BIOENERGETICS AND LIGHT-DEPENDENT REACTIONS OF PHOTOSYNTHESIS Flashcards
study of energy
transformations in living organisms
bioenergetics
has been variously described
as a measure of randomness, disorder, or chaos
entropy
mean molecular kinetic energy of matter.
temperature
some energy will be available under isothermal conditions and
is, consequently, available to do work.
Gibbs free energy
If the sign of AG is negative, the reaction is considered
spontaneous
energy yielding
exergonic
energy consuming
endergonic
electrons are transferred
from one component to another
redox reactions
tendency to
accept electrons from or donate electrons to another
redox potential
redox potential is measured in
volts
strong electron donor, reducing
agent
reductant
strong electron acceptor
oxidant
ATP synthesizing enzyme
ATP synthase
pump
protons out of the cell or the vacuole
ATPase-proton pumps
The principal
function ofthe light-dependent reactions ofphotosynthesis is
therefore to generate the NADPH and ATP required for
carbon reduction. This is accomplished through a series
of reactions called
photosynthetic electron transport chain
The key to the photosynthetic electron transport chain
is the presence of two large, multimolecular complexes
PSI and PSII
e photosynthetic unit of oxygenic photosynthetic
organisms
photosystem
photosystems are linked by a third multiprotein aggregate
cytochrome
The bulk of the chlorophyll in the photosystem
functions as
antenna chlorophyll
The augmented antenna complexes
light-harvesting complexes
considered the primary electron
acceptor in PSII
Pheophytin
a quinone that binds transiently to a binding site (QB) on the D1 reaction center protein
plastoquinone
small peripheral protein that is able to diffuse freely along
the luminal surface ofthe thylakoid membrane
plastocyanin
used to reduce NADP+
ferredoxin
