microbialstructers Flashcards
how do bacteria divide
binary fission
what unwinds DNA in bacteria for replication
DNA gyrase this can be target by quinolones
what happens during the Lg phase of bacterial growth
bacteria is metabolic active but is not actively dividing,
what happens during the stationary phase
not enough nutrients and toxins from bacteria lead to no growth or decline in cell number.
when are bacteria more sensitive to antimicrobial
during the lag and exponentiation phase
when will a bacteria form endospors
during the stationary phase.
what are the methods used to determine cell density
grothw on an agar plate or turbidity by spectrophotometry in a liquid medium
what are microaerophilic bacteria
bacteria that grow best a low o2 levels but can grow without O2 as well
what reactive forms of oxygen are toxic to cells
hydrogen peroxide and superoxide anion O2-
how do bacteria counteract these reactive oxygen species
catalase breaks down H2O2 and SOD helps detox O2- in both pro and eukaryotes
what vitamen is essential for systhesis of purines and thymidine and where does it come from?
Folate B9 and is derived in bacteria from Paraaminobezoic acid PABA and we use the folate that bacteria make so we dont have to worry about targeting the synthesis of folate.
how are peptides crosslinked in peptidoglycan
between the D-Ala from on chain and a Lys or other diamino amino from the other chain.
how is peptidoglycan created steps 1 and 2
first Nap and Nam are activated using UDP then a pentapetide is added to the UDP NAM this step is done enzymatically not as the product of mRNA
what are the amino acids added to nam is step 2
the first two are variable the third has to be an amino acid with two nitrogens like lysine and the last two are always D-Ala
what happends in step 3 of peptidoglycan creation
UDP NAM is attached to the baactoprenol through a phosphate link with release of UMP and this happends on the side of the cytoplasm
now try and list all seven steps of peptidoglycan creation
yea
