Ch.6: Microbial Nutrition & Growth Pt.1 Flashcards
what is a colony?
aggregation of cells arising from a single parent cell
What is a biofilm?
microbes living together in a community
what are nutrients?
-chemicals needed to meet energy needs and build macromolecules/cellular structures
-come from a variety of sources
-provide elements (carbon), energy, electrons
Describe an essential element
Absolutely must have 95% of cells dry weight (CHON)- Carbon, hydrogen, oxygen, nitrogen
what is the other 5%
Phosphorus- DNA backbone, ATP
Sulfur- component of some amino acids
Iron- microbial enzymes, siderophores
Carbon is organized into what two groups?
Autotrophs- inorganic carbon (carbon dioxide) feed themselves; photosynthetic; producer in the food chain
Heterotroph-organic carbon (sugar, protein) acquired from other organisms
what is the most common element?
Hydrogen, is never a limiting nutrient, all cells require electrons and hydrogens for redox reactions
Describe oxygen
can serve as a final electron acceptor in the ETC (aerobic respiration)
can be poison to anaerobes
component of many molecules (sugars=C6H12O6)
Describe Nitrogen
No anabolism without nitrogen, is limited, all cells recycle proteins and nucleic acids to recover nitrogen
Are trace elements required in small amounts?
Yes
what is a growth factor
organic chemicals necessary to growth and reproduction
what are vitamins part of
coenzymes, anabolic pathways
why are vitamins important?
good source of metabolism
sources of carbon
Autotroph – inorganic CO2 as sole carbon source
Heterotroph – organic carbon
Sources of energy
Chemotroph – energy from redox reactions
Phototroph – light energy
sources of electrons
Organotroph – electrons from the same source as carbon
(Heterotrophs)
Lithotroph – electrons from inorganic sources (autotrophs)
What are lithotrophic autotrophs
-Synthesize all metabolic and structural needs from
inorganic compounds
-Have all enzymes and cofactors needed
obligate aerobe
need oxygen or death
obligate anaerobe
no oxygen ever it’s like poison
facultative anaerobe
-Doesn’t have to use oxygen as final electron acceptor
-Can perform anaerobic respiration and fermentation
ex: E. coli (pour plate in lab)
Aerotolerant anaerobe
NO aerobic respiration but can tolerate some oxygen (can detoxify)
Microaerophile
Only 2-10% oxygen (atmosphere is 21%); limited ability to detoxify
What does toxic forms of oxygen do
highly reactive and excellent oxidizing agents, resulting oxidation causes irreparable damage to cells
what are forms of toxic oxygen
-singlet oxygen
-superoxide radicals
-peroxide anion
-Hydroxyl radical
