BCHM 4611 Final Exam Questions &
Answers
Prokaryotes - ANSWERS2 domains: archaea and bacteria, exclusively single cell organisms, no
nucleus
Benefits of being prokaryotic - ANSWERSMore adaptable to changing environments, species
have evolved to colonize extreme environments due to their simplicity and rapid cell division
Eukaryotes - ANSWERSMulticellular and unicellular organisms, more complex cellular
organization with membrane-enclosed organelles that have specialized functions, DNA stored in
nucleus
Classes of monomers - ANSWERSAmino acids, monosaccharides, nucleotides, and lipids
Classes of polymers - ANSWERSPolypeptides, polysaccharides, nucleic acids (no true polymers
for lipids - form non-covalent aggregates)
Polypeptide/protein - ANSWERSPolymer of amino acids linked together by peptide bonds
Residue - ANSWERSMonomer that has been incorporated into a polymer
Protein major roles - ANSWERSCarry out metabolic reactions, support cellular structures
Protein minor role - ANSWERSStore energy
,Nucleic acid major role - ANSWERSEncode information
Nucleic acid minor roles - ANSWERSCarry out metabolic reactions, support cellular structures
Polysaccharides major roles - ANSWERSStore energy, support cellular structures
Polysaccharides minor role - ANSWERSEncode information
Open system - ANSWERSEnergy can be transferred between the system and its surroundings
Closed system - ANSWERSOnly exchanges energy with its surroundings, not matter
Isolated system - ANSWERSDoes not exchange energy or matter with its surroundings
Gibbs free energy (G) - ANSWERSThermodynamic quantity whose change indicates the
spontaneity of a process. For spontaneous/favorable processes, ΔG < 0, whereas for a process at
equilibrium, ΔG = 0
Enthalpy (H) - ANSWERSHeat content of a biochemical system
Entropy (S) - ANSWERSDegree of randomness or disorder of a system
Free energy change equation - ANSWERSΔG = ΔH - TΔS
Coupled reaction - ANSWERSReactions that occur in concert with each other; product of the
first reaction is a reactant for the second reaction; ΔG values are added when reactions are
combined
,Why is ΔG independent of path chosen? - ANSWERSDepends only on the initial and final states
of the system, without regard to the specific chemical or mechanical work that occurred in
going from one state to the other
Oxidation - ANSWERSLoss of electrons through the addition of oxygen or removal of hydrogen;
oxidation of carbon is thermodynamically favorable so it can be coupled with otherwise
unfavorable processes
Catabolism - ANSWERSBreaking down molecules, yielding energy; some of this free energy may
be conserved in the formation of nucleotide triphosphates (NTPs) such as ATP or reduced
cofactors such as NADP+ or Q
Anabolism - ANSWERSBuilding complex molecules at the expense of energy
H2O structure/geometry - ANSWERSCentral oxygen atom forms covalent bonds with two
hydrogen atoms, leaving two unshared pairs of electrons; tetrahedral geometry
How does water's structure affect its properties and interactions with other molecules? -
ANSWERSIt is polar (uneven distribution of charge) which allows it to form hydrogen bonds with
other water molecules, this makes water highly cohesive; has high dielectric constant which
means ionic compounds dissolve in it well; polar compounds also dissolve well due to hydrogen
bonding with water
Covalent bond - ANSWERSFormed when two atoms share electrons
Ionic interaction - ANSWERSElectrostatic interaction between two groups that is stronger than a
hydrogen bond but weaker than a covalent bond
, Hydrogen bond - ANSWERSPartly electrostatic, partly covalent interaction between a donor
group such as OH or NH and an electronegative acceptor atom such as O or N
Types of Van der Waals interactions - ANSWERSDipole-dipole, dipole-induced dipole, and
London dispersion forces
Van der Waals interactions - ANSWERSWeak non-covalent association between molecules that
arises from the attractive forces between polar groups (dipole-dipole interactions) or between
non-polar groups whose fluctuating electron distribution gives rise to temporary dipoles
(London dispersion forces)
Relative strengths of chemical bonds (weakest to strongest) - ANSWERSVan der Waals, hydrogen
bond, ionic, covalent
Amphipathic/amphiphilic - ANSWERSHaving both polar and non-polar regions and therefore
being both hydrophilic and hydrophobic
How do amphiphilic molecules behave in aqueous solutions? - ANSWERSPolar groups of
amphiphiles orient themselves toward the solvent molecules and are therefore hydrated, while
the nonpolar groups tend to aggregate due to the hydrophobic effect; as a result, amphiphiles
may form a spherical micelle, a particle with a solvated surface and a hydrophobic core
Hydrophobic effect - ANSWERSExclusion of non-polar substances from an aqueous solution;
non-polar molecules are driven out of the aqueous phase by the unfavorable entropy cost of
individually hydrating them
Buffer - ANSWERSSolution containing an acid and its conjugate base, resists changes in pH when
more acid or base is added
Buffer effective range - ANSWERSWithin one unit of the pKa (pKa +/- 1)
