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) ListeriaHow 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
Spirochetes: +/-, membrane trait, form of motility?
- gram-negative cell wall
- spirochetes are surrounded by an additional phospholipid-rich outer membrane with few exposed proteins which helps it evade immune detection (“stealth” all stealthy like organisms)
- periplasmic flagella, under the outer membrane, that internally rotate propelling the organism forward
Mycoplasma: +/-, membrane trait
- neither gram negative or positive
- do not have a cell wall
- only have a simple membrane
Erythromycin inhbits protein synthesis where?
Works at the 50s subunit.
Tetracyclin inhibits protein synthesis where?
Works are the 30s subunit.
What are Obligate Aerobe examples of gram-positive, gram-negative, and acid-fast?
-Gram-positive:
Nocardia, Bacillus Cereus
-Gram-negative:
Bordetella, Brucella, Legionella, Pseudomonas, Neisseria
-Acid-fast:
Mycobacterium, NocardiaWhat are Facultative Anaerobe examples of gram-positive, gram-negative, and no cell wall?
-Gram-positive:
Coryne, Lister, Actinomyces, Bacillus Anthracis, Staph. C.L.A.B.S.
-Gram-negative: most other gram-negative rods
-No cell wall: Mycoplasma
Examples of Micoaerophilic
- Gram-positive: Streptococcus, Enterococcus, streptococci (some species are falcultative anaerobes
- Gram-negative: Spirochetes (treponema, borrelia, leptospira), and Campylobacter
What are Obligate Aerobes?
Need oxygen. Use glycolysis, the Krebs cycle, and the electron transport chain.
What are Facultative Anaerobes?
These bacteria can use oxygen or fermentation of energy. Have catalase and superoxide dismutase. Can grow without oxygen
What are Microaerophilic bacteria?
Use fermentation and have no electron transport system.
Can tolerate low amounts of Oxygen because they have superoxide dismutase
What are Obligate Anaerobes?
Hate oxygen and have no enzymes to defend against it!
Examples of obligate anaerobes?
-gram-positive-
Clostridium
-gram-negative-
Bacteroides
Pleomorphic examples of Gram-negative bacteria?
Chlamydia and Rickettsiae
these also do not have the metabolic machinery to utilize oxygen. They are energy parasites, and must steal their host’s ATP directly.
What is the Embden-Meyerhof Pathway?
This is the pathway of glycolysis that we have studied in biochemistry.
What are autotrophs?
organisms that use inorganic chemical sources such as ammonium and sulfide
What are heterotrophs?
Use organic carbon compounds.
Chemoheterotrophs
Use chemical and organic compounds such as glucose for energy.
Fermentation is what?
glucose is broken down to pyruvic acid, yielding ATP directly
What two organisms form endospores?
only 2 genera of bacteria , both of which are gram-positive , form endospores:
- Bacillus (aerobic)
- Clostridium (anaerobic)
What is a biofilm?
extracellular polysaccharide network mechanical scaffold around bacteria.
What is the most effective way to cure an infection involving a prosthetic device?
Remove the device i.e. catheter, I.V.
What are facultative intracellular organisms?
organisms that can survive inside the a neutrophil or macrophage after being phagocytosed
What are the facultative intracellular organisms?
1-Listeria monocytogenes-->LISTen 2-Salmonella typhi-->SALly 3-Yersinia-->YER 4-Francisella Tularensis-->FRiend 5-Brucella-->BRUCE 6-Legionella-->Must 7-Mycobacterium-->LEave 8-Nocardia-->NOw
Where is the spirochetes flagella?
It runs underneath their unique outer membrane sheath
What are pili?
Pili are adherence factors AKA adhesins
India Ink stain looks like?
Not taken up by cell wall so it appears as a clear halo around the cell. I.e. the fungus Cryptococcus.
Quellung Reaction looks like?
Antibodies bind to the capsule causing it to swell with water.
Opsonization is what?
Macrophages or neutrophils can bind to the Fc portion of the antibody and gobble up the bacteria
Endotoxins pathogenic to humans have only been found in gram + or - bacteria?
gram-negative
What is the most famous endogenus mediator of sepsis?
TNF which is also called a cachectin
TNF triggers the release of what?
The cytokine IL-1 which causes the release of other cytokines and prostaglandins. The emdiators act on blood vessels and organs to produce vasodilation, hypotension, and organ system dysfunction.
The mnemonic cAMP stands for the four bacteria that produce exotoxins that increase levels of cAMP. What does it stand for?
c = cholera (Vibrio cholera) A = anthrax (bacillus anthracis) M = Montezuma's revenge (popular name for enter0-toxigenic E. coli) P = pertussis (Bordetella pertussis)
