Lesson Overview

1. Lesson Overview 8.1 Energy and Life

2. Chemical Energy and ATP • Energy- ability to do work. • Your cells are busy using energy to build new molecules, contract muscles, and carry out active transport. • Without the ability to obtain and use energy, life would cease to exist. • ATP- release and store energy by breaking and re-forming the bonds between phosphate groups.

3. Storing Energy • Cells store energy by adding phosphate groups to ADP, producing ATP. • Adenosine diphosphate (ADP)- two phosphate groups instead of three. • Not as much energy as ATP.

4. Chemical Energy and ATP • ATP- adenosine triphosphate • ATP consists of adenine, a 5-carbon sugar called ribose, and three phosphate groups.

5. Releasing Energy • ATP- bonds are broken between the second and third phosphate groups to release energy stored

6. Using Biochemical Energy • Active transport uses ATP • Ex: cell membranes contain sodium-potassium pumps. ATP provides the energy that keeps these pumps working, • maintaining a balance of ions on both sides of the cell membrane. • pumps 3 Na+ ions out of the cell, & 2 K+ ions into the cell • sodium/potassium pump

7. Using Biochemical Energy • ATP powers movement • provides energy for motor proteins that contract muscle and power the movement of cilia and flagella. • cilia & flagella

8. Using Biochemical Energy • ATP powers synthesis of proteins and responses to chemical signals at the cell surface. • cell signals

9. Using Biochemical Energy • ATP does not store large amounts of energy over the long term. • It is more efficient for cells to keep only a small supply of ATP on hand. • Cells can regenerate ATP from ADP as needed by using the energy in foods like glucose.

10. Heterotrophs and Autotrophs • Photosynthesis: Plants, algae, and some bacteria (autotrophs) convert the energy of sunlight into chemical energy stored in the bonds of carbohydrates.