ATP Energy
Why do we need energy?
• Energy = the ability to do work.
• Metabolism = total of all chemical activities of
an organism that enable it to perform life
functions
• Need energy for most activities
• Living things need energy to survive.
Where does that energy come from?
Autotrophs
• The energy for life comes from the sun
• Plants and some other organisms use the light
energy from the sun to make food
• Autotrophs = organisms that make their own
food
Heterotrophs
• Heterotrophs = other organisms that can’t use
light energy directly, but instead obtain energy
from food (plants or animals)
Energy Transfer & Food Chains
• All energy comes from the Sun!
• Energy Transfer:
Sunlight  Autotroph  Heterotroph  other heterotrophs
(herbivore)
(carnivore)
• Food Chain:
Autotroph  Heterotroph  other heterotrophs
(herbivore)
(carnivore)
ATP
• Energy can be in the form of
light, heat, electricity, and in
chemical compounds
• Living things store energy in
the chemical compound
adenosine triphosphate, ATP
• The cell stores energy by
adding a phosphate group to
adenosine diphosphate, ADP,
producing ATP
• The cell releases energy by
converting ATP into ADP and a
phosphate group
• ATP is a basic energy source
for all cells! – it can move
organelles and transport
molecules
Section 8-1
Adenine
Go to
Section:
ATP
Ribose
3 Phosphate groups
Figure 8-3 Comparison of ADP and
ATP to a Battery
Section 8-1
ADP
ATP
Energy
Adenosine diphosphate (ADP) + Phosphate
Partially
charged
battery
Go to
Section:
Energy
Adenosine triphosphate (ATP)
Fully
charged
battery
Figure 8-3 Comparison of ADP and
ATP to a Battery
Section 8-1
ADP
ATP
Energy
Adenosine diphosphate (ADP) + Phosphate
Partially
charged
battery
Go to
Section:
Energy
Adenosine triphosphate (ATP)
Fully
charged
battery
ATP and Glucose
• Cells store a little bit of ATP and a lot of
glucose
• Glucose stores more energy than ATP over
long terms
• Cells use the energy stored in carbohydrates
(glucose) to regenerate ATP from ADP