Ch. 1 History of Microbiology Flashcards
list six reasons why microorganisms are important
- most populous and diverse group of organisms
- found everywhere on the planet
- play a mjor role in recycling essential elements
- source of nutrients and some carry out photosynthesis
- benefit society by production of food, beverages, antibiotics, and vitamins
- some cause disease in plants and animals
what defines a member of the microbial world?
organisms and acellular entities too small to be clearly seen by unaided eye
how large are MOST microorganisms?
less than 1mm, but some can be macroscopic
are microbes usually simple or complex?
relatively simple in their construction and lack highly differentiated cells and distinct tissues
what are the two types of microbes?
cellular and acellular
list 4 types of cellular microbes and give an example of each
- fungi: yeast molds
- protists: algae, protozoa, slime molds
- bacteria: E. coli
- archaea: mathanogens
list 4 types of acellular microbes and what they are composed of
- viruses: protein and nucleic acid
- viroids: RNA
- satellites: nucleic acid, often RNA
- prions: protein
list the 2 types of microbial cells
- prokaryotic
2. eukaryotic
define prokaryotic cells
lack a membrane-delimited nucleus
define eukaryotic cells
have a true membrane-enclosed nucleus, are more morphologically complex and are usually larger than prokaryotic cells
describe the classification scheme of microorganisms
3-domain system based on a comparison of ribosomal RNA genes
what are the 3 classifications of microorganisms
- bacteria (true bacteria)
- archaea
- eukarya (eukaryotes)
decribe domain bacteria (4)
- usually single-celled
- majority have a cell wall with peptidoglycan
- most lack a membrane-bound nucleus
- ubiquitous and SOME live in extreme environments
what distinguishes domain archaea from domain bacteria
unique RNA gene sequences
describe domain archaea (4)
- LACK peptidoglycan in cell walls
- have unique membrane lipids
- some have unusual metabolic characteristics
- many live in extreme environments
give 2 members of domain eukarya
- protists
2. fungi
describe the general size of protists
generally larger than bacteria and archaea
list 4 protists and give a feature of each
- algae: photosynthetic
- protozoa: may be motile “hunters, grazers”
- slime molds: 2 life cycle stages
- water molds: devastating diseases in plants
list 2 fungi and their amount of cells (general)
- yeath: unicellular
2. mold: multicellular
what do acellular infectious agents need to survive and live
a host
list 3 acellular infectious organisms
- viruses
- viroids and virusoids
- prions
what is the smallest of all microbes?
viruses
what do viruses require to replicate?
host cell
what do viruses cause?
a range of diseases and some cancers
what are viroids and virusoids?
infectious agents composed of RNA
what are prions?
infectious proteins