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26 terms

Human Physiology - Chapter 4 Enzymes and Energy

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Catalysts
chemical that (1) increases the rate of a reaction, (2) is not itself changed at the end of the reaction, and )3) does not change the nature of the reaction or its final result.
enzymes
Protein Catalysts (exception RNA). They lower the activation energy.
Activation Energy
energy required to break chemical bonds
Lock-and-key model
The reactant molecules have specific shapes that allow them to fit into the active site.
Substrate
The molecule that participates in the reaction
Enzyme's Basic Rules
* Enzymes are specific
* Enzymes are required for reactions to happen
* Enzymes are proteins
* Enzymes can be turned on or off
Almost all enymes end with what letters?
-ase
Temperature
A measure of Kinetic Energy. Energy of motion.
What are the effects of Temperature on a reaction?
An increase in temperature will increase the rate and chance of a reaction.
pH optimum
peak range where activity is most likely to occer
Cofactor
extra "helper" molecule that include metal ions such as Ca2+, Mg2+ and Cu2+
Coenymes
extra "helper" moleceule. Organic molecules that offen times are transporters.
Zymogens
Inactive form of an enzyme
Phosporylation
Process of activation of an enzyme
Dephosphorylation
Process of deactivation of an enzyme
Enzymes Turnover
Breakdown and resynthesis of enzymes
Substrate Concentration
The rate of product formation will increase as the substrate concentration increases until the point of saturation
Saturation
When the relationship between substrate concentration and reaction rate reaches a plateau of maximum velocity. "All enzymes are busy"
Reversible Reaction
Both the forward and backward reactions can be catalzed by the same enzymes.
Metabolic Pathways
The sequence of chemical reactions. Begins with initial substrate, than through a number of intermediates, and ends with the final product.
1st law of Thermodynamics (conservation of energy)
Energy is not created or destroyed - it is transformed
2nd law of Themodynamics
The amount of entropy increase every time enery is transformed. Energy transformations are not perfect, some "lost" as heat.
Endergonic reactions
chemical reactions that require an input of energy
Exergonic reactions
Reactions that convert milescules with more free energy to molecule with less - release energy as they proceed
Coupled Reactions
Use energy from energy releasing reactions (exergonic) to power energy requiring reactions (endergonic)
Oxidation-Reduction Reactions
*Couple reactions where electrons are transfered from one molecule to another
* 1 molecule loses e-
* 1 molecule gains e-
some energy moves with the transfer and some is lost during the transfer.