Micro1009- Gram Staining Lab Unit 1

Front 1

What year was gram staining developed, and by whom?

Back 1

1884

Hans Gram

Front 2

Gram staining is an example of what type of stain?

Back 2

Differential stain

Front 3

Differential stain

Back 3

Distinguish between various bacteria based on their ability to retain specific dyes

Front 4

How does gram staining differentiate between Gram + and Gram - bacteria?

Back 4

The dyes are retained by the peptidoglycan in the cell walls of the bacteria.

Gram + cell walls are stained dark purple due to their thick outer layer of peptidoglycan

Gram - cell walls are stained pink due to their thinner layer of peptidoglycan and additional outer membrane

Front 5

Why is gram staining important?

Back 5

Gram+ and Gram- bacteria react differently to antibiotics. This staining method is one of the fastest and easiest ways to determine which broad groups of antibiotics should be prescribed

Front 6

What is an example of an antibiotic that might not be an effective treatment due to the Gram+ or - status of the bacteria? Why is this the case?

Back 6

Penicillin

Works by blocking an enzyme needed for peptidoglycan synthesis.

This antibiotic cannot penetrate the outer layer of the bacterial cell wall to affect peptidoglycan synthesis

Front 7

Chemicals involved in Gram Staining

Back 7

1. Crystal Violet

2. Gram's Iodine

3. 95% ethanol

4. Safranin

Front 8

Crystal violet

Back 8

Primary stain

Front 9

Gram's Iodine

Back 9

Mordant

Front 10

95% ethanol

Back 10

Decolorizer

Front 11

Safranin

Back 11

Counter stain

Front 12

Mordant

Back 12

Intensifies reaction between bacteria and stain