BCMB 401 - Exam 1 With correct answers
Define the term covalent bond and discuss the bond strength. - ....🔰
VERIFIED ANSWERS.... ✔✔- covalent bond: two non-metals sharing
electrons (polar = unequal, nonpolar = equal)
- strength of bond inversely proportional to atomic weight (strength increases
as weight decreases)
Define the term resonance structures and discuss how resonance structures
affect the thermodynamic stability of organic molecules. - ....🔰VERIFIED
ANSWERS.... ✔✔- resonance structures: two or more Lewis structures that
collectively describe the fractional bonding and/or fractional charges of a
single polyatomic ion or molecule
- resonance makes an organic molecule more stable
Compare covalent bonds with non-covalent bonds. - ....🔰VERIFIED
ANSWERS.... ✔✔- covalent bonds keep atoms tightly together, have a high
bond energy, and are stabilized by resonance
- noncovalent bonds are weak and transient with lower bond energy
Name four types of non-covalent bonds and describe their characteristics.
- ....🔰VERIFIED ANSWERS.... ✔✔1) Electrostatic interactions (dipole-
dipole):
- attractive forces between oppositely charged particles
- high electric constant means weakening ionic interactions and indicates a
more polar solution
, 2) Hydrogen bonds:
- weak, transient bonds between an electronegative acceptor (O or N) and and
H covalently bonded to an electronegative donor
3) van der Waals interactions:
- occur between molecules physically close to one another when their electron
asymmetries (due to polarization) match up
- weak but additive over a large area
4) Hydrophobic interactions:
- immobile clathrate shell of water forms around nonpolar molecules in water,
limiting interactions
- association of nonpolar molecules decreases entropy, which then releases
bound clathrate water back into the solvent and raises entropy
Explain the origin of hydrophobic attractions between nonpolar molecules and
give examples of their importance in biochemical interactions. - ....🔰
VERIFIED ANSWERS.... ✔✔- nonpolar molecules cannot participate in
hydrogen bonding or ionic interactions, and so nonpolar molecules interacting
with polar water molecules are unfavorable
- clathrate shells of water will surround nonpolar molecules, decreasing
entropy
- as nonpolar molecules inside clathrate shells associate with one another,
clathrate bound water molecules are released, increasing entropy
What are the two important points about non-covalent bonds from
biochemical perspective? - ....🔰VERIFIED ANSWERS.... ✔✔1) hydrogen
bonding
2) ???
Define the term covalent bond and discuss the bond strength. - ....🔰
VERIFIED ANSWERS.... ✔✔- covalent bond: two non-metals sharing
electrons (polar = unequal, nonpolar = equal)
- strength of bond inversely proportional to atomic weight (strength increases
as weight decreases)
Define the term resonance structures and discuss how resonance structures
affect the thermodynamic stability of organic molecules. - ....🔰VERIFIED
ANSWERS.... ✔✔- resonance structures: two or more Lewis structures that
collectively describe the fractional bonding and/or fractional charges of a
single polyatomic ion or molecule
- resonance makes an organic molecule more stable
Compare covalent bonds with non-covalent bonds. - ....🔰VERIFIED
ANSWERS.... ✔✔- covalent bonds keep atoms tightly together, have a high
bond energy, and are stabilized by resonance
- noncovalent bonds are weak and transient with lower bond energy
Name four types of non-covalent bonds and describe their characteristics.
- ....🔰VERIFIED ANSWERS.... ✔✔1) Electrostatic interactions (dipole-
dipole):
- attractive forces between oppositely charged particles
- high electric constant means weakening ionic interactions and indicates a
more polar solution
, 2) Hydrogen bonds:
- weak, transient bonds between an electronegative acceptor (O or N) and and
H covalently bonded to an electronegative donor
3) van der Waals interactions:
- occur between molecules physically close to one another when their electron
asymmetries (due to polarization) match up
- weak but additive over a large area
4) Hydrophobic interactions:
- immobile clathrate shell of water forms around nonpolar molecules in water,
limiting interactions
- association of nonpolar molecules decreases entropy, which then releases
bound clathrate water back into the solvent and raises entropy
Explain the origin of hydrophobic attractions between nonpolar molecules and
give examples of their importance in biochemical interactions. - ....🔰
VERIFIED ANSWERS.... ✔✔- nonpolar molecules cannot participate in
hydrogen bonding or ionic interactions, and so nonpolar molecules interacting
with polar water molecules are unfavorable
- clathrate shells of water will surround nonpolar molecules, decreasing
entropy
- as nonpolar molecules inside clathrate shells associate with one another,
clathrate bound water molecules are released, increasing entropy
What are the two important points about non-covalent bonds from
biochemical perspective? - ....🔰VERIFIED ANSWERS.... ✔✔1) hydrogen
bonding
2) ???
