electron transport and oxidative phosphorylation

what features of the mitochondria enable this organelle to be the powerhouse of the eukaryotic cell?

the double membrane structure and cristae increasing surface area

the outer membrane contains porins

the intermembrane space contains ATP utilizing enzymes

name all the carrier proteins that transport molecule across the mitochondrial membrane

ATP-ADP translocase

phosphate carrier protein

pyruvate translocase

dicarboxylate carrier protein

tricarboxylate carrier protein

Ca²⁺ influx and eflux

what are the electron carriers

NAD+

FAD+

FMN

CoQ

Fe-S clusters

cytochromes

copper binding proteins

which electron carriers transport TWO electrons

NAD+

which electron carriers can transport one OR two electrons at a time

FAD, FMN, coenzyme Q (CoQ)

which electron carriers transport only ONE electron at a time

cytochromes, iron-sulfur clusters, copper binding proteins

complex one of the etc

aka NADH-CoQ oxidoreductase or NADH dehydrogenase

accepts electrons from NADH and is a link between glycolysis, TCA, fatty acid oxidation, and ETC

complex two of the etc

aka succinate-CoQ oxidoreductase or succinate dehydrogenase

serves as direct link between TCA and ETC

complexes one and two both produce what?

reduced CoQ (CoQH₂), which is the substrate for complex three

complex three of the etc

aka CoQ-cytochrome C oxidoreductase

transfers electron from CoQH₂ to reduce cytochrome c, which is the substrate for complex four

complex four of the etc

aka cytochrome c oxidase

transfers electrons from cytochrome c to reduce molecular oxygen in water

which complexes couple the transfer of electrons with the transport of protons across the membrane

centers 1, 3, and 4

what carries electrons between complex one and two to complex three

coenzyme Q (CoQ/ubiquinone)

what carriers electrons from complex three to complex four

cytochrome c

how is the proton gradient generated from the ETC useful in ATP synthesis

proton motive force drives synthesis of ATP as protons flow back from the intermembrane space to the matrix of the mitochondria

protons are channeled through ATP synthase to catalyze production of ATP

what are the two complexes of ATP synthase

F₁ and F₀

F₁ of ATP synthase

catalyzes synthesis of ATP and is composed of 5 polypeptide chains

F₀ of ATP synthase

forms a transmembrane pore through which protons are channeled to drive ATP synthesis

which subunits of the ATP synthase complex make up the rotor

the c-ring of F₀ and the gamma and epsilon subunits of F₁

which subunits of the ATP synthase complex make up the stator

ab₂ subunits of F₀ and the delta subunit with the alpha₃beta₃ spheroid of F₁

which subunits of ATP synthase contain the active site?

the beta subunits

which ATP synthase subunits transport protons across the membrane

the alpha subunit and c-ring

how does the transport of protons across the membrane drive ATP synthesis

the movement of protons through the F₀ channel causes the gamma subunit to rotate, driving conformational change in the beta-subunit structure, resulting in binding of ADP and Pi to release ATP

what is the P/O ratio of NADH

2.5 ATPs per NADH

what is the P/O ratio of FADH₂

1.5 ATPs per FADH₂

where does rotenone inhibit

electron transport in complex one

where does antimycin A inhibit

electron transport in complex three

where does cyanide inhibit

electron transport in complex four

where does carbon monoxide inhibit

electron transport in complex four

where does dicyclohexylcarbodiimide inhibit

it bond covalently to glutamate on the c subunit of F₀, blocking the proton channel and inhibiting ATP synthase

where does oligomycin A inhibit

it binds directly to ATP synthase F₀ subunit and blocks flow of protons through the channel

what is an uncoupler?

they uncouple electron transport from oxidative phosphorylation, collapsing the chemiosmotic gradient by dissipating protons across the inner mitochondrial membrane

what is 2,4-dinitrophenol

an uncoupler that contains a dissociable proton, allowing it to carry protons from the intermembrane space to the matrix, collapsing the pH gradient

what enzymes are involved in the glycerophosphate shuttle

cytosolic glycerol 3-phosphate dehydrogenase

mitochondrial glycerol 3-phosphate dehydrogenase

what is the P/O ratio in the glycerophosphate shuttle

1.5 ATP/NADH

what enzymes are involved in the malate aspartate shuttle

cytosolic malate dehydrogenase, mitochondrial malate dehydrogenase, and aspartate amino transferase

what is the P/O ratio for the malate aspartate shuttle

2.5 ATP/NADH

ferric iron

Fe³⁺

ferrous iron

Fe²⁺

cuprous copper

Cu¹⁺

cupric copper

Cu²⁺