Lab exam 2 Flashcards
What are the functions of endospores in bacteria?
Resting stages that allow bacteria to survive conditions unfavorable for growth
What external structure on the endospore acts as a protective barrier? What is its composition?
Protective barrier –> exosproium, composed of protein
Compared to a vegetative cell, how much less water is present in an endospore?
10-30% of the water found in the vegetative cell
What is the mordant in the spore stain?
Heat –> it causes the endospore to expand allowing stain to penetrate the structure
What unique chemical compound is important in the heat resistance of endospores?
calcium dipocolinate –> only in endospores associated with heat resistance
What conditions are necessary to destroy endospores? In what device are these conditions achieved?
121 C, 15 poison steam pressure for 15-20 min achieved in autoclave
What is the color of endospores after Gram staining? After spore staining?
Gram stain –> colorless
Spore stain –> green
What is the secondary stain in the spore stain?
Safranin - stains vegetative cell
What is the color of the vegetative cell after the spore stain?
red
Of the three genera of bacteria, which does not produce endospores?
mycobacterium
What makes mycobacterium resistant to staining?
waxy cell wall - contains mycelia acid
what other bacterial genus is acid-fast?
nocardia
What is the primary stain in the acid-fast stain?
carbon fuschin
What is the secondary stain in the acid-fast stain?
methylene blue
In the Ziehl-Neelsen acid-fast stain, what is the mordant?
heat
What is the color of mycobacterium after the addition of the secondary stain?
pink
Which stain would be most useful in staining the leprosy bacilus:
acid fast
What is the advantage of the Kinyoun staining procedure over the Ziehl-Neelson method?
It doesnt use heating therefore noxions phenol fumes are not released
What enviornment can hyperthermophile be found?
above 80C - ocean floor and volcanic hot springs
what enviornment can thermophile be found?
50-80C – compost pile
what enviornment can a mesophile be found?
between 20-50C – human body
what enviornment can a psychrophile be found?
-5-20C – waters of antartic
psychrophiles vs psychrotrophs
psychrophiles –> grow best at low temps
psychrotrophs –> grow at low temps and can cause food spoilage
Why are psychotrophic bacteria of concern to those in the food service industry?
They can grow at refrigerator temps and survive heat so they are capable of causing food spoilage
What is the optimum growth temperature for most human pathogens ?
37*C because that is human body temp
Name three cellular components involved in metabolism that are influenced by temperature changes
Ribosomes, enzymes and cellular membrane
