1. It’s Not Easy Being Green! (Photosynthesis – Part 2)

2. Stages of Photosynthesis
Stage Energy is captured from sun.
Leaves contain light absorbing substances called pigments
Pigments absorb certain wavelengths of light and reflect others (Color Brain POP)

3. Chlorophyll: the primary pigment involved in photosynthesis
Absorbs blue & red light
Reflects green & yellow light (causes plants to look green)
Carotenoids: pigments that produce red, orange, & yellow colors (fall leaves, fruits, flowers, etc.)
Both types of pigments are needed for photosynthesis they absorb different wavelengths of light

4. Impact of Pigments on Light Absorption
Purple Blue Green Yellow LightOrangeDarker

5. Clusters of pigments are embedded inside the chloroplasts (specifically, in the thylakoids)
Thylakoids: membrane-bound compartments found inside chloroplasts
Light strikes the thylakoids inside the chloroplasts & energy is transferred to the chlorophyll.
Water molecules are split to form oxygen gas (O2).

6. Thylakoid

7. Stage 2 -- Light energy is converted to chemical energy.
Excited electrons jump to nearby molecules in the thylakoid membrane
Then the electron is passed down a series of molecules along the thylakoid membrane (electron transport chain- ETC)
ETC provides the energy needed to make ATP

8. All organisms produce ATP by releasing energy stored in glucose and other sugars.
Adenosine-triphosphate (ATP)- it’s chemical energy

9. Stage 3 -- Energy is stored in organic compounds (sugars).
Carbon dioxide fixation: the transfer of CO2 from atmosphere to organic compounds
Calvin cycle: a series of enzyme-assisted chemical reactions that produces a 3-carbon sugar (uses energy from ATP)
3 CO2 molecules enter the cycle & produce a 3-carbon sugar
These sugars provide organisms energy to maintain life

10. 3CO2
3 Carbon Sugar

11. ATP is short for "adenosine triphospate“- store energy (charged battery)
When you take off one P, you get adenosine diphosphate or ADP (which is an A and 2 P's) plus an extra P. You also release a bunch of energy that can be used by the cell to do work. So an ADP is like a battery that has lost some of its charge.
NADPH has a captured electron, thus holding energy in the bond.
NADP+ has no captured electron, thus not holding the high energy.
-They are electron carriers

12. Photosynthesis increases as light intensity increases
Photosynthesis increases as the concentration of CO2 increases
Water must be available for photosynthesis to occur
Photosynthesis is most efficient within a certain temp range (enzymes)