Question

when our bodies extract energy from food and convert it to a form that our cells can use how much total food energy is lost as heat? a. 75 percent b.less than 10 percent c. More than 50 percent d. 20 percent

Answer 1

The right answer is 75%.

All cells in our body 'burn' energy substrates, such as sugar and fat, with the oxygen provided by the blood. This oxidation transforms these substrates into CO2 and water, and releases energy. About 25% of the energy released can be used for cellular processes, but about 75% is directly released as heat. Our body, also at rest, thus continuously produces heat, which is released to the environment.

Answer 2

Choice D, because we generally waste more than half of it as heat.