7322 B1 Flashcards
Obligate intracellular organisms
Cannot live outside a living cell
Prokaryotes
- 1 chromosome
- Circular DNA
- Mono- or polycistronic (messenger RNA can encode for one polypeptide or many polypeptides)
- No nucleus
- No membrane organelles
- 70s ribosomes (30 + 50_
- Binary fission
Eukaryotes
- 1 chromosome, linear DNA with histones
- Monocistronic
- Exon and introns
- Nucleus
- Membrane organelles
- Mitosis with cytokinesis
Gram (+) Positive
- 2 Layers
- inner cytoplasm membrane
- outer thick peptidoglycan layer
- No lipid content
- No endotoxin (LPS)
- No periplasmic space
- Vulnerable to lysozyme and penicillin attack
Gram (-) Negative
- 3 Layers
- Inner cytoplasmic layer
- Thin peptidoglycan layer
- Outer membrane with lipopolysaccharide (LPS)
- High lipid content
- Endotoxin (LPS)
- Periplasmic space
- Porin channel
- Resistant to lysozyme and penicillin attack
Cocci
-Spherical
Bacilli
- Rods
* short rods are called coccobacilli
Spiral Forms
- Comma
- Spiral
Pleomorphic
-No distinct shape
Gram (+) positive
3 Cocci?
4 Bacilli?
- Cocci
- Streptococcus (chains)
- Enterococcus (chains)
- Staphylococcus (clusters)
- Bacilli
- Bacillus (spores)
- Clostridium (spores)
- Corynebacterium (No spores)
- Listeria (No Spores)
Gram (-) negative
2 Cocci?
1 Spiral?
1 Comma?
- Cocci
- Neisseria (diplococci)
- Moraxella (diplococci)
- Spiral
- Spirochetes (too small to see)
- Comma
- Vibrio cholerae
REMAINING GRAM NEGATIVE ARE EITHER RODS OR PLEOMORPHIC
Neither Gram (+) or (-)
- Mycobacteria (Acid Fast)
- Mycoplasm (No cell wall)
Catalase?
Peroxidase?
Superoxide Dismutase?
Catalase - Breaks down hydrogen peroxide to water and oxygen
Peroxidase - Breaks down hydrogen peroxide to water and oxygen
Superoxide Dismutase - Breaks down superoxide radicals
Obligate Aerobes
- Use glycolysis with oxygen as the final electron acceptor
- Have Catalase, Peroxidase and Superoxide dismutase
- NEED oxygen to survive
Facultative anaerobes
- Aerobic bacteria that can grow in the absence of oxygen
- Have catalase and superoxide dismutase
- Can use fermentation as a source of energy, as well as glycolysis
Microaerophilic
- Use fermentation only
- Can tolerate low amounts of oxygen due to Superoxide dismutase
Obligate Anaerobe
- Use fermentation only
- Cannot tolerate any oxygen due to the absence of enzymes
Pathogenicity
refers to the ability of an organism to cause disease
Virulence
Often used interchangeably with pathogenicity, it refers to the degree of pathology caused by the organism
Avirulent
does not cause disease
Virulence factors
a structure, toxin, adhesion, etc… that contributes to the ability of a pathogen to cause disease
Adhesion factors
- Involved in the binding and initial interactions between pathogen and host cells.
- Can be proteins in cell walls or membranes, or structures such as pili/fimbriae
- Antigenic variation can aid in the persistence of infection (evade host response - surface proteins of bacteria can alter in such a way that it is not recognized by the immune system)
Multi-layer of endospores
- Cell membrane
- Thick peptidoglycan layer
- Another cell membrane
- Wall of keratin-like protein
- Outer layer called exosporium
Facultative intracellular organism
Like to live in the host cell