More than half a century ago, two cell biologists published details of their research involving isolated membrane vesicles from chloroplasts. Normally, the fluid inside these vesicles is near neutral. In an experiment, these membrane vesicles were soaked in an acidic solution (pH 4) until the inside of the vesicle also became pH 4. Based on the details provided in this scenario, by what mechanism could hydrogen ions have crossed the vesicle membrane, and what do you think happened at the molecular level?

Question

Quizplus · Accepted Answer

Facilitated diffusion is the process by which substances move across cell membranes through protein channels, and it does not require energy. In this scenario, hydrogen ions likely moved into the vesicle through a channel protein, equalizing the pH inside and outside the vesicle.

More Than Half a Century Ago, Two Cell Biologists Published