Question

1. What feature do acid-fast cell walls have?

2. What step does the Gram and acid-fast stain have in common?

3. Why are mycoplasma in a class by themselves?

4. What is the difference between capsule and slime?
5. Why does a capsule stain require two separate staining processes?
6. Why do pathogenic strains tend to have a capsule?

Answer 1

Question 1:

Answer: Certain bacterial and eukaryotic cells are resistance to decolorization by acids after staining procedures. This physical property is called as acid-fastness and the organisms that has this property are called acid fast organisms. The cell walls of acid fast bacteria contain peptidoglycan and the outer membrane consists of mycolic acid. For example: Mycobacteria contain high amount of mycolic acid in their cell walls that is responsible for acid fastness.

Question 2:

Answer: Decoloration step is the common step in both gram and acid-fast stains. In both the standing methods, primary staining is followed by decolorization and counterstaining.

Question 3:

Answer: Mycoplasma consisting of bacteria that lacks cell walls. This property makes them to classify under separate class.

Question 4:

Answer: Capsule/ Slime layer are the extra cellular materials secreted by many bacterial cells. Slime layer is defined as a extra cellular material that is loosely associated with the cell wall of the bacteria whereas, capsule is an extra cellular material that is tightly bound the bacterial cell wall with definite boundaries.