Cells Capture and Release Energy

1. Cells Capture and Release Energy Section 2.2

2. Energy Energy is needed by organisms to stay alive • Plants get energy from the sun • Animals get energy from food

3. Energy Chemical energy is stored in the bonds of molecules • Cells need to break the bonds of molecules to release energy • Glucose is a major energy source of cells

4. Energy Photosynthesis • Plants take energy from the sun and change it to the chemical energy in glucose • The process takes place in cell with chloroplasts • Chlorophyll, a light absorbing pigment, traps the energy from sunlight

5. Energy Photosynthesis sunlight CO2 + H2O C6H12O6 + O2 Chlorophyll Some glucose is changed to starch and stored for later use

6. Energy Energy is released from food when the chemical bonds are broken Cellular Respiration • Cells use oxygen to release stored energy in sugar • Takes place in the mitochondria • Takes place in animals and plants

7. Energy Cellular Respiration C6H12O6 + O2 H2O + CO2 + Energy • Some energy is transferred to other molecules which carry energy to where it is needed • The rest of the energy is released as heat

8. Energy Fermentation • Cells release energy without oxygen • Cells break glucose down into smaller molecules and release small amounts of energy • Small molecules ferment in cytoplasm • Alcoholic fermentation (bread) or lactic acid fermentation (yogurt, cheese) can occur

9. Energy Exercise • Muscles store energy and oxygen • During long exercise, muscles use up energy • Fermentation occurs to provide energy and lactic acid builds up (burning) • You breathe hard to break down byproducts fermentation (burning goes away) • Reserves of energy an oxygen build up again

10. Energy

11. Energy

12. Energy