Chapter 8: ATP Flashcards
(19 cards)
ATP powers cellular work by
coupling exergonic reactions to endergonic reactions
energy coupling
the use of an exergonic process to drive an endergonic one
cells manage energy resources by
energy coupling
Most energy coupling in cells is mediated by
ATP (adenosine triphosphate), cell’s energy shuttle
Exergonic reactions
release energy - These reactions occur spontaneously since they do not require energy to occur.
Endergonic reactions
absorb energy to form bonds — so they do not occur spontaneously.
Instead, they occur only if energy is available to be used in the reaction.
Metabolism
sum of chemical & physical changes occurring in tissue/cell, consisting of ANABOLISM, and CATABOLISM.
Anabolism
those reactions that convert small molecules into large
Catabolism
those reactions that convert large molecules into small
ATP is composed of
ribose (a sugar), adenine (a nitrogenous base), and 3 phosphate groups
The bonds between the phosphate groups of ATP’s tail can be broken by
hydrolysis
Energy is released from ATP when the
terminal phosphate bond is broken
The 3 types of cellular work
(mechanical, transport, and chemical) are powered by the hydrolysis of ATP
In the cell, the energy from the exergonic reaction of ATP hydrolysis can be used to drive an
endergonic reaction
coupled reactions are
exergonic
ATP drives endergonic reactions by phosphorylation,
transferring a phosphate group to some other molecule, such as a reactant
recipient molecule
called a phosphorylated intermediate
ATP is a renewable resource that is regenerated by the addition of a
phosphate group to adenosine diphosphate (ADP)
Energy to phosphorylate ADP comes from
catabolic reactions in the cell
