Glossary of Energy and Metabolism, Princ Bio I Ch 8

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The study of energy
The process of an atom or molecule loses an electron
The process of an atom or molecule gaining an electron
Oxidation-Reduction reaction
Chemical reactions using oxidation and reduction at the same time. Cell uses NAD+ to carry out.
First Law of Thermodynamics
States that energy cannot be created or destroyed; it can only change from one form to another
Second Law of Thermodynamics
States that the disorder )formally called entropy) in the universi is continuously increasing
Free energy
Net effect, the amount of energy actually available to break and subsequently form other chemical bonds
Reactions that require an input of energy
Reactions that release the excess free energy as heat
Activation energy
Extra energy required to destabilize existing chemical bonds and initiate a chemical reaction.
Active sites
Pockets or clefts on the surface of enzymes where substrates bind
Advantages of Multienzyme complexes:
1. A series of sequential reactions occur within a multienzyme complex meaning the product of one reaction can be delivered to the next enzyme without releasing it to diffuse away
2. Reacting substrate never leaves the complex, eliminating the possibility of unwanted side reactions
3. all of the reactions can be controlled as a unit.
Non-protein catalysts
RNA (ribozymes) can greatly accelerate the rate of particular biochemical reactions.
Two sorts- have folded structures and catalyze reactions on themselves. The other act on othe rmolecules without themselves being changed
intramolecular catalysis
catalyzed reactions on RNA
intermolecular catalysis
RNA Acting on other molecules without themselves being changed.
Factors effecting Enzyme activity
Inhibitors and Activators
nonprotein organic molecule cofactor.
allosteric site
sites that serve as chemical on/off switches
Nicotinamide adenine dinucleotide
two nucleotides bound together. Acts as a hydrogen acceptor
NAD+ with hydrogen. Carries two electrons and a proton.
adenosine triphosphate
Chief energy currency all cells use. Energy lies in the triphosphate group.
Drive endergonic reactions
reactions that expend energy to make or transform chemical bonds.
reactions that harvest energy when chemical bonds are broken.

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