Electron Transport Chain and Chemiosmosis: Key Concepts for Biology

What is the Electron Transport Chain (ETC)?

A series of proteins that pass electrons and use energy from electrons to pump H⁺ (protons).

What do NADH and FADH₂ do in the ETC?

They bring high-energy electrons and drop them off in the chain.

What happens to electrons as they move through the ETC?

Each step releases energy that is used to pump H⁺ across the membrane.

What is the final electron acceptor in the ETC?

Oxygen, which combines with electrons and H⁺ to form water (H₂O).

What is the main outcome of the Electron Transport Chain?

It builds the H⁺ gradient.

What is chemiosmosis?

The process that uses the H⁺ gradient to make ATP.

How does H⁺ flow during chemiosmosis?

H⁺ flows back through ATP synthase from high to low concentration.

What is produced when H⁺ flows through ATP synthase?

ATP is produced from ADP and inorganic phosphate (Pi).

Where does the Electron Transport Chain occur?

In the inner mitochondrial membrane.

In which direction is H⁺ pumped during the ETC?

From the matrix to the intermembrane space.

What happens to the ETC without oxygen?

The ETC stops and no ATP is produced from this process.

What is the relationship between ETC and ATP production?

ETC uses electrons to pump H⁺, creating a gradient that drives ATP synthesis.

What is the stored potential energy in chemiosmosis?

The high concentration of H⁺ ions.