Passage I

A scientist discovered that cells of a new strain of bacteria, Bacteria X, form colonies when incubated for 72 hr at 37°C on a growth medium having a pH of 7 and an NaCl concentration of 5 g/L. To determine whether these conditions are optimal for the growth of Bacteria X, the scientist conducted an experiment in which incubation temperature, and the pH and the NaCl concentration of the growth medium, were varied. In each trial, Bacteria X cells were incubated for 72 hr, and colony growth was then assayed by determining the average colony diameter (ACD) of the colonics that grew during the incubation (see the table).

2. How did increasing the pH of the growth medium from pH 6 to pH 7 affect the ACD when Bacteria X cells were incubated at 42℃ on a growth medium having an NaCl concentration of 5 g/L ? When the pH was increased from pH 6 to pH 7, the ACD:

Answer and Explanation

Your Answer is

Correct Answer is G

Explanation

You can compare the ACD values ​​at different pHs when the temperature is 42° C and the concentration of NaCl is 5 g/L, that is, compare trail 3 & 9. It can be seen from the table that the ACD increases from 0.8 mm to 1.0 mm