1. KEY CONCEPT All cells need chemical energy.

2. Objectives
Recognize the importance of ATP as an energy-carrying molecule.
Identify energy sources used by organisms.

3. Adenosine Triphosphate
Vocabulary
ATP
Adenosine Triphosphate
High-energy molecule that contains, within its bond, energy that cells can use.
ADP
Adenosine Diphosphate
Low-energy molecule that can be converted to ATP.
Chemosynthesis
A process by which ATP is synthesized by using chemicals as an energy source instead of light

4. The chemical energy used for most cell processes is carried by ATP.
Molecules in food store chemical energy in their bonds.
Starch molecule
Glucose molecule

5. Energy is released when a phosphate group is removed.
ATP transfers energy from the breakdown of food molecules to cell functions.
Energy is released when a phosphate group is removed.
ADP is changed into ATP when a phosphate group is added.
phosphate removed

6. Organisms break down carbon-based molecules to produce ATP.
Carbohydrates are the molecules most commonly broken down to make ATP.
not stored in large amounts
up to 36 ATP from one glucose molecule
triphosphate
adenosine
diphosphate
tri=3
di=2

7. Fats store the most energy.
80 percent of the energy in your body
about 146 ATP from a triglyceride
Proteins are least likely to be broken down to make ATP.
amino acids not usually needed for energy
about the same amount of energy as a carbohydrate

8. A few types of organisms do not need sunlight and photosynthesis as a source of energy.
Some organisms live in places that never get sunlight.
In chemosynthesis, chemical energy is used to build carbon-based molecules.
similar to photosynthesis
uses chemical energy instead of light energy

9. Question/Answer
How are ATP and ADP alike?
They both contain adenosine and phosphate groups
How are the different?
ATP has three phosphate groups
ADP has two phosphate groups
Why is this difference important?
The extra bond is a potential source of energy

10. Question/Answer
Describe the relationship between energy stored in food and ATP.
Food molecules store chemical energy in their bonds. Food is broken down into smaller molecules that are broken down further to transfer this energy to ATP.
How do lipids and carbohydrates differ in ATP production?
Lipids provide more ATP than carbohydrates do
How are chemosynthetic organisms and plants similar as energy sources?
Both chemosynthetic organisms and plants make their own food and both are eaten by other organisms that cannot make their own food.