Energy and Life Chapter 8.1

Chemical Energy and ATP Energy is the ability to do work. Cells are constantly using energy to perform LIFE FUNCTIONS. Metabolism Homeostasis Reproduction Transport

Chemical Energy and ATP Energy comes in many forms: Light Heat Sound Electricity Without ENERGY, life would not exist. Living things use CHEMICAL FUEL (ATP). ATP is the MOST important chemical fuel for cells.

Chemical Energy and ATP The chemical compound that cells use to store and release ENERGY is ADENOSINE TRIPHOSPHATE or ATP. ATP is a type of NUCLEIC ACID ATP has 3 parts: ADENINE a 5-CARBON SUGAR called RIBOSE THREE phosphate groups. The three phosphate groups are the KEY to ATP’s ability to STORE and RELEASE energy.

ATP

adenosine TRI phosphate ADP vs. ATP adenosine DI phosphate adenosine TRI phosphate Di = 2 Tri = 3

Storing Energy: ADP to ATP ADP is a compound that looks like ATP except it has 2 PHOSPHATE GROUPS instead of 3 PHOSPHATE GROUPS. Organisms STORE energy by adding a PHOSPHATE to ADP and the energy is stored in the BOND between the last 2 PHOSPHATES. ADP is like a RECHARGEABLE BATTERY.

Releasing Energy ATP to ADP Cells can release the ENERGY stored in the ATP by breaking the BOND that holds PHOSPHATE #2 and PHOSPHATE #3. This is an efficient way of STORING and RELEASING energy as the CELL needs it. Why do cells need energy?

Where do living things get ATP from? HETEROTROPHS AUTOTROPHS Consume OTHER LIVING THINGS for energy. Classifications HERBIVORES eat only plants. OMNIVORES eat plants and animals. CARNIVORES eat only animals. Can make their own energy directly from the sun through PHOTOSYNTHESIS. Classifications Plants Algae Some bacteria