Science Homework Help

[mianickle]

I just started this class and my book is late, The question is "If muscle biopsies were taken from the legs of a world-calss marathon runner and a typical couch potato, which would you expect to have a higher density of mitochondria? Why? What about a muscle biopst from the biceps of a weight lifter and a couch potato?" I looked up mitochondria on the web, and I found out that 99.99% of you mitochondrial DNA comes from your mom and they replicate when they get to large. But I can not find out why they get to large, so my only guess right now is the healthier guys because mitochondria have to do with what type of food you eat and oxygen. Does anyone know where I can look to find out the rest of the info I need?

[TeleMad]

I don't want to just come out and give you the answer, but I'm not sure how to help you without doing that.

Mitochondria are often times called the powerhouses of the cell. It is mitochondria that provide our cells with most of their ATP, or cellular energy. Glycolysis (the conversion of glucose into pyruvate) occurs in the cytosol but yields only 2 ATP per glucose molecule, whereas the conversion of pyruvate into acetyl-CoA, the tricarboxylic acid cycle, the electron transport chain and chemiosmosis all occur in the mitochondria and yield a total of about 34 more ATP. 2 outside mitochondria; 34 in mitochondria. Therefore, the more energy a cell needs the more mitochondria it needs.