MIDTERM 2 Catalase Test

Question 1

What is Superoxide Dismutase and its significance and problems?

Answer 1

Its an enzyme that protonates superoxide to form hydrogen peroxide. Hydrogen peroxide is also toxic

Question 2

How is the hydrogen Peroxide Dealt with?

Answer 2

The enzyme catalase breaks apart the hydrogen peroxide into water and O2

Question 3

Where can catalase be found?

Answer 3

its produced by and found in essentially all actively growing microbes capable of using oxygen for respiration

Question 4

Where does catalase exist?

Answer 4

It exists close to the cell surface and attacks external hydrogen peroxide.

Question 5

What cultures are most suitable for a catalase test and why?

Answer 5

Cultures not older than 24 hours because the enzyme seems most active during exponential growth.

Question 6

How do you test for catalase?

Answer 6

add a couple of drops of 3% hydrogen peroxide directly on the colony and observe if there are bubbles

Question 7

what can the catalase test distinguish?

Answer 7

It can distinguish between morphologically similar but metabolically dissimilar microorganisms like costridium and bacillus

Question 8

Is bacillus catalase positive?

Answer 8

Yes

Question 9

Is clostridia catalase negative?

Answer 9

yes

Question 10

Positive Test for catalase?

Answer 10

Oxygen gas visible with eye

Weak if visible within microscope at 10x