Bacterial Pathogens Flashcards
Explain the major structures of a bacterial cell and their functions
Cell wall- gives shape and physical barrier made of peptidoglycans as well as protects from osmotic pressure changes
Ribosomes- 70s synthesizes proteins
Single circular DNA
Plasmid- small circular optional DNA molecule for antibiotic defense
Plasma membrane- phospholipid bilayer to keep cells contents contained
Pili- used for attachment
Flagella- used for motility
Capsule- some have capsule making it immune to phagocytosis
Compare the cell wall structure of Gram-positive and Gram-negative bacteria
Gram-positive: stains purple because of thick cell wall with no outside cell membrane beyond the cell wall
Gram-negative: stains pink due to thin cell wall found two cell membranes
Describe basic shapes and arrangements of bacteria
Shapes: Rod-like: bacillus Spherical: coccus Spiral: sprichaetes One curve: vibrio Arrangements: Strepto- chain Staphylo- grape-like bunches (random only for cocci) Diplo- two Tetrads- four Sarcinae- eight
Explain the differences between endotoxins and exotoxins in regard to their production, chemical nature, and toxicology.
Endotoxins- produced by gram- negative bacteria and found in lipid A in outer membrane. when the cell is killed lipid A releases and causes severe bleeding and shock.
Exotoxins- proteins released from living bacteria both gram negative and positive. Different toxins different effects ie. neurotoxin, destruction of cell structure
Differentiate between aerobic respiration, anaerobic respiration and fermentation.
Aeriobic Respiration - oxygen is the final electron acceptor
Anaerobic - The final electron acceptor is an inorganic molecule (NO3- or SO42-)
Fermentation - the final electron acceptor is organic (derived from food)
Differentiate between aerobic, facultative and anaerobic bacteria.
Aerobic - require O2 for growth
Anaerobic - do not use O2 (it is toxic)
Facultative - can switch between aerobic and anaerobic
Explain why oxygen is toxic to cells and how aerobes detoxify oxygen.
Oxygen causes the formation of free radicals that can destroys lipids and DNA easily
Aerobes have catalysts (Superoxide Dismutase (SOD), Catalase, and peroxidase) to transform oxygen radical and hydrogen into peroxide then back into water and oxygen.
Describe the process of bacterial cell division.
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Explain the role of mobile genetic elements in bacterial pathogenesis and antimicrobial resistance.
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Explain lysogenic and lytic pathways of bacteriophage infection
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Describe transposition, transposon, insertion sequence, and other mobile elements in bacterial genetics.
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Explain the major mechanisms of horizontal gene transfer in bacteria.
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Distinguish between generalized transduction and specialized transduction in bacteria.
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Explain how chromosomal genes can be transferred by Hfr strains of bacteria.
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