Deoxyribo Nucleic Acid

8/8/2019 Deoxyribo Nucleic Acid

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VIMAL JYOTHI CONVENT MATRICULATION HIGHERSECONDARY SCHOOL

COIMBATORE-641035

BIOLOGY PROJECT

Submitted by,

E.Joel

Xth B,


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Biology Project E.Joel, th

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BOTANY

Table of Content:

S.No Content

1. De-oxyri o Nucleic Aci (DNA)2. Medicinal plants

Structure of DNA:

Medicinal plant:


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Inli in organis s DNAdoesnot usually existasasingle molecule, butinsteadasa pair of moleculest atare held tightly together.

These t o long strandsent ine li e vines, intheshape ofa double helix . Thenucleotide repeats contain

both the segment ofthebackbone ofthe molecule,which holdsthe chaintogether, and a base, whichinteracts with the other DNAstrand inthe helix. A base

linked to asugaris called anucleoside and a base linkedto asugarand one or more

phosphate groupsis called anucleotide. If multiplenucleotidesare linked together, asin DNA, this polymeris called a

polynucleotide.

Diagram shows, The Chemicalstructure of DNA. Hydrogen bondsshownasdotted lines.

The backbone ofthe DNA strand is made from alternating phosphate and sugarresidues.[10] The sugarin DNA is 2-deoxyribose, which isa pentose(five-carbon) sugar. The sugarsarejoined together by phosphate groupsthatform phosphodiester bonds betweenthe third and fifth carbonatoms ofadjacentsugar rings. These asymmetric bonds meanastrand of DNA hasa direction. Ina double helix the direction ofthe nucleotidesin one strand is opposite to theirdirectioninthe otherstrand: the strandsare antiparallel. The asymmetric endsof DNA strandsare called the5 (five prime) and 3 (three prime) ends, with the5' end having aterminal phosphate group and the 3' end aterminal hydroxylgroup. One major difference between DNA and RNA isthe sugar, with the 2-deoxyribose in DNA being replaced by the alternative pentose sugar ribose inRNA


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B an hed DNA

In DNA fraying occurs whennon-complementary regions existatthe end ofan otherwise complementary double-strand

of DNA. However, branched DNA canoccurifathird strand of DNA isintroducedand containsadjoining regionsable tohybridi e with the frayed regions ofthe pre-existing double-strand. Although thesimplest example of branched DNAinvolves only three strands of DNA,complexesinvolving additionalstrandsandmultiple branchesare also possible.Branched DNA can be used in

nanotechnology to construct geometricshapes

Sin le

b an h

Multiplebranches

A section of DNA, The baseslie hori ontally betweenthe two spiralling strands.

DNA double helix isstabili ed by hydrogen bonds betweenthe basesattachedto the two strands. The four bases found in DNA are adenine (abbreviated A),cytosine (C), guanine ( ) and thymine (T). These four basesare attached to thesugar/phosphate to form the complete nucleotide, asshown foradenosinemonophosphate.

These basesare classified into two types;adenine and guanine are fused five-and six-membered heterocyclic compounds called purines, while cytosine andthymine are six-membered rings called pyrimidines. A fifth pyrimidine base,called uracil( ), usually takesthe place ofthymine inRNA and differs fromthymine by lacking a methyl group onits ring. Uracilisnot usually found in


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MATE ALS

scissors 1/2-intransparenttape, or gluestickthumbtacks or masking tape sheets of

different colored construction papercardboard

PROCEDURES AND

OBSERVATIONS

PartI. Structure and Composition of DNA

a. Imagine that you can untwisttheDNA ladder. Thenstudy Figure 1, adiagram ofthe untwisted ladder.

Note thatthe uprights ofthe ladderconsists ofalternating units-.phosphate groupsand deoxyribosemolecules. Now study Figure 2 tosee the structures of deoxyribose and

phosphate, and how they chemicallybond together. Theirsymbolsarealso shown.

FIGUR 2

The rungs ofthe DNA ladder consist of pairs ofnitrogen bases. There are twokinds ofnitrogen bases: purinesand pyrimidines. The purines have atwo-ringedstructure;they are adenine (A) and guanine (G). The pyrimidines have a one-ring structure;they are cytosine (C) and thymine (T).


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y Figure 3 showsthe structures ofthe fournitrogen bases found in DNA.Note the symbols forthe bases.

y A nucleotide consists of one nitrogen base, one phosphate group, and onedeoxyribose molecule.

y Study Figure 4 to see how the phosphate group, deoxyribose molecule,and nitrogen base are related inanucleotide. Each nitrogen base isattached to the deoxyribose- side ofa phosphate-deoxyribosecombination. Note that because there are four differentnitrogen basesthere are four kinds ofnucleotides.

