General ---------Biology----------------------------------------------------- ------------------Online--------------------------------wilcox@sunline.net Ch. 6  Metabolism of carbohydrates, fats, proteins, nucleic acids

As cells breakdown food molecules, the energy is used to produce ATP from ADP.  Figure 6.10 of your text illustrates the regeneration of ATP from ADP.  In Ch. 9 we will explore how the food you eat is broken down by chemical pathways in and around organelles called "mitochondria," and the energy released is used to regenerate ATP by "phosphorylation" of ADP.

5.4  Coupling exergonic to endergonic reactions.

ATP and enzymes couple energy yielding reactions (exergonic/catabolic) with energy consuming reactions (endergonic/anabolic).  Food is broken down (catabolism) and some of the caloric energy is placed in an ATP; ATP then can shuttle this energy to an anabolic reaction.  Our text calls this "coupling."  To see an illustration of this, click here.