BIOD 171 Lab exam Chapter 3 Questions & Answers.

BIOD 171 Lab exam Chapter 3. BIOD 171 Lab exam Chapter 3. Lab exam Chapter 3 2. Why is it important to first clean your slide before applying your sample? You must first remove any unwanted contaminants from the slide otherwise it may be difficult to distinguish between the pathogen of interest and a contaminant. 3. When performing a wet mount technique, what is the advantage of using a wax or hydrophobic pen? Creating a hydrophobic barrier (the circle) helps to keep the water within the circle so it does not spill off of the slide. 4. What dye do Gram-positive bacteria primarily retain? Crystal violet Exam Page 2 Answer the following questions. 1. Why do Gram-negative bacteria stain red? It stain red due to the thinner pepidolglycan layer in their cell wall 2. Identify the stain and shape of the bacteria pictured below. Gram postive : cocci (Spherical) Answer the following questions.