Chemical Energy and ATP

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Chemical Energy and ATP

• Section 4.1
• Michael Slemp

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Bell WORK

• Why is ATP important? Give examples
• List the three types of high energy rich
  molecules that make up our food. Which of the
  three has the most amount of energy?

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ALL CELLS NEED ENERGY !
You are made out of billions of cells so your
body need energy too.
So, what do you do when you are tired and hungry?
YOU EAT your body is telling you that you need
more energy
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What do you EAT?
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Food high energy molecules
Carbohydrates, lipids and proteins are organic
molecules (not found in nature but made by
organisms)
Energy Molecules Examples Energy Content (calories)
Carbohydrates Sugar, bread, pasta, apples, carrots 4 calories per mg
Lipids Oil, butter 9 calories per mg
Proteins Chicken, fish, burger 4 calories per mg
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The easiest source of energy for cells are
carbohydrates (sugars)
However, sugar molecules are too HUGE and cannot
be used directly by cells.
Instead, sugars are broken down in mitochondria
to smaller units via process called cellular
respiration (covered in section 4.4)
During cellular respiration, energy stored in
bonds of sugar molecules are released and stored
in bonds of another molecule called ATP
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ATP
Adenosine triphosphate (trithree) Translation
Adenosine molecule with three phosphate groups
Majority of Energy is stored between P2 and P3
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2
3
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Use of ATP
Energy is released from ATP molecule by breaking
bond between P2 and P3
ATP molecule
ADP Adenosine diphosphate (ditwo)
Travels to various cell sites to supply energy
ENERGY (used by cell)
Free phosphate group
Transported back to mitochondria for more ATP
production
ATP made in mitochondria
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ATP cycle
ATP Energy ADP P
(released)
ADP P Energy ATP
(supplied)
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Compare Energy rich molecules
1 glucose molecule 36 ATPs
Sugar (glucose)
ATP
ADP
Stores energy in the chemical bonds (chemical
energy)
Energy rich molecule
Energy poor molecule
Usable by cells, energy rich molecule
Too large to be used by cells
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Where do sugars come from?
Animals get energy from food that they eat (as we
discussed above)
However, some organisms are able to produce their
own carbohydrates
Plants are able to make their own sugars by a
process called photosynthesis
Remember chloroplasts?
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Photosynthesis
Plants do not need to feed on organic food like
carbohydrates
Plants harvest energy from sunlight
In process of photosynthesis, plants convert
sunlight energy, carbon dioxide and water into
energy rich carbohydrates
We will be covering photosynthesis next class
session
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Chemosynthesis
Photosynthesis uses sunlight energy to produce
sugars
Sunlight energy Water Carbon Dioxide Glucose
Oxygen
Chemosynthesis uses chemical energy (instead of
light energy) to produce energy-rich molecules
like sugar
Hydrogen Sulfate Water Carbon Dioxide
Glucose other products
(chemical energy)
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Chemosynthesis
Chemosynthesis is used by some organisms that
live deep down on ocean floor near hydrothermal
vents. Because they never get sunlight here, they
had to find alternative source of energy