Henry David Thoreau. The mass of men lead lives of quiet desperation. What is called resignation is confirmed desperation. .... A stereotyped but unconscious despair is concealed even under what are called the games and amusements of mankind.--Ch.
Peptidoglycan (pep-tid-o-gly-can) is a molecule found only in the cell walls of bacteria. prokaryotes with protection from the environment. Article Summary: Amount and location of the peptidoglycan molecule in the prokaryotic cell wall determines whether a bacterium is Gram-positive or Gram-negative. You have free access to a large collection of materials used in two college-level introductory microbiology courses (8-week & 16-week).
Cell walls can be composed of polysaccharides, proteins, lipids, or a combination of these. Cell walls provide increased mechanical strength and resistance to lysis by osmotic shock (water moving into the cell). Cell walls are found in the cells of eubacteria, archaebacteria, fungi, algae, and plants. Almost all eubacterial species have cell walls containing a polysaccharide called peptidoglycan. Among the eubacteria, differences in cell wall structure are a major feature used in classifying these organisms.