8.1 – Energy and Life
Guided Reading
Chemical Energy and ATP
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What is energy? The ability to do work
Identify some forms of energy:
heat, electricity
Light,
In what compound do organisms store
and release energy? ATP
Diagram and label an ATP molecules
below (figure 8-1)
Storing Energy
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What is ADP? Adenosine diphosphate
How is ADP different from ATP? ADP has
two phosphate groups (DIphosphate),
while ATP has three phosphate groups
(TRIphosphate)
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How is ATP produced? Energy in the
cell is stored by adding a phosphate
group to ADP, forming ATP
How is this like a rechargeable
battery? Energy can continuously be
stored and released by adding or
removing the phosphate group, just
like charging and using a battery
Releasing Energy
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How is the stored energy in ATP
release? By the controlled breaking
of the chemical bond between the
2nd and 3rd phosphate groups
ATP can easily release and store
energy by breaking and reforming
the bonds between its phosphate
groups.
Using Biochemical Energy
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Give two examples of how ATP is used
in a cell
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Sodium-potassium pumps carry Na+ and
K+ ions across the membrane, balancing
the ions on either side of the membrane.
Producing proteins and other molecules
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Why do cells only hold a small
amount of ATP at a time? It is not
good at storing large amounts of
energy over the long term. It is
better for the cell to store energy in
other molecules that can store it for
longer periods of time, such as
glucose (sugar)
Heterotrophs and Autotrophs
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Where does the energy used to produce ATP
come from?
Chemical energy stored in food
What are heterotrophs? Organisms that obtain
food by consuming other living things
Give some examples of where they get their
food: eating plants (grass), eating other
animals, absorbing nutrients from other
organisms (fungus)
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What are autotrophs? Organisms that
can make their own food
Where do most autotrophs get the
energy they use to make food? The sun
Briefly describe the process of
photosynthesis: plants convert the
energy of sunlight into chemical energy
store in the bonds of carbohydrates