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

• Without ENERGY, life would not exist.• Living things use CHEMICAL FUEL (ATP).• ATP is the MOST important chemical fuel for cells.

• Energy comes in many forms:– Light

– Heat

– Sound

– Electricity

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

ADP vs. ATP

adenosine DI phosphate

• Di = 2

adenosine TRI phosphate

• 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 EnergyATP 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• Consume OTHER

LIVING THINGS for energy.

• Classifications– HERBIVORES eat only

plants.– OMNIVORES eat plants

and animals.– CARNIVORES eat only

animals.

AUTOTROPHS• Can make their own

energy directly from the sun through PHOTOSYNTHESIS.

• Classifications– Plants– Algae– Some bacteria