FIGURE 3 FIGURE 4

Pa t II. Makin Models of DNA

1. Cut outthe phosphate, deoxyribose, and nitrogen base symbols below.Paste them onto a piece of cardboard and cutthem out.

2. Then rise the cardboard symbolsto trace symbols on construction paper.Trace and cut out 20 each ofthe phosphate and deoxyribose symbolsand


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5 of each nitrogen base symbol. Use a different color paper for eachsymbol. Label each nitrogen base with itsabbreviation.

3. Make anucleotide model by laying a phosphate, a deoxyribose, and anitrogen base symbol onthe patternin Figure 5. Fastenthe symbolstogether with short pieces oftransparenttape. Prepare 20 nucleotides. Be

sure to attach the symbolsatthe correctanglesto one another. Otherwiseyour DNA model willnot fittogether properly.

4. In DNA, a particular purine always bonds with a particular pyrimidine.Adenine bondsto thymine and guanine bondsto cytosine. The purinesand pyrimidinesare bonded together by hydrogen bonds.

5. Study Figure 6 to see how the nitrogen basesare bonded togetherinaDNA segment. Then constructa 10-rung modelsegment of DNA usingthe nucleotides you have assembled. Match up two nitrogen bases, eitherA-T orG-C, in each ladder rung. Use short pieces oftape forthe bonds.The rungs ofthe ladder must be of equallength. The nucleotides of each

strand can be inany sequence, aslong asthe two nitrogen bases pairedtogetherinthe rung are correct. Attach the deoxyribose moleculesand thephosphate groups of each strand with tape.

6. Label Figure 7 to show the nucleotide sequences ofthe DNA modelthatyou constructed. Draw inthe shapes ofthe nitrogen base symbolsandlabelthem A, T, G, orC.


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Pa t III. Lea nin abo t DNA Repli ation

DNA can replicate itself. Inthis way, the hereditary information encoded initsstructure is parsed onto new cells formed by mitosis. During replication, theDNA double helix untwists, and the bonds betweenthe nitrogen bases of eachrung break. Nucleotidesare normal constituents of cells, and asthe DNA doublehelix splitsapart, free nucleotideslink up to matching nucleotides of each DNAstrand according to the rules of base pairing. The two new double-

stranded chainsthentwistinto two separate double helixes. Inthis way twoidentical DNA moleculesare formed.

a. Lay your DNA model flat onthe table. Starting at one end ofthe model,cutthe pieces oftape that connectthe nitrogen bases on five ofthe rungs.Be carefulnotto cutthe symbols. The effectissomething like un ippinga zipper. Lay the unzipped modelaside.


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b. Then prepare 20 morenucleotidesas you did in PartII. Be sure to use the patternto assemble the nucleotidesatthe properangles.

c. Matching C with Gand Awith T, attach newnucleotidesto both strands ofyour DNA model, using short

pieces oftape.d. Cutapart more rungsas you

workalong your model.Continue to add newnucleotidesto each stranduntilallthe rungs have been

cutand new nucleotidesattached.e. Compare the sequences ofthe

two new segments of DNAthat you constructed.

1. Are the two segmentsalike?

2. How do theirsequences comparewith the sequences

shownin figure 7?

Con l sion:

Thus one can prepare the model of DNA, for better understanding ofitsStructure, moleculararrangementand the way it functions.


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Medi inal plants and thei ses:

y Embelia gladuliferay Justicia paniculataBurm. f.y Aloe indicaRoyle

Syn : Embelia glandulifera Wight, Samara ribes KurzEnglish names: Embelia, Embelia fruit.Sanskritnames: Jantughna, Krimighna, Krimiripu, Vella, Vidanga.Vernacularnames: Kan : Vayuvilanga;Mar: Vaivarang, Vavadinga;Mal: Vizhal; Pun: Baburung; Tam and Tel: Vayuvilanga.

VIJACINTAMANITANTRA: consumption of powdered fruitalongwith fruits of Emblica officinalis, honey and sesame-oilimproves

quality ofsperms;BHAVAPRAKASHA: itis pungent, removesmorbidity, improves bloodcirculation, stimulatesappetite, actsagainst phlegm, makesthe bodylight, kills worms ofalltypes;RAJANIGHANTU: itis pungent,hot, light, enhances balance

between wind and phlegm,beneficialinanorexiaand improvesdigestive power.

