1. Energy in Living Systems
CH 6 pg

2. Organisms classified on how they obtain energy
Autotrophs
Make their own food from organic molecules
Most convert light energy into chemical energy
Carbon Dioxide (CO2) and water (H2O) to organic compound
Oxygen (O2) released
Heterotrophs
Cannot make their own food inorganic compounds
Eat autotrophs or other heterotrophs

3. Photosynthesis

4. Harvesting Light Energy
Photosynthetic organisms have chloroplasts
Chloroplasts are the organelles that convert light energy into chemical energy.
Contains flat, disc-like sacs called thylakoids.
this is the first stage of photosynthesis.

5. Thylakoids

6. Light Absorption in Chloroplast
Sunlight composed of ROY G BIV, different colors. (Lgth = Amt of Engy)
Color observed when light strikes an object, waves are reflected, transmitted, or absorbed
Colors react depending on the pigment present

7. Harvesting Light Energy, continued
Chlorophyll (a and b)
Absorbs blue and red light and reflects green and yellow light
Carotenoids
help plants absorb additional light energy
absorb blue and green light, reflect red, orange and yellow(fall colors)

8. Two Electron Transport Chains
First reaction in photosynthesis is the light reaction takes place in the chlorophyll
Light hits a thylakoid
Energy is absorbed by the pigment molecules and are directed to a special chlorophyll molecule that acts as a reaction center
Electrons are excited and move to other molecules and the electron transport chain.
One ETC makes ATP and Second makes NADPH

9. Understanding Terms Photosystem II (ETC #1) Photosystem I (ETC#2)
Products: Electron, Oxygen (pg 117) ATP (pg 118)
Photosystem I (ETC#2)
Products: NADPH
Light Reaction (Electron Transport Chains) create energy molecules for the Calvin Cycle

10. 1st Electron Transport Chain
Producing ATP
Step 1:
An enzyme splits water molecules , e- is released.
H+ ions stay within the thylakoid
e- is charged by pigment
Oxygen gas is released into the atmosphere

11. Step 2:
Carrier Proteins (ATP Synthase) in the membrane pump H+ ions into the thylakoid,

12. Step 3:
Energy diffusion of H+ ions through ATP synthase is used to make ATP

13. 2nd Electron Transport Chain
Step 4: Producing NADPH
Renergizing, Light excites electrons that are passed on to the second chain.

14. Step 5: Making NADPH
Excited electrons combine with H+ ions and NADP+ to form NADPH.
NADPH is used to store energy in organic molecules. (used later in dark reaction)

15. Electron Transport Chains of Photosynthesis
Click to animate the image.

16. Producing Sugar
The first two stages of photosynthesis depend directly on light to make ATP and NADPH.
In the final stage of photosynthesis, ATP and NADPH are used to produce energy-storing sugar molecules from the carbon in carbon dioxide.
The use of carbon dioxide to make organic compounds is called carbon dioxide fixation, or carbon fixation. (Light Independent, Dark Reaction, or Calvin Cycle)

18. Calvin Cycle Takes place outside of the Thylakoid in the stroma
solution surrounding the thylakoid
Carbon Fixation, CO2 is being used to make G3P
Enzyme Rubisco adds CO2 to RuBP to create G3P which is later used to make a sugar (Glucose or C6H1206)

20. What is happening in the Calvin Cycle? This is what you need to know
Part 1 Carbon Fixation
Carbon dioxide (from the atmosphere) diffuses into the plant cell and enters the stroma of the chloroplast
Rubisco (an enzyme) attaches CO2 to RuBP  as a result of this chemical reaction is now known as molecule PGA.
Write Rubisco on illustration by carbon fixation

22. PGA uses the energy molecules (ATP, NADPH) to create G3P
Part 2 Reduction
PGA uses the energy molecules (ATP, NADPH) to create G3P
ETC #1 and #2 (light reaction) create ATP and NADPH
Energy is released from the hydrogen and phosphate bonds to drive a reaction creating G3P
NADP and ADP are then recycled in the stroma to be used again in the ETC

24. Rengeneration of Ribulose (RuBP) Step 3
Some of the G3P molecules are then used to make glucose
Transported out of the chloroplast
Step 4
Other G3P molecules are recycled into making RuBP
In order to continue the Calvin Cycle

25. Factors that Affect Photosynthesis
Light intensity (ATP and NADPH)
Carbon dioxide concentration
Temperature (function of enzymes)

27. Relationship