Top Posters
Since Sunday
4
n
3
j
3
x
2
c
2
2
p
2
n
2
3
2
C
2
z
2
k
2
Home Q & A Board Biology-Related Homework Help Cell Biology
New Topic  
nursing101 nursing101
wrote...
Go to Answer
Posts: 39
Rep: 0 0
11 years ago
Why do some bacteria retain the Gram stain while others do not?

and

Can u identify beneficial and one harmful role of Gram-negative enteric bacteria found in the human body?
Read 456 times
4 Replies
Replies
wrote...
#1
11 years ago
It has to do with the cell membrane. I'll give you a hint, e-coli is a biggie.
Answer accepted by topic starter
lenazoni20lenazoni20
wrote...
#2
Posts: 38
Rep: 0 0
11 years ago
Sign in or Sign up in seconds to unlock everything for free
1

Related Topics

wrote...
#3
11 years ago
in a nut shell, G+ bacteria have a thicker cell wall then G- bacteria. G- bacteria has a thin cell wall with high lipid content because of an outer membrane that covers the cell wall. When you rinse the slide with 95%ethanol, the ethanol extracts the lipids, making it more porous and incapable of retaining the crystal violet-iodine complex. When the counterstain, Safranin, is added, G+ cells will become a darker purple while the G- cells stain pink.

beneficial: E. coli lives in the human GI tract to help digest food
harmful: If E. coli was ingested, can cause food poisoning
wrote...
#4
11 years ago
1. The "Gram stain" is actually a complex created by the combination of two stains: crystal violet and Gram's iodine followed by a decolorizer and counter stain Safranin. Basically, due to the chemical structure of their cell walls, purple color created by the stain complexes remains in the Gram-positive because of the many layers in the cell mambrane. Gram-negative does not keep the stain and loses its color because the cell wall is much thinner.

2. Generally, Gram-negative bacteria are more pathogenic / disease-causing (such as staph and strep as well as E. coli and Salmonella).
New Topic      
Quick Reply
Explore
Post your homework questions and get free online help from our incredible volunteers
  991 People Browsing
Start New Topic Take the Tour CoursesNew Study Tools Topics Trending Browse by Textbook
Live Chat
Related Images
  
 32
  
 328
  
 268
Your Opinion
Who will win the 2024 president election?
Votes: 3
Closes: November 4
Previous poll results: Does a gender wage gap exist in America?