BioChem 423 Exam 1 || 100% no Error.
Peptide bonds correct answers amino acids are covalently linked together
-peptide bonds link amino acids together
-*alpha-carboxyl* group of "last" amino acid linked to *alpha-amino* group of "next" amino
acid
-formed by *dehydration* reaction (catalyzed in the ribosome) and broken apart by *hydrolysis*
reaction
-amino group of "last" amino acid is *N-terminus* carboxyl group of "next" amino acid is *C-
terminus*
-has double bond character
-the peptide bond is made up of all the bonds that contribute to the resonance forms (double bond
C=O contributes)
Monomer correct answers A simple compound whose molecules can join together to form
polymers
ex. amino acids, fatty acids, sugar residues (glycerol and monosaccharides), nucleobases
(nucleotides)
Macromolecule correct answers (Polymer)
large molecule formed by joining smaller organic molecules together
ex. proteins, lipids, carbohydrates, DNA/RNA
functional group correct answers group of atoms/bonds that have predictable chemical behavior
,nucleophile correct answers electron rich
usually negatively charged or lone electrons that can easily form bonds with electron deficient
centers
electrophile correct answers electron deficient species
usually positively charged or attached to highly electronegative atoms, attracted to parts of
molecules which are electron rich
Non-covalent interactions correct answers do not involve sharing a pair of electrons
*Types*:
1. charge-charge
2. charge-dipole
3. dispersion (Van der Waals)
4. hydrogen bond
*practice identifying electrophiles vs nucleophiles* correct answers *Nucleophilic groups
include*:
alkoxide
hydroxide ion
carbanion
carboxylate
thiolate
amine
imidazole
,*Electrophilic groups include*:
carbonyl
protonated imine
phosphate
proton
covalent vs non-covalent bonding correct answers covalent = sharing electrons
non-covalent = not sharing electrons
-less energy associated with non-covalent bond compared to covalent
Coulomb's law equations correct answers (for non-covalent interactions)
F = k(q1*q2)/r^2
-q1 and q2 are charges
-r is distance between them
-k is a constant
*when in a medium, need dielectric constant (eps)*:
F = k(q1*q2)/eps*r^2
*Energy (work)*
-E = k(q1*q2)/eps*r
-the energy between 2 charged particles is inversely proportional to the distance between them
(If the 2 charges have different signs, E is negative - charges attract)
, (If the charges have the same sign, E is positive - charges repel)
inter- intra- molecular correct answers intermolecular = between molecules
intramolecular = within one molecule
Strength of noncovalent bonds/interactions correct answers 1. more charged and longer duration
= stronger interaction
2. many weak interactions added together create an overall strong interaction
*From strongest to weakest*:
-covalent
-ionic (permanent formal charges)
-dipole interactions (mix of permanent or temporary AND full or partial charges)
-van der Waals (temporary PARTIAL charges)
Which term describes all types of noncovalent bonds?
A. Van der waals
B. electrostatic
C. intermolecular
D. intramolecular correct answers B. electrostatic
Types of noncovalent bonds/interactions correct answers classified based on magnitude and
duration of charges of interacting atoms
Peptide bonds correct answers amino acids are covalently linked together
-peptide bonds link amino acids together
-*alpha-carboxyl* group of "last" amino acid linked to *alpha-amino* group of "next" amino
acid
-formed by *dehydration* reaction (catalyzed in the ribosome) and broken apart by *hydrolysis*
reaction
-amino group of "last" amino acid is *N-terminus* carboxyl group of "next" amino acid is *C-
terminus*
-has double bond character
-the peptide bond is made up of all the bonds that contribute to the resonance forms (double bond
C=O contributes)
Monomer correct answers A simple compound whose molecules can join together to form
polymers
ex. amino acids, fatty acids, sugar residues (glycerol and monosaccharides), nucleobases
(nucleotides)
Macromolecule correct answers (Polymer)
large molecule formed by joining smaller organic molecules together
ex. proteins, lipids, carbohydrates, DNA/RNA
functional group correct answers group of atoms/bonds that have predictable chemical behavior
,nucleophile correct answers electron rich
usually negatively charged or lone electrons that can easily form bonds with electron deficient
centers
electrophile correct answers electron deficient species
usually positively charged or attached to highly electronegative atoms, attracted to parts of
molecules which are electron rich
Non-covalent interactions correct answers do not involve sharing a pair of electrons
*Types*:
1. charge-charge
2. charge-dipole
3. dispersion (Van der Waals)
4. hydrogen bond
*practice identifying electrophiles vs nucleophiles* correct answers *Nucleophilic groups
include*:
alkoxide
hydroxide ion
carbanion
carboxylate
thiolate
amine
imidazole
,*Electrophilic groups include*:
carbonyl
protonated imine
phosphate
proton
covalent vs non-covalent bonding correct answers covalent = sharing electrons
non-covalent = not sharing electrons
-less energy associated with non-covalent bond compared to covalent
Coulomb's law equations correct answers (for non-covalent interactions)
F = k(q1*q2)/r^2
-q1 and q2 are charges
-r is distance between them
-k is a constant
*when in a medium, need dielectric constant (eps)*:
F = k(q1*q2)/eps*r^2
*Energy (work)*
-E = k(q1*q2)/eps*r
-the energy between 2 charged particles is inversely proportional to the distance between them
(If the 2 charges have different signs, E is negative - charges attract)
, (If the charges have the same sign, E is positive - charges repel)
inter- intra- molecular correct answers intermolecular = between molecules
intramolecular = within one molecule
Strength of noncovalent bonds/interactions correct answers 1. more charged and longer duration
= stronger interaction
2. many weak interactions added together create an overall strong interaction
*From strongest to weakest*:
-covalent
-ionic (permanent formal charges)
-dipole interactions (mix of permanent or temporary AND full or partial charges)
-van der Waals (temporary PARTIAL charges)
Which term describes all types of noncovalent bonds?
A. Van der waals
B. electrostatic
C. intermolecular
D. intramolecular correct answers B. electrostatic
Types of noncovalent bonds/interactions correct answers classified based on magnitude and
duration of charges of interacting atoms
