Enzymes Flashcards
What is an enzyme?
Protein that catalyzes a biological reaction in response to a signal from outside the cell
How do enzymes help maintain homeostasis?
They help transform, use, and dissipate energy
What is metabolism?
The sum of all catabolic and anabolic reactions in a cell
What is a spontaneous reaction?
A reaction that proceeds without any energy input
What determines if a reaction is spontaneous?
Free energy
What is free energy?
A measure of instability, the tendency for a molecule to change to a more stable form
What are the two things that control the free energy of a reaction?
Enthalpy and entropy
What is enthalpy?
How much heat is gained or lost during the reaction
What is entropy?
How much randomness is gained or lost during a reaction
What is an exergonic reaction?
Releases heat, has negative free energy, spontaneous, decreases enthalpy and increases entropy
What is an endergonic reaction?
Requires energy input and has positive free energy, non-spontaneous, increases enthalpy and decreases entropy
How does an enzyme catalyze a reaction?
Reduces the activation energy
What is the active site?
Where the substrate binds on the enzyme and the reaction takes place
What are the steps in an enzymatic reaction?
Substrate binds to the active site, then changes the molecular structure of the substrate by breaking bonds or changing electron distribution across the bonds
What is the turnover number?
The maximum number of substrate molecules that an enzyme can convert to product per active site per unit time
