Chapter 2: Biological Molecules (Nucleic Acids & Proteins) Flashcards
an atom is chemically reactive when ()
the shell is not full
an atom is most stable and chemically unreactive when ()
the outermost shell is filled
sharing of electrons forms ()
covalent bonds
when a double bond forms, rotation of atoms around the bond is (1), so other bonds are (2)
- restricted
- in a single plane
covalent bond that forms between 2 amino acids
peptide bonds
both the C-O and C-N bonds in peptide bonds have () character
partial double bond
radius of an imaginary hard sphere representing the distance of the closest approach for another atom
van der Waals radius
unequal sharing of electrons within a covalent bond
polar covalent bond
() bonds do not have any charge separation
non-polar bonds
separation of charge in polar bonds is called a ()
dipole
tendency of non-polar groups to associate with one another, driven by (), is a big contributor to the behavior of biomolecules, including protein structure
hydrophobic interactions
attraction between fully charged atoms
ionic interactions
ion product of water
10^-14 M
molecules that release H+ into solution are (1), those that accept H+ are (2)
- acids
- bases
weaker () can be formed and broken, allowing flexibility and dynamics in biomolecular structure
non-covalent bonds
non-covalent ionic interactions between charged atoms
salt bridges
non-covalent interactions between polar atoms with partial charges
hydrogen bonds
weak covalent interactions between atoms at a certain distance
van der Waals interactions
in salt bridges, the attraction between charged atoms is a function of the () only
distance between them
salt bridges in proteins are bonds between oppositely charged amino acid residues that are ()
sufficiently close to each other
the salt bridge most often arises from the anionic carboxylate of either (1) and the cationic ammonium from (2) or the guanidinium of (3)
- aspartic acid or glutamic acid
- lysine
- arginine
distance between the amino acid residues participating in the salt bridge should be less than ()
4 angstrom
hydrogen bond interactions are due to the ()
partial charge resulting from a polar covalent bond
hydrogen bonding results from the attractive force between a (1) and (2)
- hydrogen atom covalently bonded to a very electronegative atom (e.g. F, O, N)
- another very electronegative atom