Topic 1: The Microbial World Flashcards
Contributions made by Robert Hooke
- first to see a microorganism (fungi)
- discovered cells
- compound microscopes
(didn’t discover bacteria and archaea)
Microbiology
Study of organisms too small for the naked eye
Contributions made by Antonie Van Leeuwenhoek
- father of microbiology
- first to see and describe bacteria
- made improvements to the microscope (one lens)
Basic Requirements for Microbial Life(6)
- Metabolism
- Growth
- Reproduction
- Genetic variation/evolution
- Response/adaptation to the external environment
- Homeostasis (maintaining internal organization and order, usually by expending energy)
Macromolecule: Polypeptide
Subunit: Amino Acids
Dry weight of cell %: 50-55
Macromolecule: Nucleic Acids
Subunit: DNA, RNA
Dry weight of cell %: DNA 2-5, RNA 15-20
Macromolecule: Lipids
Subunit: Diverse structures
Dry weight of cell %: 10
Macromolecule: Polysaccharides
Subunit: Sugars
Dry weight of cell %: 6-7
Characteristics of the three domains: Nuclear membrane
B: No
A: No
E: Yes
Characteristics of the three domains: Membrane-bound organelles
B: rare, a few types found in a few species
A: rare, a few types found in a few species
E: multiple distinct types, found in all species
Characteristics of the three domains: Plasma membrane
B: similar to eukarya
A: different form B + E
E: Similar to bacteria
Characteristics of the three domains: Cell wall
B: found in nearly all species , constructed of peptidoglycan
A: found in nearly all species, constructed of various materials
E: found in some species, constructed of various materials
Characteristics of the three domains: RNA polymerase
B: single polymerase
A: single polymerase, eukaryal-like RNA pol II
E: Three main polymerases ( RNA pol I, II, III)
Characteristics of the three domains: Histones
B: Histone like proteins
A: yes
E: yes
Major events leading to origin of microbial life
- first O2 producing bacteria
- O2 atmosphere
- Endosymbiosis (chloroplasts and mitochondria)
- origin of complex eukarya
- origin of multicellular organisms
- origin of simple animals
*RNA world: hypothesis that RNA came before DNA
Cyanobacteria and Endosymbiosis and Earths History
C: first organism to release oxygen gas a waste product by oxidizing water, made world breathable
E: Prokaryotic microbes ingested other microbes starting a symbiotic relationship and forming first basic eukaryotes (mitochondria and chloroplasts came from this)
Earliest microbes would have
been able to metabolize iron and/or sulfur
been thermophiles (heat loving)
been anaerobic (producing atp with absence of oxygen)
been able to use light energy
consumed inorganic carbon (e.g., carbon dioxide)
Microbial Metabolism
Microbes obtain the energy and nutrients they need to live and reproduce
Autotrophs
primary producers
have ability to fix CO2 into organic molecules
self- feeding
Heterotrophs
ingest organic molecules from primary producers
eats other things
Photosynthesis
the process by which plants use sunlight, water, and co2 to create oxygen and energy in the form of sugar
Cellular respiration
metabolic pathway that uses glucose to produce ATP
Fermentation
uses organic matter as both electron donor and acceptor
Aerobic respiration
uses organic matter as the electron donor, but it uses oxygen as a much more powerful electron acceptor
Anaerobic respiration
doesnt use oxygen, can use carbon, nitrogen, sulfate, iron, manganese
Louis Pasteur
- discovered that living organisms discriminate between optical isomers
- discovered the biological nature of alcoholic fermentation
- developed vaccines for anthrax, fowl cholera, and rabies
- disproved spontaneous generation and developed methods for controlling growth of microorganisms
- developed pasteurization
- developed sanitization in hospitals
Kochs postulate
- suspected microbe is identified in people with a disease, not in those without illness
- a pure culture of the suspected microbe is obtained
- experimental inoculation of the suspected microbe into a healthy test host causes the same illness
- the suspected microbe is recovered from the experimentally inoculated host organism and has to be same as original
Impact of microorganisms on human health
Diseases,
- stomach ulcers (bacteria Helicobacter pylori)
- bubonic plague (bacteria Yersinia pestis)
- small pox (smallpox virus)
- influenza (virus)
Infections
Viruses
