L12 Proteins Flashcards
Define a protein
Proteins are macromolecules made up of amino acid building blocks.
How many common amino acids are in human proteins?
20
Amino acids are classified according to what?
the chemical properties of the R-group
Name the specific group terms for each arrow

Blue = Carboxylic group
Red = Central alpha carbon atom
Green = Side chain
Pink = Amino Group
Nonpolar amino acids are ________.
Hydrophobic
List the nonpolar amino acids
Alanine (Ala) (A)
Glycine (Gly) (G)
Isoleucine (Ile) (I)
Leucine (Leu) (L)
Methionine (Met) (M)
Phenylalanine (Phe) (F)
Proline (Pro) (P)
Tryptophan (Trp) (W)
Valine (Val) (V)
List the polar (neutral) amino acids
Asparagine (Asn) (N)
Cytesine (Cys) (C)
Glutamine (Gln) (Q)
Serine (Ser) (s)
Threonine (Thr) (T)
Tyrosine (Tyr) (Y)
List the negatively-charged polar amino acids
Aspartate (Asp) (D)
Glutamate (Glu) (E)
List the positively-charged polar amino acids
Arginine (Arg) (R)
Histidine (His) (H)
Lysine (Lys) (K)
There are how many essential amino acids that are not synthesized in the body and have to be supplied in the diet?
List them.
8
Isoleucine
Leucine
Lysine
Methionine
Phenylalanine
Threonine
Tryptophan
Valine
The primary structure of a protein is the ________.
Amino acid sequence
The secondary structure of a protein is the _______
Alpha helix and beta sheet
True or False?
The primary structure is the order in which the amino acids are linked together.
True
The amino acids are linked through their _______ by ________ to form a polypeptide chain or backbone.
Head groups; peptide bonds
True or False?
The amino end on the first amino acid is added to the carboxyl end of the first one.
False
The amino end on the SECOND amino acid is added to the carboxyl end of the first one.
True or False?
The amino terminus of the first amino acid remains unchanged, and polypeptide grows in the carbon to nitrogen direction.
False.
the polypeptide grows in the Nitrogen to Carbon direction
The repeating N-C(R)-C subunit remaining after the dehydration reaction is an ________.
amino acid residue
Peptide bond have a partial double bond character due to what?
Peptide bonds are a resonance structure
Which conformation of a peptide bond is favored?
Trans conformation
True or False?
With a planar peptide bond, bond rotation is hindered because peptide bond has resonance.
True
True or False?
Bond rotation is only allowed on either side of each peptide bond.
True
Peptide bonds form what kind of bonds with side chains?
Hydrogen bonds
What determines the secondary structure of a protein?
the attractive and repulsive forces among the amino acids
In the coiling of the protein chain, there are how many amino acid residues per turn?
3.6