Copyright © 2010 Pearson Education, Inc. Bell Ringer  A new chemical was synthesized that inhibits the Golgi body from functioning. How would this affect eukaryotic cells? What about prokaryotic cells?

Copyright © 2010 Pearson Education, Inc. Bad News   Exam Scores were low…  Extra credit opportunity…  Current event in microbiology  1 paragraph summarizing the article  1 paragraph about your thoughts on the article   10 points extra credit  Due Friday!

Copyright © 2010 Pearson Education, Inc. Worse News     Ivy Tech cannot accredit this class for college credit  We are contacting other colleges in hopes of getting a dual credit class

Copyright © 2010 Pearson Education, Inc. Objective  Use the bright field microscope in the study of microorganisms  Describe and recognize various bacterial morphologies.  Use appropriate microbiology media, test systems, and lab equipment  Students will perform a simple stain using the basic dye crystal violet.

Copyright © 2010 Pearson Education, Inc. Preparing Smears for Staining  Smear: A thin film of a solution of microbes on a slide  A smear is usually fixed to attach the microbes to the slide and to kill the microbes  To heat fix, pass slide through flame 3x  To chemically fix, cover smear with alcohol for 1 minute

Copyright © 2010 Pearson Education, Inc. Goals of making a good smear  1) Cause cells to adhere to microscope slide so they are not washed away  2) Make sure shrinking of cells doesn’t occur  Distorts image  Fresh culture  Don’t overdue the heat-fixing step  3) Prepare a thin smear  Little bit of bacteria  Cannot see detail if to much bacteria on slide

Copyright © 2010 Pearson Education, Inc. Preparing Smears for Staining  Simple staining: Coloring the microbe with a dye that emphasizes certain structures  Crystal violet (purple)  Live or unstained cells have little contrast with the surrounding environment. Therefore, staining is important to visualize an organism.

Copyright © 2010 Pearson Education, Inc. Preparing Smears for Staining  A simple stain improves the contrast between the microbe and the background  A stain contains a dye and a solvent  The chromogen (dye) is the color molecule  Chromophore is the portion of chromogen that gives off color  In a basic dye, the chromophore is a cation (+)  Used to stain bacteria cells… Why?  Direct stain  In an acidic dye, the chromophore is an anion (-)  Used for negative stains… Why?

Copyright © 2010 Pearson Education, Inc. Preparing Smears for Staining  Used to study morphology, size, and arrangement