Microbial cells differ fundamentally from the cells of higher organisms in several ways: • The microorganisms are single-celled organisms. They can be viewed only under the microscope, due to their minute size. While, many cells of higher organisms can be seen with our naked eye. • Microbial cells have a very rapid rate of growth and reproduction comparative to the cells of higher organisms. • Microbial cells can exist independently, whereas cells of higher organisms cannot exist independently. • A single microbial cell can carry out all the necessary metabolic functions for its survival, whereas the cells of higher organisms cannot carry out all the metabolic functions needed for its survival. It is dependent on other cells for its existence.

Learning Objectives. The Requirements for Growth. 6-1 Classify microbes into five groups on the basis of preferred temperature range. 6-2 Identify how and why the pH of culture media is controlled. 6-3 Explain the importance of osmotic pressure to microbial growth. Copyright © 2010 Pearson Education, Inc. Texturepacker Mac Serial Port.