Energy Processing
4A
Energy
• Organisms must have energy to…
…grow
…maintain homeostasis. The organism is
fighting against entropy
…manufacture substances and tear down
others
Energy
• It is not recyclable
• Organisms need a constant supply of it
• It can be stored in the chemical bonds
of molecules
• It escapes constantly (entropy)
Energy
• It comes in many different forms
How organisms
obtain energy
• Autotrophs (producers)organisms that make their
own food
– Photosynthetic- make food
using light energy
• (plants, algae, some bacteria)
– Chemosynthetic- make food
using energy from inorganic
molecules
• (bacteria next to hydrothermal
vents at the bottom of the ocean)
How organisms obtain energy
• Heterotrophs (consumers)- organisms that
depend on other organisms for their food
– (animals, fungi, and some bacteria)
How organisms obtain energy
• Types of heterotrophs
– Herbivore- eats plants
– Carnivore- eats meat
– Omnivore- eats both plants and meat
Cellular Respiration
• Energy is stored in food (chemical energy)
• Organisms must break food down in order to
get the energy out so their bodies can use the
energy
• They release the energy from food during
cellular respiration and it is temporarily stored
in ATP.
• Energy is there, but
it’s not in a usable
form
Organic molecules that store
energy
• Carbohydrates
– Glycogen in animals
– Starch in plants
• Lipids
ATP
ATP ~ adenosine triphosphate, usable unit of
energy in living organisms
Components of ATP:
1. Ribose ~ 5 carbon sugar that forms
backbone
2. Adenine ~ one of the bases found in DNA
3. Three phosphate groups attached to the
ribose backbone.
ATP-ADP Cycle
The energy in ATP is found between the bonds
of the three phosphate groups. They are
bound by unstable high energy covalent
bonds. When the bonds are broken, a large
amount of energy is released, and is
available for use in the cell.
In most reactions, the phosphate group on the
end of the chain is broken off. This produces
ADP (adenosine diphosphate), a free
phosphate group, and energy.
The ADP can be reused, and a phosphate can
be attached to change it back to ATP
(phosphorylation)
ATP-ADP
Cycle
Energy in a Molecule
CELLS USE ATP TO STORE and RELEASE
ENERGY
•
•
•
•
ADP
Adenosine
Diphosphate
Adenine
Ribose (sugar)
2 phosphates
•
•
•
•
ATP
Adenosine
Triphosphate
Adenine
Ribose
3 phosphates
Photosynthesis- the process of absorbing light energy and converting it into
stored chemical energy.
Chemical equation:
Cellular Respiration- the breaking down of a food substance into usable
cellular energy in the form of ATP
Chemical equation:
Cellular respiration is the opposite of photosynthesis:
•Photosynthesis combines water, carbon dioxide and light energy to form
glucose, and oxygen is a waste product.
•Cellular respiration uses oxygen to help break down glucose to form ATP, and
water and carbon dioxide are waste products.
•The reactants of photosynthesis are the products of cellular respiration and the
reactants of cellular respiration are the products of photosynthesis.
•In photosynthesis light energy is stored in glucose as chemical energy so it is
endergonic.
•In cellular respiration energy is released from glucose so it is exergonic.