Chapter 3 - Energy & Enzymes Flashcards
energy
The capacity to do work.
kinetic energy
The energy of motion.
potential energy
Stored energy.
entropy
Disorder, in thermodynamics.
enthalpy
Potential energy in a system.
endothermic
Refers to reactions that absorb energy.
exothermic
refers to processes that release energy.
spontaneous reactions
Chemical or physical reaction that occurs without outside help.
exergonic reactions
Reaction that has a negative ΔG because it releases free energy.
endergonic reactions
Reaction that can proceed only if free energy is supplied.
activation energy
The initial input of energy required to start a reaction.
transition state
An intermediate arrangement of atoms and bonds that both the reactants and the products of a reaction can assume.
enzymes
Protein that accelerates the rate of a cellular reaction.
catalyst
Substance with the ability to accelerate a spontaneous reaction without being changed by the reaction.
active site
The region of an enzyme that recognizes and combines with a substrate molecule.
cofactors
An inorganic or organic nonprotein group that is necessary for catalysis to take place.
competitive enzyme inhibition
Inhibition of an enzyme reaction by an inhibitor molecule that resembles the normal substrate closely enough that it fits into the active site of the enzyme.
negative feedback inhibition
The primary mechanism of homeostasis, in which a stimulus—a change in the external or internal environment—triggers a response that compensates for the environmental change.
a reaction that causes a decrease in function
positive feedback inhibition
A mechanism that intensifies or adds to a change in internal or external environmental condition.
positive feedback inhibition
A mechanism that intensifies or adds to a change in internal or external environmental condition.
first law of thermodynamics
principle that energy can be transferred and transformed but cannot be created or destroyed
second law of thermodynamics
Principle that for any process in which a system changes from an initial to a final state, the total disorder of the system and its surroundings always increases.
anabolic pathways
Type of metabolic pathway in which energy is consumed to build complicated molecules from simpler ones; often called a biosynthetic pathway.
catabolic pathways
Type of metabolic pathway in which energy is released by the breakdown of complex molecules to simpler compounds.
