1. An Overview of Photosynthesis

2. Photosynthesis is the process by which plants and other producers transform solar energy into the chemical energy of glucose. Photosynthesis is…. Slide # 2 What is in these bubble? O 2 gas

3. 1.H 2 0 enters a plant through its _______ Photosynthesis Slide # 3 2. CO 2 enters a plant through its _______ 3. H 2 O exits a plant through its _______ 4. O 2 exits a plant through its _______ roots leaves 5. C 6 H 12 O 6 is produced by a plant in its _______ leaves

4. Photosynthesis Equation In photosynthesis, energy is stored in the bonds of glucose (C 6 H 12 O 6 ) 6 CO 2 + 6 H 2 O + Light energy C 6 H 12 O 6 + 6 O 2 Chlorophyll Enzymes Enters through leaf Enters through roots Made in leaf Exits through leaf REACTANTSPRODUCTS

5. Go to Section: Photosynthesis Vocabulary 1. Chloroplast: organelle of photosynthesis 2. Chlorophyll: green pigment molecule; absorbs light 3. Pigment: colored chemical compound; absorbs light Slide #5 Photosynthesis occurs in plants and algae

6. Slide # 6 Go to Section: Chloroplast Vocabulary 1. Thylakoid: saclike structure a.contains chlorophyll b.absorbs light 2. Granum: stack of thylakoids 3. Stroma: fluid filled space outside thylakoids

7. Absorption of Light by Chlorophyll a and Chlorophyll b V B G YO R Chlorophyll b Chlorophyll a Slide #6 Go to Section: Light Absorption by Chlorophyll 1. Chlorophyll BEST absorbs red & blue light 2. Plants appear green because they reflect green light 3. Plants grown in green light don’t grow very well

8. Photosynthesis Occurs in Leaves 1.The main photosynthetic organ for MOST plants is the leaf 2.Have broad, flat surface that increases surface area for light absorption Photosynthesis occurs in the STEM of a cactus Slide #7

9. Factors that Affect the Rate of Photosynthesis 1.Light intensity: The stronger the light intensity, the greater the rate of photosynthesis – to a certain point. 2.Temperature: The rate of photosynthesis is optimal at ~ 30°C. The rate is lower at lower and higher temperatures. Slide # 9 Why does photosynthesis drop off at temperatures above 40°C? Enzymes that control photosynthesis begin to lose their shape and cannot function!

10. 1. Animals INDIRECTLY obtain energy from sun a. Animals get food from plants b. Animals get O 2 from plants c. Plants remove CO 2 from atmosphere 2. Plants & algae benefit DIRECTLY by obtaining energy to create food Slide # 12 Go to Section: Benefits of Photosynthesis

11. 1. Carbon, oxygen, and hydrogen atoms are recycled in the environment. 2. A constant input of solar energy is needed for energy to continue flowing to support life. Elements are Cycled Through the Environment Slide # 13 Photosynthesis and Respiration are very important in the carbon cycle (carbon is recycled in the environment)

12. TAKS PRACTICE The picture shows the results of a demonstration using the simple water plant Elodea. When the setup was placed in strong light, a space gradually appeared above the water in the graduated cylinder containing the plant. The gas in the space above the water was mostly — A oxygen B carbon dioxide C hydrogen D nitrogen What gas is given off during photosynthesis? O2O2 Correct answer: A 11 th Grade 2005 TAKS EXIT TEST