BCH 451 EXAM 2 QUESTIONS AND ANSWERS WITH COMPLETE
SOLUTIONS VERIFIED GRADED A++
Enzymes
Catalyst of biological reactions
Catalyst
promotes a reaction by increasing the reaction rate but is not changed by the reaction
Enzymes are typically
a protein
Why are enzymes important for biological reactions?
1. They increase the speed of the reaction
2. Permits reactions to occur under physiological conditions.
Enzymes and reaction equilibrium
Enzymes DO NOT change the reactions equilibrium
Transition state
An unstable arrangement of atoms with the chemical bonds in the process of being
formed or broken
Activation Energy
The energy barrier of the reaction that must be overcome for the reaction to occur
How does an enzyme speed up a chemical reaction?
By decreasing the activation energy. This decrease in the activation energy has a
smaller barrier to overcome and thus the rate of reaction is increased.
Basis of Enzyme Reaction
, E + S -> (K1/K-1) -> ES -> (K2/K-2) -> E + P
First step of Enzyme Reaction
E + S -> ES
Relatively fast
Reversible Step
Substrate "finds" enzyme in solvent.
Rate of ES complex formation
K1 (forward reaction rate or formation of ES complex rate)
Dependent of substate concentration.
Larger the concentration, greater likelihood that the enzyme interacts with substrate.
Rate of ES binding
Limited by diffusion rate. Very ligand-specific recognizing only its substrate. Weak
interaction because dissociable
Dissociation of ES complex
K-1 (reverse reaction rate or dissociation of ES complex rate)
Binding strengths of ES complex reflected in..
Reaction rate constants or Km
Second step of Enzyme Reaction
ES -> E + P
Slower and rate limiting
Generally considered irreversible
When will second step of enzyme reaction take place after ES complex is formed?
SOLUTIONS VERIFIED GRADED A++
Enzymes
Catalyst of biological reactions
Catalyst
promotes a reaction by increasing the reaction rate but is not changed by the reaction
Enzymes are typically
a protein
Why are enzymes important for biological reactions?
1. They increase the speed of the reaction
2. Permits reactions to occur under physiological conditions.
Enzymes and reaction equilibrium
Enzymes DO NOT change the reactions equilibrium
Transition state
An unstable arrangement of atoms with the chemical bonds in the process of being
formed or broken
Activation Energy
The energy barrier of the reaction that must be overcome for the reaction to occur
How does an enzyme speed up a chemical reaction?
By decreasing the activation energy. This decrease in the activation energy has a
smaller barrier to overcome and thus the rate of reaction is increased.
Basis of Enzyme Reaction
, E + S -> (K1/K-1) -> ES -> (K2/K-2) -> E + P
First step of Enzyme Reaction
E + S -> ES
Relatively fast
Reversible Step
Substrate "finds" enzyme in solvent.
Rate of ES complex formation
K1 (forward reaction rate or formation of ES complex rate)
Dependent of substate concentration.
Larger the concentration, greater likelihood that the enzyme interacts with substrate.
Rate of ES binding
Limited by diffusion rate. Very ligand-specific recognizing only its substrate. Weak
interaction because dissociable
Dissociation of ES complex
K-1 (reverse reaction rate or dissociation of ES complex rate)
Binding strengths of ES complex reflected in..
Reaction rate constants or Km
Second step of Enzyme Reaction
ES -> E + P
Slower and rate limiting
Generally considered irreversible
When will second step of enzyme reaction take place after ES complex is formed?
