Test 1

Cell bio Daughdrill Fall 2026

At a pH of 7, the amino and carboxyl groups are what? What does this allow it to do?

Ionized. Allows for specific protein folding and water solubility

What are the 5 parts to an amino acid?

Alpha carbon, R group (side chain), Amino group, Carboxyl group, Hydrogen

Peptide bonds link _______ together to form _______

amino acids; polypeptides / proteins

Dehydration = ?

Hydrolysis = ?

Dehydration = building, releases water, requires energy

Hydrolysis = breaking down, uses water, releases energy

The peptide bond between the n-terminus and the c-terminus has what special trait?

Resonance occurs here. It has partial double bond characteristics

Polar side chains interact with eachother mainly through what type of bonds?

Hydrogen bonding

Nonpolar side chains interact mostly through what type of bonds? Is it able to form Hydrogen bonds?

Mainly interact through Van Der Waals forces

Able to make hydrogen bonds just very weak ones

Name the 3 basic side chains. What charge do they have?

Arginine ARG R, Lysine LYS K, Histadine HIS H

All positively charged

Name the 2 acidic side chains. What charge do they have?

Aspartic acid ASP D, Glutamic acid GLU E

Both negatively charged

Name the 5 uncharged polar side chains

Aspargine ASN N, Glutamine GLN Q, Serine SER S, Theronine THR T, Tyrosine TYR Y

Name the 10 nonpolar side chains

Alanine ALA A, Glycine GLY G, Valine VAL V, Leucine LEU L, Isoleucine ILE I, Proline PRO P, Phenylalanine PHE F, Methionine MET M, Tryptophan TRP W, Cysteine CYS C

What is special about two Cysteine CYS C side groups bonding to each other?

They are able to form a disulfide bond (covalent)

What is the Phi angle determined by?

Amide nitrogen and α carbon

What is the Psi angle determined by?

Carbonyl carbon and α carbon

Why is there such a narrow range of dihedral angles available?

Steric hindrance between the amide hydrogen and the carbonyl

What type of side chains are on the outside structure of a protein? What about the inside?

Outside = Polar side chains

Inside = nonpolar side chains

What are proteins stabilized by? Give examples

Stabilized by weak noncovalent interactions. Electrostatic attraction, hydrogen bonding, van der waals forces