Science Buddies: "Ask an Expert"

Alright so our science teacher asked us to make a working model, so I was going to build burglar's alarm but I couldn't make it work, so I finally decided to do the experiment on gram staining, it worked so far except that I have a little difficulty in adjusting microscope's but I'm getting better, I'm in 9th grade we have to submit our project on 10th of October, and I'm worried if our teacher would consider it as a working model or should I work on something else in the limited time I've got? Also is the project suitable enough for a 9th grader?

Alright let the question be, atleast can someone tell how is gram staining useful in real life??

Hi harry14,

The gram staining is useful because it will tell us whether certain strains of bacteria are gram positive or gram negative. On a medical level, different treatments are needed to treat people with infections from gram positive bacteria or infections of gram negative bacteria. The difference is that gram positive bacteria have a thicker cell wall while gram negative bacteria have a thinner cell wall.

Hope that helps!

-Sam

Thanks Sam! I have another query, what exactly is peptidoglycan and what is its importance in the gram staining procedure?

Hi Harry,

This sounds like a really good project. Sam has given your some very useful advice so far, and I think the following will answer your latest question.

Peptidoglycan is the polymer that comprises the major component of the cell wall for bacteria. This is very important for you to understand so you can explain the science behind your project.

First, the Gram stain should always be capitalized because it is named for the bacteriologist who invented it, Hans Christian Gram. Here is a website that gives a brief review of the he history and significance of this stain.

http://health.upenn.edu/bugdrug/antibio ... /Gram1.htm

Here is information from the Science Buddies website on staining bacteria. The protocol includes a very detailed explanation, which should help you if you are doing a Gram stain for the first time. . This procedure uses crystal violet, which is the first step of the Gram stain.

https://www.sciencebuddies.org/science- ... cteria.pdf

The Wikipedia article contains very good background information with some references that should be useful for your project.

http://en.wikipedia.org/wiki/Gram_staining

The You Tube information on this topic is general, but the difference between Gram-positive and Gram-negative bacteria is explained. You can "see" the difference in the peptidoglycan structure of Gram-positive and Gram-negative bacteria:

http://www.youtube.com/watch?v=-sct8GUye-0

There's more. Have you had chemistry yet? Peptidoglycan is the major component of the cell of bacteria. It is a polymer of two amino sugars, N acetylglucosamine and N acetyl muramic acid. Here is a website that includes complete information on prokaryotic cell walls, including the structure and function. You can abstract as many details as you need for your project from this website. Please let me know if you have any questions about the information, as this is very complex.

http://faculty.ccbcmd.edu/courses/bio14 ... ct/cw.html

Good luck!

Donna Hardy