The Colorless Molecule O-Nitrophenyl Galactoside (ONPG) Can Be Used as an Artificial

question 12

Multiple Choice

The colorless molecule o-nitrophenyl galactoside (ONPG) can be used as an artificial substrate to assay b-galactosidase in cell extracts of Escherichia coli in which lacZ is used as a reporter gene. Which of the following statements is NOT true with respect to the use of ONPG?

• A) Hydrolysis of ONPG by b-galactosidase produces yellow o-nitrophenol.
• B) o-nitrophenol can be measured with a spectrophotometer.
• C) Hydrolysis of ONPG by b-galactosidase also releases colorless galactose.
• D) The o-nitrophenol moiety is blue and more suitable for use in solid media.
• E) The o-nitrophenol moiety is green and less suitable for use in solid media.

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Definitions:

O-Bromobenzoyl Chloride

An organic compound used in the synthesis of other chemical compounds, characterized by a bromine atom attached to the benzoyl chloride group.

Boiling Point

The temperature at which a substance changes from a liquid to a gas at atmospheric pressure.

Ethanamide

A chemical compound known as the simplest amide derived from acetic acid, with the formula CH3CONH2.

1-Propanol

A three-carbon alcohol with the formula CH3CH2CH2OH, commonly used as a solvent in the pharmaceutical industry.