Date post: | 20-Jan-2016 |
Category: |
Documents |
Upload: | patience-king |
View: | 216 times |
Download: | 0 times |
Cells Capture and Release Energy
Section 2.2
Energy
Energy is needed by organisms to stay alive–Plants get energy from the sun–Animals get energy from food
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
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
Energy
Photosynthesis sunlight
CO2 + H2O C6H12O6 + O2
Chlorophyll
Some glucose is changed to starch and stored for later use
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
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
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
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
Energy
Energy
Energy