Question

Microbiology - Gram Positive (ONLY answer)

[Q1] A positive catalase test shows

- Bubbles

- Appearance of Clots

- Change of color from blue to green.

- All answers are correct.

[Q2] A complete blood cell lysis is also known as

- Alpha hemolysis

- Beta hemolysis

- Gamma hemolysis

- No answer text provided.

[Q3] How do you know whether your organism completely lysed the blood cells?

- By the presence of a green halo around the bacterial growth

- The blood agar will be unchanged (red color)

- By the presence of a clear halo around the growth

- Two answers are correct.

Answer 1

1 Ans: The correct option is A (Bubbles).

Catalase enzyme breakdown hydrogen peroxide into water and oxygen. So, Bacteria that is positive for catalase test indicates that it can produce catalase enzyme that will results in breakdown of hydrogen peroxide and formation of oxygen bubble.

2 Ans: The correct option is B (Beta hemolysis)

Beta hemolysis is sometimes referred as complete hemolysis.

3 Ans: The correct option is C.

During complete hemolysis, a clear zone around the bacterial growth.