WGU BioChem C785 Unit Quiz Questions w/Rationale (no pictures)

Document Content and Description Below

WGU BioChem C785 Unit Quiz Questions w/Rationale (no pictures) Rationale: The primary structure of a protein is the sequence of amino acids held together by peptide bonds. Peptide bonds are forme... d by dehydration reactions and disrupted by hydrolysis. ANS Which level of protein structure is disrupted through the hydrolysis of peptide bonds? a. Secondary b. Primary c. Quaternary d. Tertiary c. Placement of the protein in a solution with a low pH Rationale: Changes in pH affect hydrogen bonds and ionic bonds. Hydrogen bonds in the backbone of amino acids occur in secondary structure, and both hydrogen bonds and ionic bonds occur in the side chains of amino acids in tertiary structure. ANS Secondary, tertiary, and quaternary levels of protein structure can all be impacted by exposing a protein to which treatment? a. Increase in the concentration of the protein in solution b. Addition of a reducing agent c. Placement of the protein in a solution with a low pH d. Change of a hydrophobic amino acid to a different hydrophobic amino acid a. Aggregation of the proteins in the brain Rationale: This question is describing changes in protein structure. Aggregation occurs when proteins clump together inappropriately, causing plaques like amyloid deposits to accumulate. ANS An increase in beta-pleated sheet structure in some brain proteins can lead to an increase in amyloid deposit formation, characteristic of some neurodegenerative diseases. What is the primary biochemical process that follows the increase in beta-pleated sheet structure that leads to the development of the amyloid deposits? a. Aggregation of the proteins in the brain b. An increase in anaerobic metabolism of glucose in the brain c. Secretion of glucagon, leading to excess ketogenesis d. An increase in glycogen formation in the brain cells a. Primary structure Rationale: The primary structure of a protein is simply the sequence of amino acids held together by peptide bonds. ANS Which level of protein structure is determined by the sequence of amino acids? a. Primary structure b. Secondary structure c. Quaternary structure d. Tertiary structure c. Hydrogen bonding Rationale: The secondary structure of a protein is built by hydrogen bonds between the carboxyl groups and amino groups on the backbones of the amino acids. ANS Which force is most influential in determining the secondary structure of a protein? a. Electrostatic interactions b. Hydrophobic effect c. Hydrogen bonding d. Disulfide bonding a. A mutation of the gene for a protein that leads to the substitution of a nonpolar amino acid with a charged amino acid ANS Which change would most likely result in permanent modification of an expressed protein's function? a. A mutation of the gene for a protein that leads to the substitution of a nonpolar amino acid with a charged amino acid b. The mutation of a gene for an enzyme involved in protein synthesis following exposure to X-rays, causing the protein not to be synthesized c. A mutation of the gene for a protein that leads to the substitution of a hydrophobic amino acid with a nonpolar amino acid d. An increase in the pH of a solution in which a protein is dissolved from 6.5 to 8.0, when it is known that the proteins has an optimal activity of pH 7.8 a. None of these Rationale: Two positively charged amino acids would repel each other. Only opposite charged attract. ANS Which of the following interactions can occur between two positively charged amino acids? a. None of these b. Disulfide bond c. Hydrophobic interaction d. Ionic bond e. Hydrogen bond b. Amino acids linked together in a specific order by peptide bonds [Show More]

Last updated: 2 years ago

Preview 1 out of 23 pages