1. Chemical Energy and ATP
Section 4-1
Chemical Energy and ATP

2. Organisms are classified according to their energy usage:
Autotrophs – make their own food.
Ex. Plants & algae

3. ATP is Adenosine Triphosphate
ATP is the energy molecule used by the cell.

4. Chemical Structure of ATP
Adenine- Nitrogen Base
3 Phosphates (tri = 3)
Ribose: 5-carbon Sugar

5. ADP Adenosine Diphosphate is ADP
ADP has the same structure as ATP, except it only has
2 phosphates.

6. ADP-ATP Cycle Diagram

7. ATP Facts
ATP is good to transfer energy in the cell, but not to store energy.
Cells depend on the sugar, glucose, for stored energy.
Cells then convert glucose into ATP as needed.

8. Photosynthesis Overview
Section 4-2
Photosynthesis Overview

9. Photosynthesis Defined
Plants use energy from sunlight to convert water and CO2 into glucose, releasing oxygen as a by-product.
The chemical equation of photosynthesis is:
Light
6CO2 + 6H2O → C6H12O6 + 6O2

10. Requirements of photosynthesis
Pigments are light absorbing compounds. Some are found in plant leaves and stems.
Chlorophyll is a pigment that absorbs light energy.
In plants, chlorophyll is found in organelles called chloroplasts.

11. Overview of Photosynthesis
Section 4-2
Overview of Photosynthesis

12. Photosynthesis takes place in the chloroplasts of the plant cell.
A chloroplast has two primary areas.
Grana are stacks of thylakoid membranes.
Stroma is the fluid surrounding the membranes.

13. Diagram of a chloroplast

14. Two Stages of Photosynthesis
Light-dependent reactions- need light and occur in the grana and thylakoid membranes of the chloroplast.
Light-independent reactions- does not need light and occurs in the stroma. (AKA – the Calvin Cycle)

15. Light Dependent Reactions
take place in thylakoids
water and sunlight are needed
chlorophyll absorbs energy
energy is transferred along thylakoid membrane then to light-independent reactions
oxygen is released

16. Electron Transport System

17. The END PRODUCTS of the light reactions
NADPH
ATP
Oxygen (released)

18. Light Independent Reactions
take place in stroma
needs carbon dioxide from atmosphere
use energy to build a sugar in a cycle of chemical reactions

19. Light and Dark reactions combined

20. The END PRODUCTS of the light independent reactions
Sugar (C6H12O6)