1. Chemical Energy and ATP
Section 4.1
Michael Slemp

2. Bell WORK Why is ATP important? Give examples
List the three types of high energy rich molecules that make up our food. Which of the three has the most amount of energy?

3. ALL CELLS NEED ENERGY ! YOU EAT You are made out of billions of cells
so your body need energy too.
So, what do you do when you are tired and hungry?
YOU EAT
your body is telling you that you need more energy

4. What do you EAT?

5. Food = high energy molecules
Carbohydrates, lipids and proteins are organic molecules (not found in nature but made by organisms)
Energy
Molecules
Examples
Content (calories)
Carbohydrates
Sugar, bread, pasta, apples, carrots
4 calories per mg
Lipids
Oil, butter
9 calories per mg
Proteins
Chicken, fish, burger

6. The easiest source of energy for cells are carbohydrates (sugars)
However, sugar molecules are too HUGE and cannot be used directly by cells.
Instead, sugars are broken down in mitochondria to smaller units via process called cellular respiration (covered in section 4.4)
During cellular respiration, energy stored in bonds of sugar molecules are released and stored in bonds of another molecule called ATP

7. ATP Adenosine triphosphate (tri=three)
Translation: Adenosine molecule with three phosphate groups
Majority of Energy is stored between P2 and P3 1 2 3

8. Use of ATP ATP molecule ADP
Energy is released from ATP molecule by breaking bond between P2 and P3
ATP molecule
ADP
Adenosine diphosphate (di=two)
Travels to various cell sites to supply energy
ENERGY
(used by cell)
Free phosphate group
Transported back to mitochondria for more ATP production
ATP made in mitochondria

9. ATP cycle ATP Energy + ADP + P ADP + P + Energy ATP (released)
(supplied)

10. Compare Energy rich molecules 1 glucose molecule = 36 ATPs
Sugar (glucose)
ATP
ADP
Stores energy in the chemical bonds (chemical energy)
Energy rich molecule
Energy poor molecule
Usable by cells, energy rich molecule
Too large to be used by cells

11. Where do sugars come from?
Animals get energy from food that they eat
(as we discussed above)
However, some organisms are able to produce their own carbohydrates
Plants are able to make their own sugars by a process called photosynthesis
Remember chloroplasts?

12. Photosynthesis Plants harvest energy from sunlight
Plants do not need to feed on organic food like carbohydrates
Plants harvest energy from sunlight
In process of photosynthesis, plants convert sunlight energy, carbon dioxide and water into energy rich carbohydrates
We will be covering photosynthesis next class session

13. Chemosynthesis Photosynthesis = uses sunlight energy to produce sugars
Sunlight energy + Water+ Carbon Dioxide = Glucose + Oxygen
Chemosynthesis = uses chemical energy (instead of light energy) to produce energy-rich molecules like sugar
Hydrogen Sulfate + Water+ Carbon Dioxide = Glucose + other products
(chemical energy)

14. Chemosynthesis
Chemosynthesis is used by some organisms that live deep down on ocean floor near hydrothermal vents. Because they never get sunlight here, they had to find alternative source of energy