1. Photosynthesis and ATP
2-9

2. Where does the mass come from??

3. 1653 – Jan van Helmont
Planted seed, 5 years later there was a small tree weighing 75grams. Soil mass was unchanged. Concluded it must all be water weight. This was partially true. He had the “hydrate” but from where did the “carbo” come from?
CO2 in air made a major contribution to the mass of his tree. C in CO2
is used to make sugars and
other carbs in photosynthesis.

4. 1771 Joseph Priestly
Took candle and placed glass jar over it. Flame died. Concluded something in air was necessary to keep flame going. This was/is oxygen.
He then placed a small plant in
the jar, waited several days, the candle could then remain lit for much longer. Conclusion  plants must release oxygen!

5. 1779 Jan Ingenhousz
Took Priestly’s experiment one step further. He showed that aquatic plants produce bubbles in light.

6. Photosynthesis…
PROCESS by which plants, some bacteria, and some protists us energy from sun to convert water and carbon dioxide into high energy carbohydrates (sugarsstarches) and oxygen, the waste product.

8. …which contains chlorophyll
occurs in the chloroplast
STROMA
Thylakoid
disc
grana
…which contains chlorophyll

9. Photosynthesis is a 2 Stage Process
Light reactions (light dependent) Takes place in the thylakoid membranes
-Produces high energy electrons, ATP, and oxygen…which it then releases
Dark reactions (light independent)
Take place in the stroma (region outside thylakoid membrane)
Makes high energy sugars via CO2 from the atmosphere

10. Photosynthesis Equation
6CO2 + 6H2O  C6H12O6 + 6O2
Plants obtain CO2 from air or water in which they grow. Plants then use the sugars to produce complex carbohydrates  starches.
What’s missing from the equation above??? ADD IT!

12. Photosynthesis requires chlorophyll, a molecule in chloroplasts.
Light is a form of energy, so when you absorb light, you absorb energy.
Chlorophyll absorbs light (energy) and makes photosynthesis work.
Plants are green because green light is reflected by chlorophyll in the leaves.

13. Remember… Plants are autotrophs because they make their own food.
Organisms that cannot make their own food are known as heterotrophs.

14. Chemosynthesis … process by which some organisms, such as bacteria, use chemical energy to produce sugar

15. Adenosine Triphosphate (ATP)
Composed of adenine, a 5 carbon sugar (ribose), and 3 phosphate groups

16. Adenosine Triphosphate (ATP)
… a chemical compound that cells use to store and release the energy.
The phosphate groups are key to storing and releasing energy.

17. Adenosine DIphosphate (ADP)
…is similar to ATP but has one less phosphate group. Cells store energy by adding another phosphate. Energy is stored in the bond connecting the 2nd and 3rd
phosphate
groups.

18. ADP to ATP
Energy is released by breaking the bond between the 2nd and 3rd phosphate.

19. Think of it this way…
ATP – fully charged battery
ADP – uncharged
(without available energy)

20. How is ATP used? Cells use energy via ATP for - active transport
- organelle movement
- protein synthesis
Cool fact: Light from
a firefly is from an
enzyme powered by
ATP.