Microbiology, 2021

CHAPTER 7
Microbial Biochemistry
Figure 7.1 Scientist Stanley Miller and Harold Urey demonstrated that organic compounds may have originated
naturally from inorganic matter. The Miller-Urey experiment illustrated here simulated the effects of lightning on
chemical compounds found in the earth’s early atmosphere. The resulting reactions yielded amino acids, the
chemical building blocks of proteins. (credit: modification of work by Courtney Harrington)
Chapter Outline
7.1 Organic Molecules
7.2 Carbohydrates
7.3 Lipids
7.4 Proteins
7.5 Using Biochemistry to Identify Microorganisms
INTRODUCTION The earth is estimated to be 4.6 billion years old, but for the first 2 billion years, the
atmosphere lacked oxygen, without which the earth could not support life as we know it. One hypothesis about
how life emerged on earth involves the concept of a “primordial soup.” This idea proposes that life began in a
body of water when metals and gases from the atmosphere combined with a source of energy, such as