Who is Mrs. Popper from Mr. Popper's Penguins and what is their importance?

Mrs. Popper is the "polar" opposite of Mr. Popper, pun intended. Whereas Mr. Popper is an idealist and a dreamer, Mrs. Popper is down to earth and practical. It is Mrs. Popper who voices logical concern about housing penguins in the home, though she does warm to the penguins over time. Mrs. Popper is also the holder of the purse-strings in the Popper household, paying bills and such. Mrs. Popper must warn Mr. Popper that the penguins are breaking them financially.