Chapter 4 Flashcards
metabolism
sum total of all chemical rxns that occur in cell
catabolic rxns
energy releasing metabolic rxns
anabolic rxns
energy requiring metabolic rxns
nutrients
supply of monomers (or precursors) required by cells for growth
macronutrients
nutrients required in large amounts
micronutrients
nutrients required in trace amounts
carbon
- required by all cells
- typically bacterial cell is 50% carbon (dry weight)
- major element in all classes of macromolecules
- heterotrophs use organic carbon
- autotrophs use inorganic carbon
nitrogen
- typical bacterial cell is 12% nitrogen
2. key element in proteins, nucleic acids
phosphorous
synthesis of nucleic acids and phopholipids
sulfur
sulfur containing amino acids, vitamins, coenzyme A
potassium
required by enzyme for activity
magnesium
- stabilizes ribosomes, membrane and nucleic acids
2. required for many enzymes
calcium
- helps stabilize cell walls in microbes
2. plays key role in heat stability of endospores
sodium
required by some microbes
iron
- key component of cytochromes and FeS proteins involved in electron transport
- anoxic conditions –> ferrous (Fe2+) form, exists as insoluble materials
- oxic conditions –> ferric (Fe3+) form, exists as insoluble minerals
- cells produce siderophores to obtain iron from insoluble mineral form
siderophores
iron binding agents
growth factors
organic compounds require in small amounts by certain organisms (vitamins, aa, purines, pyrimidines)
vitamins
most commonly required growth factor, function as coenzyme
culture media
nutrient solutions used to grow microbes in lab
defined media
precise chemical composition is known
complex media
composed of digests of chemically undefined substances (yeast, meat extracts)
selective media
contains compounds that selectively inhabit growth of some microbes but not others
differential media
contains indicator (dye) that detects particular chemical rxns during growth
pure culture
culture containing only a single kind of microbe
contaminants
unwanted organisms in culture
cells can be grown in _______ or _______
liquid, solid culture media
pure culture technique
streak plate, pour plate, spread plate
free energy
energy released that is available to do work
delta G
change in free energy during a rxn
exergonic
reactions w/ negative delta G
endergonic
reactions w/ positive delta G
free energy of formation
energy released or required during formation of given molecule from elements
activation energy
energy required to bring all molecules in a chemical reaction into reactive state
catalyst
substance that lower activation energy of reaction, increases reaction rate, does not affect energetics or equilibrium of reaction
redox reactions
oxidation-reduction
energy from redox rxns is used in synthesis of _______
energy-rich compounds
electron donor
substance oxidized in redox reaction
electron acceptor
substance reduced in redox reaction
two classes of electron carriers
prosthetic groups, coenzymes
prosthetic groups
attached to enzymes
coenzymes
diffusable (NAD+, NADP)
_______ and _______ facilitate redox rxns without being consumed, they are recycled
NAD+, NADH
chemical energy released in redox rxns primarily stored in certain _______
phosphorylated compounds (ATP, phosphoenolpyruvate, glucose 6-phosphate)
long term energy storage involves insoluble polymers that can b oxidized to generate _______
ATP (glycogen, sulfur in prokaryotes; starch and lipids in eukaryotes)
two reaction series linked in energy conservation in chemoorganotrophs
fermentation, respiration
fermentation
substrate-level phosphorylation; ATP directly synthesized from energy-rich intermediate
respiration
oxidative phosphorylation; ATP produced from proton motive force by transport of electrons
glycolysis (embden-meyerhof)
common pathway for catabolism of glucose, anaeorbic process, three stages
glycolysis
glucose consumed, two ATPs produced, fermentation products generated (some harnessed by humans for consumption)
aerobic respiration
oxidation using O2 as terminal electron acceptor, higher ATP yield than fermentations
electron transport system
membrane associated, medicate transfer of electrons, conserve some energy released during transfer and use it to synthesize ATP, redox enzymes are involved in electron transport
NADH dehydrogenases
proteins bound to inside surface of cytoplasmic membrane; active site binds NADH and accepts 2 electrons and 2 protons that are passed to flavoproteins
flavoproteins
contains flavin prosthetic group that accepts 2 electrons and 2 protons and donated electrons to next protein in chain
cytochromes
proteins contain heme prosthetic groups, accept and donate a single electron via the iron atom in heme