Answers
Prokaryotes - ANSWERS2 domains: archaea and bacteria, exclusively single cell organisms, no
nucleus
Benefits of being prokaryotic - ANSWERSMore adaptable to changing environments, species
have evolved to colonize extreme environments due to their simplicity and rapid cell division
Eukaryotes - ANSWERSMulticellular and unicellular organisms, more complex cellular
organization with membrane-enclosed organelles that have specialized functions, DNA stored in
nucleus
Classes of monomers - ANSWERSAmino acids, monosaccharides, nucleotides, and lipids
Classes of polymers - ANSWERSPolypeptides, polysaccharides, nucleic acids (no true polymers
for lipids - form non-covalent aggregates)
Polypeptide/protein - ANSWERSPolymer of amino acids linked together by peptide bonds
Residue - ANSWERSMonomer that has been incorporated into a polymer
Protein major roles - ANSWERSCarry out metabolic reactions, support cellular structures
Protein minor role - ANSWERSStore energy
,Nucleic acid major role - ANSWERSEncode information
Nucleic acid minor roles - ANSWERSCarry out metabolic reactions, support cellular structures
Polysaccharides major roles - ANSWERSStore energy, support cellular structures
Polysaccharides minor role - ANSWERSEncode information
Open system - ANSWERSEnergy can be transferred between the system and its surroundings
Closed system - ANSWERSOnly exchanges energy with its surroundings, not matter
Isolated system - ANSWERSDoes not exchange energy or matter with its surroundings
Gibbs free energy (G) - ANSWERSThermodynamic quantity whose change indicates the
spontaneity of a process. For spontaneous/favorable processes, ΔG < 0, whereas for a process at
equilibrium, ΔG = 0
Enthalpy (H) - ANSWERSHeat content of a biochemical system
Entropy (S) - ANSWERSDegree of randomness or disorder of a system
Free energy change equation - ANSWERSΔG = ΔH - TΔS
Coupled reaction - ANSWERSReactions that occur in concert with each other; product of the
first reaction is a reactant for the second reaction; ΔG values are added when reactions are
combined
,Why is ΔG independent of path chosen? - ANSWERSDepends only on the initial and final states
of the system, without regard to the specific chemical or mechanical work that occurred in
going from one state to the other
Oxidation - ANSWERSLoss of electrons through the addition of oxygen or removal of hydrogen;
oxidation of carbon is thermodynamically favorable so it can be coupled with otherwise
unfavorable processes
Catabolism - ANSWERSBreaking down molecules, yielding energy; some of this free energy may
be conserved in the formation of nucleotide triphosphates (NTPs) such as ATP or reduced
cofactors such as NADP+ or Q
Anabolism - ANSWERSBuilding complex molecules at the expense of energy
H2O structure/geometry - ANSWERSCentral oxygen atom forms covalent bonds with two
hydrogen atoms, leaving two unshared pairs of electrons; tetrahedral geometry
How does water's structure affect its properties and interactions with other molecules? -
ANSWERSIt is polar (uneven distribution of charge) which allows it to form hydrogen bonds with
other water molecules, this makes water highly cohesive; has high dielectric constant which
means ionic compounds dissolve in it well; polar compounds also dissolve well due to hydrogen
bonding with water
Covalent bond - ANSWERSFormed when two atoms share electrons
Ionic interaction - ANSWERSElectrostatic interaction between two groups that is stronger than a
hydrogen bond but weaker than a covalent bond
, Hydrogen bond - ANSWERSPartly electrostatic, partly covalent interaction between a donor
group such as OH or NH and an electronegative acceptor atom such as O or N
Types of Van der Waals interactions - ANSWERSDipole-dipole, dipole-induced dipole, and
London dispersion forces
Van der Waals interactions - ANSWERSWeak non-covalent association between molecules that
arises from the attractive forces between polar groups (dipole-dipole interactions) or between
non-polar groups whose fluctuating electron distribution gives rise to temporary dipoles
(London dispersion forces)
Relative strengths of chemical bonds (weakest to strongest) - ANSWERSVan der Waals, hydrogen
bond, ionic, covalent
Amphipathic/amphiphilic - ANSWERSHaving both polar and non-polar regions and therefore
being both hydrophilic and hydrophobic
How do amphiphilic molecules behave in aqueous solutions? - ANSWERSPolar groups of
amphiphiles orient themselves toward the solvent molecules and are therefore hydrated, while
the nonpolar groups tend to aggregate due to the hydrophobic effect; as a result, amphiphiles
may form a spherical micelle, a particle with a solvated surface and a hydrophobic core
Hydrophobic effect - ANSWERSExclusion of non-polar substances from an aqueous solution;
non-polar molecules are driven out of the aqueous phase by the unfavorable entropy cost of
individually hydrating them
Buffer - ANSWERSSolution containing an acid and its conjugate base, resists changes in pH when
more acid or base is added
Buffer effective range - ANSWERSWithin one unit of the pKa (pKa +/- 1)
