Chapter 6 Flashcards
Kinetic energy
Energy in motion
Potential energy
Stored energy
First Law of Thermodynamics
Energy cannot be created or destroyed. Energy can only change from one form to another (e.g., potential to kinetic)
Second Law of Thermodynamics
Energy cannot be transformed from one form to another with 100% efficiency
Entropy
measure of randomness or disorder of a system
Free energy
energy available to do work
Endergonic
products have more free energy than reactants.
In an endergonic reaction, ∆G is ________.
Positive
Exergonic
products have less free energy than reactants
In an exergonic reaction, ∆G is ______.
Negative
Activation energy
energy that must be processed by a molecule in order for it to undergo a chemical reaction
Catalysis
ATP is composed of three components:
- Ribose (5-carbon sugar)
- Adenine (composed of two carbon-nitrogen rings)
- Three phosphates
Synthesis of ATP from ADP + Pi is _______, which results in a _______ delta-G.
Endergonic; positive
Hydrolysis of ATP to ADP + Pi is ________, which results in a _______ delta-G.
Exergonic; negative
Substrate
molecule on which an enzyme acts
Active site
region of an enzyme surface to which a substrate binds
Enzyme-substrate complex
complex formed when an enzyme binds with its substrate
Multienzyme complex
assembly of several enzymes catalyzing different steps in a sequence of reactions
What is the optimum temperature of enzymes?
35-40°C
What is the optimum pH of enzymes?
pH 6-8
Inhibitor
substance that binds to an enzyme and decreases its activity
Competitive inhibitor
Competes with substrate for the same active site
Noncompetitive inhibitor
Binds to enzyme in a location other than the active site, changing the enzyme’s shape so it cannot bind the substrate