Electron Transport Chain + Oxidative Phosphorylation

SBI4U - Birrell

electrons involved in the electron transport chain are carried by ______ and ______ molecules, that bring them to the ______ _______ of the mitochondria

NADH, FADH₂, inner membrane

where did the NADH and FADH₂ molecules get their electrons from?

sugar molecules, during Krebs and Glycolysis

e- are passed through a series of _______ in the _______ via ______ reactions

proteins, membrane, redox

energy is ________ in the proteins’ redox reactions, and is then used to ____ __ ions

released, pump, H⁺

what do proton pumps do?

pump H⁺ ions out of the matrix into the intermembrane space

electrons are passed through a series of acceptors in the ETC, but the final acceptor of electrons is:

oxygen!

The driving force of the ETC is oxygen, and without it we die. Explain how oxygen is the driving force.

it’s highly electronegative, so it removes e- from complex 4, which kicks off electron transport (complex 4 takes from complex 3, and so on)

Thanks to protein pumps, hydrogen ions accumulate in the intermembrane space. What does this create?

an electrochemical gradient across the inner membrane

☆ stores free energy! (🔋)

___ ________ is a membrane-spanning ________ _______ used after ETC, during __________ __________.

ATP synthase, protein complex, oxidative phosphorylation

explain how ATP synthase synthesizes ATP

• acts like a water turbine 🌊

• the flow of H⁺ ions back down their electrochemical gradient turns the turbine 🛞

• as it turns, it catalyzes the phosphorylation of ADP ⚡

• this forms ATP in the matrix

NADH vs FADH₂

NADH	FADH2
enters ETC @ complex 1 passes through 3 proton pumps capable of producing 3 ATP	enter ETC @ complex 2 passes through 2 proton pumps capable of producing 2 ATP

UQ

a mobile protein that is trapped inside the bilayer

besides UQ, another mobile protein involved in the ETC is __ _, which acts as an ________ _______

cyt c, electron carrier

recall that NADH and FADH₂ are ________. When they are _________, giving their electrons to the _________, they reform NAD+ and FAD, and return to the ____ ____.

reusable, oxidized, complexes, krebs cycle

Cystolic NADH

NADH made in glycolysis 🍰

⇨ too big to pass through inner membrane, so has to transfer e- to one of 2 e- shuttles

for our purposes, we assume that cystolic NADH uses which shuttle?

🚋 one that will transfer the electrons to another NAD+ inside the matrix