ch 10 bacterial metabolism Flashcards
aspects of metabolism common to all organisms
- life obeys the laws of thermodynamics
- the energy cells obtain from their environment is most often conserved as ATP
- oxidation-reduction (redox) reactions play a critical role in energy conservation
- the chemical reactions that occur in cells are organized into pathways
- each reaction of a pathway is catalyzed by an enzyme or a ribozyme
- the functioning of biochemical pathways is regulated
three major types of work
chemical work - synthesis of complex molecules
transport work - take up of nutrients, eliminate wastes, and maintain ion balances
mechanical work - cell motility and movement of structures within cells
substrate level phosphorylation
mechanisms for making ATP using molecules such a phosphoenolpyruvate (PEP) as a source of the phosphoryl group
phosphate transfer potential
anility to donate a phosphoryl group to other molecules
- ATP is high
electron transport chain (ETC)
system of electron carriers membrane-bound and organized
electron carriers
located in plasma membranes and intracytoplasmic membranes of bacterial and archaeal cells
localized in the internal membranes of mitochondria and chloroplasts in eukaryotic cells
- NAD, NADP, FAD, FMN, CoQ, cytochromes, nonheme iron proteins, ferredoxin
biochemical pathways
sets of chemical reactions performed by organisms that convert a starting substrate into one or more products
can be linear, cyclic, branching
metabolite flux
rate of turnover of a metabolite (rate at which a metabolite is formed and then used)
apoenzyme
protein component of an enzyme
cofactor
nonprotein component of an enzyme
holoenzyme
the complete enzyme consisting of the apoenzyme and its cofactor
prosthetic group
if the cofactor is tightly or covalently attached to the apoenzyme
coenzyme
if the cofactor is loosely attaching and can dissociate from the apoenzyme after products have been formed
six classes of enzymes
- oxidoreductase: oxidation-reduction reactions
- transferase: reactions involving the transfer of chemical groups btw molecules
- hydrolase: hydrolysis (break down) of molecules
- lyase: breaking of C-C, C-O, C-N and other bonds by a means other than hydrolysis
- isomerase: rearranges molecules to isomer form
- ligase: joining of two molecules using ATP (or the energy of other nucleoside triphosphates)
enzyme activity is significantly impacted by:
- substrate conc
- pH
- temp