electron transport chain

what is the first stage of oxidative phosphorylation

Electron transport chain

what is electron transport chain

a series of protein complexes and other molecules that transfer electrons from donors to acceptors

where is the electron transport chain occur

along the inner membrane of the mitochondria

-cristae

what are the protien complexes called

I,II,III,IV

what are the electron donors in the electron transport chain

10 NADH -from glycolysis, oxidative decarbox., citric acid cycle

2 FADH₂ - from Krebs cycle

what is the final electron acceptors in the electron transport chain

O₂

which protein complexes are pumps

I,III,IV

what do complexes I,III,IV pump

H+ ions are pumped from the matrix into the inter membrane space

what type of transport are H+ moving

primary active transport

-low to high concentration

-H+ is greater in the intermembrane

where does NADH donate its electrons

Complex I

where does FADH₂ donate its electrons

Complex II

what energy is used to operate the H+ pumps

 Proton Motive Force

 what is Proton Motive Force 

energy created from the flow of electrons from NADH & FADH₂ through the complexes

how does complex III get electrons

From Coenzyme Q

1. it recieves electrons from complex I & II

2. carries the electrons through the inner membrane to complex III and donates them

how does complex IV get electrons 

From cytochrome c

1. it receives electron from complex III

2. delivers electron to complex IV

what does complex IV do with the donated electron

it transfers the electron to O₂

to form H2O as a byproduct.

what is the goal of the electron transport chain 

create PMF

If Complex I is inhibited

electrons from NADH cannot enter the membrane

-atp can still be produced but less efficiently 

If Complex II is inhibited

Complex I still pumps protons and contributes to PMF, complex II doesn't

ATP production decreases a little, but not as much as blocking Complex I. since 10>2

Which is worse — blocking Complex I or Complex II?

Blocking Complex I is worse, because:

• NADH contributes more electrons than FADH₂ (from glycolysis + Krebs).

If ATP synthase is blocked

Protons can’t flow back, so the PMF builds up and eventually electron flow through the ETC stops

ATP production essentially stops completely.