PRELIM 02 - Proteins Flashcards
Are polymers of amino acids
Proteins
Are molecules that contains an amino, carboxyl, and side chain group
Amino acid
A chemical group that gives identity to the amino acid
Side chain group (R)
All amino acids, except __________ have at least one stereocenter and are achiral
Glycine
Molecules that contain both positive and negative charges
Zwitterion
Proton donor
Bronsted acid
Proton acceptor
Bronsted base
The pH at which the net charge of an amino acid/peptide is zero
Isoelectric pH (pl)
Is an amide bond between the α-carboxyl group of one amino acid and the α-amino group of another amino acid
Peptide bond
Molecules that are two or more amino acids linked by peptide bonds
Peptides
Are amino acids not or inadequately synthesized by the body; essential in the diet
Essential amino acids
Are amino acids that can be synthesized in the body; not required in the diet
Non-essential amino acids
Refers to the spatial arrangement of atoms in a protein
Conformation
The three-dimensional structure of a protein is called __________
Native conformation
Are proteins in any of their functional, folded conformation
Native proteins
4 levels of protein organization
Primary, Secondary, Tertiary, Quaternary
It refers to the sequence of amino acids in a polypeptide chain (Levels of protein organization)
Primary structure
It refers to the ordered 3D arrangements in localized regions of a polypeptide chain (Levels of protein organization)
Secondary structure
3 types of secondary structure of proteins
α-Helix, β-sheet, Random coil
Spiral structure; stabilized by intramolecular hydrogen bonds (Types of secondary structure of proteins)
α-Helix
Pitch of α-Helix
5.4 Angstrom
It is formed when 2 or more polypeptides line up side by side (Types of secondary structures of proteins)
β-sheet/β-pleated sheet
2 types of β-sheets/β-pleated sheets
Anti-parallel β-sheet, Parallel β-sheet