1. TOPIC: STRUCTUREOFBACTERIALCELL BYMEHAKGHUMRO 3RDYEARMEDICALSTUDENT

2. BACTERIAL CELL General propertyTypical prokaryotic cellContain both DNA and RNAMost grow in artificial mediaReplicate by binary fissionAlmost all contain cell wall ,there is also exception lie as in the example of mycoplasma Sensitive to antimicrobial agent 3. Structure of bacterial cell Classificationofbacteria Itcanbemadeon Basisofshape BASISOFARRANGEMENT BASISOFSTAININGBASISOFOXYGEN 4. ON THE BASIS OF SHAPE BACTERIABYSHAPECLASSIFIEDINTO3BASICGROUPS COCCI....(ROUNDSHAPED) BACILLI....(RODSHAPED) SPIROCHETES...(SPIRALSHAPED) NOTE..SOMEBACTERIAAREVARIABLEINSHAPEAND ARECALLEDPLEOMORPHIC 5. ONTHEBASISOFARRANGEMENT INADDITIONTOSHAPE,ARRANGEMENTOF BACTERIAISALSOIMPORTANT EXAMPLE=CERTAINCOCCIAREPRESENTIN PAIRS(DIPLOCOCCI) CHAINS(STREPTOCOCCI) CLUSTERS(STAPHYLOCOCCI) WHILERODSCANBESTRAIGHTORCURVED 6. SIZE OF BACTERIA BACTERIA RANGE IN SIZE FROM 0.2 TO 5 MICRO METER SMALLEST BACTERIA IS MYCOPLASMA WHICH IS ABOUT THE SIZE OF LARGEST VIRUSES (POXVIRUSES) LONGEST BACTERIA ARE RODS BACTERIA WHICH ARE SIZE OF SOME YEAST AND HUMAN RED BLOOD CELL 7. BACTERIAL CELL ESSENTIAL STRUCTURESACCESSORY STRUCTURESCELL ENVELOPECAPSULECELL WALL CELL MEMBRANEFLAGELLACYTOPLASMFIMBRIENUCLUES (BACTERIAL CHROMOSOME)SPORES INCLUSION BODIESRIBOSOMES 8. BACTERIAWITHOUTCELLWALLAREOF FOURTYPES CELL WALL DEFICIENT BACTERIAL VARIENTS C.W.D PROTOPLAST SPHEROPLAST L-FORM MYCOPLASMA1.PROTOPLAST::DERIVED FROM GRAM POSITIVE BACTERIA EXAMPLE (BACILLUS MAGATERUM) BY DISSOLVATION OF CELL WALL WITH EGG WHITE LYSOZYME2.SPHEROPLASTS.THEY ARE READILY PRODUCED FROM GRAM NEGATIVE BACILLI SUCH AS ESCHERICHIA COLI BY GROWING ORGANISM IN CELL WALL INHABITORS (e.g PENCILLIN,BACITRACIN)THAT SPECIFICALLY BLOCK THE SYNTHESIS OF PEPTIDOGLYCAN COMPONENT OF CELL WALL 9. OTHER TWO FORMS 3.LFORMSOFBACTERIA THE NAME L FORM IS AFTER THE LISTNER INSTITUTE OF LONDON WHERE SWOLLEN AND ABRENNANT MORPHOLOGICAL FORMS FROM THE CULTURE OF STREPTOBACILLUS MONILIFORMS WAS STUDIED.THESE MUTANT BACTERIA WITHOUT CELL WALL ARE CELL WALL DEFICIENT FORMS OF BACTERIA4.MYCOPLASMA: IT IS INDEPENDIENT BACTERIAL GENUS OF NATURALLY OCCURING BACTERIA WHICH LACKS CELL WALLS AND ALSO STABLE AND DONOT REQUIRE HYPEROSMOTIC CONDITIONS FOR MAINTENANCE 10. PROTOPLASTDERIVED FROM GRAM +VE BACTERIASPHEROPLAST DERIVED FROM GRAM -VE BACTERIA BY PENCILLIN OR OTHERBY HYDROLYSIS ACTION OFANTIBIOTICS WHICH INHABITLYSOZYMESCELLWALL SYNTHESISUNSTABLE AND OSMOTICALLYLESS OSMOTICALLY SENSITIVESENSITIVE PARTIAL CELL WALL ABSENT COMPLETE CELL WALL ABSENT METABOLICALLY ACTIVE BUT CAN NOT PRODUCED (MULTIPLIED) THEY CAN NOT ABLE TO THEIR NORMAL FORMSRESIDUAL AND NON FUNCTIONAL CELL WALL IS PRESENT METABOLICALLY ACTIVE BUT ALSOREVERTMULTIPLY THEY ARE ABLE TO CHANGE BACK TOTHEIR NORMAL FORMS 11. CELL WALL ITISVERYRIGIDSURROUNDINGTHEPRTOPLASTWHICHLIES IMMEDIATELYEXTERNALTOTHECYTOPLASMICMEMBRANE ITISOUTERMOSTCOMPONENTCOMMONTOALLBACTERIA EXCEPTMYCOPLASMAWHICHISBOUNDEDBYCELL MEMBRANENOTCELLWALL CELLWALLISCOMPOSEDOFPEPTIDOGLYCAN THEPEPTIDOGLYCANPROVIDESTRUCTURAL SUPPORTANDMAINTAINTHECHARACTERISTICSHAPEOF CELL 12. Component of cell wall of gram -ve bacteria Outer membrane Peptidoglycan( thin layer) Lipoproteins Phospholipid Periplasmic space 13. GRAM -VE BACTERIA PORIN CHANNELS PERIPLASM WITH PEPTIDOGLYCAN 14. GRAM +VE BACTERIAComponentofcellwall ofgram+vebacteria Peptidoglycan(thick layer) Teichoicacid 15. Outermembraneofgramvebacteria Outermembrane Isabilayeredstructure Innerleafletiscytoplasmicmembrane..outerleafletisoflipopolysaccharide