Chapter 8: An Introduction to Metabolism

3 Main Questions:
- What is metabolism?
The totality of an organism's chemical reactions.
- What is the first law of thermodynamics?
Energy can be transferred and transformed, but it can not be created or destroyed.
- What is chemical energy?
Chemical is a term used by biologists to refer to the potential energy available for release in a chemical reaction.

5 Main Facts:
- Metabolism as a whole manages the material and energy resources of the cell.
- An object not presently moving may still possess energy.
- During catabolic reaction, atoms are rearranged and energy is released, resulting in lower energy breakdown products.
- Moving objects can perform work by imparting motion to other matter.
- During every energy transfer or transformation, some energy becomes unusable energy, unavailable to do work.

Diagram

This diagram is the active site and catalytic cycle of an enzyme. An enzyme can convert one or more reactant molecules. The enzyme shown in the diagram is converting two substrate molecules to two product molecules.

Summary
The living cell is a chemical factory in a small world where thousands of reactions occur within a microscopic space. Small molecules are assembled into polymers, which may be hydrolyzed later for the needs of the cell change.
Sugars can be converted into amino acid that are linked together into proteins when needed, and proteins are dismantled into amino acids that can be converted to sugars when food is digested.

Video
http://www.youtube.com/watch?v=cbZsXjgPDLQ

10 Key Terms:
- Energy: the capacity to cause change.
- Chemical energy: a term used by biologists to refer to the potential energy available for release in a chemical reaction.
- Bioenergetic: the study of how energy flows through living organisms.
- Potential energy: it is energy that matter possesses because of its location or structure.
- Entropy: a measure of disorder, or randomness.
- Free energy: the portion of a system's energy that can perform work when temperature and pressure are uniform throughout the system, as in a living cell.
- Endergonic reaction: is one that absorbs free energy from its surroundings.
- Enzyme: a macromolecules that acts as a catalyst, a chemical agent that speeds up a reaction without being consumed by the reaction.
- Subtract: the reactant on which an enzyme works.
- Coenzyme: an organic molecule serving as a cofactor. Most vitamins function as coenzymes in metabolic reactions.