MOD II Final Exam Flashcards
What color do gram-positive organisms stain?
They stain BLUE! Gram-positive = BLUE. I’m positively BLUE over you!!
What color do gram-negative organisms stain?
They stain RED! Gram-negative = RED. No (negative) RED commies!
What enzyme cross links the 4 chain amino acid sidechains in the peptidoglycan layer or cell wall?
Transpeptidase, located in the inner cytoplasmic membrane, catalyzes this cross linking.
What medication binds to transpeptidase?
Penicillin binds to and inhibits this enzyme. Earning transpeptidase the name Penicillin binding protein.
Gram-postive cell wall is thick/thin?
Gram negative cell wall is thick/thin?
Gram-positive cell wall is thick.
Gram-negative cell wall is thin.
Do gram-positive cell cellular membranes contain cholesterol or other sterols?
No
What is the antigenic determinant in in gram-positive cell walls?
Teichoic Acid
What are the layers of the gram-positive membrane?
1) Outer cell wall composed of complex cross-linked peptodoglycan, teichoic acid, ploysaccharides, and others
2) Cytoplasmic cell membrane
What are the layers of the gram-negative membrane?
1) Outer membrane containing LPS and Porin
2) Petidoglycan Layer (cell wall)
3) Cytoplasmic Membrane
The thing peptidoglycan layer does not have is teichoic acid, what does it have instead?
A helical Murein lipoprotein. Originating from the peptidoglycan layer is extends to and binds to unique third outer layer.
What makes the the outer membrane unique?
It contains lipopolysaccharide (LPS).
Lipopolysaccharide is composed of what three covalently linked components?
1) Outer carbohydrate polysaccharide chains of Oligosaccharides, called the O-specific side chain or O-antigen
2) The center part is water soluble core polysaccharide
3) Inferior to the center part is Lipid A.
What is known as the gram-negative endotoxin?
Lipid A. When bacterial cells are lysed by our immune system fragments of their membranes are released into circulation causing fever, diarrhea, and possibly fatal endotoxic septic shock.
Gram-Postive cell traits are:
1- 2 layers 2- Low lipid content 3- No endotoxin 4- No periplasmic space 5- No porin channel 6- Vulnerable to lysozyme and penicillin attack
Gram-Negative cell traits are:
1- 3 layers 2- High lipid content 3- Endotoxin (LPS) -lipid A 4- Periplasmic space 5- Porin Channel 6- Resistant to lysozyme and penicillin attack
What are four major shapes of bacteria?
1-Cocci-spherical
2-Baccilli- rods. short bacilli called coccobacilli
3-Spiral forms- comma-shaped, S-shaped, or spiral shaped
4-Pleomorphic-lacking a consistent shape, like jello
How many gram-positives are cocci and what are they?
Three are cocci and they are:
1) Streptococcus
2) Enterococcus–> forms strips of cocci
3) Staphylococcus–>forms clusters of cocci
How many gram-positive are rod-shaped (bacilli) and what are they? Which produce spores?
Four are rod-shaped and they are: Spore producers: 4)Bacillus (aerobic) 5) Clostridium (anaerobic) Non-Spore producers: 6) Corynebacterium 7) Listeria
How many gram-negative are cocci and what are they?
Two gram-negative are actually diplococci (kissing coffee beans) and they are:
1) Neisseria
2) Moraxella
A “Neiss”eria donut gives “Mor”axella
How many gram-negative are spiral-shaped and what are they?
One group of spiral-shaped organisms and they are:
1)Treponema pallidum–>causes syphilis
Mycobacteria: +/-, staining, and disease?
- weakly gram-positive
- better with a special stain called acid-fast stain
- organisms in this group cause tuberculosis and leprosy