Malate-Aspartate Shuttle Mitochondrial NADH Transport

The video explains the challenge of transporting NADH from the cytosol to the mitochondria due to the lack of NADH transporters. It introduces the malate-aspartate shuttle as a solution, where electrons are transferred via malate. The process involves converting aspartate to oxaloacetate, then to malate, which carries electrons into the mitochondria. Inside, malate is converted back, regenerating NADH for the electron transport chain. The video concludes with a preview of the Glycerophosphate shuttle as an alternative method.

What is the main issue with NADH produced in the cytosol?

• It is immediately converted to ATP.

• There are no transporters for NADH across the mitochondrial membrane.

• It is not stable in the cytosol.

• It cannot be used by the electron transport chain.

Which molecule is initially converted from aspartate in the cytosol during the malate-aspartate shuttle?

• Alpha-ketoglutarate

• Glutamate

• Oxaloacetate

• Malate

What role does malate play in the electron transport process?

• It directly donates electrons to complex I.

• It acts as a carrier for electrons into the mitochondria.

• It is converted into ATP in the cytosol.

• It stabilizes NADH in the cytosol.

In the mitochondrial matrix, what happens to malate during the reverse reaction?

• It is used to produce ATP.

• It is oxidized to oxaloacetate, regenerating NADH.

• It is converted to glutamate.

• It is converted to aspartate.

What is the key point about the movement of NADH in the malate-aspartate shuttle?

• NADH is directly transported into the mitochondria.

• Only the electrons from NADH are transferred, not the molecule itself.

• NADH is stored in the cytosol for later use.

• NADH is converted to ATP before entering the mitochondria.

What is the alternative method to the malate-aspartate shuttle mentioned in the video?

• Electron transport chain

• Oxidative phosphorylation

• Krebs cycle

• Glycerophosphate shuttle

What is the primary function of the malate-aspartate shuttle?

• To convert glucose into pyruvate

• To transfer electrons from NADH into the mitochondrial matrix

• To produce ATP directly in the cytosol

• To transport NADH molecules into the mitochondria