t 3q0 ,u11t k0aiczp points to a cell in anaphase?

  During which stage of mitosis does the nuclear envelope break down?i- -hm-q*nu 0cmz vhweiq6, a4

  Which one of the following t:z24 enefk: *r+3e,oeouyapi ransport proteins only carries out active transport?oe:f42z ru,:e*ni+koey p 3ae

  Which process does not happen in the shoot ape;owzkgni ced94e;+wi8v8( za x?

  Which type/s of membrane transpouri;8 sju9d6 t9s zf:jrt do/does not require energy expenditure?
I. Facilitated diffusion
II. Active transport
III. Osmosis

  The diagram below represents a cell with a diploid number of 4. Wvm8e0d5ofo* yzm36ye )p qy1j17xxe phich stage of cell division is the cell currently underm)qp3ez761vym8y5 0d1eox jfxyp *eogoing?

  The photomicrograph below shows a root tip meristem. Which of the follx bq7sar:5cpky se ,k-2/f o)towing sentences correctly defines aye2ka)7 pfrq -b s:s /,tcko5x meristem?

  When does the random orientation of homologous chrfbn:tua 02ue/ldj+2fomosome pairs occur?

  Which process does not occur during m wa k4;yf- ybqh-d/yno25k *gw4yki*oeiosis?

  If a cell with a diploid number of 36 undergoes mitosis, 5i/ 79cpv1rsizv h1tqhow many chromosomes will be present in each daughter cell after cytokinesi iz15 hrqc9vv p1sit7/s?

  The image shows a mi-yl*qw rryf;)xg 2y:jcrograph of a cell.


What explains the appearance of the cell in the micrograph?

  Which statement(s) about homojg9 u(6xn w / 3r9n8bm0aqzugulogous 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 individual with Down syndrome. t(4., /j afmwkwruat3

Which statement is not correct?

  In the cells of a horse ( wx* ncvfhm/).r a :.4axtrkr:E. caballus) during prophase I of meiosis I there are 64 chromosomes. What is the haploid number of chromo .vxkrrtmh.4axfc*:/a n:rw )somes?

  Which arrow is pointing to a chiasma?tbfyuu .3. ud5

  The diagram below represents the structulqnl2 u 5kk-n5re of a shoot apical meristem. Which row in the table correctly identifies the processes occuring in the stkn5qnk l 2-ul5ructures labeled in the diagram?

  How does meiosis promote vad 6+0b r3o o .mt-ovkbwdmi2a-riation?

  Which of the following statements is/are correct 5 g .m6f(uvde4d*sarcfor 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 chromosomessd9:ed5ood) w n5tcj).


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 9 xoy: w+i.i gf3 wmnyc-1pu+efrom primary tumours as a result of the movece:.9f +xwo-gw+3 iyin myp1ument of cells?

  How many chiasmata are p 32+dww lqy :qsxv.u6zresent in the diagram?

  Which statement is a si ibw3wk)-18hqtjdse-g2k 3ob milarity between cytokinesis in animal and plant cells?

  Which stage of meiosis is matched to the e;j+; dk vg :,mxomeqa5:2on ucorrect description?

  Which statement(s) are true of meiosis I but rc)lli; );y fkgk+* af zn,2qunot 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 dit (ot)3ys+ ndivision. This results in the formation of one large cell and one smalli+ n()sd t3oyt cell. What is the fate of the large cell?

  Which row correctly describes diploid and xzdc. 3gpoy37 haploid cells in humans?

  The following table shows the diploid chromosome number of a ra *qraf/8tgoi0 nge of species.


Which of these statements is correct?

  What conclusion can be drawn from the d0b w:lprz0; x5.jcix karyogram below?

  Which of the following processes is characteristic of+ ag2hc1l bcnqun -83k the meiotic and not the mitotic cell cyclecuh 8nl1q 2ck-+n gab3?

  The diagram represents a buds cyf44ewn0 igtbc(f6cs. .- u 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 (Pan troglodytes) is .8w mp95 j;2x;x-d dlvrrxk vc48. Which row shows the correct chromosome number for dif.;;w8xd5lk9r pr c xjxvmvd -2ferent cell types and cell division stages?.

  At the end of which phase of meiosis I does cr s rck3;m9rr*yfkdi*2v ypx3;ossing over occur, and what is the outcomeridkrvcp3;s3;mx k r** f 92yy of crossing over?

