Cytosolic NADH

Question

Cytosolic NADH
A) Enters the mitochondrial matrix through a countertransport mechanism
B) Enters the mitochondrial matrix by active transport
C) Enters the mitochondrial matrix by passive transport
D) Enters the m itochondrial matrix by osmosis
E) NADH does not cross the inner mitochondrial membrane

Accepted Answer

NADH cannot directly cross the inner mitochondrial membrane due to its impermeability to NADH. Instead, its electrons are transferred into the mitochondria through shuttle systems like the malate-aspartate shuttle or the glycerol phosphate shuttle, allowing for the indirect entry of the reducing equivalents into the mitochondrial electron transport chain.