Exam 21: Amino Acids,proteins,and Enzymes

Tuftsin is a peptide that stimulate and promotes the destruction of tumor cells. Its primary structure is Thr-Lys-Pro-Arg. Which statement is NOT a valid interpretation of its primary structure?

It is possible for two different proteins to contain the same number and type of amino acids.

What is the charge on an amino acid at a pH below its pI?

Which protein stores O₂ in tissues?

The β-pleated sheet arrangement of a protein is favored by amino acids with small side chains.

________ proteins are composed of long linear polypeptide chains that are bundled together to form rods or sheets that are insoluble in water and serve structural roles.

What is the one-letter abbreviation of arginine?

Which choice is the only amino acid capable of forming a disulfide bond?

Based on its name,which compound is an enzyme?

What is the charge on a zwitterion?

Amino acids with an additional COOH group in the side chain are classified as acidic amino acids.

What is a zymogen?

Zwitterions have low melting points and are water-soluble.

Amino acids are the building blocks of the body's proteins. Which statement concerning amino acids is false?

Trypsin is a digestive enzyme that hydrolyzes peptide bonds only when the carbonyl group in the amide bond comes from Lys or Arg. What fragments result when the peptide Gly-Lys-Arg-Ala-Ala-Arg is hydrolyzed by trypsin?

What is the structure of the dipeptide Ser-Gly?

The β-pleated sheet forms when two or more peptide chains,called strands,line up side-by-side with the C=O and N-H bonds in the plane of the sheets.

About one half of the 223 amino acid residues in the enzyme trypsin are hydrophobic. Where in the tertiary structure of this globular protein are these residues most likely to be found?

The pH at which an amino acid exists primarily in its neutral form is called its ________ point.

What type of intermolecular forces exist between the side chains of serine and asparagine?