History of Microbiology
Who was first to DISCOVER cells?
Robert Hooke
List 6 general characteristics of prokaryote (you discussed 8)
Unicellularity, very small in size, nucleoid, binary fission, genetic recombination through horizontal gene transfer, internal compartmentalization via folding of plasma membrane, simple flagella, metabolic diversity.
List the 4 main differences
Plasma membranes, cell walls, dna replication, and gene expression.
Name the 3 types of horizontal gene transfer
Transformation, conjugation, and transduction.
Why does antibiotic resistance spread so fast in hospitals?
Lots of bacteria located in close quarters. Resistance is carried on plasmids, which can quickly be transferred via conjugation between cells.
Who was first to DESCRIBE cells?
Anton van Leeuwenhoek
Compared to eukaryotes, discuss the size of prokaryotes (in general)
In general, prokaryotes are much smaller than eukaryotes. Even their ribosomes are smaller!
How do these differences help archaea survive in their environments?
Many answers
Describe how transformation works. Where does dna being transferred come from?
Bacterial cell will die and release dna in to environment. Surround cells may pick up dna fragments. Incorporate into own dna by homologous recombination.
What can increase mutation likelihood?
Radiation and chemicals
Who refuted spontaneous generation and how?
Louis Pasteur and his swan neck flask experiment
Found in gram negative bacteria and aid in conjugation
Pili
Can an F- cell transfer to a F+ cell? Explain
No. F- can not transfer to the F+ because it doesn't have the fertility factor, the plasmid, to transfer. However, F+ can transfer to F-
Two examples of resistant bacteria that can rapidly spread in our population
MRSA and VRSA, streptococcus aureus resistant to methicillin and vancomycin
Who made the postulates of disease?
Robert Koch
What do I call a round bacteria? A rod shaped bacteria?
Coccus and bacillus.
Walk through the process of F plasmid transfer. Discuss Hfr as well.
F+ comes in to contact with an F- using a pilus. This creates a conjugation bridge through which the plasmid is exchanged. At the same time, F plasmid begins to be synthesized using rolling circle replication. At the end, results in TWO F+ cells. Hfr is when the plasmid integrates in to the host chromosome, replicating with host dna. This can excise at any time as well creating an F' plasmid if host dna is also excised with it.
What two things greatly decreased disease in the 20th century?
Sanitation and antibiotics
What are the postulates?
1. The microorganism must be present in every case of the disease and absent from healthy individuals.
2.The putative causative agent must be isolated and grown in pure culture.
3. The same disease must result when the cultured microorganism is used to infect a healthy host.
4.The same microorganism must be isolated again from the diseased host.
Difference between gram positive and gram negative bacteria.
Gram positive is very thick. Gram negative contains a lipopolysaccharide layer and is resistant to many antibiotics.
Discuss the two types of transduction. How are they different?
Generalized: LYTIC CYCLE, any gene can be transferred, virus encapsulates bacterial dna to transfer
Specialized: LYSOGENIC CYCLE, happens with imprecise excision of virus dna from host, both host and bacterial dna are transferred.
BOTH ARE ACCIDENTAL PROCESSES
How do bacteria cause disease?
Gain entry to the body
Colonize at the site of infection.
Evade the immune system.
Spread to other sites in the body.
Cause damage by the production of toxins or by triggering inflammatory responses.