location

location

inner mitochondrial membrane

what are cristae

A: Folds of the inner mitochondrial membrane that increase surface area for ETC complexes and ATP production.

Q: Why are electron shuttles needed for glycolysis-derived NADH?

A: NADH produced during glycolysis is in the cytoplasm and cannot freely cross the inner mitochondrial membrane, so electron shuttles transfer its electrons into the mitochondrion.

Q: Can NADH produced in the mitochondrial matrix deliver electrons to the ETC directly?

A: Yes. NADH produced during the preliminary step and citric acid cycle can donate electrons to the ETC.

Q: What is the purpose of the glycerol phosphate shuttle?

A: To transfer electrons from cytoplasmic NADH into the mitochondrion so they can enter the ETC.

Q: What molecule accepts electrons from NADH in the cytoplasm during the glycerol phosphate shuttle?

DHAP

Q: What does DHAP become after accepting electrons from NADH? + what happens

• glycerol-3-phosphate

A: It transfers its electrons to FAD, producing FADH₂.

Q: Which electron acceptor is used inside the mitochondrion in the glycerol phosphate shuttle?

FAD

Q: Where do electrons from the glycerol phosphate shuttle enter the ETC?

A: They enter downstream of Complex I, bypassing it.

Q: How much ATP is produced per pair of electrons transferred through the glycerol phosphate shuttle?

1.5 ATP

Q: What is the purpose of the malate-aspartate shuttle?

A: To transfer electrons from cytoplasmic NADH into the mitochondrial matrix, where they can enter the ETC through Complex I.

Q: What molecule accepts electrons from cytoplasmic NADH in the malate-aspartate shuttle?

A: Oxaloacetate, which is converted into malate.

Q: What happens to malate in the malate-aspartate shuttle?

A: Malate crosses the inner mitochondrial membrane into the matrix.

Q: How much ATP is produced per pair of electrons transferred through the malate-aspartate shuttle?

2.5 ATP