In the alkaline phosphatase assay, you will you be monitoring the formation of product by measuring the absorbance of the solution using a spectrophotometer. Why are you monitoring the formation of product at a pH of 9 and a wavelength of 400nm. A. At pH 9, the product, p-nitrophenol, will be ionized, the solution will appear yellow in color, and thus can be monitored at the wavelength of maximum absorption for the phenolate ion which is 400nm.
B. At pH 9, the product, p-nitrophenol, will be ionized and colorless
C. At pH 9, the product, p-nitrophenol, will be un-ionized and yellow in color

a. At pH 9, the product, p-nitrophenol, will be ionized, the solution will appear yellow in color, and thus can be monitored at the wavelength of maximum absorption for the phenolate ion which is 400nm

Explanation:

In alkaline phosphatase assay, the hydrolysis of p nitrophenyl phosphate to p nitrophenol happens. When the ph is 9, the product which is p nitrophenol would undergo ionization. The solution is going to appear to be of yellow and it can be monitored at a wavelength for maximum absorption of phenolate ions at 400nm.

Option A is the answer to the question.

c- cold periods in earth's history during which glaciers covered much of the surface.

explanation: