1. Photosynthesis & Cellular Respiration
Seventh Grade Science

2. What is Photosynthesis?
Photosynthesis is an endothermic reaction wherein energy is absorbed from the sun and utilized to convert carbon dioxide (CO2 ) and water (H2O) into glucose (C6H12O6) and oxygen (O2).
6 CO H2O → 6 C6H12O O2
The energy stored in the glucose molecules is ready to be used when needed.

3. Vocabulary
Photosynthesis- A process by which plants convert sunlight, water, and carbon dioxide into food energy (sugar), oxygen and water.
Chloroplast- An elongated cell organelle containing chlorophyll where photosynthesis takes place.
Chlorophyll- A green molecule which uses light energy from sunlight to change water and carbon dioxide gas into sugar and oxygen

4. The chlorophyll absorbs the sunlight.
Chlorophyll is the green pigment inside the chloroplasts of plant cells that makes leaves green

5. Chlorophyll then uses sunlight to change water, carbon dioxide and, nutrients from the soil.
CO2

6. What is Cellular Respiration?
Cellular respiration is the reverse reaction of photosynthesis: the combustion of glucose to form carbon dioxide and water
Cellular respiration is an exothermic reaction.
6 C6H12O O2 → 6 CO H2O

7. Vocabulary
Respiration- The process by which the chemical energy of "food" molecules is released and changed into ATP. (chemical energy cells use)
Mitochondria- Rod-shaped organelles (small part of a cell with a specific function) with a double membrane which converts the energy stored in glucose into ATP (energy) for the cell.

8. Plants and Animals Rely on Each Other
Animals use:
Sugar (from producers/plants)
Oxygen (from producers/plants)
Plants use:
Carbon dioxide (from animals)

9. Examining the Reactants and Products
Photosynthesis Reactants: 6 CO2 + 6 H2O Products: 6 C6H12O6 + 6 O2
Cellular Respiration Reactants: 6 C6H12O6 + 6 O2 Products: 6 CO2 + 6 H2O

10. Comparing & Contrasting
Photosynthesis and cellular respiration have the exact same components in the chemical equation
The reactants of photosynthesis are the same as the products of cellular respiration
The products of photosynthesis are the same as the reactants of cellular respiration

11. Quick Quiz
What is meant by “reverse reaction” when discussing photosynthesis and cellular respiration?
How do the reactants and products of photosynthesis and cellular respiration compare?
What is the formula for glucose?