Exam 3 Energetics Flashcards
Is it energetically favorable for ice to melt at 263 K (-10 ˚C), where ΔH is +5630 J/mol and ΔS is +20.6 J/K•mol?
ΔG is positive and the melting of ice at 263 K is unfavorable.
True or False? The entropy of an open system can decrease.
True
An organism takes in nutrients, often in the form of high-entropy small molecules, and from them it builds enormous, complex, highly ordered macromolecules like proteins and nucleic acids, which constructs elegantly structured cells, tissues, and organs. This is an example of what?
Entropy decreasing in an open system.
In order for the entropy of an open system to decrease, it requires what?
An accompanying large decrease in enthalpy.
True or False?
Living organisms spend energy to overcome entropy.
True
True or False?
For these life processes to occur, the overall free energy changes in the organism must be positive; thus, life is an irreversible process
False
What does it mean when an organism comes to equilibrium with its surroundings.
That organism is dead.
True or False?
The portion of an energy change in process that is available, or free, to do useful work at constant T, P is the definition of Delta G.
True
True or False?
The sign of ∆H for a process tells us whether that process, or its reverse, is thermodynamically favorable.
False it is ∆G
True or False?
The magnitude of ∆G is an indication of how far the process is from equilibrium and how much useful work may be obtained from it.
True
True or False?
A thermodynamically favored process tends in the direction that maximizes free energy because it results in a negative ∆G.
False. minimizing ∆G would cause it to be negative which is favored.
True or False?
Since free energy is a state function, free energy change for any reaction will equal the free energy of the products minus that of the reactants.
True
True or False?
For a reaction that is exergonic, ΔG = 0 because there is no driving force in either direction.
False. ΔG = 0 at equilibrium
True or False?
The metabolic processes can occur only when each has a favorable thermodynamic driving force, that is, when ∆G < 0, within relatively narrow ranges of temperature, pH, and concentrations for ions and metabolites.
True
True or False?
The concentrations of certain solutes inside cells remain relatively constant.
True
True or False?
In the steady state, continuous free energy is put into the system to maintain homeostasis.
True
Thermodynamic definition of entropy change at constant pressure is __________.
_______represents the heat transferred from the system to the surroundings at constant pressure and some temperature T.
∆Hsystem
True or False?
The negative sign represents a loss of energy by the system and a gain of energy by the surroundings.
True
True or False?
Free energy is not relevant to bioenergetics because most cells and organisms live under conditions of constant pressure and temperature.
False. it is relevant
Define Delta G
The amount of ‘free’ energy in a system to do useful work under the given conditions, specifically constant temperature
What is the formula for free energy?
What is the formula for The free energy of solute?
For a typical favorable process ∆G must be what?
∆G must be negative, i.e. ∆G < 0