Lab 7

Question 0

What is the first step of gram staining

Answer 0

Primary stain. Crystal violet which stains purple and is basic

Question 1

What is a gram stain

Answer 1

Differential stain that classifies gram - or gram +

Question 2

What is the second step in gram staining

Answer 2

Mordant. Grams iodine.

Question 3

What is the third step of gram staining

Answer 3

Decolorizing agent. Ethanol

Question 4

What is the fourth step of gram staining.

Answer 4

Secondary stain. Safranin.

Question 5

What is the color of gram negative

Answer 5

Pink

Question 6

What is the color of gram positive

Answer 6

Purple

Question 7

What are bacterial cell walls composed of

Answer 7

Peptidoglycan

Question 8

What bacteria were used in this lab

Answer 8

S. Aureus
E. Coli
B. Subtilus

Question 9

Describe the procedure for a Gram stain

Answer 9

With a fixed smear: cover smear with crystal violet for 30 seconds. Wash. Cover smear with grams iodine for 10 seconds. Wash. Decolorize. Wash. Cover smear with safranin for 30 seconds. Wash. Blot.

Question 10

Are staphylococcus gram negative or Positive

Answer 10

Gram positive