1. KEY CONCEPT The overall process of photosynthesis produces sugars that store chemical energy.

2. Let’s talk Producers………….HCA Biology, Take One!!!!
You thought this was Biology, not film class!
What do producers do in film, radio, television, and music recording?
They OVERSEE the production of something that they do NOT actually make!

3. HCA Biology, Take Two!!!!
Okay, now we’re talking Science again!
What is a producer in the field of Science?
How is a producer in this field similar to the entertainment field?
Plants do not make energy, they capture it, store it and deliver it!

4. The energy for almost ALL organisms begins as sunlight!
Sunlight radiates several types of energy:
Ultraviolet
Microwaves
Visible light (what we see)
Plants absorb visible light
appears white to human eye, but contains several wavelengths of light

5. Photosynthetic organisms are producers.
Producers make their own source of chemical energy by capturing visible light.
Plants use photosynthesis and are producers.
Photosynthesis is a process that captures energy from sunlight to make sugars.

6. Chlorophyll is a molecule that absorbs light energy.
chloroplast
leaf cell
leaf
In plants, chlorophyll is found in organelles called chloroplasts.
Two types of chlorophyll:
Chlorophyll a
Chlorophyll b
They absorb mostly red and
blue wavelengths of visible light.
They absorb little green.
The green color of plants comes
from the reflection of green
wavelengths by chlorophyll.

7. Apply Question
Describe the importance of producers and photosynthesis.
Photosynthesis enables producers to capture energy from sunlight to make sugars and store chemical energy.
The food produced by producers (plants) becomes a source of energy for nonproducers.

8. Photosynthesis in plants occurs in chloroplasts.
Chloroplasts are membrane-bound organelles
They are found in leaf cells specialized for photosynthesis.
Photosynthesis takes place in two parts of chloroplasts.
Grana (thylakoids)
Coin shaped, membrane enclosed compartments
Stroma
Fluid that surrounds the grana inside the chloroplast
chloroplast
stroma
grana (thylakoids)

9. STAGE ONE: The light-dependent reactions capture energy from sunlight.
take place in thylakoids
water and sunlight are needed
chlorophyll absorbs energy
energy is transferred along thylakoid membrane
Water molecules are broken down
oxygen molecules are released
Energy carried by thylakoid membrane is transferred to ATP molecules (carry energy)
then to light-independent reactions

10. STAGE TWO: The light-independent reactions use energy from light-dependent reactions to make sugars (carbohydrates).
take place in stroma
needs carbon dioxide from atmosphere
use energy to build a larger molecules of sugar in a cycle of chemical reactions
A molecule of simple sugar is formed, usually glucose
Glucose stores some of the energy, and is used to build starches and cellulose (makes up cell wall)

11. The equation for the overall process is:
6CO2 + 6H2O  C6H12O6 + 6O2
C6H12O6
granum (stack of thylakoids)
thylakoid
sunlight
1 six-carbon sugar
6H2O
6CO2
6O2
chloroplast 1 2 4 3
energy
stroma (fluid outside the thylakoids)
What are the reactants?
What are the products?

12. Summarize: How is energy from sunlight used to make sugar molecules?
Energy from sunlight is absorbed to generate energy-carrying molecules.
Energy-carrying molecules are transferred to the reactions that make sugars.
Summarize: Is photosynthesis endothermic or exothermic?
Endothermic – it absorbs energy to produce sugars