Flashcards in 1-4 Bacterial Function and Growth Deck (16)
What are some bacterial structures that are important to pathogenesis?'
1. flagella - long polymers of flagellin. corkscrew propulsion. rotate. powered by transmem e- gradients
2.Ribosomes (70s not 80s) - chemical differences between eu and pro ribosomes make them great drug target.
3.Spores(endospores) allow survival in extreme conditions. Triggered by nutrient depletion. Standard for autoclaving.
How does the whip-like motion of flagella differ from the movement of eukaryotic cilia?
bacteria flagella do not whip.
Describe the signficance of exponential growth to pathogenesis and lab diagnosis
Pathogenesis - immune system has small window to fight before infection gets out of control
Lab diagnosis - able to quickly culture large amounts of bacteria for identification
Bacterial generation time is limited primarily by
availability of nutrients
Predictable pattern of bacteria in culture
1. lag - sense new environment, up-regulate metabolism and growth
2. log - rapid cell division, exponential growth curve
3. stationary - nutrient depletion/waste accumulation slows growth rate to death rate
4. death - waste accumulation/nutrient depletion kills remaining bacteria
Describe fermentation and its significance in vitro culture
fermentation - bacteria lacking enzymes to detoxify oxygen radicals and regerate oxidized coenzymes will metabolism sugar into organic acid (inefficient), only 2 ATP.
Lab significance - acids can be detected by pH indicators in media, revealing ability of bacteria to ferment the sugar and narrowing the differential.
Describe oxygen based ATP generation and describe its significance in vitro culture
Rely on oxygen as the final electron acceptor in the efficient electron transport chain
lab significance - able to grow in wide variety of settings. Able to easily reveal if bacteria require oxygen, narrowing differential.
What is "quorum sensing"?
the ability of some bacteria to sense population density and alter genetic expression accordingly. conserve energy, and coordinate attack
What are some molecule types that are common to many quorum sensing systems?
Inducers, Receptors, transcription activators, density dependent gene products.
at low pop density - inducers are produced, and either floats off or is eventually accepted by receptor but there is not enough to trigger the transcription activator
at high enough density, high levels of inducer bind to receptor and trigger the transcription activator. A "density dependent gene product" is produced.
____ mediate the interaction of bacteria with mucosal epithelium
______ retard phagocytosis
both gram (-) have ______ in their cell wall
the survival ability of spores is based on their enhanced metabolism (t/f)
spores are formed under_____
adverse environmental conditions
spores are are metabolically _____ and contain dipicolinic acid which is a/an ____
inactive, calcium chelator