Amino Acids and Proteins

Question 1

which amino acid lacks a side chain?

Answer 1

glycine

Question 2

acidic amino acids

Answer 2

have side chains with ionizable carboxylic acid groups

aspartate, glutamate

Question 3

basic amino acids

Answer 3

have side chains with ionizable basic groups containing nitrogen atoms
arginine, histidine, lysine

Question 4

hydrophilic/polar amino acids

Answer 4

have side chains with polar groups that can form hydrogen bonds
asparagine, cysteine, glutamine, serine, threonine

Question 5

aliphatic amino acids

Answer 5

have side chains with hydrocarbon groups
are hydrophobic
alanine, isoleucine, leucine, methionine, proline, valine

Question 6

aromatic amino acids

Answer 6

have side chains with aromatic groups
are hydrophobic
phenylalanine, tryptophan, tyrosine

Question 7

primary structure

Answer 7

a sequence of amino acids linked by peptide bonds

Question 8

which conformation is favored for peptide bonds?

Answer 8

trans (less steric clashes)

Question 9

secondary structure

Answer 9

3D structure resulting from hydrogen bonding between the N-H and C=O of amino acids in the polypeptide bond

Question 10

types of secondary structures

Answer 10

alpha helix and beta strands

Question 11

alpha helix

Answer 11

multiple = helical bundles
regularly repeating amino acid structure with 3.6 residues (5.4 angstroms) per turn
all of the amino side chains are outside the helix
is right handed
can be polar, hydrophobic, or amphipathic