Question

Where do phosphates come in, in cellular respiration

Answer 1

The phosphates themselves are taken-in by the organism externally. Bacteria transport them across their cell membrane, heterotrophs eat other organisms and take in phosphates, plants take them in from the soil.

In the case of mammals, the phosphates are absorbed in the gut, diffused through the vascular system, and transported to individual cells which have a few different mechanism available for transporting the phosphates in. Once taken into the cytosol, they are synthsized by enzymes into structures like ADP.

Answer 2

Source: http://answers.yahoo.com/question/index?qid=20090409224119AA1dL1D
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