Learning Objectives By the end of this section, you will be able to: The majority of the gram-negative bacteria belong to the phylum Proteobacteria, discussed in the previous section. Those that do not are called the nonproteobacteria. In this section, we…
Learning Objectives By the end of this section, you will be able to: In 1987, the American microbiologist Carl Woese (1928–2012) suggested that a large and diverse group of bacteria that he called “purple bacteria and their relatives” should be defined as…
Learning Objectives By the end of this section, you will be able to: Clinical Focus Part 1 Marsha, a 20-year-old university student, recently returned to the United States from a trip to Nigeria, where she had interned as a medical…
Figure 4.1 The bacterium Shewanella lives in the deep sea, where there is little oxygen diffused in the water. It is able to survive in this harsh environment by attaching to the sea floor and using long appendages, called “nanocables,” to sense oxygen. (credit…
3.1 Spontaneous Generation 3.2 Foundations of Modern Cell Theory 3.3 Unique Characteristics of Prokaryotic Cells 3.4 Unique Characteristics of Eukaryotic Cells
Learning Objectives By the end of this section, you will be able to: Eukaryotic organisms include protozoans, algae, fungi, plants, and animals. Some eukaryotic cells are independent, single-celled microorganisms, whereas others are part of multicellular organisms. The cells of eukaryotic…
Learning Objectives By the end of this section, you will be able to: Cell theory states that the cell is the fundamental unit of life. However, cells vary significantly in size, shape, structure, and function. At the simplest level of…
Learning Objectives By the end of this section, you will be able to: While some scientists were arguing over the theory of spontaneous generation, other scientists were making discoveries leading to a better understanding of what we now call the cell…
Learning Objectives By the end of this section, you will be able to: Clinical Focus Part 1 Barbara is a 19-year-old college student living in the dormitory. In January, she came down with a sore throat, headache, mild fever, chills,…
Figure 3.1 Microorganisms vary visually in their size and shape, as can be observed microscopically; but they also vary in invisible ways, such as in their metabolic capabilities. (credit a, e, f: modification of work by Centers for Disease Control and Prevention;…