Chapter 8 Section 3 - ATP

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.

ATP Structure

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.

Hydrolysis of ATP

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?

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

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.

The ATP cycle