Question

Two molecules of acetyl Co-A produced
from
(formed in glycolysis),
enter the mitochondria.
(A) citric acid
(B) pyruvic acid
(C) fatty acid
(D) tri-carboxylic acid​

Answer 1

Answer:

glycolysis),

enter the mitochondria.

Explanation:

Acetyl-CoA is synthesized in mitochondria by a number of reactions: oxidative decarboxylation of pyruvate; catabolism of some amino acids (e.g., phenylalanine, tyrosine, leucine, lysine, and tryptophan); and β-oxidation of fatty acids (see earlier). Since acetyl-CoA cannot be transported directly across the inner mitochondrial membrane to the cytosol, its carbon atoms are transferred by two transport mechanisms:

1.

Transport dependent on carnitine: Carnitine participates in the transport of long-chain acyl-CoA into the mitochondria and plays a similar role in the transport of acetyl-CoA out of mitochondria. However, carnitine acetyl transferases have a minor role in acetyl-CoA transport.

2.

Cytosolic generation of acetyl-CoA (citrate shuttle): This pathway is shown in Figure 16.8. Citrate synthesized from oxaloacetate and acetyl-CoA is transported from mitochondria to the cytosol via the tricarboxylate anion carrier system and cleaved to yield acetyl-CoA and oxaloacetate.