Section 3 - ATP

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Chapter 8

• Section 3 - ATP

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Three main types of work

• Mechanical work cilia beating, muscle cells
  contracting, chromosomes moving
• Transport work pumping substances across
  membranes against the gradient
• Chemical work Synthesis of polymers from
  monomers
• Energy coupling the use of an energy releasing
  reaction to drive an energy requiring one.

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ATP Structure
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Hydrolysis of ATP

• ATP water ADP P
• Releases energy
• Why is ATP able to release so much energy?
• The three phosphate groups are all negatively
  charged and repel each other so they act like a
  loaded spring.

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Hydrolysis of ATP
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ATP produces

• When ATP is hydrolyzed in a test tube the release
  of energy heats the surrounding water
• In an organism the process of shivering uses ATP
  hydrolysis during muscle contraction to generate
  heat and warm the body
• Our bodies need to do much more than keep us warm
  when we are cold so how is this energy
  transferred to other processes that require
  energy?

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Phosphorylation

• Enzymes couple the energy of ATP hydrolysis to
  reactions requiring energy by transferring a
  phosphate group to another molecule.
• The recipient of the phosphate group is said to
  be PHOSPHORYLATED.
• The phosphorylated molecule undergoes a change
  that performs work

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Regeneration of ATP

• ATP is a renewable resource in the cell
• ATP cycle is extremely fast
• ATP is made through the processes of cellular
  respiration in the mitochondria and
  photosynthesis in the chloroplasts of plants.

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The ATP cycle