L5 Flashcards
confusing terms
electron transport chain = respiratory chain
respiration (breathing)≠ Respiration (energy metabolism with ETC and Oxidative Phosphorylation)
- Aerobic respiration = Energy metabolism with ETC, oxygen as the final electron acceptor, and Oxidative Phosphorylation
- Proton gradient = Proton Motive Force (PMF)
- Chemiosmosis = Osmosis of a chemical other than water? I only hear it applied to proton gradients making ATP.
metabolism
nterconversion of life’s molecules by
enzymatic reactions
catabolism
Breakdown of organic compounds to simpler
components.
* Often by oxidation reactions.
* Examples of catabolic processes:
* Extracting energy from nutrients
* Detoxification reactions
anabolism
Buildup complex molecules from simpler ones.
* Many reaction mechanisms
* Usually requires energy.
* Examples of anabolic process
* Phospholipid formation
* Energy storage: Fats, glycogen
* Formation of Hormones, Nucleic acids, Amino acids
redox reactions
LEO = loss of electrons oxidation (Xe- -> X); X is oxidized, in the process it reduces Y
GER = gain of relectrons reduction (Y -> Ye-); Y is reduced, in the process it oxidizes X
which way do electrons go
From reagents with low electron affinity (low electronegativity)…
…to reagents with high electron affinity (high electronegativity)
Extracting Energy from Glucose
- Glycolysis (cytoplasm, rest r in mitochondria)
- Pyruvate oxidation
- Tricarboxylic acid cycle (aka TCA cycle or citric acid cycle)
- Oxidative phosphorylation
Get Power Thru Oxidation
glycolysis
catabolic
breaks down glucose (INPUT) into 2 molecules of pyruvate
occurs twice per glucose; 2 phases, 3 energetic outputs (pyruvate, ATP, NADH)
2 enzymes subjected to feedback inhibiotn and postive regulation
pyruvate oxidation
catabolic
oxidzes pyruvate (INPUT) to 2 acetyl-CoA + 2 CO2 + 2NADH (OUTPUT)
involves decarboxylation, oxidation (NAD+ is reduced, pyruvate oxidized), acetyl-CoA synthesis
TCA cycle
catabolic
oxidizes acetyl-CoA (INPUT) making NADH, FADH2, CO2 and ATP (OUTPUT)
oxidative phosphorylation
electron transport chain
INPUTS: NADH+ & FADH (reduced compounds)
As NADH is oxidized, released e- are transported sequentially down a chainn of proteins - electron transport/respiratory chain
O2 final electron acceptor (most electronegative)
as chain passes e-, it pumps H+ ions into intermembrane space (Phase 1 electron transport)
protons flow down the gradient (Phase 2 chemiosmosis) through active proton pump (F1F0 ATP synthase) that can work in reverse to generate ATP from the proton gradient (4H+ make 1 ATP)
inner membrane of mitochondria
site of electron transport chain and ox phos reactions
matrix of mito
enclosed by inner membrane. where ATP made
intermembrane space of mito
where protons accumulate
most energy from glucose metabolism is from
ox. phos. in mitochondria
proton motive force
H+ gradient across the mito membrane
electron transport chain
4 diff protein complexes accept e - from NADH, FADH2 and transports them to other proteins to acceptors w/ increasing electronegativity
proteins go into the inter membrane matrix of the mito
proton pumping is coupled to NADH oxidation
coupling requires proteins inserted in mito membrane in proper orientation
proton gradient drives ATP production
PMF is the gradient used to drive ATP synthesis
Chemiosmosis –movement of ions across
semipermeable membrane, down their concentration gradient
F1F0 ATPase
Chemiosmotic flow of H + rotates the F1FO -type ATPase
ATPase normally catalyzes: ATP -> ADP + Pi
activity is reversible when energy put in by H+ gradient:
-creates high local concentration of ADP + Pi on the enzyme
-shifts the equilibrium and drives them to combine, making ATP
chemiosmotic theory
explained how ATP was made by respiration
proton gradient and F1 ATPase was sufficient to make ATP
uncoupling
when protons flow down their concentration gradient, but not through the F1F0 ATPase
First Law of Thermodynamics:
Conservation of energy…says that if ATP not made, then
heat is produced.
UCP1 = uncoupling protein
the good: when you need heat - hibernating, infancy, low muscle activity
the bad: diet aid - bad idea
