BCH 403 - Exam 1 Questions and Answers Latest Update 2025 Already Passed
Equilibrium - Answers If only start with reactants, wait an infinite period of time, the concentration of
reactants and products will be at a constant value. Thus at...
Keq - Answers A constant which describes the ratio of the concentrations of reactants and products that
exist at equilibrium
Equation for Keq - Answers Keq = [C][D]/[A][B]
: concentrations of reactants / concentrations of products
ΔG - Answers Gibbs Free Energy
-quantitatively expresses the driving force for a reaction in terms of entropy and enthalpy
Equation for ΔG - Answers ΔG = ΔH - TΔS
ΔG < 0 - Answers the reaction proceeds spontaneously in the forward direction
ΔG = 0 - Answers the system is at equilibrium and there is no net reaction
ΔG > 0 - Answers the reaction will not proceed spontaneously in the forward direction
When might a reaction be favorable for Gibbs Free Energy - Answers when ΔH < 0 (favorable enthalpy
change) or ΔS > 0 (favorable entropic change)
Remember a favorable entropic change corresponds to..... - Answers An increase in disorder
Can Keq be related to ΔG? - Answers Yes, if define standard state
What is standard state? - Answers 1M concentration of each reactant and product
Relating ΔG and Keq - Answers ΔG° = -RTlnKeq = ΔH°-TΔS°
R is gas constant: 8.3 J/deg*mol
What does ΔG° express? - Answers The free energy change going from 1M reactants and products to
equilibrium
What happens to thermodynamically unfavorable reactions? - Answers It can be driven by being coupled
to a favorable one. Frequently, hydrolysis of ATP
, Water - Answers quite viscous, high boiling point, and high heat of vaporization. Therefore, is liquid over
large temp range which makes for a good solvent
Where do the properties of water result from directly? - Answers Its structure
Isn't arranged linearly so it has a permanent dipole moment
Due to its dipole moment each water molecule can.... - Answers interact electrostatic ally with up to 4
other water molecules; provided the molecules are oriented properly.
Also known as hydrogen bond
Net effect of extensive hydrogen bonding in water - Answers Water is somewhat ordered. This order is
entropically unfavorable BUT favorable enthalpy resulting from the H-bonds compensate for it.
What molecules interact with water favorably? - Answers Polar/charged molecules
-will be soluble in water
Hydrogen bond is - Answers a weak, non-covalent electrostatic interaction which is important in
stabilizing the structure of macromolecules
What happens when non polar substance is put into water? - Answers Can't hydrogen bond because the
carbon isn't very electronegative. Water molecules must become more ordered.
Hydrophobic Effect - Answers -The tendency of non polar substances to self-associate in water.
-Is the major force stabilizing biomembranes; also major force driving protein folding.
Constituents of proteins and biomembranes - Answers amino acids and fatty acids, respectively
Acid-base behavior allows... - Answers there to be charged groups (amino acid side chains) in proteins
and biomembranes
Presence of charged groups in enzymes is frequently important for.... - Answers substrate binding
and/or catalysis
Enzymes often catalyze reactions.... - Answers by catalyzing the transfer of protons (hydrogen ions)
Biological macromolecules are... - Answers frequently stable and active only over a narrow range of
proton concentration (pH)
Equilibrium - Answers If only start with reactants, wait an infinite period of time, the concentration of
reactants and products will be at a constant value. Thus at...
Keq - Answers A constant which describes the ratio of the concentrations of reactants and products that
exist at equilibrium
Equation for Keq - Answers Keq = [C][D]/[A][B]
: concentrations of reactants / concentrations of products
ΔG - Answers Gibbs Free Energy
-quantitatively expresses the driving force for a reaction in terms of entropy and enthalpy
Equation for ΔG - Answers ΔG = ΔH - TΔS
ΔG < 0 - Answers the reaction proceeds spontaneously in the forward direction
ΔG = 0 - Answers the system is at equilibrium and there is no net reaction
ΔG > 0 - Answers the reaction will not proceed spontaneously in the forward direction
When might a reaction be favorable for Gibbs Free Energy - Answers when ΔH < 0 (favorable enthalpy
change) or ΔS > 0 (favorable entropic change)
Remember a favorable entropic change corresponds to..... - Answers An increase in disorder
Can Keq be related to ΔG? - Answers Yes, if define standard state
What is standard state? - Answers 1M concentration of each reactant and product
Relating ΔG and Keq - Answers ΔG° = -RTlnKeq = ΔH°-TΔS°
R is gas constant: 8.3 J/deg*mol
What does ΔG° express? - Answers The free energy change going from 1M reactants and products to
equilibrium
What happens to thermodynamically unfavorable reactions? - Answers It can be driven by being coupled
to a favorable one. Frequently, hydrolysis of ATP
, Water - Answers quite viscous, high boiling point, and high heat of vaporization. Therefore, is liquid over
large temp range which makes for a good solvent
Where do the properties of water result from directly? - Answers Its structure
Isn't arranged linearly so it has a permanent dipole moment
Due to its dipole moment each water molecule can.... - Answers interact electrostatic ally with up to 4
other water molecules; provided the molecules are oriented properly.
Also known as hydrogen bond
Net effect of extensive hydrogen bonding in water - Answers Water is somewhat ordered. This order is
entropically unfavorable BUT favorable enthalpy resulting from the H-bonds compensate for it.
What molecules interact with water favorably? - Answers Polar/charged molecules
-will be soluble in water
Hydrogen bond is - Answers a weak, non-covalent electrostatic interaction which is important in
stabilizing the structure of macromolecules
What happens when non polar substance is put into water? - Answers Can't hydrogen bond because the
carbon isn't very electronegative. Water molecules must become more ordered.
Hydrophobic Effect - Answers -The tendency of non polar substances to self-associate in water.
-Is the major force stabilizing biomembranes; also major force driving protein folding.
Constituents of proteins and biomembranes - Answers amino acids and fatty acids, respectively
Acid-base behavior allows... - Answers there to be charged groups (amino acid side chains) in proteins
and biomembranes
Presence of charged groups in enzymes is frequently important for.... - Answers substrate binding
and/or catalysis
Enzymes often catalyze reactions.... - Answers by catalyzing the transfer of protons (hydrogen ions)
Biological macromolecules are... - Answers frequently stable and active only over a narrow range of
proton concentration (pH)
