× Didn't find what you were looking for? Ask a question
Top Posters
Since Sunday
s
5
g
5
K
5
o
5
g
5
o
4
k
4
s
4
I
4
k
4
j
4
o
4
Home Q & A Board Biology-Related Homework Help Cell Biology
New Topic  
smoran1 smoran1
wrote...
Posts: 31
Rep: 0 0
11 years ago
A student completed the Gram stain technique, but neglected to use the Gram?s Iodine.  What effect would this have on a Gram-positive bacterium?  What effect would this have on a Gram-negative bacterium?  And why for both bacteria?
Read 680 times
2 Replies

Related Topics

Replies
wrote...
#1
11 years ago
In both, the crystal violet will not be attached to the cell wall.  The Gram-positives will destain and give an inaccurate result.  The improper staining will not impact the Gram-negative outcome.
wrote...
#2
Educator
8 years ago
Gram’s iodine acts as an astringent causing the crystal violet dye to penetrate and stain gram-positive organisms. The gram-positive organisms will not be decolourized as easily as gram-negative organisms by an acetone-alcohol. Safranin is added as a “counter stain” which stains all non-gram-positive organisms a pink/red colour. If Gram’s iodine is not used in this process, the gram-positive organisms will not show up violet, they will instead show up a pink/red colour (Gram’s stain, 2003). 
New Topic      
Quick Reply
Explore
Post your homework questions and get free online help from our incredible volunteers
  960 People Browsing
Start New Topic Take the Tour CoursesNew Study Tools Topics Trending Browse by Textbook
Live Chat
Related Images
  
 271
  
 47
  
 204