Oxidative phosphorylation and electron transport chain

what is most of the energy in the form of?

reduced electron carriers (NADH and FADH)

oxidative phosphorylation

process that couples oxidation of NADH and FADH2 by ETC with synthesis of ATP

where are majority of ATP molecules produced

fourth stage

what acts as the final election acceptor and combines with H+ ions to form H2O

oxygen (without it, ETC shuts down, ATP not produced)

electron transport chain

series of electron carriers and protein complexes embedded in inner mitochondrial membrane that accepts and donates electrons in a series of reactions 

how are the compounds in the ETC arranged

in order of increasing electronegativity (weakest-NADH dehydrogenase, strongest- cytochrome oxidase) 

what are the three proton or H+ pumps in ETC

1. NADH dehydrogenase

2. bc1 complex

3. cytochrome oxidase complex 

what are the two mobile electron carriers within membrane

1. Q- ubiquinone

2. C-cytochrome C

how does the chain provide energy

electrons are donated by NADH and FADH2 causing them to return to oxidized forms

explain how the ETC is highly exergonic

it releases a large amount of free energy as electrons move through the chain from high-energy electron carriers (NADH and FADH₂) to low-energy acceptors (O₂ → H₂O).

how is a hydrogen ion gradient created across membrane

electrons from NADH pass through three major complexes, each one uses energy released from passing electron to actively transport or pump hydrogen atoms out of matrix and into intermembrane space, creating a hydrogen ion gradient

describe passing of electrons from FADH2

electrons skip first major complexes in the chain, and energy released by electron transfer pumps hydrogen ions through only the second and third complex

how much H+ does each reduced electron carrier have the ability to pump

NADH→ 3H+ (electrons pass through all three complexes)

FADH2→ 2H+ (electrons only pass through second and third complexes)

what is the final electron acceptor

oxygen, accepts electrons and reacts with H+ ions to produce water

do hydrogen ions use active or passive transport in ETC

active, against concentration gradient

what type of reactions occur when reduced electron carriers are oxidized

redox reactions

explain the glycerol phosphate shuttle

Eukaryotic innermmebrane cannot diffuse NADH into membrane, so glycerol phosphate shuttle is required, transports electrons, reduces shuttle and goes into membrane, reduces FAD to FADH2 therefore starts at Q and only pumps 2 H+ across membrane 

chemiosmosis

process that uses energy in hydrogen ion gradient cross inner mitochondrial membrane to drive phosphorylation of ADP to ATP

explain how ATP is made at ATP synthase

When H + ions are moving down their gradient through an ATP

synthase complex, there is a reduction in electrochemical

energy

• this energy is used to phosphorylate ADP to form ATP (process

is called chemiosmosis)

• ATP can leave through the membrane by facilitated diffusion

into the cytoplasm where they are used to drive endergonic

processes. (eg. movement, active transport, etc.)