MCB 354 Exam UPDATED QUESTIONS
AND CORRECT ANSWERS
Enantiomers - CORRECT ANSWER two stereoisomers that are mirror images of one another
Properties of carbons - CORRECT ANSWER complex chains, form four bonds, can form
single or double bonds, sp3 hybridized or sp2
Which type of chiral amino acids are found in nature? - CORRECT ANSWER L-amino acids,
have an @ configuration for chiral carbon except glycine and cysteine
Diasteromers - CORRECT ANSWER not mirror images, differ at one or more chiral carbon
Epimer - CORRECT ANSWER differ at a single chiral carbon
Internal energy - CORRECT ANSWER the total energy within a system
Enthalpy - CORRECT ANSWER sum of internal energy of a system and the product of its
volume and external pressure
Entropy - CORRECT ANSWER meaure of thermal energy per unit temperature that becomes
unavailable for doing work, randomness of disorder of the components of a chemical system
Gibbs free energy - CORRECT ANSWER combines entropy and enthalpy into a single value
Standard state - CORRECT ANSWER 1 molar for concentrations
Reaction at equilibrium, delta G... - CORRECT ANSWER should equal zero, there will be no
change in free energy
, When Keq is less than one.. - CORRECT ANSWER delta G not is negative, reaction proceeds
forward
When Keq is 1 - CORRECT ANSWER delta G not is zero, reaction is at equilibrium
When Keq is more than one - CORRECT ANSWER delta G not is positive, reaction proceeds
backwards
Condensation bonds - CORRECT ANSWER are generally unfavorable, need to be coupled
with a highly favorable reaction
Water is.... - CORRECT ANSWER a solvent, polar, has a high dielectric constant,
Favorable reactions have _______ in Gibb's free energy - CORRECT ANSWER decrease
Stereoisomers - CORRECT ANSWER can be calculated by number of chiral carbons 2n
S configuration - CORRECT ANSWER counterclockwise, knowsn as L configuration in
biology ( shows up in biology more)
R configuration - CORRECT ANSWER clockwise, known as D in biology, not common in the
real world
Secondary structure - CORRECT ANSWER lone pair of electrons on the amide nitrogen are
delocalized with carbonyl pi orbital electrons, amide bond has partial double bond, unable to rotate
freely, rotation permitted around the alpha Carbon
Ca-C bond angle - CORRECT ANSWER psi angle, on the y axis of ramachandran plot
N-Ca bond angle - CORRECT ANSWER phi angle, on the x axis of ramachandran plot
Distance between Ca to Ca - CORRECT ANSWER 3.7 A
AND CORRECT ANSWERS
Enantiomers - CORRECT ANSWER two stereoisomers that are mirror images of one another
Properties of carbons - CORRECT ANSWER complex chains, form four bonds, can form
single or double bonds, sp3 hybridized or sp2
Which type of chiral amino acids are found in nature? - CORRECT ANSWER L-amino acids,
have an @ configuration for chiral carbon except glycine and cysteine
Diasteromers - CORRECT ANSWER not mirror images, differ at one or more chiral carbon
Epimer - CORRECT ANSWER differ at a single chiral carbon
Internal energy - CORRECT ANSWER the total energy within a system
Enthalpy - CORRECT ANSWER sum of internal energy of a system and the product of its
volume and external pressure
Entropy - CORRECT ANSWER meaure of thermal energy per unit temperature that becomes
unavailable for doing work, randomness of disorder of the components of a chemical system
Gibbs free energy - CORRECT ANSWER combines entropy and enthalpy into a single value
Standard state - CORRECT ANSWER 1 molar for concentrations
Reaction at equilibrium, delta G... - CORRECT ANSWER should equal zero, there will be no
change in free energy
, When Keq is less than one.. - CORRECT ANSWER delta G not is negative, reaction proceeds
forward
When Keq is 1 - CORRECT ANSWER delta G not is zero, reaction is at equilibrium
When Keq is more than one - CORRECT ANSWER delta G not is positive, reaction proceeds
backwards
Condensation bonds - CORRECT ANSWER are generally unfavorable, need to be coupled
with a highly favorable reaction
Water is.... - CORRECT ANSWER a solvent, polar, has a high dielectric constant,
Favorable reactions have _______ in Gibb's free energy - CORRECT ANSWER decrease
Stereoisomers - CORRECT ANSWER can be calculated by number of chiral carbons 2n
S configuration - CORRECT ANSWER counterclockwise, knowsn as L configuration in
biology ( shows up in biology more)
R configuration - CORRECT ANSWER clockwise, known as D in biology, not common in the
real world
Secondary structure - CORRECT ANSWER lone pair of electrons on the amide nitrogen are
delocalized with carbonyl pi orbital electrons, amide bond has partial double bond, unable to rotate
freely, rotation permitted around the alpha Carbon
Ca-C bond angle - CORRECT ANSWER psi angle, on the y axis of ramachandran plot
N-Ca bond angle - CORRECT ANSWER phi angle, on the x axis of ramachandran plot
Distance between Ca to Ca - CORRECT ANSWER 3.7 A
