4. Acetyl-CoA is
such an important molecule in the cell because it is also created by the breakdown
of proteins and lipids. If glucose (and the other
carbohydrates such as glycogen) is in short supply as occurs during lengthy
exercising or as a result of starvation, proteins and fats may be broken down
to Acetyl-CoA so they can be utilized to make many ATP during aerobic respiration.
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Slichter