Gram Staining Flashcards
Developed in 1884 by Christian Gram, the gram stain had what purpose?
To differentiate between gram positive and gram negative cells
Gram’s Iodine is considered a what?
Mordant
What does the Mordant, Gram’s iodine, cause within the cell?
The crystallization of the crystal violet, which is then trapped within the cell
Why are gram negative cells decolorized with the application of acetone alcohol?
The thin cell wall in gram negative cells allows the dye to flow out of the cell
Why are gram positive cells not decolorized with the application of acetone alcohol?
The thick cell wall of gram positive cells prevents the dye from escaping
Which bacteria naturally lack cell walls
Mycoplasma - sterols in their plasma membranes protect from osmotic lysis
Most stains cannot penetrate the cell walls of Mycobacterium. Why is this?
Their thick cell walls contain mycolic acid causing them to be waxy, preventing most stains from entering the cell
Which staining technique is used for identifying mycobacterium?
Acid fast stain
What are the structures that are embedded in the plasma membrane that aid in transport of materials into the cell?
Proteins called permeases
What type of transport requires ATP and can happen against a concentration gradient?
Active transport
What type of transport happens on a gradient from high to low concentrations and does not require ATP?
Passive transport
What are the three types of passive transport?
Facilitated diffusion (uses transporters)
Osmosis (water only)
Diffusion (non water molecules)
A substance is modified as it crosses over the plasma membrane and changes to another substance.
Group Translocation
(This new substance is now impermeable to the membrane)
