Obtaining Food

1. Obtaining Food • Life can be thought of as solar- powered • All energy comes from the sun

2. Potential and Kinetic Energy

3. Kinetic Energy Potential Energy Elastic Potential Energy Gravitation Potential Energy Chemical Potential Energy How is all energy divided? All Energy

4. What is Potential Energy? • Energy that is stored and waiting to be used later

5. What is Gravitational Potential Energy? • Potential energy due to an object’s position • P.E. = mass x height x gravity Don’t look down, Rover! Good boy!

6. What is Elastic Potential Energy? • Potential energy due compression or expansion of an elastic object. Notice the ball compressing and expanding

7. What is Chemical Potential Energy? • Potential energy stored within the chemical bonds of an object

8. What is Kinetic Energy? • Energy an object has due to its motion • K.E. = .5(mass x speed2)

9. Autotrophs • Greek for “self feeder” (make their own food) • Also called producers • Use sunlight and CO2 to make glucose • Called photosynthesis • On land :plants • In water: algae

10. Heterotrophs • Greek for “other eaters” • Must eat producers for energy

11. Harvesting energy in food • We use food to make energy through cellular respiration • Use oxygen and sugar to make energy in the form of ATP • Plants use sunlight to make energy through photosynthesis • Use CO2 and water to convert sunlight into chemical energy • The two processes are related!!! We need plants and plants need us.

12. Before the energy can be used, it is first transformed into a form which the organism can handle easily. This special carrier of energy is the molecule adenosine triphosphate, or ATP.

13. Its Structure • The ATP molecule is composed of three components. • At the center is a sugar molecule, ribose • (the same sugar that forms the basis of RNA).

14. Attached to one side of this is a base (a group consisting of linked rings of carbon and nitrogen atoms); in this case the base is adenine. The other side of the sugar is attached to a string of phosphate groups. These phosphates are the key to the activity of ATP.

15. ATP • Made in the _______________________. • Adenosine Triphosphate • A currency for cells to convert food into a usable energy source. • Think a $100 bill is glucose and ATP is a $1 bill. It is easiest to use the $1

16. Types of energy • Energy- the ability to perform work • Potential – stored energy/ energy of location • Chemical energy- how much work the molecules can do is dependant on how the molecules are arranged. • Carbs, lipids, proteins have structures that make them rich in energy

17. Chemical energy is the energy that is available for release in chemical reactions

18. Kinetic- energy of motion • Thermal energy- random molecular motion