Photosynthesis and respiration are opposing but complementary processes. Photosynthesis uses sunlight, carbon dioxide, and water to produce glucose and oxygen through chlorophyll in plant cells. Respiration uses glucose and oxygen to produce carbon dioxide, water, and energy in the form of ATP in both plant and animal cells through mitochondria. Together these processes sustain life on Earth.

1. Photosynthesis and Respiration
Overview

2. Photosynthesis
 Certain cells can
generate their own
food (autotrophic)
 Specialized plant cells,
some bacteria, and
some protists.
 Chlorophyll (chemical)
 Chloroplast
(organelle)

4. Photosynthesis (cont.)
 Chlorophyll is responsible for capturing light
energy so that a cell can generate food for
itself.
 Glucose is the “plant food” that is produced.

6. Process of Photosynthesis
Reactants Products
1. Carbon Dioxide 1. Glucose
2. Water 2. Oxygen
3. Sunlight

7. Heterotrophic vs. Autotrophic
 Cellsthat don’t have chlorophyll, cannot
make their own food (heterotrophic).
 Heterotrophs and autotrophs are dependent
on each other. How?

8. Respiration
 Both heterotrophic
and autotrophic
organisms
 Plants and Animals
 Mitochondria
 Use of oxygen and
carbohydrates to
create energy (ATP)

9. Process of Respiration
Reactants Products
1. Glucose 1. Carbon Dioxide
2. Oxygen 2. Water
3. ATP (energy)
Glucose + Oxygen 
Carbon Dioxide + Water + ATP (energy)

10. Contrast Photosynthesis/Respiration
 Photosynthesis: (chloroplast- plants only)
6CO2 + 6H2O + light  C6H12O6 + 6O2
 Respiration: (mitochondria- plants/animals)
C6H12O6 + O2  6CO2 + 6H2O + ATP