Biochem Lesson 7 - Bioenergetics and ATP Flashcards
what is a catabolic pathway
catabolic pathways combust carbon fuels to synthesize ATP
what are anabolic pathways
anabolic pathways use ATP and reducing power to synthesize large biomolecules
what is an amphibolic pathway
one that can function anabolically or catabolically.
do anabolic and catabolic pathways share reactions
although they may have reactions in common, the regulated, irreversible reactions are always distinct
what do carbon atoms in fuels oxidize to yield
they’re oxidized to yield CO2, and the electrons are ultimately accepted by oxygen to form H2O
what determines how much free energy is released on oxidation
the more reduced a carbon atom is, the more free energy is released when oxidized. fats are more efficient food source than glucose because fats are more reduced
what two criteria must be met to construct a metabolic pathway
the individual reactions must be specific, and the pathway in total must be thermodynamically favorable. a thermodinamically unfavorable reaction in a pathway can be made to occur by coupling it to a move favorable reaction
is ATP hydrolysis endergonic or exergonic
the hydrolysis of ATP is exergonic because the triphosphate unit contains two phosphoanhydride bonds that are unstable. the energy released on ATP hydrolysis is used to power a host of cellular functions
how does ATP hydrolysis drive metabolism
by shifting the equilibrium of coupled reactions
what is phosphoryl-transfer potential
the standard free energy of hydrolysis. it is a means of comparing the tendency of organic molecules to transfer a phorphoryl group to an acceptor molecule.
does ATP have high phosphoryl-transfer potential or low and what is it due to
it has a high phorphoryl-transfer potential due to three key factors: charge repulsion, resonance stabilization, and stabilization by hydration
describe why phosphoryl-transfer potential is an important form of cellular energy transformation
ATP has a phorphoryl-transfer potential intermediate between high phorphoryl-potential compounds derived from fuel molecules and acceptor molecules that require the addition of a phosphoryl group for cellular needs
describe the action of creatine phosphate
muscle contains only enough ATP to power muscle contraction for less than a second. creatine phosphate can regenerate ATP from ADP, allowing for a short burst of activity as in a sprint. once creatine phosphate stores are depleted, ATP must be generated by metabolic pathways
