Vocab - Bioenergetics and Enzymes

metabolism

consists of all the biochemical reactions by which
organisms transform matter and energy

catabolic pathways

release energy by breaking down complex molecules into simpler molecules (part of metabolism)

anabolic pathways

consume energy by using simple molecules to
build more complex molecules (part of metabolism)

free energy

energy that is available to do work

work

any physical motion or change, other than the random motions of particles (thermal energy)

exergonic reactions

release free energy and can occur spontaneously

endergonic reactions

absorb free energy and do not occur spontaneously

reaction coupling

happens by means of the transfer of a phosphate group from ATP to a substrate molecule

ATP

used as one of the monomers in the synthesis of RNA, but is also used as an energy carrier in cells

energy carrier

picks up energy from exergonic reactions and processes, and gives some of that energy to endergonic reactions and processes to make them happen

ATP hydrolysis

an exergonic process. (G’o is the free energy
change of a chemical reaction under certain standard, specified reaction conditions.)

the reaction has a high activation energy and will not happen quickly unless it is catalyzed

ATPases

enzymes needed to make the hydrolysis reaction
go at a rapid rate

ATP synthesis

an endergonic process

ATP cycle

the linking of cellular exergonic and endergonic
reactions and processes by ATP synthesis and ATP hydrolysis

enzymes

molecules that catalyze biochemical reactions, increasing the reaction rate enormously (almost all are proteins)

activation energy

enzymes reaction go faster by lowering the activation energy of the reaction

transition state

A-B + C ——> [A . . . B . . . C] ——> A + B-C
transition state

enzyme specificity

the specificity of enzymes comes from the specificity of the interaction between the substrate(s) (the molecule or molecules that the enzyme acts upon) and the active site

active site

regenerated during the reaction, with no net change to them, and the enzyme can then undertake further catalytic cycles

saturation kinetics

there are only so many active sites in a given
quantity of enzyme, and they cannot process substrates faster than a maximum rate

protein denaturation

if the temperature exceeds the optimal range it will cause the enzyme to denature

cofactor

small, non-protein molecules and ions required by some enzymes for their catalytic activity

enzyme inhibitor

binds to an enzyme and deforms the active site and deactivates them

enzyme activator

binds to an enzyme and stabilizes the active site, increasing activity

metabolic pathways

enzymes act sequentially in regulated metabolic pathways

feedback inhibition

the product of a pathway inhibits the
first enzyme of the pathway

oxidation-reduction reactions

The loss and gain may involve entire electrons or shares of electrons

oxidation

loss of electrons

reduction

gaining of electrons

electron carriers

NADH, NADPH, FADH2