Metabolism: Energy and Enzymes

This chapter focuses on the basic nature of energy as well as the production and functions of ATP. The role of enzymes and the laws of thermodynamics are also used.
the capacity to do work
kinetic energy
energy of motion
potential energy
stored energy
chemical energy
food is an example
First Law of Thermodynamics
-Energy cannot be created or destroyed
-However, it can be changed from one form to another
Second Law of Thermodynamics
-Energy cannot be changed from one form to another without a loss of energy
-this loss of energy is usually in the form of heat
disorder, disorganization
the organic processes that are necessary for life
the starting materials in a chemical reaction
the elements or compounds produced by a chemical reaction
activation energy
energy needed to get a reaction started
free energy
energy stored in products-after a chemical reaction occurs- that is available to do work
reactions that RELEASE energy
reactions that ABSORB energy
-main energy source: used to drive metabolic reactions
-high energy compound
-a cells "currency"
-made up of: adenine, ribose, 3 phosphate groups
coupled reactions
when the energy released by an exergonic reaction is used to drive an endergonic reaction
chemical work
ATP supplies energy needed to synthesize macromolecules
transport work
ATP supplies energy needed to pump substances across a plasma membrane
mechanical work
ATP supplies energy needed for movement-related activity
(ex: muscle contraction)
metabolic pathways
a series of linked reactions in th cell; being with a particular reactant and terminate with a particular product.
several small reactions in a metabolic pathway
-catalysts that speed up chemical reactions
-reduce amount of activation energy needed
the substance acted upon by an enzyme
active site
the site on an enzyme that attaches to a substrate
induced fit
a change in the shape of an active site of an enzyme to better accommodate it
Enzymes affected by
-temperature (high temp.=denature of proteins)
-pH (change in pH is VERY BAD for enzyme!)
-concentration of substrate (GOOD THING!!! faster reactions) :)
-Cells (affect presence/absence of enzyme, affect concentration, activate and deactivate an enzyme)
organic cofactors
small organic molecules required for synthesis of coenzymes
addition of phosphate in an enzyme
-binds to an enzyme and DECREASES its activity
-keeps an enzyme from catalyzing a reaction
competitive inhibition
the substrate and inhibitor can both bind to the active site
noncompetitive inhibition
the inhibitor binds to an area other than the active site (allosteric site), thus changing the shape of the enzyme so the substrate cannot bind to it
feedback inhibition
the end product of a [metabolic] pathway blocks the first enzyme from working
irreversible inhibition
materials that irreversibly inhibit an enzyme
(also known as poisons.)