Lewis/Life - Review of Key Concepts

Review of Key Concepts - Chapter 22

Monera are abundant, widespread, and occupy diverse, sometimes extreme, habitats. They include the bacteria and archaea. Monera support other species by forming the bases of food webs, recycling chemicals to the environment, and controlling global levels of essential gases.
Enrichment culturing enables us to study certain species but does not accurately replicate natural conditions.
Signature sequences are DNA sequences unique to specific taxonomic groups.
Characteristics used to classify monera include shape, color, biochemical characteristics and sequences, and staining properties. Gram staining is based on cell wall structure.
Archaea have different cell wall components and organization and different RNA polymerases than bacteria.
Autotrophs get energy from CO2, and heterotrophs from reduced organic molecules from other organisms. Mixotrophs use inorganic molecules for energy and organic molecules for carbon. Saprobes are decomposers, whereas symbionts live in or on other organisms. Phototrophs capture light energy, and chemotrophs harness chemical energy. Lithotrophs get hydrogen or electrons from reduced inorganic molecules, and organotrophs do so from organic molecules. Obligate aerobes use oxygen, obligate anaerobes are poisoned by oxygen, and facultative anaerobes can use oxygen or not.
Bacteria may have the following characteristics: pili (short projections that provide adhesion), flagella (extensions that provide motility); and/or a glycocalyx (sticky outer layer). An endospore protects a bacterial cell in stressful conditions.
In binary fission, monera replicate DNA and duplicate other structures and distribute their contents into two cells. The cell membrane grows between the two copies of DNA and pinches off.
In conjugation, a sex pilus passes the sex factor as well as some copied genes from a donor cell to a recipient cell, where the incoming genes swap places with their counterparts. Conjugation mixes gene combinations.
A bacterial infection can be diagnosed by culturing the microorganism, detecting a toxin or antibody response, or using a DNA probe bearing a signature sequence.
Bacterial infections may be transmitted in the air, by arthropods, or through direct contact or passed in water or food.
Archaea are diverse and many live in extreme conditions. They are classified by habitat and metabolism and by molecular sequence similarities. Methanogens are anaerobic and produce methane. Halophiles live in high-salt conditions. Hyperthermophiles live in hot, sulfur-rich environments. Thermophiles include members of genus Thermoplasma.
Monera affect the earth's mineral deposits, and their metabolism affects many species. Some bacteria fix atmospheric nitrogen into a biologically useful form. Industrial microbiology uses microbial metabolism to detoxify substances and to produce useful biochemicals.