Bacteria Structure and Characteristics Flashcards
1
Q
Bacterial Classifications
A
1) Structural Components
2) Cell Wall
3) Genetic Make-up
2
Q
Cocci
A
- Circular
- mainly gram positive
- Streptococci divides forming long chains
- Staphylococci divides forming grape like structures
3
Q
Bacilli
A
- Rod like appearance
- Normally gram negative
4
Q
Beta hemolytic Bacteria
A
- complete hemolysis lysing the red blood cells
- zone of exclusion = bacteria secreting lysin destroying RBCs
- generally more dangerous than other forms
5
Q
Gamma Bacteria
A
- nothing is happening, not secreting anything; therefore no damage to the RBCs
6
Q
Alpha Bacteria
A
- hemoglobin is converted to methamoglobin resulting in the color change from red to brown
7
Q
Structures common to ALL bacteria cells
A
- Cell membrane/envelope
- Cytoplasm
- Ribosomes
- One (or few) chromosome
8
Q
Cell Envelope
A
- composed of multiple layers
- Gram + = 2 layers
- Gram - = 3 layers
- Acid fast bacteria = 2.5 layers
9
Q
Gram + bacteria
A
- inner phospholipid bilayer membrane
- outer peptidoglycan layer consisting of teichoic acid and lipotechoic acid (LTA)
10
Q
Gram - bacteria
A
- inner phospholipid bilayer membrane
- small peptidoglycan layer
- outer layer composed mainly of lipopolysaccharide (LPS) forming an asymmetrical membrane
11
Q
Acid Fast bacteria
A
- inner phospolipid bilayer
- middle skinny peptidoglycan layer with lipoarabomannans and arabinogalactans
- half outer layer with mycolic acid head groups that are attached to peptidoglycan layer
12
Q
Gram + Cell Wall Structure
A
- thick peptidoglycan cell wall
- resists lysis by complement
- teichoic acids and lipotechoic acids
- TLR 2 recognition of LTA
13
Q
Gram - Cell Wall Structure
A
- asymmetric outer membrane
- thin peptidoglycan layer
- periplasmic space
- barrier to non-polar molecules
- outer membrane porins
- TLR-4 recognition of LPS
14
Q
Gram Staining
A
- Gram positive turns dark violet due to cross linking that occurs changing it from very porous to tight crystal lattice
- Gram positive turns pink due to the safranin stain because it does not retain the crystal violet stain
15
Q
Acid Fast Cell Wall Structure
A
- most similar to gram positive cells - mycobacteria
- cell wall comprised of fatty acids and waxes
- lipid components are difficult to stain, but once stained stay stained
- Mycolic Acid, Wax D present in cell wall
- TLR-1/2/6 recognition
