BCH 403 Exam 1-Questions With 100%
Verified Answers.
What molecules interact with water favorably? - ✔✔Polar/charged molecules
-will be soluble in water
Hydrogen bond is - ✔✔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? - ✔✔Can't hydrogen bond because
the carbon isn't very electronegative. Water molecules must become more ordered.
Hydrophobic Effect - ✔✔-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 - ✔✔amino acids and fatty acids, respectively
Acid-base behavior allows... - ✔✔there to be charged groups (amino acid side chains)
in proteins and biomembranes
Presence of charged groups in enzymes is frequently important for.... - ✔✔substrate binding
and/or catalysis
Enzymes often catalyze reactions.... - ✔✔by catalyzing the transfer of protons (hydrogen
ions)
, Biological macromolecules are... - ✔✔frequently stable and active only over a narrow
range of proton concentration (pH)
Acid - ✔✔ANY proton donor
Base - ✔✔ANY proton acceptor
What happens to strong acids and bases in aqueous solution? - ✔✔They are
completely dissociated.
HCl + H2O -------> H30+ + Cl-
What happens when an acid undergoes dissociation. - ✔✔It loses one positive charge
AH + H2O -------> A- + H3O+
A defined acidity constant for acetic acid and water (Ka) - ✔✔Since acetic acid is weak,
the conc of water is very high, but will not change significantly under normal circumstances.
pKa = -logKa
What happens to weak acids and bases in an aqueous solution? - ✔✔They are only slightly
dissociated.
CH3COOH + H2O <------> CH3COO- + H3O+
(acid) (base) (conj base) (conj acid)
Kdiss is equilibrium const.
Verified Answers.
What molecules interact with water favorably? - ✔✔Polar/charged molecules
-will be soluble in water
Hydrogen bond is - ✔✔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? - ✔✔Can't hydrogen bond because
the carbon isn't very electronegative. Water molecules must become more ordered.
Hydrophobic Effect - ✔✔-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 - ✔✔amino acids and fatty acids, respectively
Acid-base behavior allows... - ✔✔there to be charged groups (amino acid side chains)
in proteins and biomembranes
Presence of charged groups in enzymes is frequently important for.... - ✔✔substrate binding
and/or catalysis
Enzymes often catalyze reactions.... - ✔✔by catalyzing the transfer of protons (hydrogen
ions)
, Biological macromolecules are... - ✔✔frequently stable and active only over a narrow
range of proton concentration (pH)
Acid - ✔✔ANY proton donor
Base - ✔✔ANY proton acceptor
What happens to strong acids and bases in aqueous solution? - ✔✔They are
completely dissociated.
HCl + H2O -------> H30+ + Cl-
What happens when an acid undergoes dissociation. - ✔✔It loses one positive charge
AH + H2O -------> A- + H3O+
A defined acidity constant for acetic acid and water (Ka) - ✔✔Since acetic acid is weak,
the conc of water is very high, but will not change significantly under normal circumstances.
pKa = -logKa
What happens to weak acids and bases in an aqueous solution? - ✔✔They are only slightly
dissociated.
CH3COOH + H2O <------> CH3COO- + H3O+
(acid) (base) (conj base) (conj acid)
Kdiss is equilibrium const.
