An Introduction to Metabolism: Chp 8 Flashcards
metabolism
the totality of an organism’s chemical reactions. metabolism as a whole manages the material and energy resources of the cell
catabolic pathway
leads to the release of energy by the breakdown of complex molecules to simpler compounds
anabolic pathways
consume energy to build complicated molecules from simpler ones
energy
the capacity to do work
kinetic energy
when anything is moving it has this energy
potential energy
wen anything has stored energy as a result of its position or structure
chemical energy
a form of potential energy, is stored in molecules, and the amount of chemical energy a molecules possesses depends on its chemical bonds
thermodynamics
the study of energy transformations that occur in matter
first law of thermodynamics
states that the energy of the universe is constant and that energy can be transferred and transformed, but it cannot be created or destroyed
second law of thermodynamics
states that every energy transfer or transformation increases the entropy in the universe
entropy
amound of disorder or randomness
free energy
defined as the part of a system’s energy that is able to perform work when the temperature of a system is uniform (symbol=/\G)
exergonic reaction
is one in which energy is released. Exergonic reactions occur spontaneoulsy and release free energy to the system
endergonic reaction
one that requires energy in order to proceed. endergonic reactions absorb free energy; that is, they require free energy from the system
energy coupling
the use of an exergonic process to drive an endergonic one. this is a key feature in the way cells manage their energy resources to do cell work
ATP
primary source of energy for cells. Made up of the nitrogenous base adenine, bounded to ribose and a chain of three phosphate groupes. When a phosphate group is hydrolyzed, energy is released in an exergonic reaction
ADP
when ATP trandfers one phosphate through hydrolysis ADP is the outcome.
catalysts
substances that can change the rate of a reaction without being altered in the process
enzymes
macromolecules that are biological catalysts
activation energy
the amount of energy it takes to start a reaction, the amount of energy it takes to break the bonds of the reactant molecules. Enzymes speed up reactions by lowering the activations energy of the reaction but without changeing the free energy
substrate
the reactant that the enzyme acts on
active site
the part of the enzyme that binds to the substrate
enzyme-substrate complex
the complex the enzyme and substrate form
products
what the substrate is converted into during the catalytic cycle of an enzyme
cofactors
nonprotein helpers many enzymes require to function properly
coenzymes
organic cofactors
competitive inhibitors
reversible inhibitors that compete with the substrate for the active site on the enzyme
noncompetitive inhibitors
do not directly compete with the substrate molecule; instead, they impede enzyme activity by binding to another part of the enzyme
allosteric
a specific binding site many enzyme regulators bind to on the enzyme. (once bound, the shape of the enzyme is changed either inhibiting or stimulating activity)
feedback inhibition
when the end product switchs off its pathway by binding to the allosteric site of an enzyme. this increases the efficiency of the pathway by turning it off when the end product accumulates in the cell
