8/3/2019 The Bacteria Cell http://slidepdf.com/reader/full/the-bacteria-cell 1/21 THE BACTERIA CELL GROUP MEMBERS : Ø Rosnitah Bt Yacob D20091035118 Ø Nur Eliana Bt Mohmad Noor D20091035093 Ø Nurushuhada Bt Yahya D20091035102 Ø Phua Wan Jien D20091035
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-used to differentiate bacterial speciesinto two large groups (Gram-positive and Gram-negative) based on thephysical properties of their cell walls.• Gram staining is not used to classify
Cell membrane and cell wall plus an outermembrane if one is present.
• The cell wall consists of the peptidoglycan layerand attached structures. Most bacterial cellenvelopes fall into two major categories
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Gram positive and Gram negative.• The peptidoglycan
– a single bag-shaped, highly cross-linkedmacromolecule that surrounds the bacterialcell membrane and provides rigidity.
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Peptidoglycan consists of a glycan(polysaccharide) backbone consisting of N-acetyl muramic acid and N-acetyl glucosaminewith peptide side chains containing D- and L-amino acids and in some instances
•Purpose : motility•Structures : longspecialized appendageswhich rotate by meansof a ‘motor’•Located : under cytoplasmic membrane•May have one, a few or many flagella in differentposition on the cell
PILI• An elongate and hollow appendage-allows the transfer of plasmid DNA from
one bacterial cell to another (called sex pili)
FIMBRIAE• Fine, hairlike made of protein(pilin) – allowbacteria to attach to other cell
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Found mostly in male cells•Most in Gram negative bacteriaEx : Neisseria gonorrhoeae and N.menigitidis
•The DNA appear as long coil distributed through the cytoplasm.•Mostly DNA present as a single, circular chromosome.•But, some consist 2 chromosomes, some linear form.•Consist plasmid. (carry auxiliary information)•Sequence of bases in the DNA determined bacteria.Exp:
§ Mycoplasma gallinarum (580,000 base pairs)§ E. coli (4,700,000 base pairs)§ Myxococcus xanthus (9,140,000)
• High concentrations of enzymes, metabolites, and salts.• Ribosomes scattered throughout the cytoplasm• But smaller, have fewer constituents compare to ribosomes of eukaryoticcells• Can be inhibited by antibiotics• Consists numerous inclusion bodies, or granules in the bacterial cytoplasm.• Not enclosed by membrane and served as storage vessels.• Possess lipid droplets that contain polymeric esters of poly-β-hydroxybutyric acid.• Storage granules produced under favourable growth conditions.• Consumed after nutrients have been depleted from the medium.• Aquatic bacteria produces gas vacoule.• Consist internal membranous.
• Distinguishable by serological tests.• Identify bacteria by the presence of specific molecules on their surfaces, detected by antibodies.• Antibodies are serum protein that bind very tightly to foreign molecules(antigens).• Antibodies have remarkable specificity.• Bacteria able to respond effectively to the intense defensive actions of the immunesystem.