AYURVEDA : (a) Root: acrid,astringent, usefulin colic, dyspepsia, flatulence, odontalgia, stomach

painand increases exothermic metabolism;(b) Leaf: astringent,demulcent, depurative, thermogenic, usefulinskin diseasesincludingleprosy;(c) Fruit: acrid, alexeteric, alterant, anodyne, anthelmintic,astringent, bitter, braintonic, carminative,contraceptive, depurative, digestive,diuretic, febrifuge, laxative, rejuvenating,stimulant, tonic, vulnerary, and usefulin

amnetia, asthma, colic, constipation,cardiopathy, dental caries, dyspepsia,dyspnoea, fever, flatulence, generaldebility, hemicramia, odontalgia,

psychopathy, respiratory troublesand ring-worms;(d) Seed: a constituent of VidangadiYoga, anantifertility drug.


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SIDDHA : dried fruitsare used to prepare the drug Vaivitankam.Modern use : Plant: curesabdominaltumours, and aenemeas, cystictumours, pyorrhoea, usefulagainsttape- worms; EtOH extract of plant:slightly active against Ecoli; one ofthe constituents of 'Gasex', and someoral contraceptives; Fruit: cures dental, oral, throattroubles except

cancer oflipsand ptyslism, constituent ofsome quickaboriticide;Aqueous extract of fruit: pronounced antifertility activity, anthelminticagainst earthworms; Fruit-powder: expelstapeworms within 6-24 hours,iftaken with curd in empty stomach, effective against giardia; Seed:antibiotic, anthelmintic, antituberculosis, alterative and stimulative.Phytography : Large scandentshrub; brancheslong, slender, flexible,

bark with many lenticels;leavessimple, alternate, petioles 0.8 cm,lamina elliptic, leathery, glabrous, shining above, silvery beneath,glandular pits present onthe lowersurface nearthe midrib; racemesaxillary and terminal, laxly panicled; flowers white, may be greenish,

0.2 cm long; berries dull red to black, globular, small, 1- or 2-seeded;seeds globose, hollowed atthe base, white spotted, albuminous.Phenology: Flowering: peakinMarch-April; Fruiting: August.Distribution: ThroughoutIndia up to 1750 m in hilly regions; commoninlower hills; Sri Lanka, Malaya.Ecology and cultivation: Growsinshola border, thickets; wild.Chemical contents: Fruit: embelin.Remark: Ethnic communities ofCannanore (Kerala) make bowstringwith the bark..

Justi ia pani ulata Burm. f.

English names: The greatking of bitters, the creat.Sanskritnames: Bhunimba,Kirata.VernacularnamesKan:

Nelabaru;Mar: Olikiryata;Tam and Tel: Nelavemu.Trade names: Kalmegh,Kirayat.Traditional use: Plant:.febrifuge, alterative,anthelmintic, anodyne,usefulin debility, diabetes,


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consumption, influenza, bronchitis, itchesand piles;inBengal,household medicine knownas 'Kalmegh', made from leaves, is giventothe childrensuffering from stomach complaints.

HOEMOEPATHY: used fortreatment of differentailments of head,

mind, eyes, nose, mouth, tongue, throat, abdomen, stool, urine, feverand other modalities.Modern use: Drug constitute stem, leafand inflorescence: asatonicand inthe treatment of fevers, worms, dysentery and also beneficialtoliverand digestive ailments;itis reported thatit hassome antityphoidand antibiotic activity; Decoction: used forsluggishness ofliverand in

jaundice.Phytography : An erect herb with square stem, glabrous below,glandular hairy above;leaveslinear, lanceolate, glabrousand distinctly

pedicelled; flowers white or pale purple; capsules compressed

transversely;seeds bony.Phenology: Flowering and Fruiting:September-May.Distribution: ThroughoutIndiainthe

plainsand hills;Bangladesh, Pakistan, allSouth East Asianand SAARC countries.Ecology and cultivation: Commoninstony linesin forestsand in wastelands.Cultivated asan ornament. Chemicalcontents: Plant: kalmeghin, bitter principle

andrographolide; bitternessis due tononbasic principle.Adulterants: Itis used asadulterants forChirata, and isasubstitute for quinine.Remark: Whole plantis bitter.

Aloe indi a Royle, A.

