AP BIOLOGY

CELL RESPIRATION

OXIDATIVE PHOSPHORYLATION

Question [CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
The electron transport chain (ETC) makes water. To make this water, where do the hydrogen atoms come from?
A
glucose
B
pyruvate
C
NADH and FADH
D
oxygen
Explanation: 

Detailed explanation-1: -The electron transport chains are on the inner membrane of the mitochondrion. As the high-energy electrons are transported along the chains, some of their energy is captured. This energy is used to pump hydrogen ions(from NADH and FADH2) across the inner membrane, from the matrix into the intermembrane space.

Detailed explanation-2: -Oxygen sits at the end of the electron transport chain, where it accepts electrons and picks up protons to form water.

Detailed explanation-3: -The electron transport chain is a series of electron transporters embedded in the inner mitochondrial membrane that shuttles electrons from NADH and FADH2 to molecular oxygen. In the process, protons are pumped from the mitochondrial matrix to the intermembrane space, and oxygen is reduced to form water.

Detailed explanation-4: -Electrons carried by NADH + H+ and FADH2 are transferred to oxygen via a series of electron carriers, and ATPs are formed. Three ATPs are formed from each NADH + H+, and two ATPs are formed for each FADH2 in eukaryotes.

Detailed explanation-5: -The electrons from from NADH and FADH2 flow through the electron transport chain in the inner mitochondrial membrane generating a H+ buildup in the inner membrane space. This proton gradient (gradient of H+) flowing through the membrane enzyme complex ATP synthetase is the direct energy source for producing ATP.

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