No life without energy
All life depends on the continuous
input of energy. Many chemical reactions in our bodies are tuned
to extract energy from food and use this energy to make new cells
and keep cells already made alive. In this process food molecules
play two roles; first, they contain energy that can be converted
to forms generally useful for biological reaction; second, they
contain molecular structures that can be used to make macromolecules.
The energy for all life originates from the sun. Light energy is
converted into chemical energy (organic molecules) in the presence
of water and minerals. Some of the captured energy is used to make
more biomass (plants) to sustain animal life, provide energy to
grow and do work (animals walk around), while some energy is lost
as heat and waste molecules. The most effective way of converting
chemical energy into useful energy to sustain life is respiration.
Warm blooded animals have found ways to use the heat to maintain
a relatively high body temperature which gives them an advantage
in colder environments.
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Copyright © 1999-2011
Lukas K. Buehler