1-4 Bacterial Function and Growth Flashcards Preview

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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.

3. spores


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

polysaccharide capsules


both gram (-) have ______ in their cell wall

LPS endotoxin


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


spores are formed primarily by organisms of the genus neisseria (t/f)


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