10.3 Phosphorus-Containing Compounds

LEARNING GOALS

After   Chapter 10.3,   you will    be  able    to:

Recognize   the traits  that    make    inorganic   phosphate   a   useful  molecule    for energy  transfer

Explain why phosphoric  acids   are good    buffers

Recall  what    makes   a   molecule    an  organic phosphate

Phosphoric acid is an extremely important molecule biochemically. This molecule forms the high-
energy bonds that carry energy in adenosine triphosphate (ATP).

DESCRIPTION

In a biochemical context, phosphoric acid is sometimes referred to as a phosphate group or
inorganic phosphate, denoted Pi. At physiological pH, inorganic phosphate includes molecules of

both hydrogen phosphate and dihydrogen phosphate

In addition to the energy-carrying nucleotide phosphates, phosphorus is also found in the backbone
of DNA in phosphodiester bonds linking the sugar moieties of the nucleotides, as shown in Figure
10.9.