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Prokaryotes and 2 Examples
- Unicellular Organisms with no nucleus/genetic material;
- Bacteria and Archaea
Bacteria: Characteristics and Features
- -Relatively simple, unicellular organisms.
- -Enclosed in cell walls that're mostly composed of Peptidoglycans. (in contrast, cellulose is the main substance of plant and algal cell walls)
- - Reproduce = by dividing into 2 equal cells via binary fission.- Nutrition = use organic chems, in nature can be derived from either dead or living organisms, some bacteria can manufacture own food via photosynthesis.
- -Movement = "swim" by moving appendages (flagella)
- 1.) Bacillus (rodelike)
- 2.) Coccus (spherical or ovoid)
- 3.) Spiral (corkscrew or curved)
Archaea: Characteristics and Features
- -Like bacteria, consist of prokaryotic cells.
- -If they have cell walls, the walls lack peptidoglycan.
- -Often found in extreme environments.
- -Not known to cause disease in humans.
3 Main Archaea Groups
- 1.) Methanogens - produce methane as a waste product from respiration.
- 2.) Extreme Halophiles (Halo=salt, Philic=loving) - live in extremely salty environments such as the Dead Sea
- 3.) Extreme Thermophiles - live in hot sulfurous water, such as hot springs in Yellowstone Park.
Fungi: Characteristics and Features
- -Eukaryotes; organisms whose cells have a distinct nucleus, surrounded by nuclear membrane.
- -May be unicellular or multicellular
-Large Multicellular (ie Mushrooms) - may look somewhat like plants but they cannot carry out photosynthesis.-True fungi have cell walls composed of chitin.
- -yeasts; oval microorganisms
- -larger than bacteria
- -most typical fungi are molds.
- -Form visible masses called mycelia, which are composed of long filaments (hyphae) that branch and intertwine.
- -Cottony growths on bread and fruit are mold mycelia.
- -Reproduce=sexually or asexually.
- -Nourishment=absorbing solutions of organic material from their environment--whether soil, seawater, fresh water, or an animal or plant host)
- -Slime Molds have characteristics of both fungi and amoebas.
Protozoa: Characteristics and Features
- -unicellular eukaryotic microbes.
- -move by pseudopods, flagella, or cilia.
- -Amoebas move by using extension of their cytoplasm called pseudopods (false feet).
- -Variety of shapes and live either as free entities or as parasites (organisms that derive nutrients from a living host) that absorb or ingest organinc compounds from their environment.
- -Reproduce=sexually or asexually.
Algae: Characteristics and Features
- -photosynthetic eukarotes with a wide variet of shapes and both sexual and a sexual reporductive forms.
- -unicellular most interesting to microbiologists.
- -Cell walls of many algae=cellulose (carbohydrate)
- -Abundant in fresh and salt water, in soil, and in association with plants.
- -Need light, water, and CO2 for food production and growth.
- -Generally don't require organic compounds from the environment.
- -Result of photosynthesis, algae produce O2 and carbohydrates that are utilized by other organisms.
- -Thus play important role in balance of nature.
Viruses: Characteristics and Features
- -very different from the other microbial groups mentioned.
- -So small that they can only be seen w/ electron microscope.
- -Structurally very simple, a virus particle contains a core made of only on type of nucleic acid, either DNA or RNA.
- -This core is surrounded by a protein coat.
- -Sometimes the coat is encased by a lipid membrane (envelope)
- -Can only reproduce by using cellular machinery of other organisms.
- -Only considerd living when they multiply within host
Two Major Groups of Multicellular Animal Parasites
- -Flat worms
- -Round worms
- -Collectively called helminths.
- -During some stages of their life cycle, microscopic in size.
Classification of Microorganisms
- -In 1978, Carl Woese devised a system of classification based on the cellular organization of organisms.
- -It groups all organisms into 3 domains:
- 1.)Bacteria (cell walls contain a protein-carbohydrate complex called peptidoglycan.)
- 2.)Archaea (cell walls, if present, lack peptidoglycan.
- 3.) Eukarya
- -Protists (slime molds, protozoa, and algae)
- -Fungi (unicellular yeasts, multicellular molds, and mushrooms.)
- -Plants (includes mosses, ferns, conifers, and flowering plants.)
- -Animals (includes sponges, worms, insects, and vertebrates.