Bacterial Nutrition and Nutrient Uptake Flashcards
What are prototrophs?
Organisms that have no nutritional requirements beyond simple C, N, and S sources
What are auxotrophs?
Organisms that require specific sources of C, N and S added to the growth medium
What is the role of the General Secretory System in G+ and G- organisms and where is it located?
GSS transports proteins to the G+ extracellular space or to the periplasm of G- organisms
Located in the cytoplasmic membrane
What is the role of the specialized secretory systems in G- bacteria and what are the two types?
To transport proteins to the outside of the cell or inject them directly into the mammalian cell
Sec-dependent - require the GSS to deliver proteins to the periplasm
Sec-independent - multiprotein complexes that span the inner and outer membrane
What are 4 general transport mechanisms for molecule uptake in bacteria?
Simple diffusion
Energy independent channels
Facilitated diffusion
Active Transport Systems
What are three active transport systems bacteria use?
Proton gradient active transport
ATP-dependent active transport
Group Translocation
What is the Sugar Phosphotransferase system (PTS)?
A mechanism of the transport of glucose and other sugars
Transfers phosphate groups from phosphoenolpyruvate (PEP) ultimately to sugar as it crosses the membrane
What are the functions of the PTS system?
Phosphorylate sugars as they enter the bacteria
PTS components interact with chemoreceptors to tell the cell to (swim) towards the nutrients
Phosphorylated-III(glc) component of PTS serves as key regulator int he glucose effect
What are siderophores?
Siderophores are macromolecules that bind iron in the medium and transport it inside the cell
Compete for Fe bound to lactoferrin and transferrin
Kind of virulence factor
What are the two types of siderophores?
Enterobactin (enterochelin)
Hydroxamate
