The Sun powers on the living systems

Autotrophs
Produce their own food from the sun’s energy

Photosynthesis
Turning light energy from the sun into chemical energy

- Chloroplasts = organelles where photosynthesis occurs
- Contain chlorophyll = a light-absorbing pigment
- Light reaction = splits water by using solar energy
- Calvin cycle = links carbon atoms from carbon dioxide into sugar (glucose)
- Photosynthesis:
6CO2 + 6H20 + the Sun’s energy ---------->   C6H12O6 + 6O2

- Organisms use chemical energy from photosynthesis
- Oxygen is used to convert glucose into water + carbon dioxide + energy
- Heterotrophs = organisms that gain energy by feeding on others
- Animals, fungi, microbes
- Cellular Respiration:
C6H12O6 + 6O2   ------------>  6CO2 + 6H20 + energy