EXAM 3 Lec 13 Flashcards
electron transport chain (ETC)
has mobile electron carriers linking trans-membrane complexes that make a proton gradient
what is the proton gradient used for in the ETC
to make ATP
electrochemical gradient
formed by energy released as electrons flow along ETC
what is an orbit
an electron in an atom has a specific level of energy that can increase or decrease a specific amount of energy
function of a pathway of proteins and compounds
can pass an electron along and capture its orbital energy
what is the cristae
the inner mitochondrial membrane
where is the ER in association to mitochondria
the ER is proximal to mitochondria but separate
there is a lipid shuttle between the two
mitochondrial physical ETC
3 transmembrane protein complexes use electron energy to pump proton into the intermembrane space
ubiquinone
a membrane bound mobile carrier transfers electrons from complex 1 to complex 3
cytochrome c
a water-soluble mobile carrier shuttles electrons from complex 3 to complex 5
what is the terminal acceptor of electron flow
oxygen, which generates H2O
mitochondrion NADH
has a covalently bound hydrogen which is released as a hydride ion composed of a proton and two high energy electrons
high energy electrons are taken up by the ETC and the proton is released into the intermembrane space
chloroplasts have 3 independent membranes
double membrane (outer and inner) defines an intermembrane space, the inner membrane defines the interior stroma
characteristics of the stroma
the stroma has independent membrane vesicles (thylakoids) usually stacked like pancakes (grana, granum)
purpose of the single membrane of thylakoids
defines internal lumen where protons are pumped into by photosynthesis electron transport
stage one of photosynthesis
light reactions
photon of light energy is absorbed with energy shifting an electron into a more energetic orbital
electron energy is captured in an ETC to produce ATP and NADPH
stage two of photosynthesis
dark reactions
inorganic CO2 fixed into glyceraldehyde-3-phosphate, which is exported to the cytosol
antenna complex
chlorophyll pigments in the thylakoid membrane
can absorb photons of particular wavelengths
photon of light energy absorbed with energy shifting an electron into a more energetic orbital
light energy recapture
reaction center chlorophylls transfer their electrons to electron carrier proteins. PSII electrons replaced from water splitting. PSI electrons from plastocyanin
where do protons accumulate in light-dependent reactions
on the lumen side of the thylakoid relative to the stromal side
chemiosmotic coupling
electron energy from electromagnetic radiation or high energy carriers NADH, is released stepwise and captured in protein complexes
captured energy pump hydrogen ions across a membrane to create a H+ gradient
energy from H+ flows through an ATP synthase enzyme complex to drive ATP formation from ADP + phosphate
where does chemiosmotic coupling occur
on the prokaryotic cell membrane or eukaryotic mitochondrial inner membrane
potential energy of the mitochondrial ETC
protons accumulating in the intermembrane space creates a large positive charge different and a H+ gradient (pH difference)
AKA proton motive force
function of the proton motive force in the mitochondrial ETC
moves protons (H+) back into the matrix coupled with ATP production from ADP and Pi
