Gram positive cells take up the crystal violet, which is then fixed in the cell with the iodine mordant. This forms a crystal-violet iodine complex which remains in the cell even after decolorizing. It is thought that this happens because the cell walls of gram positive organisms include a thick layer of protein-sugar complexes called peptidoglycans. This layer makes up 60-90% of the gram positive cell wall. Decolorizing the cell causes this thick cell wall to dehydrate and shrink, which closes the pores in the cell wall and prevents the stain from exiting the cell. At the end of the gram staining procedure, gram positive cells will be stained a purplish-blue color.
Gram negative cells also take up crystal violet, and the iodine forms a crystal violet-iodine complex in the cells as it did in the gram positive cells. However, the cell walls of gram negative organisms do not retain this complex when decolorized. Peptidoglycans are present in the cell walls of gram negative organisms, but they only comprise 10-20% of the cell wall. Gram negative cells also have an outer layer which gram positive organisms do not have; this layer is made up of lipids, polysaccharides, and proteins. Exposing gram negative cells to the decolorizer dissolves the lipids in the cell walls, which allows the crystal violet-iodine complex to leach out of the cells. This allows the cells to subsequently be stained with safranin. At the end of the gram staining procedure, gram negative cells will be stained a reddish-pink color.
Remember:
If the Gram Stain is completed properly, gram positive should stain purple; however, if you over decolorize a gram positive organism, the organism will appear appear pink, which is a gram negative reaction. To summarize, if you over decolorize a gram positive organism it will show as a gram negative organism.
Dark blue spots appear to show that there is starch on the plant cells. -Anonymous-
Gram positive bacteria stain purple due to the chemistry and structure of their petidoglycan cell wall
It is used in gram staining to differentiate gram negative and gram positive bacteria. After being dyed, the cells are washed with ethanol. Gram positive bacteria will retain the methylene blue due to the amount of peptidoglycan in their cell walls, where gram negative cells will not. Iodine is used as a counter stain, which is up-taken by gram negative cells. After the gram staining procedure is finished, gram positive cells will appear dark purple or blue due to the retained methylene blue. Gram negative cells will appear pink or red due to the iodine counter stain.
No, it will not. Methylene blue agar is used to identify gram negative bacteria, staphylococcus is gram positive.
methylene blue
If the Gram Stain is completed properly, gram positive should stain purple; however, if you over decolorize a gram positive organism, the organism will appear appear pink, which is a gram negative reaction. To summarize, if you over decolorize a gram positive organism it will show as a gram negative organism.
Their eggs can be from a teal with brown spots to a light blue with spots.
pale or grayish blue with spots of purple gray or blue
Dang, dude!
A greyish blue but, more grey then blue. They also have white spots and strips. Strips on the back and, a lot of spots on his head
Bacteria are those that are stained dark blue or violet by Gram Staining.
Gram-negative bacteria Gram-negative bacteria have an outer membrane. However, they have a thinner peptidoglycan cell wall. This means they do not hold the blue dye used in Gram testing and do not appear blue. Instead, they appear red or pink in color.
there are alot more but one species is the house finch with pale blue eggs and black spots on the larger bottom of the egg
pink with blue spots.
7.5
Purple with Blue Spots