Survey
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Kingdoms Eubacteria and Archaebacteria - Answers 1. Archaebacteria, commonly called ancient bacteria lives and thrives in environments that are normally not conducive to life and often do not contain oxygen. They can be found in swamps and habitats with high salt contents such as the Dead Sea. They also live in habitats with high temperatures and high acidity such as near underwater thermal vents and sulfur springs. 2. The three main groups of archaebacteria are methanogens, extreme thermophiles, and extreme halophiles. The methanogens are bacteria that produce methane gas. The thermophiles live in environments with extremely hot temperatures (up to 110°C). The halophiles live in environments that have a high salt content. 3. Although they are now classified into separate kingdoms archaebacteria and eubacteria still share many common characteristics. All bacteria are prokaryotic and are single celled organisms. They are lacking membrane bound organelles such as mitochondria and nuclei. They have a single chromosome and they reproduce asexually by binary fission. 4. Eubacteria are classified based on three basic shapes. There is spherical (plural: cocci; singular: coccus), rod-shaped (plural: bacilli; singular: bacillus) and spiral (plural: spirilla; singular: spirillum) 5. Bacteria reproduce by dividing into two new bacteria (binary fission) and will often remain together in groups or clusters however some will remain as individual cells. 6. Generalized structure of a bacterium: 7. Bacteria in the kingdom Eubacteria are often classified according to their modes of respiration and nutrition. In terms of respiration they are classified based on whether or not they use oxygen. In terms of nutrition they are classified based on how they obtain energy (autotrophs or heterotrophs). 8. Obligate aerobes are bacteria that respire in the presence of oxygen. Obligate anaerobes grow and respire in the absence of oxygen and can be found in deep soils, and marine and fresh water sediments. 9. A facultative aerobe is a bacterium that can perform respiration either with or without oxygen. This advantage allows them to adjust to a variety of environments. 10. During fermentation bacteria produce carbon dioxide and alcohol. Some groups of bacteria will also produce ethyl alcohol, lactic acid, acetone, and acetic acid. 11. Heterotrophic bacteria obtain their nutrients from other organisms and are often grouped as parasites or saprophytes. Parasitic bacteria obtain nutrients from a host and do not contribute to the health of the host. In other words, parasitic bacteria feed off of their host often causing damage. Many parasitic bacteria are also pathogenic. Saprophytic bacteria obtain their nutrients from dead and decaying organic matter and play a vital role in recycling organic matter. They can be used in the treatment of sewage. 12. Autotrophic bacteria produce their own food using either energy from the sun or energy from chemical reactions. Photosynthetic bacteria use energy from the sun to convert inorganic (carbon dioxide and water) materials into organic materials (glucose). Chemosynthetic bacteria perform the same conversion but it is driven by energy that is trapped during the breakdown of chemicals. 13. Binary fission is asexual reproduction in bacteria. The single strand of bacterial DNA replicates (copies) and the result is a copy for each new cell. After the replication a cross wall begins to form and divides the bacterium into two separate bacteria. They may separate or remain attached. 14. Although sexual reproduction (combination of gametes) does not occur often in bacteria, conjugation can occur in some intestinal bacteria such as E.coli. A donor bacterium and a recipient bacterium make cell-to-cell contact and a cytoplasmic bridge forms between the two cells. Pieces of DNA known as plasmids can be transferred from the donor to the recipient. A change has now been made in the set of characteristics (DNA) for the recipient. The two bacteria will separate once the exchange has occurred. 15. Some bacillus type bacteria have been able to survive very harsh conditions because of its ability to form an endospore. A thick wall will form around the genetic material and a small amount of cytoplasm. The rest of the cell disintegrates and the heat resistant endospore remains dormant until conditions become favorable again. 16. The following are benefits of bacteria: Type of Bacteria Clostridia Acetobacter Intestinal bacteria Lactobacilli Aztobacter, nitrobacter Streptococci, lactobacilli Streptomyces Beneficial Effects Production of butanol and acetone from molasses Production of vinegar from alcohol Food digestion; synthesizing of vitamins in human Production of lactic acid from sugar Fixation of nitrogen in soils Production of dairy products (cheese, yogurt) Source of antibiotics (streptomycin and erythromycin) 17. The bacteria dismantle complex toxic penta molecules, leaving nontoxic carbon dioxide, water and harmless chlorides & they work cheaply requiring only oxygen & nutrients normally found in the soil. They are also much cheaper to use and once the toxic chemical is gone, they die. 18. Three types of bacteria are used to eliminate three components of gasoline so they can be used to help clean up gasoline spills. 19. Antibiotic resistance develops from variations within a bacterial population. When first exposed, the weaker strains of bacteria are killed. Others with slight variations in their genetic material may allow them to survive the antibiotic. These bacteria then survive and pass their resistance on to the next generation.