  Which of the following stab0bg p -)snpw )k-kn*ctements does not describe a step in the sodium-potassium pump cycle in the neuronal cells?s )wnc gbk0bp)nk -p-*

  Which row in the table below is true of p0fax oqo5t 8;n0kn:umeiosis?

Membrane transport is importanv3*0l5nrc: jxe : ,oyvrs6b1 ya +oawst for allowing particles to move across the cell membrane5a ro6 oev c1s* yl30:yw,b janx:s+rv and respond to changes 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+qu61 3gplz :b;4z) fkd5gc*q kajq vj 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 shows the concentrations of different 33qu1kg68 wqf*l(tf35 wi idu)i gwgs0i yxd9cyclins during the cell cycle. Which cyclin iss) 3dufi gukg*f1id8qw93 3iqwg yw5 x6l 0(it involved in preparing for DNA replication?

The diagram below showmpnpx5wl6h:t (j:eq)or +h p5s 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 chwqu8uvc:rdt 3 h+*)hp romosomes?

  The mitotic index of throat tissues taken from 4 diffb )jkbt (t,6hls) j;fx9 9jkoqerent patients is shown below. jls9j 9,tqbxfk)(okjht6;) bWhich patient is most likely to have cancerous throat tissue?

1.Draw a labelled dia(s,vvk0vumk+/woz 2hgram to represent the process of crossing over.

2.Compare and contrast random orientation and crossing over.

3.Outline the stages of meiosis.

  The image shows an abnormal human karyotypeel1) gkabj.k:+5t1 wz wb k3mj.


What is the abnormality in this karyotype and its cause?

The graph below shows the relative amount of DNA in one cell duc-(. ;;c/pqbfl .ah) jw vvbeuring one complete cell cycle. Each llw.e -)cv.vba b ;uq; hf(/pcjetter 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 a male cat that is ho k0d*k7. 2c:bqhfrt vnmozygous for brown, long hair q. * cht2:dvkkf7 br0nand a female cat that has black, short hair.


Which of the offspring has a recombinant genotype?

1.Outline how polygenu ( v:sq2h4crdic 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 me+/jddt9 /:okkmc a,non-sister chromatids shown in the diagram bee,/:a odk jm+/cd9tmk low?

  The photomicrograph shows a pollen grain from L. candid9pk,t 1gfww (dum (Lily). Which stage of 9 d1w,gkf(tp wmeiosis is shown?

1.Outline the events whicy/m8r mjgr -.dh would lead to an individual being born with Down syndrome, which is cr.gy8m/dm - rjharacterised 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 plantgo.l fjm9*(wqgla6 8 z-p6 est growth. A study was conducted on white onions (Allium cepa), under controlle-l.(tgq9 agz*8s66el jmfo pwd 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 two ways in which cells can dpx- )j q.zijfdr6w ybgoh111 3ivide. The diagrams below show two cells from an organism with a diploidpiwd.rg6f) xyq3z-h1 bj1o j1 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 expression in stem growtkmgp (o 1kqjf;8k s l8:yxk()jh.

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 c ef; ojsq; 98h4)yxogoell, with a diploid number of 8, in different stages of meiosis. Which row correctly names eyox98 oj ; )gosh4;eqfach stage?

  The micrographs show four phases of meiosis I in a plant. In wha,0mqa nsg e-r2t order do these phases occen20 g maqr,s-ur?

Mitochondria are responsibd2a8or+hu9:num ip(n le for supplying metabolic 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 parents. It has been suggested that, in sopn:uh(au8d+2 i r 9nmome 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 the cell cycle in+e6dei pa jbc69 v41)s3yw+bp5xw dmf four samples of lung tbi6w49+cxdej e3w1d )ba y +sfmvp56pissue from four patients. Which tissue has the lowest mitotic index?

  The diagram shows the dojwzi+-)ud d+887 rfh;n mrzuominant cyclin/CDK complexes at different time points in the cell cycle. Which cyclin/CDKn z zu8h m+r8od+wu7dj i;-)rf complex activates DNA replication machinery?

  Studies have shown that genes such as Cyclin Dependent Kinase 3 (CDKN3) are kp61h/ l1s(a7,jqbk wlnah / fhighly overexpressed in cervi1al,7k lhw(1k qbsa/h/pfn6 jcal 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 yy 83:o:ba 8gi 0bkgpg?