A challenge!

March 6, 2006

Not a crafty one, but a science one and I will take it!

Comments in my last post from the Shrone (goddess):
Quick flashback from my microbiology days: Tell me what it means to be Gram positive/negative! Ha!

Posted by The Shrone to Crazy Crafter at 3/06/2006 11:20:28 PM

Gram Positive: When staining a slide with the Gram Stain Method, Gram Positive bacteria retain the Crystal Violet, a purple stain because they have thick layers of peptidoglycan in their cell walls.

Gram Negative: Gram Negative bacteria lose the Crystal Violet stain because their cell walls only have thin layers of the peptidoglycan. Peptidoglycan is a protein/sugar mortar like substance in the cell walls of bacteria. It gives the cell walls strength and shape. In the staining method 95% ethanol is used to wash the Crystal Violet stain off of the bacteria. The Gram negative bacteria will lose all of the stain. The slide is then stained with Safronin, that stains everything. However, the purple Crystal Violet bacteria will still be purple. Everything else gets stained pink. So, Gram Negative bacteria look pink in a microscope.

This is how they determine the difference between Gram + and Gram – Bacteria. There is a reason they need to know this.

Penicillin, you know, the antibiotic, stops peptidoglycan from being made in the cell wall. With a weak cell wall the cell will rupture during cell division. Also, it is susceptible to be eaten by your own white blood cells.

Some bacteria, such as Mycoplasma pneumoniae (known for walking pneumonia) do not have cell walls, therefore Penicillin, which is a common antibiotic for pneumonia will not kill this bacteria and you will still feel sick.

***Big Lab test tomorrow*** sigh…

I have done nothing in the craft world because of it, and keep finding myself online more than I should be.

Thank you for all of your comments about calories and dieting. I will be making another trip to my doctor soon, maybe I can get him to diagnose me with something (yeah, like way too fat) so I can be referred out to see a nutritionist. Crazy thing is it probably isn’t covered in my health insurance. We bought a treadmill and should be getting that sometime next week.



  1. Good luck on your test!

  2. I think you’ll have no problems passing your Microbiology course. You gave an A+ answer! You even went into the significance of the Gram testing.

    Trying saying “peptidoglycan” with your mouth full of food or after a couple of mixed drinks. 😉

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