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1) You innoculate the following bacteria in thioglycolate medium and allow them

ID: 219951 • Letter: 1

Question

1) You innoculate the following bacteria in thioglycolate medium and allow them to grow overnight at 37 degrees in the incubator. Next day you observe their growth patterns. Indicate in the test tubes where you would observe the growth of these bacteria. . Sample A as an example
e.g. A) Obligate aerobe – growth only at TOP because they absolutely need oxygen for survival and growth.
B) Obligate anaerobe
C) Facultative anaerobe
D) Microaerophiles
E) Aerotolerant anaerobe
F) Capnophiles

Of the bacteria mentioned at top which ones contain the enzyme superoxide dismutase and which ones do not? 2)

Explanation / Answer

1.

B. obligate anaerobe cannot grow in the presence of oxygen. Therefore, they grow at the bottom of the tube.

C. facultative anaerobe- can grow in presence or absence of oxygen. However, they make more ATP in the presence of oxygen. Therefore, they grow all over the tube. However, they gather mostly at top.

D. microaerophiles- require oxygen but not at higher concentrations. However, higher concentrations of oxygen are not suitable for their growth. Therefore, they grow at upper part of the tube but not at top.

E. aerotolerant anaerobe- grow all over the tube evenly. They do not require oxygen. Oxygen does not effect their growth.

F. Capnophiles- grow at higher concentrations of carbon dioxide. The presence of bacteria in test tube is similar to microaerophiles.