Department of Energy Argonne National Laboratory Office of Science NEWTON's Homepage NEWTON's Homepage
NEWTON, Ask A Scientist!
NEWTON Home Page NEWTON Teachers Visit Our Archives Ask A Question How To Ask A Question Question of the Week Our Expert Scientists Volunteer at NEWTON! Frequently Asked Questions Referencing NEWTON About NEWTON About Ask A Scientist Education At Argonne Membrane Significance
Name: Saad H.
Status: Student
Age: 16
Location: N/A
Country: N/A
Date: September 2002

I do not quite understand the significance of membranes in the biochemical events which occur in mitochondria and chloroplasts. Your explanation would be much appreciated.

The membranes of these organelles are essential to their biological function! Both mitochondria and chloroplasts convert energy into ATP, the cell's short-term energy storage molecule. They do this by first using the energy to create a H+ concentration difference across a barrier (membrane). Then, they harness the natural flow of H+ from the side of greater concentration to the side of lower concentration by coupling it to ATP synthesis. Exactly how this is accomplished is still the subject of vigorous and fascinating research. I predict that several more Nobel prizes will be awarded to researchers in the field by the time it is understood. But this ATP synthesis could not be powered by the concentration difference unless the membrane is there to keep the two parts (inside and outside) separated!

Richard E. Barrans Jr., Ph.D.
Director of Academic Programs
PG Research Foundation, Darien, Illinois

Click here to return to the Molecular Biology Archives

NEWTON is an electronic community for Science, Math, and Computer Science K-12 Educators, sponsored and operated by Argonne National Laboratory's Educational Programs, Andrew Skipor, Ph.D., Head of Educational Programs.

For assistance with NEWTON contact a System Operator (, or at Argonne's Educational Programs

Educational Programs
Building 360
9700 S. Cass Ave.
Argonne, Illinois
60439-4845, USA
Update: June 2012
Weclome To Newton

Argonne National Laboratory