Bacterial Growth and Metabolsim Flashcards
How do bacteria replicate?
binary fission
What are prototrophs?
bacteria that can synthesize all essential metabolites
What are auxotrophs?
bacteria that have acquired mutation sthat require them to obtain certain essentail metabolites from the environment
What is a psycrophile?
Bacteria that thrives in extreme cold
How do transferrin and lactoferrin help fight infection?
They bind free iron, making it less available to infectious bacteria.
How do bacteria counter the bodies attempts to keep iron from it?
They secrete siderophores, which chelate iron and actively transport it into the cell.
When are bacteria most vulnerable to antibiotics?
during the exponential phase of growth, when they are experiencing maximal DNA and protein synthesis. This is also the best time to Gram stain
During what stage are bacteria somewhat resistant to antibiotics and some form spores?
stationary phase
What is a biofilm?
a protective carbohydrate matrix that is ahesive and formed after a series of events requireing motility and adhesion of planktonic bacteria.
How aerobes deal with the toxic hydrogen peroxide and superoxide anions produced by aerobic respiration? Do anaerobes produce these?
the produce superoxide dismutase, catalase and peroxidase to duffuse the damage.
Facultative anaerobes lack catalase, but always synthesize superoxide and peroxidase.
Strict anaerobes lack superoxide dismutase and oxygen will kill them.
Do bacteria synthesize folic acid or take it up from the environment like humans?
they synthesize their own. This is often a target of antimicrobials
What is bacteremia?
presence of bacteria in the blood, a normally steril substance
What is the virulence factor?
any number of products produced and often secreted by pathogens that allow the pathogen to invade and cause disease in a host and evade defenses. (ex: adhesion factors, capsules, endotoxins, siderophores)
What is a siderophore?
secretion of bacteria that chelates free iron and imports it back into bacterial cell.
