THE CHEMICAL LEVEL OF ORGANIZATION
Every structure of the body is made of chemicals and every function is related to
Therefore this chapter provides students with the
essential chemical background needed to understand the anatomy and
physiology of the body.
Among the topics considered are matter and energy,
chemical elements, atomic structure, molecule formation, isotopes (radioactive
and stable forms), the role of electrons in chemical reactions, chemical bonds
(including ionic, covalent, and hydrogen bonds), forms of energy and chemical
reactions, energy transfer in chemical reactions, and the detailed mechanisms of
chemical reactions (including synthesis, decomposition, exchange, and
The importance of chemical compounds in life processes
is discussed, and the unique roles that inorganic and organic compounds play in
living systems are pointed out.
The structure and significance of the inorganic
substances (water, acids, bases, and salts) are emphasized.
carbon-based molecules are explained before introducing the major organic
compounds: carbohydrates, lipids, proteins, nucleic acids (deoxyribonucleic acid,
or DNA, and ribonucleic acid, or RNA), and adenosine triphosphate (ATP).
concept of pH and the role of buffer systems and enzymes in maintaining
homeostasis are also explored. Clinical applications include lactose intolerance