Photosynthesis & Respiration The Big Picture

Photosynthesis 6CO 2 + 6H 2 O + Light C 6 H 12 O6 + 6O 2 Six molecules of carbon dioxide plus six molecules of water plus light yields one molecule of glucose plus six molecules of oxygen.

Respiration C 6 H 12 O 6 + 6O 2 6CO 2 + 6H 2 O + Energy One molecule of glucose plus six molecules of oxygen yields six molecules of carbon dioxide plus six molecules water plus energy.

The Big Picture These two processes form a cyclic relationship. Out puts (waste) of one are the inputs (resources) of the other.

The Big Picture Nature has developed this circular mechanism for trapping the energy from the sun and converting it into the chemical energy that fuels all food chains in the biosphere.

1 st and 2 nd Laws of Thermodynamics How are these two laws relevant to these two processes?

1 st Law of Thermodynamics Energy is continually being passed from light energy to chemical energy to mechanical energy to heat energy. Never created or destroyed. Constant transformation.

2 nd Law of Thermodynamics Energy being passed on is not 100% efficient. Some energy is being lost with every transformation and transfer. Think of the different trophic levels.