Chapter 10-Introduction to Metabolism Flashcards
biodegradation
catabolism
biosynthesis
anabolism
breakdown of a larger molecule into smaller ones, breaks covalent bonds and releases energy, exergonic, enzyme catalyzed, most are oxidations and precursors for anabolism
catabolism
the synthesis of a larger molecule from a smaller one, creates many new covalent bonds, requires energy input, endergonic, enzyme catalyzed, mostly seen in reductions
anabolism (biosynthesis)
What 3 types of work must microbial cells do?
(1) chemical work- synthesis of complex molecules
(2) transport work- up take of nutrients, elimination of wastes and ion balance
(3) mechanical work- cell motility and movement of structures within cells
changes in matter of a system
thermodynamics
energy can neither be created or destroyed, total energy in the universe remains constant
first law of thermodynamics
physical and chemical processes show disorder
second law of thermodynamics
amount of disorder or randomness in a system
entropy
amount of heat needed to raise one gram of water from 14.5 to 15.5 C
calorie
units of work capable of being done by a unit of energy
joule
when delta G is negative, ___________
the reaction is spontaneous
when delta G is positive, ___________
the reaction is not spontaneous
rate of forward reaction is equal to rate of reverse reaction
equilibrium
expresses the equilibrium concentrations of products and reactants to one another
equilibrium constant (Keq)
high energy molecule, exergonic breakdown to ATP coupled with endergonic reactions to increase favorability
role of ATP in metabolism
transfer of electrons, from donor to acceptor, transfer of energy with electrons
redox reactions
loss of electrons or an H atom, becomes more positive, exergonic
oxidation
gain of electrons or an H atom, becomes less positive, endergonic
reduction
tendency of a compound to donate or gain electrons, standard condition expressed as volts, more negative = better donor, more positive = better acceptor
standard redox potential
electron carrier, 1st electron carrier has the most energy, potential energy is stored in first redox couple is released and used as ATP, 1st carrier is reduced and electrons move to next carrier
electron transport chain
NAD, NADP, NADH
electron carriers
use iron to transfer electrons (part of heme group)
cytochromes
organic molecules, serve as catalysts, increase the rate of reaction, protein catalysts are specific to the reaction
enzymes
increases the rate of reaction without permanent alteration
catalyst
reacting molecule
substrate
formed by reaction
product
protein component of an enzyme
apoenzyme
loosely attached
coenzyme
firmly attached
prosthetic group
holoenzyme
loosely attached
energy required to form a transition state complex
activation energy
increasing concentrations of substrates at the active site of an enzyme, proper orientation of substrates to quickly from transition state complex
how to lower Ea
What environmental conditions effect enzyme activity?
substrate concentration, pH, temperature
directly competes with binding of substrate to the active site
competitive inhibition
binds enzyme at site other than active site
non-competitive inhibition
discovered by Cech and Altman, RNA molecules that can catalyze a reaction, self splicing, self replication, and catalyze peptide bond formation
ribozymes
differential in localization of enzymes and metabolites
metabolic channeling
includes metabolic channeling, can generate marked variations in metabolic concentration
compartmentation
allosteric regulation and covalent modification
post translational regulation
most regulatory enzymes, small molecule that alters activity (bonds noncovalently at regulatory site, changes shape of enzyme and alters activity of catabolic site), positive effector increases enzyme activity, negative effector inhibits the enzyme
allosteric regulation
reversible on/off switch, add/remove chemical group, respond to more stimuli in varied and sophisticated ways, regulation of enzyme that catalyze covalent modifications, add a second level of control
covalent modifications of enzymes
aka end product inhibition, inhibition of 1 or more critical enzymes in a pathway, each end product regulates own branch of pathway, each end product regulates initial pacemaker enzyme
feedback inhibition
catalyzes slowest rate limiting reaction of pathway
pacemaker enzyme
different enzymes that catalyze same reaction
isoenzymes
