MadSci Network: Biochemistry
Query:

Re: is there a way to determine calorie usage for various, individual cells?

Date: Mon Jan 24 19:30:00 2000
Posted By: Brian Cobb, Grad student Biochemistry
Area of science: Biochemistry
ID: 948205224.Bc
Message:

The short and rather unsatisfying answer to your question is no. The reason lies in (1) the definition of a calorie and (2) the complexity of a living cell. First, a calorie is simply a measure of heat or energy in a "system", with "system" usually refering to a chemical reaction. Second, every process that occurs in a cell involves calories (a topic referred to as thermodynamics), thus it is far too complex to measure every single process and every molecule's energy level at any given time.

However, there is one other alternative to determining the energy uptake of a cell or tissue - ATP (adenosine triphosphate). ATP is the main "power" source that fuels cells. In fact, the main reason we need to breathe oxygen is because our cells use it with glucose (sugars) to produce vast amounts of ATP, which in turn powers various processes in the cell. Using various detection methods, it should be theoretically possible to directly measure ATP levels, though I don't know how off the top of my head. That would give you a good idea about the energy usage of that tissue.

You mentioned the comparison of eyes and muscles. My feeling about this is that muscles use much more energy (calories) than our eyes because the chemical signals that allow us to see are mostly powered by the energy within the light itself. When light hits our retina, the pigments in the cells change conformation, and thus a signal that is sent to the brain for interpretation. This requires very little energy compared to our muscles, especially the larger ones that help us walk and such. This is why we wouldn't loose any weight sitting around reading all day! Physical exercise is much better for that.

:)

I hope this helps!


Current Queue | Current Queue for Biochemistry | Biochemistry archives

Try the links in the MadSci Library for more information on Biochemistry.



MadSci Home | Information | Search | Random Knowledge Generator | MadSci Archives | Mad Library | MAD Labs | MAD FAQs | Ask a ? | Join Us! | Help Support MadSci


MadSci Network, webadmin@www.madsci.org
© 1995-2000. All rights reserved.