biochemistry

from The American Heritage® Dictionary of the English Language, 5th Edition.

• noun The study of the chemical substances and vital processes occurring in living organisms; biological chemistry; physiological chemistry.
• noun The chemical composition of a particular living system or biological substance.

from The Century Dictionary.

• noun The chemical study of living matter; also, physiological chemistry.

from the GNU version of the Collaborative International Dictionary of English.

• noun (Biol.) The chemistry of living organisms; the chemistry of the processes incidental to, and characteristic of, life.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun uncountable The chemistry of those compounds that occur in living organisms, and the processes that occur in their metabolism and catabolism
• noun countable The chemical characteristics of a particular living organism
• noun countable The biochemical activity associated with a particular chemical or condition

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• noun the organic chemistry of compounds and processes occurring in organisms; the effort to understand biology within the context of chemistry