What level of protein structure is determined by the following:
a. Peptide bonds between amino acids?

Insulin is a protein hormone that functions as two polypeptide chains whose amino acid sequences are as follows:

A chain: GIVEQCCTSICSLTQLENYCN

B chain: FVNQHLCGDHLVEALYLV CGERGFFYTPKT

b. Considering the amino acid sequences, suggest how these two polypeptide chains might be held together in an active insulin molecule.

Explain how a protein is denatured by the following:

c. Organic solvents

For each of the conjugated proteins described, identify to which class of conjugated protein it belongs.

b. Ionized zinc is attached to this protein so the protein can function.

For each of the conjugated proteins described, identify to which class of conjugated protein it belongs.

c. Phosphate groups are attached to this protein.

What level of protein structure is determined by the following:

b. Hydrogen bonds between backbone carbonyl oxygen atoms and hydrogen atoms attached to backbone nitrogen atoms?

How do the following noncovalent interactions help to stabilize the tertiary and quaternary structure of a protein? Give an example of a pair of amino acids that could give rise to each interaction.

a. Hydrophobic interactions

Determine which of the following statements describes a tertiary structure of a protein.

Indicate whether each of the following statements describes a primary, secondary, tertiary, or quaternary protein structure:

______ a) Hydrophobic R groups seeking a nonpolar environment move toward the inside of the folded protein.  

______ b) Protein chains of collagen form a polypeptide chain composed of 3 alpha helices. 

______ c) An active protein contains 4 tertiary subunits. 

______ d) Two polypeptide chains held together by disulfide bridges.