OutermembranealsohasproteinchannelscalledPORINS 16. Peptidoglycanlayer Also called murein IS a glycan polymer (mixed or complex layer) consisting for the purpose of description of three parts. ABACKBONE........which is composed of alternating stands of two hexose ABACKBONE. sugars N-ACETYLEGLUCOSAMINE AND N-ACETYLMURAMIC ACID WITH TETRAPEPTIDE SIDE CHAINS ASETOFIDENTICALTETRAPEPTIDE............Attached to NASETOFIDENTICALTETRAPEPTIDE ACETYLMURAMIC ACIDASETOFIDENTICALPEPTIDES....;;;;;;CROSS BRIDGED (cross linkages) NOTE THAT PEPTIDOGLYCAN IS PRESENT IN BACTERIA BUT NOT IN HUMAN SO IT IS GOOD TARGET FOR ANTIBACTERIAL DRUGS SUCH AS PENICILLIN,CEPHALOSPORINS AND VANCOMYCINS.WHICH INHABIT THE SYNTHESIS OF PEPTIDOGLYCAN BY INHABITING TRANSPEPTIDASE THAT MAKE THE CROSS LINKS BETWEEN TWO ADJACENT TETRAPEPTIDES 17. LYSOZYME.IT CAN CLEAVE THE PEPTIDOGLYCAN BACKBONE BY BREAKING ITS GLYCOSYL BONDSLIPOPROTEINLAYERIN GRAM -VE BACTERIA. LIPOPROTEINS CROSS LINK THEOUTER MEMBRANE AND THE PEPTIDOGLYCAN CELL LAYER. THEY SERVE TO STABILIZE THE OUTER LAYER 18. .Lipopolysaccharide LPSOFOUTERMEMBRANEOF GRAMVEBACTERIAIS ENDOTOXIN.. LPSisacomplexlipidCOMPOSED OFTHREEDISTINCTUNITS LIPIDA.. itisburiedtooutermembrane itisresponsiblefortoxiceffect COREPOLYSACCHARIDE..itis linkedtoLIPIDA..itisunusualin structure Osidechain....itisimportant somaticor''o''antigenthatisusedto identifycertainorganism 19. Teichoicacid Thesearefiberslocatedin outermembraneofingram positivebacteria,theymay composedofpolymersof glycerolphosphateorribitol phosphateLipoteichoicacid Somepolymersofglycerol phosphateteichoicacid penetratepeptidoglycan andarecovalentlylinked tolipidincytoplasmic membrane 20. CYTOPLASM ITCONSISTOFTWODISTINCTAREA OUTERAMORPHOUSMATRIXWHICHCONTAIN RIBOSOMES,NUTRIENTGRANULES,METABOLITIESAND PLASMID INNERNUCLEOIDREGIONCOMPOSEDOFDNACytoplasmicmembrane itiscomposedofphospholipidbilayer Theyarechemicallysimilarbuteukaryoticmembranecontainsterols whereasprokaryoticdonot. NOTE..theonlyprokaryoticmembranewhichcontainsterolsintheir membranearethemembersofgenusmycoplasma 21. FUNCTIONOFCYTOPLASMICMEMBRANE ACTIVETRANSPORTOFMOLECULEINTOCELL ENERGYGENERATIONBYOXIDATIVE PHOSPHORYLATION SYNTHESISOFPRECURSORSOFCELLWALL SECRETIONOFTOXINSANDENZYMES 22. RIBOSOMES Itconsistoflargeandsmallsubunits Ineukaryotictheyare80SinsizewhereasinprokaryoticTHEYARE 70SINSIZEWITH30SAND50SSUBUNITS THEYARETHESITEOFPROTEINSYNTHESIS 23. GRANULESCYTOPLASMCONTAIN DIFFERENTTYPESOF GRANULESANDTHEY SERVEASSTORAGE AREASFORNUTRIENTSNUCLEOID WHERE ISTHEAREAOFCYTOPLASM IT SINGLE DNAISLOCATEDANDDNAIS CIRCULARMOLECULE EAR NUCLEOIDCONTAINNONUCL OMITOTIC MEMBRANE,NONUCLEOLUS,N SPINDLE,ANDNOHISTONE 24. plasmid Plasmidareextrachromosomal,doublestranded,circularmolecules Theyarecapableofreplicatingindependentofbacterialchromosome Theyoccurebothingram+vebacteriaandgramvebacteria Theycanbeintegratedintobacterialchromosome Types Transmissble Plasmidcanbetranferfromcelltocellbyconjugation Theycontainaboutdozengenesresponsibleforsynthesisofsexpilusand enzymesrequiredfortransfer Nontransmissble: Theydonotcontainthetransfergenes 25. Plasmidcanbetranferfromcelltocell byconjugation 26. Glycocalyx(capsuleandslimelayer) Slimelayer... Slimelayerarediffuseandunorganized Slimelayersareregularlystructuredlayersofproteinor glycoproteinobservedinbothbacteriaandarchaea,whereit maybetheonlystructureoutsidetheplasmamembrane Slimelayerisgeleasilywashedofffromcellenvelope. Allbacteriahaveatleastathinslimelayer theyprotectagainstionandpHfluctuations,osmoticstress, hydrolyticenzymes,orthepredaciousbacterium 27. >>..Capsule..