Chapter 6: Energy, Enzymes, and Metabolism Flashcards
energy
ability to promote change or do work
kinetic energy
associated with movement
potential energy
due to structure or location
chemical energy
the energy in molecular bonds, a form of potential energy
First Law of Thermodynamics
energy cannot be created or destroyed, but can be transformed from one type to another
Second Law of Thermodynamics
transfer if energy from one form to another increases the entropy of a system
entropy
degree of disorder of a system
free energy (Gibbs Free Energy)
amount if energy available to do work
spontaneous reactions
occur without the input if additional energy
ATP binding site
parficular amino acid sequences in proteins used to bind to ATP
catalyst
an agent that speeds up the rate of a chemical reaction without being consumed during a reaction
enzymes
protein catalysts in living cells
ribozyme
RNA molecules with catalytic properties
activation energy
initial input of energy to start reaction
active site
location where reaction takes place
substrates
reactants that bind to active site
enzyme-substrate complex
formed when enzyme and substrate bind
lock and key metaphor
only the right key (substrate) will fit into the lock (enzyme)
saturation
plateau where nearly all active sites are occupied by substrate
Michaelis constant (Km)
substrate concentration where velocity is half maximal value
competitive inhibition
molecule binds to active site
noncompetitive inhibition
lowers Vmax without affecting Km
- inhibitor binds to allosteric site and changes active site shape through binding
prosthetic groups
small molecules permanently attached to enzyme
cofactor
usually inorganic ion that temporarily binds to enzyme
