1. Photosynthesis Objectives: Describe the structure of a chloroplast
Explain who ATP releases energy
Explain the steps to photosynthesis

2. Energy
Energy is stored in chemical bonds and released at a later date.
Cellular energy is stored by ATP
Adenosine Triphosphate
Contains 2 high energy phosphate bonds
Also contains nitrogen base adenine and a ribose sugar

3. ADP Adenosine diphosphate What is formed when ATP loses 1 phosphate
ATP releases energy and a free phosphate. This forms ADP
When ATP turns to ADP….energy is released
Energy is used to make ATP again

4. Importance of ATP Main compound used to store energy in living things
Provides all of the energy for cell activities
Adding a phosphate group to ADP stores energy
Removing a phosphate group from ATP releases energy and makes ADP

5. Pigments and Chloroplasts
Chlorophyll—primary light-absorbing pigment in autotrophs
Found inside chloroplasts
Chlorophyll a
Found in all plants
Participates directly in light reactions
Chlorophyll b
Accessory pigment
Indirectly works in photosynthesis
Both a and b absorb red and blue light

6. Structure of a Chloroplast

7. Structure of a Chloroplast
Smooth outer membrane
Inside: stacks of connected sacs called thylakoids
One thylakoid stack—granum (grana plural)
Gel-like material around the grana--stroma

8. Function of Stroma Light independent reaction ATP makes glucose
Calvin cycle

10. Function of Thylakoid Membrane
Light dependent reaction
Made up of chlorophyll molecules

11. Photosynthesis Equation

12. Photosynthesis Overview

13. Light Dependent Reactions
Occurs across the thylakoid membranes
Uses light energy
Produces oxygen from water
Converts ADP to ATP
Converts NADP+ to energy carrier NADPH

15. Steps of the Light Dependent Reaction
Photosystem II absorbs light energy
Electrons are energized and passed to the Electron Transport Chain (ETC)
Lost electrons are replaced from the splitting of water into 2 H+ , free electrons and oxygen
2 H+ pumped across the thylakoid membrane

16. More..
High energy electrons move to photosystem I through the electron transport chain
Energy is used to transport H+ from stroma to inner thylakoid membrane
NADP picks up 2 electrons from the ETC and a H+ to form NADPH
As H+ ions pass through the thylakoid, ATP synthase binds them to ADP to form ATP

17. Summary Reactants: Products Water, light
ATP, NADPH—energy for dark reaction
Oxygen—by product for cellular respiration

18. Light Independent Reaction
ATP and NADPH from light reaction are used for energy of this reaction
CO2 from the atmosphere is used to make sugars (glucose)
Six carbon sugars made in calvin cycle
Occurs in stroma

20. The Calvin Cycle
Two turns of the Calvin Cycle are required to make one molecule of glucose
3-carbon dioxide molecules enter the Calvin Cycle to form PGA
Two molecules of PGA form 1 molecule of glucose

21. DONE!