1. Photosynthesis and Cellular Respiration1

2. What you already know… Plants use CO2 and produce O2
Animals use O2 and produce CO2
This is a process that recycles materials so we can continue to use them and life can continue
What are these processes called?
What exactly is used in the processes? 2

3. The Processes Plants use PHOTOSYNTHESIS
Animals use CELLULAR RESPIRATION
But the cycling of CO2 and O2 are just part of the picture…. 3

4. Photosynthesis This is the GENERAL IDEA
What do plants take in in this picture?
What do they give off?
What else do you think they produce? 4

5. Let’s Break it Down Photo means light and synthesis means put together
The plant is taking in sunlight, water, and carbon dioxide
It is giving of oxygen
And it is also making sugar ---as far as the plant is concerned, this is the most important part!
Carbon dioxide + water + sunlight = sugar + oxygen 5

6. Photosynthesis in words and symbols
Carbon dioxide + water + sunlight = sugar + oxygen
This is the same thing as:
CO2 + H2O + sunlight = C6H12O6 + O2
What are the REACTANTS?
What are the PRODUCTS? 6

7. So how is the plant set up to do photosynthesis?
Plant leaves are set up so they can perform the functions of photosynthesis
Do you remember seeing some of these structures under the microscope? 7

8. Leaf Structure
The leaf is the organ which plants use to make food by photosynthesis
The epidermis protects the leaf and is transparent to let light through.
Palisade mesophyll cells are tall and closely packed to absorb maximum light. They contain many chloroplasts. Most photosynthesis takes place in the palisade cells. 8

9. Leaf structure continued
Spongy mesophyll also captures light and makes food. Spongy mesophyll cells have air spaces between them to allow easy gas exchange.
Veins are designed to transport water and nutrients
Stomata (underside of the leaf) allow gas exchange; since a lot of water vapor can be lost through the stomata they only open for photosynthesis in daylight; at night they close to reduce loss of water vapor. 9

10. Can you name the structures now?
More importantly, can you tell why they are important to photosynthesis? 10

11. Now that you know about photosynthesis…
What’s the other half of the cycle?
Cellular respiration! 11

12. Cellular Respiration
Is the opposite of photosynthesis (at least when we are talking about the “Big Picture”
So take the formula for photosynthesis: Carbon dioxide + water + sunlight (ENERGY) = sugar + oxygen
And flip it around….
So sugar + oxygen = carbon dioxide + water + ENERGY 12

13. Cellular Respiration vs. Photosynthesis
In cellular respiration ENERGY is released when C6H12O6 is broken down
In phototosyntheis ENERGY is captured from the sun and used to produce C6H12O6 13

14. THINK! In which organelles do you think these processes occur?
Given what you know about these organelles, can plants do cellular respiration?
Can animals do photosynthesis? 14