Lecture 3 Feb 20 Flashcards
What free energy?
G; portion of a systems’s energy that can do work
What does it mean to have less free energy?
the system in its final state is less likely to change and more stable, less work capacity
Free energy change=?
Delta G; Delta G=Final G minus the initial G
What does it mean to have more free energy?
The system is more likely to change and less stable; it has more work capacity
When a reaction is spontaneous, delta G is…
negative; system is more stable
What is an exergonic reaction?
It is the net release of free energy; spontaneous with a negative delta G
What is an exergonic reaction?
It is the net input of free energy; non-spontaneous with a positive delta G
What is activation energy?
It is the initial energy required to start a reaction
What is a catalyst?
Catalysts selectively speed up reactions without being consumed by the reaction; lower Ea
What are enzymes?
Enzymes are catalytic proteins that lower Ea. They are specific (recognize what to bind to, picky)
What are reactants in an enzyme reaction?
Subtrates
What is induced fit?
Substrate binds to active site; both change shape to complete binding (H-bond or Ionic bond)
What is the active site of an enzyme?
Where substrate enters/binds; held together by weak interactions
What are the steps of the enzymatic reaction cycle?
- Substrates enter active site
- Substrates are held in active site by weak interactions
- The active site lowers Ea
- Substrates are converted to products
- Product are released
- Active site is available for new substrates
What are some physical/chemical effects on enzyme activity?
Temperature, pH
