2. Energy Transfer (8.1)
State Standard
SB3A. Explain the cycling of energy through the processes of photosynthesis and respiration.

3. Transformation of Energy
Chapter 8
Cellular Energy
8.1 How Organisms Obtain Energy
Transformation of Energy
Energy is the ability to do work.
All organisms depend on the flow of energy.
The sun is the ultimate source of energy for almost all food chains.
Exception: Hydrothermal Vents deep in the ocean.

4. Autotrophs and Heterotrophs
Chapter 8
Cellular Energy
8.1 How Organisms Obtain Energy
Autotrophs and Heterotrophs
Autotrophs are organisms that make their own food. (They are the entry point for energy into the food chain.)
Heterotrophs are organisms that need to ingest food to obtain energy.

5. All of the chemical reactions in a cell
Chapter 8
Cellular Energy
8.1 How Organisms Obtain Energy
Metabolism
All of the chemical reactions in a cell
Photosynthesis—light energy from the Sun is converted to chemical energy (carboyhydrates) for use by the cell
Cellular respiration—organic molecules (mainly carbs) are broken down to release energy for use by the cell

6. Photosynthesis = Energy Storage
Chapter 8
Cellular Energy
8.1 How Organisms Obtain Energy
Metabolism cont’d.
REMEMBER…
Photosynthesis = Energy Storage
Cellular respiration = Energy Release

7. ATP: The Unit of Cellular Energy
Chapter 8
Cellular Energy
8.1 How Organisms Obtain Energy
ATP: The Unit of Cellular Energy
Adenosine Triphosphate
- a special molecule that stores & releases energy in its bonds for the needs of the cell.

9. Chapter 8
Cellular Energy
8.1 How Organisms Obtain Energy
ATP cont’d
ATP releases energy when the bond between the second and third phosphate groups is broken, forming a molecule called adenosine diphosphate (ADP) and a free phosphate group.

10. Chapter 8
Cellular Energy
8.1 How Organisms Obtain Energy
ATP cont’d
Phosphorylation = when the last phosphate group is transferred to another molecule with the help of an enzyme.

11. Chapter 8
Cellular Energy
8.1 How Organisms Obtain Energy
Energy can be stored by adding a phosphate group back to the ADP molecule.
ATP cont’d

12. build organelles & membranes maintain homeostasis move
Chapter 8
Cellular Energy
8.1 How Organisms Obtain Energy
ATP cont’d
Cells use ATP to…
make new molecules
build organelles & membranes
maintain homeostasis
move
transmit impulses
produce light
etc.

13. All of the energy from the food you eat comes from the sun.
Chapter 8
Cellular Energy
8.1 Formative Questions
All of the energy from the food you eat comes from the sun.
true
false A B
FQ 2

14. Why is adenosine triphosphate (ATP) such an
Chapter 8
Cellular Energy
8.1 Formative Questions
Why is adenosine triphosphate (ATP) such an
important biological molecule?
It captures light energy from the sun.
It is produced in anabolic pathways.
It stores and releases chemical energy.
It converts mechanical energy to thermal energy. A B C D
FQ 4

15. Chapter 8
Cellular Energy
Chapter Assessment Questions
Look at the following figure. Which molecule is released when ATP becomes ADP?
phosphate group
water molecule
ribose sugar
energy cells A B C D
CAQ 3