Lecture 3: Amino Acids Flashcards
Ionization state of amino acids varies with
PH
Amino acids are the building blocks of
proteins
CORN Law
Look at the H-Ca bonf and see, if clockwise CO R N then it is L isomer
D isomer of amino acid
- This form would not be a unit of a protein in the natural world
Zwitterion form
Under neutral conditions, the amino acid will exist in its zwitterion form. A zwitterion is a molecule that contains both a positive and a negative charge. For the zwitterion amino acid, the negative charge comes from the carboxylate ion while the positive charge comes from the ammonium ion.
Zwitterionic form predominates at
PH 7.4
All forms of life use a common set of — amino acids to build proteins
20
Each amino acid difers by its
Side chain (R group)
Side chains contain different —- with different —–
- functional groups
- chemical properties
Glycine’s R group is a —- so it is —- —-
- hydrogen
- not chiral
Alanine’s R group is a —- group
methyl
Isoleucine is a —- —- of leucine
Constitutional isomer
Secondary amine (2)
What it is + who is included
- 5 membered ring
- proline
The amino acids are all chiral, with the exception of —, whose side chain is —.
- glycine
- H
Methionine has a —- group but not at the end and therefore —–
- sulfur group
- less reactive
The amino acids that are hydrophobic, because of their R groups are often found
away from water when part of a protein
Cysteine has a —- group at the end where it is reactive
thiol
Which amino acid is classified as “polar” because of the electronegative groups in their “R” groups? (6)
- Serine
- Threonine
- Tyrosine
- Cysteine
- Asparagine
- Glutamine
Cysteine is often considered a
hydrophobic amino acid
These amino acids have “R” groups that are generally negatively charged (2)
- Asparatate
- Glutamate
guanidinium
Which amino acid has guanidinium?
- Arginine
Arginine, lysine and Histidine is generally —-
protonated
Lysine, arginine, and histidine are —- charged at neutral pH.
positively
which of the 20 amino acid lacks a primary amine?
proline
