1. Autotrophs – make their own food
Plants and some other types of organisms are able to use light energy from the sun to produce their own food.
Autotrophs – make their own food
Heterotrophs – obtain energy from the foods they consume or absorb.
All organisms must release the energy in sugars and other compounds.
Address misconceptions:
Ask: Do cells “think” about the life processes they carry out?
Cells have no thoughts. Often speak of how a cells “uses” energy or of how a cell can “add” a phosphate group, these words should not suggest that cells decide when or how to act.

2. Adenine Ribose 3 Phosphate groups
ATP
Ribose
3 Phosphate groups
Energy comes in many forms, including light, heat, and electricity.
Energy can be stored in chemical compounds.
ATP is one of the principle compound that organisms use to store and release energy.

3. ADP ATP Energy Energy Adenosine triphosphate (ATP) Fully Partially
Section 8-1
Energy
Energy
Adenosine diphosphate (ADP) + Phosphate
Adenosine triphosphate (ATP)
Partially
charged
battery
Fully
charged
battery
ADP looks almost like ATP, except it has 2 phosphate groups instead of 3.
This difference is the key to the way in which living things store energy. When a cell has energy available, it can store small amounts of it by adding a phosphate group to ADP molecules, producing ATP.
ATP is like a fully charged battery, ready to power the machinery of the cell.
What happens when a phosphate groups is removed from ATP?
Energy that is stored in ATP is released by breaking the chemical bond between the second and third phosphates. Energy is released.

4. ADP ATP Energy Energy Adenosine triphosphate (ATP) Fully Partially
Section 8-1
Energy
Energy
Adenosine diphosphate (ADP) + Phosphate
Adenosine triphosphate (ATP)
Partially
charged
battery
Fully
charged
battery
ADP looks almost like ATP, except it has 2 phosphate groups instead of 3.
This difference is the key to the way in which living things store energy. When a cell has energy available, it can store small amounts of it by adding a phosphate group to ADP molecules, producing ATP.
ATP is like a fully charged battery, ready to power the machinery of the cell.
What happens when a phosphate groups is removed from ATP?
Energy that is stored in ATP is released by breaking the chemical bond between the second and third phosphates. Energy is released.

5. If ATP is such a useful source of energy, why do most cells have only enough ATP to last them for a few seconds of activity?
ATP is a great molecule for transferring energy; it is not a good molecule for storing large amounts of energy over the long term.
A single molecule of glucose stores more than 90 times the chemical energy of a molecule of ATP.
It is more efficient for cells to keep only a small supply of ATP on hand.
Cells regenerate ATP from ADP as needed by using the energy in glucose.

6. Light and Pigments
In addition to water and carbon dioxide, photosynthesis requires light and chlorophyll, a molecule in chloroplasts.
Sunlight is a mixture of different wavelengths of light.
Plants gather the sun’s energy with light-absorbing molecules called pigments.
Chlorophyll is the plants’ principle pigment (chlorophyll a and chlorophyll b).
Chlorophyll absorbs light in the blue-violet and red regions of the visible spectrum. Green light is reflected by leaves.
When chlorophyll absorbs light, the energy from the sun is transferred to the electrons of the chlorophyll molecule.

7. Chlorophyll a and Chlorophyll b
Figure 8-5 Chlorophyll Light Absorption
Section 8-2
Absorption of Light by
Chlorophyll a and Chlorophyll b
Chlorophyll b
Chlorophyll a V B G Y O R

8. Photosynthesis: Reactants and Products
Section 8-2
Light Energy
Chloroplast
CO2 + H2O
Sugars + O2

11. Figure 8-7 Photosynthesis: An Overview
Section 8-3
Chloroplast
H2O O2
Sugars
CO2
Light
Chloroplast
NADP+
ADP + P
Light-
Dependent
Reactions
Calvin
Cycle
ATP
NADPH

12. Light-Dependent Reactions
Figure 8-10 Light-Dependent Reactions
Light-Dependent Reactions
Section 8-3
Hydrogen
Ion Movement
Photosystem II
Chloroplast
ATP synthase
Inner
Thylakoid
Space
Thylakoid
Membrane
Stroma
Electron
Transport Chain
Photosystem I
ATP Formation

13. Calvin Cycle Figure 8-11 Calvin Cycle Section 8-3 CO2 Enters the Cycle
Energy Input
ChloropIast
5-Carbon
Molecules
Regenerated
6-Carbon Sugar
Produced
Sugars and other compounds

14. Factors that affect the rate of photosynthesis:
Availability of water
Light intensity
Temperature

15. Concept Map Photosynthesis CO2 H2O Light- dependent reactions
Section 8-3
Photosynthesis
includes
Light-
dependent
reactions
Calvin cycle
CO2
H2O
takes place in
uses
use
take place in
Thylakoid
membranes
Stroma
NADPH
ATP
Energy from
sunlight
to produce of
to produce
ATP
NADPH O2
Chloroplasts
High-energy
sugars