Bacteria Main Menu

Classification Obtaining Energy Respiration Growth and Reproduction Importance Of Bacteria Title Page

Classification Eubacteria Cyano- bacteria Archae- bacteria Prochloro- bacteria Main Menu

Eubacteria Back Eubacteria, also called “true” bacteria, is the largest Moneran phyla. Some live in the soil while others infect larger organisms. Others still, are photosynthetic.

Cyanobacteria Back All cyanobacteria are photosynthetic. They are a bluish-greenish color. They are found throughout the world and can survive in hot and cold water.

Archaebacteria Archaebacteria is a phylum that include organisms that live in extremely harsh environments. One example of Archaebacteria live in oxygen-free environments such as thick mud and the digestive tracts of animals, or at the bottom of the seas. Back

Prochlorobacteria Newly discovered group of photosynthetic organisms. They are more similar to chloroplasts than cyanobacteria. There are only two species of them.

Obtaining Energy HeterotrophsAutotrophsMain Menu

Autotrophs Monerans that live in harsh environments and obtain energy from inorganic molecules are called chemotrophic autotrophs. Monerans that trap the energy of sunlight in a manner similar to green plants are called phototrophic autotrophs. Autotrophs are organisms that are able to use a source of energy to produce their food from inorganic raw materials. Back

Heterotrophs Heterotrophs are organisms that cannot produce their own food but obtain energy from the food they eat. Monerans that take in, break down and absorb organic molecules are called chemotrophic heterotrophs. Monerans that are photosynthetic but also need organic compounds for nutrition are called phototrophic heterotrophs. Back

Respiration Energy is supplied through respiration and fermentation. Organisms that require constant supply of oxygen are obligate aerobes, and those that don’t require oxygen are obligate anaerobes. Bacteria produce toxins as they grow, which are poisons that cause botulism. Bacteria that can live with or with out oxygen are facultative anaerobes. Main Menu

Growth And Reproduction Binary Fission Conjugation Spore Formation Main Menu

Binary Fission When a bacterium has grown so that it has nearly doubled in size, it replicates its DNA and splits in half, producing two identical daughter cells. This is known as binary fission. Back

Conjugation One form of sexual reproduction for bacteria is conjugation. During conjugation, a long bridge of protein forms between and connects the two bacteria cells. The cells then exchange genetic information. This is usually followed by binary fission, producing two new bacteria that are genetic mixtures of the original two. Back

Spore Formation When conditions are bad, spores encase their DNA and wait until times are good again. This is called an endospore. The ability to form spores makes bacteria able to survive a harsh area. It is not for propagation of the species, rather, it is for survival of the species. For this reason, some scientists hesitate to call it reproduction. Back

Importance of Bacteria Main Menu Some monerans form a mutually beneficial relationship with their host, this is called symbiosis. In many of these relationships, man is unaffected in any way. By far, most bacteria are helpful or benign to man than are harmful. Specific types of monerans can break down oil in small oil spills. Other types of Monerans help us digest foods in our intestines. Bacteria decompose the litter and waste of the world, tan leather, make cottage cheese, and many other helpful tasks. And, of course, many bacteria cause illness and disease. This costs humans time, money, and lives. Now that’s important!