Prokaryotes Flashcards
What is meant by gram-positive vs. gram-negative? Which tend to be more antibiotic resistant?
Gram positive bacteria have simpler cell walls with large amount to of peptidoglycan. Gram-negative bacteria have less peptidoglycan and the outer membrane can be toxic. They are more antibiotic resistant.
What is peptidoglycan?
A network of sugar molecules cross linked by polypeptides. It makes up the bacterial cell wall.
What are fimbriae?
Hair like appendages that allow prokaryotes to stick to their substrate or other individuals in a colony.
What are pili?
Appendages (longer than fimbriae) that allow prokaryotes to exchange DNA.
Where is the DNA of prokaryotes located?
In the nucleoid.
What are plasmids?
Smaller rings of DNA.
What are the key features of prokaryotic reproduction?
- Small
- Reproduce by binary fission.
- Short generation times.
- Evolve very rapidly.
What are endospores?
A thick coated, resistant cell produced by some bacterial cells when they are exposed to harsh conditions.
What contributes to the genetic diversity of prokaryotes?
- Rapid reproduction.
- Mutation.
- Genetic recombination.
What is transformation? Transduction?
Transformation is when a prokaryotic cell takes up and incorporates foreign DNA from the surrounding environment. Transduction is the movement of genes between bacteria by bacteriophages (viruses that infect bacteria).
What are the different forms of metabolism in relation to oxygen?
- Obligate aerobes.
- Obligates anaerobes.
- Facultative anaerobes.
What is nitrogen fixation?
Conversion of atmospheric nitrogen (N2) to ammonia (NH3).
What are the three categories of archaea?
- Extreme halophiles live in highly saline environments.
- Extreme thermopiles thrive in very hot environments.
- Methanogens live in swamps and marshes and produce methane gas as a waste product.
They are strict anaerobes.
What is proteobacteria?
Include gram negative bacteria; photo, Chemo, and heterotrophs.
What are chlamydias?
Parasites that live within animal cells.
