Bacteriology Part 1 Flashcards
What is a bacterium?
single celled microorganism of kingdom prokaryota
what does it mean that bacteria are prokaryotes?
= no nucleus
in what conditions do bacteria grow?
aerobic, anaerobic, microaerophilic conditions
what kind of cell wall do gram positive bacteria have?
thick cell wall
What antigenic property is on the cell wall of gram positive bacteria?
lipoteichoic acid
used to recognize antigen and trigger immune response
What does the cell wall contain?
peptidoglycan
gram negative bacteria have what kind of cell wall and plasma membrane?
Thin cell wall in between two plasma membrane layers (sandwich)
What is on the outer layer of gram negative bacteria?
Lipopolysaccharide layer (LPS-virulence factor)
what type of cell wall do mycobacteria have?
Thin cell wall
What is on mycobacteria’s cell wall? (2 things)
1) Mycolic acid (virulence factor)
2) Glycolipids
What is lipopolysaccharide?
is a toxin, lipid A component, present on cell surface of gram negative bacteria, that activates immune response, and can be harmful to the host
Gram staining: what determines how much color you have?
how thick the cell wall of the bacteria is
Gram positive stains what color?
violet/blue; picks up crystal violet, and iodine
Gram negative stains what color?
pink; picks up safranin
Types of staining:
1) Gram staining
2) Acid staining
acid fast staining is due to the presence of what?
mycolic acid
Acid fast staining: positive bacteria have gram positive or negative cell wall? And how does it stain?
Gram positive cell wall
stains pink
retains Carbol Fuchsin
b/c it has mycolic acid in cell wall
Acid fast staining: Negative gram bacteria stains?
stains blue
due to absence of mycolic acid
Flagella: what’s it used for? (3)
1) Locomotion
2) Motility
3) identification
What is the flagella called for bacteria that have it in the periplasmic space? What bacteria can you find it in?
Endoflagella
Spirochetes
Pilli/ Fimbriae
- threadlike located on bacterial surface
- helps attach bacteria to host cell surface
- contributes to antigenicity
In what animal example can you find pilli / fimbriae bacteria?
Neonatal pigs
What is a capsule?
The capsule is a thick polysaccharide layer OUTSIDE the cell wall
What is the capsule used for? (4)
1) Sticking cell together
2) Food reserve
3) Protection against desiccation and chemicals
4) Helps bacteria evade phagocytosis
What are endospores?
highly resistant dormant form of gram positive bacteria
What are endospores used for?
Survival mechanism of GRAM POSITIVE bacteria
When are endospores produced?
When bacteria are exposed to adverse conditions or food is depleted
What orientation do endospores have? (3)
central
terminal
subterminal
How can BACTERIAL GROWTH be measured? (4)
1) colony counting
2) turbidimetry
3) flow cytometer
4) hemocytometer chamber
Can bacteria’s need for oxygen be used for identification?
yes!
Oxygen required for growth (3)
- aerobic
- microaerophilic
- capnophilic
oxygen not required or used for growth (2)
- obligate anaerobe
- aerotolerant anaerobe
oxygen not required but can be used for growth (1)
facultative anaerobe
All bacteria have a cell wall except:
Mollicutes (Mycoplasma)
Bacteria have a single circular chromosome except:
Leptospira has 2!
Bacteria have circular DNA except:
Borrelia Burgdorferi:has linear chromosome
