Question

name: date: structure of proteins and sds - page srd 1. what is the basic unit that forms a protein? a. nucleotide b. monosaccharides c. amino acid 2. what is the type of bond that forms the primary structure of a protein? a. hydrogen bonds b. peptide bonds c. glycosidic bonds d. phosphodiester bonds 3. the sequence of amino acids in a protein represents which level of protein structure? a. primary b. secondary c. tertiary d. quaternary 4. the α - helix and β - pleated sheet are examples of which level of protein structure? a. primary b. secondary c. tertiary d. quaternary 5. the secondary structure of a protein is stabilized mainly by: a. ionic bonds b. disulfide bonds c. hydrogen bonds d. hydrophobic interactions 6. the overall 3d folding of a single polypeptide chain is known as the: a. primary structure b. secondary structure c. tertiary structure d. quaternary structure 7. quaternary structure of a protein refers to: a. the arrangement of amino acids in a single chain b. the 3d structure of one polypeptide c. the association of multiple polypeptide chains into a functional protein d. the presence of α - helices and β - sheets 8. disulfide bonds are covalent bonds formed between which amino acid residues? use your chart of amino acids. a. cysteine b. serine c. methionine d. tyrosine 9. which of the following interactions is least likely to be found stabilizing a protein’s tertiary structure? a. hydrogen bonds b. peptide bonds c. ionic interactions d. hydrophobic interactions 10. denaturation of a protein usually disrupts all levels of structure except: a. primary b. secondary c. tertiary d. quaternary

Explanation:

1. Proteins are polymers of amino acids.
2. Peptide bonds link amino acids in the primary structure.
3. Amino acid sequence = primary structure.
4. α - helix and β - pleated sheet = secondary structure.
5. Hydrogen bonds stabilize secondary structure.
6. 3D folding of a single chain = tertiary structure.
7. Quaternary structure is about multiple chains.
8. Disulfide bonds form between cysteine residues.
9. Peptide bonds are for primary structure, not tertiary.
10. Denaturation usually leaves primary structure intact.

Answer:

1. c. amino acid
2. b. Peptide bonds
3. A. Primary
4. B. Secondary
5. C. Hydrogen bonds
6. C. Tertiary structure
7. C. The association of multiple polypeptide chains into a functional protein
8. A. Cysteine
9. B. Peptide bonds
10. A. Primary