Final answer:
The statement is false since not only electrically excitable cells like nerve and muscle cells, but also epithelial and connective tissue cells can have gated ion channels that help in various functions including signaling and maintaining ionic balance.
Step-by-step explanation:
The statement 'Cells that aren't electrically excitable often lack gated ion channels in their plasma membrane.' is false. While it is true that electrically active cells such as nerve and muscle cells are particularly rich in gated ion channels, other cell types, including those in epithelial and connective tissues, can also possess gated ion channels.
Gated ion channels can open or close in response to different types of stimuli, such as electrical, chemical, or mechanical signals.
Although these channels are primarily associated with the generation and propagation of electrical signals in nerve and muscle cells, they can also be found in other cell types, serving various functions. For example, they play a role in maintaining ionic balance, and signaling in epithelial cells, and contributing to the tissue-specific functions of connective tissue cells.