Med Micro Exam 2 Flashcards
What are some growth requirements for microbes?
-electrons sources(organic and inorganic compounds)
-carbon sources(autotrophs and heterotrophs)
-energy sources [light(phototrophs) and chemical (chemotrophs)]
What is microbial growth?
-increase in population of microbes
-due to reproduction of individual microbes
What are results of microbial growth?
-colonies
-biofilms
What elements do most nutrients need to reproduce?
-carbon
-oxygen
-nitrogen
-hydrogen
Oxygen and obligate anaerobes relationship:
-oxygen is deadly for obligate anaerobes
-toxic forms of oxygen are highly reactive and excellent oxidizing agents
-resulting oxidation causes irrepairable damage to cells
What are the 4 toxic forms of oxygen?
-Singlet O2
-superoxide radicals
-peroxide anion
-hydroxyl radical
Obligate aerobes
only live in oxygen
Obligate anaerobes
can’t live in oxygen
Facultative anaerobes
prefer to live in oxygen but can live without it
Aerotolerant anaerobes
they don’t give a shit they live all over in both
Nitrogen requirements:
-insufficent nitrogen ends anabolism to make amino acids and nucleotides
-nitrogen fixation by certain bacteria is essential to life
Chemical requirements
-phosphorus
-sulfur
trace elements:
only required in small amounts
Growth factors:
necessary organic chemicals that can’t be synthesized by certain organisms.
Temperature:
-organisms have an optimal temperature due to protein structure and lipid membranes of cells and organelles
pH ranges:
-organisms sensitive to changes in acidity
-H ions interfere with H bonding
Neutrophiles:
grows best in narrow range around neutral pH
Acidophiles:
grows best in acidic habitats