Problem:
According to the First Law of Thermodynamics, energy cannot be created or destroyed, only changed in form (p. 10). This is also known as the principle of conservation of energy. In a biological system, this energy change is often referred to as the change in enthalpy (p. 10). For an exothermic reaction, the change in enthalpy is: Less than 0 (triangle H < 0) The Second Law of Thermodynamics states that the total entropy (S) of a system and its surroundings tends to increase for a spontaneous process (p. 12). This natural tendency is for the universe to become more disorganized (p. 12). Which of the following statements about spontaneity is correct? (p. 17) A reaction is spontaneous at all temperatures if delta H is less than 0 and delta S is greater than 0. The spontaneity of a reaction is determined by the GIBBS free energy change deltaG which is calculated using the equation deltaG =DeltaH - TdeltaS. A negative deltaG value indicates an exergonic reaction that will occur spontaneously (p. 15). Catalysts, including enzymes, affect a reaction by: (p. 31) Lowering the activation energy of the reaction. Enzymes are highly specific biological catalysts, typically proteins, that increase reaction rates (pp. 22, 25). The molecules that an enzyme acts upon are called: (p. 23 Substrates Short answer questions: Explain the key differences between potential energy and kinetic energy, providing an example for each as described in the course materials (pp 4-5) Need Assignment Help?