Prokaryotes Flashcards
Characteristics of Prokaryotes
No nucleus or membrane bound organelles, no centrioles or mitosis, one chromosome
Prokaryotic Chromosome
Circular, double stranded DNA. In the cytoplasm
Where does transcription and translation take place?
Both in cytoplasm so they are coupled
Prokaryotic structures
plasmid (extrachromosomal DNA), cilia (no locomotion, used for cell attachment), flagellum (Locomotion, differs from Eukaryotic flagella), cell membrane, Call wall
What is the cell wall made out of
Peptidoglycan
Eubacteria
True bacteria
Archaebacteria
Separate domain from eubacteria. Eukaryotes are more related to these than to eubacteria. Extremophiles.
Cocci
Round-shaped
Bacilli
Rod-Shaped
Spirilla
Spiral-shaped
Gram +
Stains purple with crystal violet. Has cell wall with peptidoglycan
Gram -
stains pink with counter stain. Has cell wall with peptidoglycan and additional defense, another lipid membrane called LPS (lipid polysaccharide). LPS doesn’t allow for violet stain to pick up. Contains endotoxins which cause a bad immune response.
Flagella
Not all bacteria have them. differs from Eukaryotic. Uses a lot of ATP
Chemotaxis
Use flagella to move toward chemoattractant. concentration of chemoattractant increases, concentration of chemorepellant decreases.
Bacterial Growth
Lag phase, log phase, stationary phase, death phase
lag phase
cell growth
log phase
(exponential phase) population explodes
stationary phase
nutrients are used up, cell division stops
death phase
no more nutrients left at all, cells die.
What does an autoclave do?
heats liquid water up to 120C using pressure to kill endospores
Endospores
Thick peptidoglycan coat to keep cell dormant under harsh conditions. Can survive 100C. will germinate once conditions are favorable again.
Aerobes
Live in presence of oxygen
anaerobes
live in the absence of oxygen. Gangrene is an obligate anaerobe so it is killed by exposing it to oxygen.
Facultative Anaerobes
live in the presence or absence of oxygen
How to bacteria get genetic diversity?
Conjugation
Conjugation
F+ (male) makes additional copy of plasmid and transfers one copy via the sex pili to a F- (female) who has no plasmid yet. Once female receives plasmid, it now becomes male.
