1. PHOTOSYNTHESIS

2. Autotrophs
Are organisms that are able to synthesize their own food from inorganic substances using sunlight for energy.

3. Heterotrophs
Heterotrophs are organisms that can NOT make their own food
They NEED the autotrophs as a source of “organic macromolecules that contain energy” AKA Food!
Heterotrophs can NOT directly use the sun’s energy

4. What is Photosynthesis?
An anabolic, endergonic, carbon dioxide (CO2)-requiring process that uses light energy and water (H2O) to produce organic macromolecules (e.g. Glucose and starch).
6CO2 + 6H2O  C6H12O6 + 6O2
Sunlight

5. Where in plants does photosynthesis occur?
Photosynthesis takes place in any cell of a plant that is green (mostly the cells in the leaves)

6. Structure of a Leaf Cell
Chloroplast
[The green part]

7. The Chloroplast
The structure within a cell (organelle) where photosynthesis takes place.
Thylakoids: Disk shaped membranes containing photosynthetic pigments. Site of light dependent reactions.
Grana: Stacks of thylakoids.
Stroma: Fluid filled space surrounding grana. Site of light independent reactions.

8. Pigments
In addition to water, carbon dioxide, and light energy, photosynthesis requires Pigment molecules.
Chlorophyll is the primary light-absorbing pigment in autotrophs.
Chlorophyll is found inside the thylakoids [inside the chloroplast].

9. Light & Pigments
Photons of light “excite” electrons in the plant’s pigments
Excited electrons carry the absorbed energy.
Other molecular machinery use the electrons to make ATP

10. Photosynthesis Reactions
Two main parts (reactions)
Light Reaction or Light Dependent Reaction produces energy from sunlight to form ATP & NADPH
Dark Reaction or Light Independent Reaction uses ATP and NADPH to convert CO2 into Glucose

11. Light Reaction
Occurs in the Thylakoid membranes
The light reaction uses light energy to split water into O2, H+, and e-
O2 is released and the H+ and e- is used to produce ATP and NADPH.

12. Lets give Hydrogen a break!
Hydrogen is the smallest atom.
It consists of a single proton [+] and a single electron [-].
In photosynthesis the H+ is carried by NADP and the electrons energy goes to make ATP

13. Light Dependent Reaction

14. Dark Reaction Calvin Cycle or Light Independent Reaction
Uses energy (ATP and NADPH) from light reaction to make glucose

15. Photosynthesis Overview

16. Matter cycles as energy is transformedP
Glucose
ATP
LIGHT
ENERGY
CHEMICAL
ENERGY
ENERGY
FOR CELLULAR
WORK P
Carbon dioxide
ADP P +

17. Trace how the energy is transformed
Photosynthesis
Cellular respiration P
Glucose
ATP
LIGHT
ENERGY
CHEMICAL
ENERGY P
Carbon dioxide
Light
energy
Energy stored
in glucose
Energy stored
in ATP
Photosynthesis
Cellular respiration