Bio thermodynamics Flashcards
(25 cards)
What determines chemical reactions and energy?
The concentration of reactants and products.
What are the two types of metabolic reactions?
Anabolic and catabolic.
What is an anabolic reaction?
Small molecules assemble to form a larger molecule.
What is a catabolic reaction?
Large molecules are broken into smaller molecules.
What are the two types of energy changes in reactions?
Exergonic and endergonic.
What is an exergonic reaction?
Free energy is released (spontaneous with -ΔG).
What is an endergonic reaction?
Free energy is absorbed (nonspontaneous with +ΔG).
What is the role of enzymes in reactions?
Enzymes act as catalysts by lowering the activation energy needed for a reaction.
What are most enzymes made of?
Most are proteins, but some are made of RNA (ribozymes).
What is the active site of an enzyme?
The area of the enzyme where the substrate binds.
What is an allosteric site?
A secondary location where an effector binds (effectors can be activators or inhibitors).
What happens when substrates enter the active site?
Enzyme and substrate change shape slightly to better catalyze the reaction (induced fit model).
What is the enzyme-substrate complex?
Formed when the substrate binds the enzyme.
What are the characteristics of enzyme function?
Substrate specific, unchanged by the reaction, catalyze forward and reverse reactions, vary depending on pH and temperature, and have an active site that binds substrates via induced fit.
What is competitive inhibition?
A substance that mimics the substrate inhibits the enzyme by binding to the active site, preventing substrate binding.
How can competitive inhibition be overcome?
By increasing substrate concentration.
What happens to Km and Vmax in competitive inhibition?
Km increases and Vmax stays the same.
What is noncompetitive inhibition?
A substance inhibits the enzyme by binding to the allosteric site, preventing the reaction.
What happens to Km and Vmax in noncompetitive inhibition?
Km stays the same and Vmax decreases.
What is ATP?
A source of chemical energy formed via phosphorylation, creating energy-rich triphosphate bonds.
What is ATP hydrolysis?
Broken apart via hydrolysis, releasing energy and phosphate.
What is the difference between potential and kinetic energy?
Kinetic energy is energy in motion (i.e., jumping), while potential energy is stored energy (i.e., glycogen).
What is Vmax?
The maximum velocity of the reaction at peak substrate saturation.
What is the Michaelis Constant (Km)?
The substrate concentration at which the rate of the reaction is half of the maximum velocity.
