Midterm 1.1 Flashcards
(26 cards)
Who is the first person to depict microorganisms?
Robert Hooke
Who is considered the Father of microbiology?
Antoni van Leeuwenhoek
Who disproved spontaneous generation?
Louis Pasteur
What are the major accomplishments of Louis Pasteur? (5) sfgid
- Sterilization techniques (pasteurization)
- Fermentation by microbes
- Germ theory of disease with others
- Important contributions to the advancement of vaccine development
- Disproved spontaneous generation
Who provided evidence for germ theory of disease?
Robert Koch
What are some significant limitations to Koch’s postulates? (2)
- Not all pathogens can be cultured in isolation
- Some disease-causing microbes can be present in healthy people, only cause disease in certain people/conditions
What did Robert Koch discover?
The cause of tuberculosis and of cholera
Who developed the first vaccine for smallpox?
Edward Jenner
Who discovered the spore formation (bacterial cell differentiation)?
Ferdinand Cohn
Who discovered enrichment culturing for growing the desired microbes?
Martinus Bejerinck
Who developed antibiotics?
Alexander Fleming (Penicillin)
Gerhard Domagk and others (Sulfonamides)
Selman Waksman (Albert Schatz) (Streptomycin)
Who discovered archaea and reworked the tree of life?
Carl Woese and George Fox
Virus
Genetic elements (DNA/RNA) that can only multiply within a living cell
Explain the RNA world hypothesis
Life on earth started with lifeforms that used RNA only
- Because RNA can catalyze reactions just like proteins and can store genetics
What were some evolutionary forces that supposedly kicked in in RNA world hypothesis? (3)
Improved replication
Simple functions
More complex functions
What is the evidence of RNA world hypothesis?
RNA can form intricate, stable structures
Proteins are still made today using RNA components
Many apparent “relics” from RNA world
- Common biological molecules with ribonucleotide components
When and where did the first microbe evolve?
4 billion years ago
Not known where, but one hypothesis is that it happened in hydrothermal systems on ocean floor
- Stable environment, low UV light, compartments (cells) energy, organic molecules
What are the presumed features of LUCA? (4)
DNA replication, transcription, translation, cell division
ATP served as energy intermediate
Lipid bilayer membrane
Anaerobic metabolism (no oxygen) - likely used H2 as energy source and CO2 as carbon source
Cyanobacteria
Bacteria that can carry out photosynthesis
- Oxygenic photosynthesis
What did oxygen in the atmosphere cause?
It made ideal electron acceptor - gave rise to aerobic organisms
Ozone (O3 layer) - protects against UV (lethal to cells, damages DNA)
Explain the endosymbiotic theory
Eukaryotes emerged when an archaea-like ancestor engulfed a bacterium that became endosymbiont (organism living within another organism in symbiotic relationship)
Eventually this bacterium became the mitochondria
Plants emerged in a second event when an engulfed photosynthetic bacteria became basis for chloroplast
What are the evidences of endosymbiotic theory?
DNA replication, transcription, translation machinery of eukaryotes more similar to archaea than bacteria
Mitochondria and chloroplasts:
- Have their own genomes, ribosomes, tRNA
- This machinery is bacterial
- Mitochondria related to Proteobacteria, chloroplasts related to Cyanobacteria
Explain the serial endosymbiosis theory
Mitochondria: Stable engulfing of an aerobic respiring bacterium from Alphaproteobacteria into early eukaryotic cell organism
Chloroplasts: Stable engulfing of a photosynthetic cyanobacterium-like cell into cytoplasm of a eukaryotic cell
Ubiquitous
Present or existing everywhere
