Energy Storage in Biological Systems
Living organisms use two major types of energy storage. Energy-rich molecules such as glycogen and triglycerides store energy in the form of covalent chemical bonds. Cells synthesize such molecules and store them for later release of the energy. The second major form of biological energy storage is electrochemical and takes the form of gradients of charged ions across cell membranes. This learning project allows participants to explore some of the details of energy storage molecules and biological energy storage that involves ion gradients across cell membranes.
Energy storage molecules
Examples of energy storage molecules
Glucose is a major energy storage molecule used to transport energy between different types of cells in the human body.
Fat itself has a high energy or calorfic value and can be directly burned in a fire. In the human body and presumably other animals, it serves a number of roles as there are different kinds of fats, but for the purpose of the discussion here, fats are frequently found associated with each of the organs in the body.
For example there is a deposit of fat on the heart and it was only relatively recently that it was realized that this acts as a temporary storage of buffer for energy. If one thinks of the blood system flowing around a heart, the glucose levels in it can fluctuate depending on a number of factors, such as whether one has recently digested a meal or engaged in strenous activity. As with most machines, steady inputs cause less strain on the system than large fluctuations. And so the role of the fat is to help smooth out these lean periods and allow the heart to continue operating without putting additional strain on it.
Adenosine triphosphate or ATP is one of the key molecular energy carriers in the biological world.
The term chemiosmosis refers to the inter-conversion of chemical energy (energy in the form of chemical bonds) and energy in the from of a transmembrane electrochemical gradient. The idea of "chemiosmotic coupling" arose largely from the work of Peter D. Mitchell and revolutionized the way biologists think about energy storage in biological systems.
Transmembrane ion gradients