lecture 2 (18) microbial metabolism, structure and fxns Flashcards
bacteria exist in a haploid or diploid state?
how many chromosomes?
haploid =
1 chromosome
binary fission
an exact copy of the genome is made and a single cell divides into 2 (binary) daughter cells
how bacteria replicate
what phases of bacterial growth make the bacteria sensitive to antimicrobials
lag and exponential phases
what phase of bacterial growth is more likely to develop spores? what kind of bacteria does this?
- decline phase
- gram pos
what are the phases of bacterial growth
lag
exponential
decline
what two elements are needed for growth always
carbon and nitrogen
what two ways can bacteria be divided into groups in terms of their metabolic props
via how organism deals with oxygen and via what carbon and energy source they use
aerobes
anaerobes
facultative anaerobes
microaerophilic
aerobes- require oxygen to meet energy demands
anaerobes- use fermentation, die in oxygen
facultative anaerobes- can respire and ferment
microaerophilic- grow best at low oxygen but can growth without too
how can you tell if a bacteria is an anaerobe or an aerobic bacteria?
aerobes can die in the presence of certain forms of oxygen like hydrogen peroxide and superoxide. therefore, aerobes have developed a mechanism by which they can break them down. that is with catalase (breaks down hydrogen peroxide into water and oxygen) and superoxide dismutase that detoxifies oxygen. if a bacteria dies in the presence of these oxygen species, we know it’s anaerobic
in terms of catalase and superoxide dismutatse, peroxidase what do these have obligate aerobes facultative anaerobes microaerophilic bacteria obligate anaerobes
obligate aerobes- catalase, superoxidase, peroxidase
facultative anaerobes-catalase, superoxidase
microaeophilic bacteria-catalase, superoxidase
obligate anaerobes-none
aerobic vs anaerobic vs fermentation
aerobic- oxygen is the terminal electron acceptor
anaerobic- some inorganic composing serve as the electron acceptor
fermentation- ORGANIC metabolic substrate used if it’s fermentable
how is folate involved in targeting and killing bacteria?
in bacteria, folate which is essential for the synthesis of purines and thymidine, is derived from PABA (para-aminobenzoic acid) wheras in humans, it’s obtained from diet.
if wanna get rid of the bacteria, target PABA
what two antifolates are used to kill of bacteria
sulfonamides which inhibit dihydropteroate synthase
and DHFR inhibitors which inhibits dihydrofolate reductase (trimethoprim)
quinolones
-target bacterial DNA gyrase that is required to unwind/wind DNA during DNA polymerization
what is an important aspect of bacterial replication that we can target because it’s different from our replication
- bacteria use a 70s ribosome vs an 80s so we can target that ribosome to kill it
- bacteria also replicate via co-transcriptional translation meaning it does both at once- we can use this as a target
