You Have Some Old Plastic Petri Dishes That You Would

question 78

Multiple Choice

You have some old plastic Petri dishes that you would like to use for pouring bacteriological agar plates.The only method of physical sterilization is ultraviolet radiation sterilization with your UV light (you cannot use the autoclave because it will disfigure and melt the plastic) .After sterilizing the plates, pouring the sterilized agar medium, and then leaving the plates out at room temperature for a day or two to let them solidify and dry, you find contaminating bacterial colonies growing on the agar.Predict what has happened in this situation.

• A)The room temperature enhanced the growth of normal biota of the agar.
• B)Air got into the poured agar plates, contaminating them.
• C)The lids of the Petri dishes were inadvertently left on while being sterilized.
• D)The agar had bacteria in it, even after sterilization in the autoclave.

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Definitions:

Behaviorist

A psychologist who studies and practices behaviorism, focusing on observable behaviors and disregarding mental activities.

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A term used in psychoanalytic theory to describe the energy of the sexual drive as a component of the life instinct.

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The junction between neurons where nerve impulses are transmitted from one neuron to another.

Energy

The ability to do work or produce change, existing in forms such as thermal, mechanical, electrical, chemical, or nuclear, and can be transformed from one form to another.