1. Cellular Energy Every living thing needs energy
The sun is the source of energy for most living things
Photosynthesis
Photo- light synthesis- to put together
Nearly all living things obtain energy either directly or indirectly from the energy of sunlight captured during photosynthesis
Autotroph- makes its own food Heterotroph- consumes food

2. Sources of Energy
Nearly all living things obtain energy either directly or indirectly from the energy of sunlight captured during photosynthesis.

3. Photosynthesis- Stage 1
Photosynthesis: Stage 1- Capturing the energy in sunlight
Happens in chloroplasts in leaves
Pigments- colored chemical compounds that absorb light.
Gives leaves their green color
Cholorphyll- the main pigment in chloroplasts

4. Photosynthesis- Stage 2
Photosynthesis: Stage 2- Using energy to make food
Cells need water (absorbed by roots from soil)
Cells need carbon dioxide (enters leaves from air)
Stomata- opening in leaves, allows carbon dioxide and oxygen to move in to and out of leaves
Happens inside chloroplasts, water and CO2 undergo chemical reactions

5. Photosynthesis- Stage 2
Reactions are powered by energy from the first stage
Plants produce sugar with the formula C6H12O6
Oxygen is produced and exits through stomata
sunlight
6CO2 + 6H2O  C6H12O6 + 6O2
Carbon Dioxide + Water  Sugar + Oxygen

6. The Two Stages of Photosynthesis
During photosynthesis, plants and some other organisms use energy from the sun to convert carbon dioxide and water into oxygen and sugars.

8. Cellular Respiration
Cellular Respiration- cells break down sugar and obtain energy
Your cells store energy until you need it
Respiration: Stage 1
Happens in cytoplasm
sugar is broken up into smaller molecules
oxygen is not involved (Anaerobic)
Releases a small amount of energy

9. Cellular Respiration Respiration: Stage 2 Happens in mitochondria
Small molecules from step one are broken down even further
Requires oxygen (aerobic)
Releases LOTS of energy
C6H12O6 + 6O2  6CO2 + 6H2O
Sugar + Oxygen  Carbon Dioxide + Water

10. Two Stages of Respiration
During respiration, cells break down simple food molecules such as sugar and release the energy they contain.

11. Photosynthesis and Respiration
You can think of photosynthesis and respiration as opposite processes.

12. Fermentation Energy-releasing process that DOES NOT require oxygen
Energy released is much less than during cell. resp.
Happens in environments that lack oxygen

13. Alcoholic Fermentation
d) Alcoholic Fermentation
- Happens in yeast and single-celled organisms
- Releases alcohol
- Also releases carbon dioxide and energy
- Used to make bread and beer

15. Lactic Acid Fermentation
-Happens in your muscles
-Produces lactic acid
-Makes your muscles sore
-Happens when muscle cells use up oxygen faster than it can be replaced