Biochemistry I Exam 5 Flashcards
Autotroph
use CO2 from the atmosphere as their sole source of carbon
Heterotroph
cannot use atmospheric CO2 and must obtain carbon from their environment
Metabolites
series of intermediates through which precursors are converted to product
Intermediary Metabolism
the combines activities of all the metabolic pathways that interconvert precursors, metabolites, and products of low molecular weights
Catabolism
the degradative phase of metabolism; releases energy
Anabolism (biosynthesis)
the building phase of metabolism; requires energy
Energy Transduction
changes of one form into another
Free Energy
expresses the amount of energy capable of doing work during a reaction at constant temperature and pressure
Enthalpy
the heat content of the reacting system
Entropy
a quantitative expression for the randomness or disorder in a system
Free Energy Change Equation
delta G=delta H-T delta S
Exergonic
energy-releasing reaction
Endergonic
requires energy input
Exothermic
releases heat
Endothermic
takes up heat
Understand the relationship between Keq and DG
-Keq>1.0=negative delta G (reaction proceeds forward)
-Keq=1.0=zero delta G (reaction is at equilibrium)
-Keq<1.0=positive delta G (reaction proceeds in reverse)
Heterolytic Cleavage
cleavage of a covalent bond where each atom leaves the bond as a radical, carrying one unpaired electron
Nucleophile
functional groups rich in and capable of donating electrons; combine with and give up electrons to electrophiles
Electrophiles
electron-deficient functional groups that seek electrons
Kinase
transfer a phosphoryl group from ATP to an acceptor molecule; catalyzes a phosphorylation reaction
Phosphorylases
catalyze a displacement reaction where phosphate attacks and becomes covalently attached at the point of bond breakage; catalyze a phosphorolysis reaction
Phosphateses
catalyze the removal of a phosphoryl group from a phosphate ester; catalyze dephosphorylation reactions
Synthase
catalyze condensation reactions in which no nucleotide triphosphate is required
Synthetases
catalyze condensation reactions that require a nucleotide triphosphate
Oxidases
catalyze biological reactions where oxygen is the electron acceptor and oxygen does not appear in the oxidized product
Oxygenases
catalyze biological oxidation reactions where oxygen is the electron acceptor and oxygen does appear in the oxidized product
Dehydrogenase
-catalyze oxidation-reductase reactions in which NAD+ is the electron acceptor and molecular oxygen is not involved
-Electron acceptor is NAD+