Laboratory Exercise 2 Proper Handling of Microorganisms

Question 1

Aseptic Transfer of Cultures

Answer 1

Broth to broth
Slant to broth
Slant to slant

Question 2

Slant, broth, plate components

Answer 2

Slant - nutrient agar (with slant and butt parts)
Broth - water and nutrients (sometimes with durham tube to observe gas)
Plate - solid media in plate, nutrient agar

Question 3

Procedure of Heat Fix Smear and Stain

Answer 3

Step 1. Heat Fix Smear
- Liquid Media - loop from broth to slide -> air dry -> heat fix 1x/2x
- Solid Media - water -> from plate or slant -> air dry -> heat fix 1x/2x

Step 2. Stain
Methylene blue (1 min) -> water -> blot dry and view slide

Primary stain -> Mordant -> Decolorizer -> Counterstain

Question 4

Introduction to Staining
2 Steps

Answer 4

1. Heat fixation
2. Staining

Question 5

Staining
Different types of dyes

Answer 5

1. Basic dye - cationic (methylene blue, crystal violet)
2. Acidic dye - anionic (eosin, acid fuchsin)

Question 6

Staining
Different types of staining techniques

Answer 6

1. Simple stain (methylene blue - 1 dye is used)
2. Differential stain (Gram stain - more than 1 dye)

Question 7

What temperature are the tubes inoculated?

Answer 7

37 degrees C