1. The Gram Stain
Can you say
Peptidoglycan?

2. a brief yet tasty guitar riff by Chris Impelliteri
Friggin ice ant
get the hell out of my way
But first,
a brief yet tasty guitar
riff by Chris Impelliteri

3. I. Bacterial Cell Surface
A. The majority have cell walls
1. structure that immediately surrounds the plasma membrane
2. maintains cell shape, protecting the cell in both hypotonic and hypertonic environments
3. contains peptidoglycan - a modified sugar polymer cross linked by short polypeptides
a. found only in prokaryotes

4. II. The Gram Stain [0nly effective on 24 hr. cultures]
A. Used to differentiate bacteria into two groups
B. Gram Positive bacteria
1. simple cell walls with a thick peptidoglycan layer
2. stain blue when using Gram stain protocol
C. Gram Negative bacteria - stains pink
1. more complex cell walls w/smaller amounts of peptidiglycan
2. more likely to be pathogenic
3. lipopolysaccharide layer covering the cell wall (often toxic, protecting the cell from drugs and host immune system)

5. Cell Wall: Gram (+) v. Gram (-)
pg. 529

6. The End