English names: Barbadosaloe, Curacasaloe, Indianaloe, Jafarabadaloe.Sanskritname: Ghritakumari.Vernacularnames: Kan : Lolesara; Kon : Kantikkor, Katkunvor;Mal:Kattarvazha kumariTam: Alagai, Chirukuttali, Kuttilai; Tel:Chinnakata banda, Kala banda, Kittanara.Trade names: Ghritakumari, Ghee kunvar.Traditional use: TRIBAL: Leaf-pulp: inlivertroubles,jaundice, fever,gonorrhoea, spleen disorder, rheumatism, piles, dysmenorrhoea,


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sterility in women;Leaf-mucilage: mildlaxative, to curehardening of breasttissues, ininsect

stings.AYURVEDA:alternative, bitter,cooling, purgative,sweet, tonic,anthelmintic, usefulineye diseases, tumours,enlargement ofspleen,livertroubles,vomiting, skin

diseases, biliousness,asthma, leprosy,jaundice, strangury, ulcer; Flowers: anthelmintic.

UNANI: Gheekawaris usefulininflammation ofspleen, lumbago,muscular pain, ophthalmia, digestive, purgative; Leaves good for pilesand biliousness.Modern use: Aloe: in menstrual diseases, stomach pain, tonic after

pregnancy, uterine disorders, high fever; Pulp: menstrualsuppressions,nervousimbalance; Aloe compound: intreatment of womensterility;Mucilage: painfulinflammation;Root: colic pain; Aloe mixture with

other plant extracts: fortreating obstruction oflymphatic system.Phytography : A coarse-looking plant with ashort(30-60 cm high)stem;leavessucculent, green, large (37 cm long, 10 cm broad, 2 cmthick), densely crowded; flowersin racemes, bright yellow, tubular,stamens frequently projected beyond the perianth tube.Phenology: Flowering: September-December; Fruiting: scarce.Distribution: A native of North Africa, Canary Islandsand Spain;naturalised inIndia; many varietiesare found inasemi-wild state inall

parts ofIndia;also cultivated in potsand gardens.Ecology and cultivation: Xerophyte; propagated by suckers.

Chemical contents: Plant: aloin, aloe-emodinand resins.Adulterant: Aloe candelabrum Bergeris used assubstitute for AloebarbadensisMiller.


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Zoolo y

Table of Content:

S.No Content

1. CT scan2. Blood Smear

CT Scan

Blood Smear:


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Computed Tomo raphy S an

X-ray omputed tomo raphy

Computed tomography (CT) isa medicalimaging method employingtomography created by computer processing.[1] Digital geometry processing isused to generate athree-dimensionalimage ofthe inside ofan object from alarge series oftwo-dimensional X-ray imagestakenaround asingle axis ofrotation.[2]

CT producesa volume of data which can be manipulated, through a processknownas "windowing", in orderto demonstrate various bodily structures basedontheirability to blockthe X-ray beam. Although historically the images

generated were inthe axial ortransverse plane, orthogonalto the long axis ofthe body, modernscannersallow this volume of datato be reformatted invarious planes or evenasvolumetric (3D) representations ofstructures. Although most commonin medicine, CT isalso used inother fields, such asnondestructivematerialstesting. Another exampleisarchaeological usessuch asimaging the contents ofsarcophagi

orthe DigiMorph projectattheUniversity of Texasat Austinwhich usesaCT scannerto study biologicaland paleontologicalspecimens.

Terminolo y

The word "tomography" is derived from the Greektomos(slice) and graphein(to write). Computed tomography was originally knownasthe "EMIscan" asitwas developed ata research branch of EMI, a company best knowntoday foritsmusic and recording business. It waslater knownas computed axialtomography (CAT orCT scan) and body section rntgenography.

Although the term "computed tomography" could be used to describe positronemissiontomography and single photon emission computed tomography, in

practice it usually refersto the computation oftomography from X-ray images,especially in older medicalliterature and smaller medical facilities.


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History

Inthe early 1900s, the Italian radiologist Alessandro Vallebona proposed amethod to representasingle slice ofthe body onthe radiographic film. Thismethod was knownastomography. The ideais based onsimple principles of

projective geometry: moving synchronously and in opposite directionsthe X-ray tube and the film, which are connected together by a rod whose pivot pointisthe focus;the image created by the points onthe focal plane appearssharper,while the images ofthe other pointsannihilate asnoise. Thisis only marginallyeffective, as blurring occurs only inthe "x" plane. There are also more complexdevices which can move in more than one plane and perform more effective

blurring.

