Lecture 8 Flashcards
How the bacteria cope to environmental factors
Change the conditions
Change the cell
Extreme halophiles
Require salt concentrations of 2M to 6.2M
Halotolerant
Can grow under elevated salt conditions but do not require
Halophiles
Grow optimally at >0.2 M
Extreme halophiles
Require >2 M
Aerobic respiration
uses oxygen as terminal electron acceptor in the electron transport chain
Fermentation and anaerobic respiration
do not use oxygen as terminal electron acceptor
Aerobe
Grows in presence of atmospheric oxygen (O2) which is 20% O2
Obligate aerobe
Requires O2
Anaerobe
Grows in the absence of O2
Obligate anaerobe
Requires the absence of O2
Microaerophiles
Requires 2–10% O2
Facultative anaerobes
If necessary can grow without O2
Aerotolerant anaerobes
Grow equally well with or without O2
Barotolerant
Adversely affected by increased pressure
Barophilic
Require or grow more rapidly in the presence of increased pressure
Ionizing radiation
Disrupts chemical structure of many molecules, including DNA
Carotenoid pigments
To protect themselves many bacteria produce
biofilms
Microbes can grow free floating in liquid and Can also grow attached to surfaces
Biofilms
Consist of bacteria and extracellular polymeric substances.
They are not uniform
quorum sensing
Bacterial cells in/out of biofilms communicate in a density-dependent manner
