Several times this semester we learned that membranes function to define separate microenvironments in cells; settings wherein different components may be distributed on the two sides of the membrane or where different concentrations of the same component may be established for some purpose. Identify two different systems where concentration gradients are responsible for an important cellular function. Briefly describe the function and how it is dependent on a microenvironmental difference. Please organize your answers using the headings below. To do so, simply copy the four headings below into the answer space and then type your answers to the parts of each question in alignment with its proper heading.

Name of System 1:

How is function dependent on microenvironmental difference?

Name of System 2:

How is function dependent on microenvironmental difference?