Tomography had been one ofthe pillars of radiologic diagnostics untilthe late1970s, whenthe availability of minicomputersand ofthe transverse axialscanning method, thislast due to the workofGodfrey Hounsfield and South African-

born AllanMcLeod Cormack, graduallysupplanted itasthe modality ofCT

The first commercially viable CT scannerwasinvented by SirGodfrey Hounsfieldin Hayes, United Kingdom at EMICentralResearch Laboratories using X-rays.Hounsfield conceived hisideain 1967.[6]The first EMI-Scanner wasinstalled in AtkinsonMorley HospitalinWimbledon, England, and the first patient brain-scan was done on 1 October1971

[7]. It was publicly announced in 1972.

The first commercially viable CT scanner wasinvented by SirGodfreyHounsfield in Hayes, United Kingdom at EMICentralResearch Laboratoriesusing X-rays. Hounsfield conceived hisideain 1967.[6] The first EMI-Scannerwasinstalled in AtkinsonMorley Hospitalin Wimbledon, England, and the first

patient brain-scan was done on 1 October 1971[7]. It was publicly announced in

1997

It has been claimed thatthanksto the success of The Beatles, EMI could fund

research and build early models for medical use.[8] The first production X-ray

CT machine (in fact called the "EMI-Scanner") waslimited to making

tomographic sections ofthe brain, butacquired the image datainabout 4


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of dataacquisition requires enormous processing power, asthe dataare arrivingina continuousstream and must be processed in real-time.

In conventionalCT machines, an X-ray tube and detectorare physically rotatedbehind a circularshroud (see the image above right);inthe electron beam

tomography (EBT) the tube is farlargerand higher powerto supportthe hightemporal resolution. The electron beam is deflected ina hollow funnel-shapedvacuum chamber. X-raysare generated whenthe beam hitsthe stationary target.The detectorisalso stationary. Thisarrangement can resultin very fastscans,

butis extremely expensive.

CT is used in medicine as a diagnostic tool and as a guide for interventional

procedures. Sometimes contrast materials such as intravenous iodinated

contrast are used.T

his is useful to highlight structures such as blood vesselsthat otherwise would be difficult to delineate

from their surroundings. Using contrast

material can also help to obtain functional

information about tissues.

Once the scan data has beenacquired, the datamust be processed using a form oftomographic reconstruction, which producesaseries of cross-sectionalimages. The most

commontechnique in general use is filteredback projection, which isstraight-forward toimplementand can be computed rapidly.However, thisisnotthe only technique available: the original EMIscannersolved the tomographic reconstruction problem by linearalgebra, butthisapproach waslimited by its high computational complexity, especially giventhecomputertechnology available atthe time. More recently, manufacturers havedeveloped iterative physical model-based expectation-maximizationtechniques.These techniquesare advantageous because they use aninternal model ofthescanner's physical propertiesand ofthe physicallaws of X-ray interactions. By

contrast, earlier methods have assumed a perfectscannerand highly simplifiedphysics, which leadsto anumber ofartefactsand reduced resolution - the resultisimages with improved resolution, reduced noise and fewerartefacts, as wellasthe ability to greatly reduce the radiation dose in certain circumstances. Thedisadvantage isa very high computational requirement, which isatthe limits of

practicality for currentscan protocols.


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Pixelsinanimage obtained by CTscanning are displayed interms ofrelative radiodensity. The pixelitselfis displayed according to the meanattenuation ofthe tissue(s) thatit

correspondsto onascale from +3071(mostattenuating) to -1024 (leastattenuating) onthe Hounsfield scale.Pixelisatwo dimensional unit basedonthe matrix size and the field ofview. Whenthe CT slice thicknessisalso factored in, the unitis knownasaVoxel, which isathreedimensional unit. The

phenomenonthat one partofthe detector cannot

differentiate betweendifferenttissuesis calledthe "Partial Volume Effect".That meansthata bigamount of cartilage and athinlayer of compact bonecan cause the sameattenuationina voxelashyperdense cartilage alone.Water hasanattenuation of

0 Hounsfield units(HU)while airis -1000 HU,cancellous bone istypically+400 HU, cranial bone canreach 2000 HU or more (ostemporale) and can causeartifacts. The attenuation ofmetallic implants depends onatomic number ofthe element used: Titaniumusually hasanamount of +1000 HU, ironsteel can completely extinguish the X-ray and istherefore responsible for well-knownline-artifactsin computed

tomograms. Artifactsare caused by abrupttransitions betweenlow- and high-density materials, which resultsin data valuesthat exceed the dynamic range ofthe processing electronics.


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lymphocyte

basophil

Some images ofBlood smears.


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