B(beta)-oxidation Question?

Question

Another review question I'm having trouble on...

During B(beta)-oxidation, methylene (-CH2-) groups in the fatty acid are oxidized to carbonyl (C=O) groups, yet no oxygen is consumed by the reactions of B(beta)-oxidation. How is this possible?

The question gives no details on the COOH group.

Answer 1

Because the oxygen is derived from water. In the oxidation, the CH2-CH2 bond is converted to CH=CH, which is later hydrated (H2O). So you don't use oxygen directly in this reaction (although indirectly, during the first oxidation FAD gets reduced to FADH2 which later is reoxidized in the electron transport chain, where the final electron acceptor is O2).

There's no COOH group at this point. After the attack of S from acetylCoA it's converted to a thioester (C(=O)SAcCoA)

Answer 2

Before the Siderian period the world had much less oxygen in it. Meaning, seas devoid of oxygen. Durring the Siderian the algae activity that signifies the period began to pump oxygen into the oceans. Allowing then unreactive metalic iron in the sea to be precipitated out into iron oxide. In the case of temperature being a culprit in the Siderian, most likely not. Unless you factor it into giving the agal life energy. Temperature does affect oxidation, but oxidation cannot occur without oxygen. The higher the temperature, the easier it is for oxygen to bond with iron, the lower, the slower it will react.

Answer 3

What happens to the acid COOH group?