Protein Structure

Question 1

peptide bond

Answer 1

Polypeptides consist of amino acids linked by a peptide bond

Question 2

each amino acid in a protein is called a

Answer 2

residue

Question 3

the beginning
of the polypeptide chain

Answer 3

amino terminal end

Question 4

the end of the polypeptide chain

Answer 4

carboxyl terminal end

Question 5

In some proteins, the polypep-de chain can be cross-linked by disulfide bonds by

Answer 5

oxidation of two cysteines

Question 6

PHI

Answer 6

Φ bond = N-Cα bond

Question 7

PSI

Answer 7

ψ bond = C -carbonyl bond

Question 8

Secondary structure

Answer 8

the 3-D structure formed by hydrogen bonds between peptide NH and CO groups of amino acids that are near one another in the primary structure

The α-helix, β-sheets and turns are prominent examples of secondary structure

Question 9

α-helix

Answer 9

tightly coiled rod-like structure, with the R groups bristling out from the axis of the helix

Question 10

Tertiary structure

Answer 10

refers to the spatial arrangement of amino acids that are far apart in the primary structure and to the pattern of disulfide bond formation

Question 11

Motifs

Answer 11

super secondary structure, are combinations of secondary structure that are found in many proteins

Question 12

domains

Answer 12

Some proteins have two or more similar or identical compact structures

Question 13

subunits

Answer 13

Many proteins are composed of multiple polypeptide chains

Question 14

Quaternary structure

Answer 14

can be as simple as two identical polypeptide chains or as complex as dozens of different polypeptide chains

Question 15

urea

Answer 15

the enzyme regained its structure and its activity

Question 16

Hydrophobic Amino Acids

Answer 16

glycine (Gly), alanine (Ala), valine (Val), leucine (Leu), isoleucine (Ile), proline (Pro), phenylalanine (Phe), methionine (Met), and tryptophan (Trp).

Question 17

Hydrophilic Amino Acids

Answer 17

Tyrosine, Glutamine, Threonine, Serine, Asparagine