1. Don’t call them bad names, call them these names…
Key terms to start…
Don’t call them bad names, call them these names…

2. Definition time!
Metabolism – the sum of all chemical reactions in a cell or organism
Energy – the capacity to do work, the potential for change in a physical system
Two states of energy:
Kinetic – the energy of motion
Potential – the stored energy an object possesses due to its position relative to other objects

3. More…
Work – the transfer of energy, used to move an object against an opposing force
Reaction types
Anabolic reaction (endergonic) – when energy is required to build complex molecules from simple ones
VERSUS
Catabolic reaction (exergonic) – when energy is released by breaking up complex molecules into simpler ones

4. Adenosine Triphosphate
ATP!
Adenosine Triphosphate

5. ATP Structure
ATP has the same overall structure of RNA, but has three (tri) phosphate groups
[Recall: nucleic acids all have a nitrogenous base, a 5-C ringed sugar, and phosphate group(s)]

6. A Powerhouse… Is considered universal energy “currency” for the body
Provides energy for movement of cells and within cells, for movement of substances across cell membranes against the concentration gradient, and all mediated endergonic reactions (see Table 1, p141)
Allows for mechanical, transport, and chemical work

7. ATP + H2O  ADP + Pi ΔG = -30.5kJ/mol
Why so energetic?
The three negatively charged phosphate groups contain large amounts of energy
Their electrons “mutually repel” each other and so these bonds are quite weak
These bonds are easily broken by water through catalyzed hydrolysis
ATP + H2O  ADP + Pi ΔG = -30.5kJ/mol

8. The Reaction

9. How does this really work?
Energy Coupling – the transfer of energy from one reaction to another to drive the second reaction