Microbiology Lesson 1 - Characterization of Microorganisms

• Cellular microorganisms include bacteria, protozoa, microscopic algae, and fungi
• Bacteria are prokaryotes and small in size
• Protozoa are eukaryotes and larger in size
• Acellular infectious agents include virus, viroid, and prions
• Viroid causes agricultural crises
• Robert Hooke formulated the Cell Theory
• Cell Theory: All living organisms are composed of one or more cells, Cell is the basic unit of structure and organization of organisms, and Cell arises from pre-existing cells
• Eukaryotic Cells - Membrane-bound organelles, double-membrane bound nucleus with DNA chromosomes; Animal, Plant, and Fungi; >700 um in diameter
• Prokaryotic Cells - No nucleus or other membrane-bound organelles; 0.2 um in diameter; High surface area to volume ratio; Generally, haploid
• Prokaryotic Cells have one circular chromosome
• Eukaryotic Cells have paired chromosomes in nuclear membrane
• Prokaryotic Cells' cell wall is composed of peptidoglycan
• Eukaryotic Cells' cell wall is composed of polysaccharide
• Prokaryotic Cells do not have histones
• Eukaryotic Cells have histones
• Bacteria's size is typically 1-20 um or larger
• The three shapes of bacteria are cocci, bacilli, and spirochetes
• Cocci are spheres
• Bacilli are rods
• Spirochetes are spirals
• The three types of spirochetes are leptospira, treponema, and borreliella
• Leptospira - Leptospirosis
• Treponema - Syphilis
• Borreliella - Lyme Disease
• Pair - Diplococci
• Chains - Streptococci
• Cluster - Staphylococci
• 8-membered cocci formation - Sarcina
• Archaea Lipids may be monolayer, bilayer, or mixed; Ether bonds, L-glycerol, and branched tails
• Bacterial/Eukaryotic Lipids - Ester bonds, D-glycerol, and unbranched tails
• All bacterial cell wall are composed of peptidoglycan except Mycoplasma
• Peptidoglycan - glycan (sugar backbone) + peptido (peptide side chain); Cross-linked by transpeptidase
• NAG means N-acetylglucosamine
• NAM means N-acetylmuramic acid
• Porin Proteins facilitate the passage of small, hydrophilic molecules into the cell
• Gram Negative - less amount of peptidoglycan; Lipopolysaccharide, Periplasmic Space, Endotoxin; Salmonella. Shigela, and E. Coli
• Gram Positive - Several sheets of peptidoglycan; Eichoic Acid, No Endotoxin except Listeria monocytogenes
• Primary stain is crystal-violet
• Mordant is iodine
• Decolorizer is alcohol