Enzymes Quiz
1. How does the second law of thermodynamics apply to living organisms?
LIVING ORGANISMS REQUIRE A CONSTANT INPUT OF ENERGY TO MAINTAIN COMPLEX STRUCTURES AND ORDER.
2. In any closed system, the total energy includes usable and unusable energy. The unusable energy is a measure of the disorder of the system and is referred to as
ENTROPY
3. A readily reversible reaction, in which reactants and products have almost the same free energies, is indicated by a
DELTA G NEAR ZERO
4. Knowing the change in free energy (delta G) of a reaction tells us
THE EQUILIBIRUM POINT OF THE REACTION
5. The hydrolysis of sucrose to glucose and fructose is exergonic. However, if sucrose is dissolved in water and the solution is kept overnight at room temperature, there is no detectable conversion to glucose and fructose. Why?
THE ACTIVATION ENERGY OF THE REACTION IS HIGH
6. The phosphorylation of glucose to glucose-6-phosphate has a delta G of +4.0 kcal/mol. If hexokinase is added to speed up the rate of this reaction, the delta G will
STAY THE SAME
7. Trypsin and elastase are both enzymes that catalyze hydrolysis of peptide bonds. But trypsin only cuts next to lysine and elastase only cuts next to alanine. Why?
THE SHAPE OF THE ACTIVE SITE FOR THE TWO ENZYMES IS DIFFERENT
8. The molecular structure that is short-lived and neither substrate nor product is known as the
TRANSITION STATE
9. In some cases, a substrate-enzyme complex is stabilized by
HYDROGEN BONDS, COVALENT BONDS, IONIC ATTRACTIONS, AND HYDROPHOBIC INTERACTIONS
10. Which of the following is true?
ENZYMES DO NOT FORCE REACTIONS TO PROCEED IN ONLY ONE DIRECTION, ENZYMES DO NOT ALTER THE EQUILIBIRUM OF THE REACTION, AND ENZYMES DO NOT ALTER THE STANDARD FREE ENERGY OF THE REACTION