Photosynthesis and respiration are chemical reactions that are inversely related. Photosynthesis uses sunlight, carbon dioxide, and water to produce glucose and oxygen through chloroplasts in plants. The glucose is stored as a carbohydrate or changed to starch. Respiration takes place in mitochondria and uses glucose and oxygen to produce energy, carbon dioxide, and water. Both can be represented by balanced chemical equations that are the reverse of each other.

1. Photosynthesis
and
Respiration
How are they related?

2. Photosynthesis
The process of photosynthesis is a
chemical reaction.
It is the most important chemical
reaction on our planet.

3. What is the Process?
 The process of changing light energy (from
the sun or other light source) to chemical
energy
 This energy is stored as sugar (a
carbohydrate)
 Occurs in plants and some algae
 Plants need light energy,
CO2, and H2O
 Photosynthesis takes place
in the chloroplasts, using
chlorophyll, the green

4. What Happens in this
Chemical Reaction?

5. How Do Scientists Write
this Chemical Reaction?
 What does this mean?
 Six molecules of carbon dioxide react with six
molecules of water to form 1 molecule of glucose
and six molecules of oxygen.

6. HUH?
 Plants capture light energy and use that
energy to make sugar (which can be
changed to starch, a carbohydrate, also)
 Sunlight provides the energy needed by
chlorophyll to change molecules of carbon
dioxide and water into glucose
 Oxygen is also released in this reaction

7. Why Is This So
Important?
 We cannot make our own food (glucose,
energy), we must get our food from plants.
 Plants are the first step in the food chain.
 The oxygen released during photosynthesis
is necessary for all living things.

8. Respiration
 There are two types of respiration:
and

9. What is Cellular
Respiration?
The process of cellular respiration
is a chemical reaction.
 It is the most important
chemical reaction in our bodies

10. What is the Process?
 Cellular respiration is a process, like
photosynthesis.
 Cellular respiration takes place in the
mitochondria.
 The mitochondria take in nutrients (glucose and
oxygen), break them down, and create energy for
the cell.
 This process of creating cell energy is known as
cellular respiration.
 Takes place in all living things (even plants!)

11. Let’s Write the Chemical
Equation
Glucose + Oxygen Carbon Dioxide +
Water
Or another way of writing the equation is:
C6H12O6 + 6O2 6CO2 +
6H2O

12. Notice Any Similarities?


13. 
Notice any now?

14. Photosynthesis and
Respiration are Related
 It is the basic cycle on Earth.

15.  Some information from Science-class.net