1. Photosynthesis & Respiration

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

3. What is the equation for the chemical reaction of photosynthesis?

4. What is the equation for the chemical reaction of photosynthesis?
Sunlight
Six molecules of carbon dioxide react with six molecules of water to form 1 molecule of glucose and six molecules of oxygen.

5. Describe Photosynthesis
The process of changing light energy to chemical energy
Energy stored as sugar
Occurs in plants and some algae
Plants need light energy, CO2, and H2O
Takes place in the chloroplasts, using chlorophyll, the green pigment in plants

6. What happens during photosynthesis?
Plants capture light energy and use that energy to make glucose
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. What happens during photosynthesis?
Carbon dioxide enters the leaf through holes called stomata
CO2 combines with the stored energy in the chloroplasts through a chemical reaction to make glucose
The sugar is moved through tubes in the leaf to the roots, stems and fruits of the plants
Some of the sugar is used right away by the plant for energy; some is stored as starch; and some is built into plant tissue

8. Why is this important to us?
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.

9. Plants Autotrophs – produce their own food (glucose)
Process called photosynthesis
Mainly occurs in the leaves:
a. stoma - pores
b. mesophyll cells
Mesophyll
Cell
Chloroplast
Stoma

10. Chloroplast STROMA– where Calvin Cycle occurs Outer Membrane Thylakoid
Granum
Inner Membrane

11. Grana make up the inner membrane
Thylakoid
Thylakoid Membrane
Granum
Thylakoid Space
Grana make up the inner membrane

12. Chloroplasts
Chlorophyll molecules are embedded in the thylakoid membrane
Act like a light “antenna”
These molecules can absorb sunlight energy.
Image from Biology 11: College Preparation. Pg 73. Nelson, Toronto

13. Light (dependent)Reactions
Happen ONLY in sunlight
Hence they depend on light!
Light is absorbed by chlorophyll molecules
The energy generates molecules of ATP
Image from: Biology 11: College Preparation. Pg 74. Nelson, Toronto

14. Light Independent Reactions (formerly the “dark reactions”)
Happen in sunlight, and in the dark.
Hence “independent of light”
ATP generated by sunlight drives the Calvin Cycle.
Monosaccarides (eg. glucose) are manufactured in the cycle.
Monosaccarides are used to “build” polysaccharides (eg. Starch).
Image from: Biology 11: College Preparation. Pg 74. Nelson, Toronto

15. What is Cellular Respiration?
The release of chemical energy for use by cells.

16. What is Cellular Respiration?
Once the energy that was in sunlight is changed into chemical energy by photosynthesis, an organism has to transform the chemical energy into a form of energy that can be used by the organism.
This process is cellular respiration.

17. Describe Cellular Respiration
The breakdown of glucose and other food molecules in the presence of oxygen to release energy

18. What is the chemical equation for cellular respiration?
and energy