Bacteria - A Survey
Laboratory Investigation

to gain an appreciation of the diversity of organisms that are called bacteria

to note some similarities and differences between the Eubacteria and the Archaebacteria

to learn the various characteristics of the fungal groups

to recognize the role fungi play in our global and local lives

to sample various areas of your environment to determine the types of organisms present

Introduction

Part I
Organisms today are classified into three Domains. Two of these Domains are prokaryotic: the Archae and the Bacteria (sometimes called the Eubacteria). Organisms in the Archae Domain appear like bacteria but have a very different biochemical, and thus genetic, makeup. The Archae live in extreme anaerobic environments and have been called the Extremophiles. Some of the major categories the Archae have been divided into are the heat-loving Thermophiles, the salt-loving Halophiles, the acid-loving Acidophiles and the methane-producing Methanogens. The following link will provide general information and graphics for the Archae.

Eubacteria consist of the bacteria and cyanobacteria. The typical prokaryotic organization lacks membrane-limited organelles such as nucleus, mitochondria, and lysosomes. They have a cell wall of peptidoglycan, a unique amino acid and simple sugar combination. Reproduction is simple splitting or binary fission and may occur, in some species, within 12-15 minutes under optimum conditions.

Bacterial shape, while genetically determined, is influenced by environmental factors. Shape is round or coccal shape, rod-shaped or bacillus shape or spiral or spirillum shaped. A variety of views are available in the links below. The following link will provide general Information and graphics for the Eubacteria. Use the links below to get a closer view of the organisms.

The cyanobacteria, originally called the blue-green algae, are photosynthetic prokaryotes. Their cells are generally larger than the bacteria and are covered or surrounded by a gelatinous covering or sheath. Cyanobacteria come in all the colors of the rainbow and some contain a swollen or enlarged region of specialized cells called a Heterocyst. The heterocyst contains the enzymes necessary to carry out the process of nitrogen fixation where atmospheric N₂ is converted into other forms usable by plants.

Use the links below to get a closer view of the organisms.

In the absence of microscopes and slides, use the embedded links below to learn about the various organisms.

See also pages 25-28 in A Photographic Atlas for the Biology Laboratory, 4th Edition.