1. Photosynthesis

2. What are autotrophs?
Why are they important?

3. 
Energy for Life
AUTOTROPHS are organisms that can make their own food.
Also called PRODUCERS.
Ex. PLANTS, ALGAE

4. 
Energy for Life
HETEROTROPHS are organisms that depend on other organisms for food.
Also called
CONSUMERS.
Ex. ANIMALS,
BACTERIA

5. 
Energy for Life
TWO biological processes are needed to create usable energy for organisms.
Photosynthesis – the process that converts sunlight into sugar. (autotrophs only)
Respiration – process that releases energy in sugar into usable energy for cells. (autotrophs and heterotrophs)

6. ATP  Adenosine triphosphate (ATP) – energy storage molecule. Adenine
(nitrogen base)
Ribose
(sugar)
3 Phosphate groups

7. ATP  ATP is the universal currency for energy
ATP stores energy in the BONDS BETWEEN THE PHOSPHATE GROUPS.
When a BOND IS BROKEN energy is released.
ATP
(tri)
ADP
(di) +
phosphate
energy +

8. Structure of a Chloroplast
Structure of a Chloroplast
A chloroplast is the structure in a plant cell where photosynthesis occurs.
Internal Structure:
Thylakoid membrane – internal membrane, look like stacks of pancakes.
Lumen – space inside thylakoid membrane.
Grana – stacks of thylakoids.
Stroma – solution that thylakoids are embedded in.

9. Structure of a Chloroplast

10. Pigments  Pigments are light absorbing molecules.
Each pigment absorbs and reflects different wavelengths of light. (we see the reflected color)

11. Pigments  CHLOROPHYLL is the primary pigment in photosynthesis.
Gives plants their GREEN color.
CAROTENOIDS are accessory pigments that absorb light that chlorophyll cannot.
They are YELLOW, ORANGE, AND BROWN.

12. Checkpoint Why do leaves turn yellow, orange and brown in the fall?
Production of chlorophyll is slowed down in the fall due to lower temperatures and less sunlight!

13. Pigments

14. Photosynthesis  6 CO2 + 6 H2O + sunlight C6H12O6 + 6O2
Glucose
Carbon
Dioxide
Oxygen
Water 
6 CO2 + 6 H2O + sunlight C6H12O6 + 6O2
Photosynthesis song :)

15. 
Van Helmont
Measured plant mass and soil mass before and after 5 years of growth
Most of gain in mass came from water

16. Priestly Candle with a jar over it would die out
Required oxygen
Sprig of mint plus candle caused candle to last longer
Plant produced oxygen

17. Ingenhousz
Effect showed by Priestly occurred only in the presence of light

18. Photosynthesis
There are two stages to photosynthesis, the light-dependent reactions and light-independent (dark) reactions.

19. Light-dependent Reactions
Light-dependent Reactions
Occur in the THYLAKOID MEMBRANES.
Light is absorbed by chlorophyll in Photosystem II and electrons are excited.
The excited electrons move through a series of reactions – the electron transport chain.

20. Light-dependent Reactions

21. Light-dependent Reactions
The light energy splits water molecules into H and O2
The O2 is released into the atmosphere and the H bonds to a carrier molecule (NADPH) to be carried to the Dark Reactions.
Splitting the water also creates ATP.

22. 
Light Reactions
Sunlight, water, and CO2
Chloroplast
Light- dependent
Reactions
Chloroplast
Light
Reactions
ATP
ATP
ATP
NADPH
NADPH
NADPH O2
The end products of the light reactions are NADPH, ATP, and O2

23. Light-independent Reactions
Light-independent Reactions
Don’t Require LIGHT
Also called the DARK REACTIONS OR THE CALVIN CYCLE.
Occur in the STROMA
Melvin Calvin

24. Light-independent Reactions
Light-independent Reactions
Carbon dioxide enters the plant and attaches to a sugar molecule.
This is called carbon fixation
Carbon Dioxide, NADPH, and ATP combine with enzymes to make glucose (C6H12O6) and more CO2.

25. Dark Reactions  Light, water, and CO2 CO2 NADP+ Carbon Fixation
Chloroplast
Chloroplast
NADP+
Carbon Fixation
ADP + P
Light- dependent
Reactions
Light- independent
Reactions
NADPH+H
ATP
Glucose

26. Factors Affecting Photosynthesis
Factors Affecting Photosynthesis
Light Intensity – the more light the faster the rate of photosynthesis.
CO2 Concentration – the more CO2, the faster the rate of photosynthesis.
Temperature – rate of photosynthesis slows down at extremes of hot or cold.
Photosynthesis video