UIUC MCB 450 Exam 1 UPDATED
ACTUAL QUESTIONS AND CORRECT
ANSWERS
Biomolecules can be divided into four different classes. Which of the following is NOT a major class
of biomolecule? - CORRECT ANSWER Fatty Acids
Which of the following molecules are the major components of the collagen? - CORRECT ANSWER
proteins
Water is said to be highly cohesive because water molecules interact with one another through: -
CORRECT ANSWER hydrogen bonds
Which of the following is considered a noncovalent bond? - CORRECT ANSWER -
electrostatic interactions
-hydrogen bonds
-Van der Waals interactions
-ALL OF THE ABOVE
What is the [A-]/[HA] ratio when the weak acid is in a solution two pH units above its pKa? -
CORRECT ANSWER 100:1
Brownian motion is due to: - CORRECT ANSWER The random fluctuation of the energy
content of the environment and thermal noise
Consider a biochemical reaction that is taking place in a 0.1 M buffer. The initial pH is 7.4, and the
pKa of the buffer is 7.2. If, in a final reaction volume of 1.0 mL, 10 micromol of protons are
generated, what would be the final pH of the solution? - CORRECT ANSWER 7.22
Solution X is at a pH of 3; solution Y is at a pH of 8. Which of the following statements is TRUE? -
CORRECT ANSWER solution X contains more protons than solution Y
, What are the primary chemical components present in a phosphate buffer at pH 7.4? - CORRECT
ANSWER H₂PO₄⁻ and HPO₄ ⁻²
Which of the following characterize α-helix regions of proteins? - CORRECT ANSWER They
are formed principally by hydrogen bonds between a carbonyl oxygen atom in one peptide bond and
the amide hydrogen from a different peptide bond.
Autopsies of patients with Alzheimer disease show protein aggregates called neurofibrillary tangles
and neuritic plaques in various regions of the brain. These plaques exhibit the characteristic staining
of amyloid. Which of the following structural features is the most likely characteristic of at least one
protein in these plaques? - CORRECT ANSWER A high content of beta pleated sheet structure
Which of the following secondary structures is most likely to be found in a membrane-embedded
portion of a protein? - CORRECT ANSWER an alpha helix composed entirely of hydrophobic
residues
Which of the following statements regarding peptide bonds is least accurate? - CORRECT ANSWER
favored conformation of peptide bonds is with the sequential alpha carbons in the cis position
Which is an appropriate statement of involvement of the hydrophobic effect in protein folding? -
CORRECT ANSWER Nonpolar portions of the molecule associate with one another in the
interior of the protein.
All of the following would disrupt quaternary structure except: - CORRECT ANSWER Treat
with ascorbic acid (vitamin C).
The process of digestion in the stomach is carried out in two main ways. One way involves the
_____environment that exists in the stomach. - CORRECT ANSWER low pH
The pancreas releases _________ to buffer the pH of the stomach juices. - CORRECT ANSWER
NaHCO3
Pepsin requires _________ to achieve activity. - CORRECT ANSWER -zymogen activation
-low pH
-Partial denaturation of protein
ACTUAL QUESTIONS AND CORRECT
ANSWERS
Biomolecules can be divided into four different classes. Which of the following is NOT a major class
of biomolecule? - CORRECT ANSWER Fatty Acids
Which of the following molecules are the major components of the collagen? - CORRECT ANSWER
proteins
Water is said to be highly cohesive because water molecules interact with one another through: -
CORRECT ANSWER hydrogen bonds
Which of the following is considered a noncovalent bond? - CORRECT ANSWER -
electrostatic interactions
-hydrogen bonds
-Van der Waals interactions
-ALL OF THE ABOVE
What is the [A-]/[HA] ratio when the weak acid is in a solution two pH units above its pKa? -
CORRECT ANSWER 100:1
Brownian motion is due to: - CORRECT ANSWER The random fluctuation of the energy
content of the environment and thermal noise
Consider a biochemical reaction that is taking place in a 0.1 M buffer. The initial pH is 7.4, and the
pKa of the buffer is 7.2. If, in a final reaction volume of 1.0 mL, 10 micromol of protons are
generated, what would be the final pH of the solution? - CORRECT ANSWER 7.22
Solution X is at a pH of 3; solution Y is at a pH of 8. Which of the following statements is TRUE? -
CORRECT ANSWER solution X contains more protons than solution Y
, What are the primary chemical components present in a phosphate buffer at pH 7.4? - CORRECT
ANSWER H₂PO₄⁻ and HPO₄ ⁻²
Which of the following characterize α-helix regions of proteins? - CORRECT ANSWER They
are formed principally by hydrogen bonds between a carbonyl oxygen atom in one peptide bond and
the amide hydrogen from a different peptide bond.
Autopsies of patients with Alzheimer disease show protein aggregates called neurofibrillary tangles
and neuritic plaques in various regions of the brain. These plaques exhibit the characteristic staining
of amyloid. Which of the following structural features is the most likely characteristic of at least one
protein in these plaques? - CORRECT ANSWER A high content of beta pleated sheet structure
Which of the following secondary structures is most likely to be found in a membrane-embedded
portion of a protein? - CORRECT ANSWER an alpha helix composed entirely of hydrophobic
residues
Which of the following statements regarding peptide bonds is least accurate? - CORRECT ANSWER
favored conformation of peptide bonds is with the sequential alpha carbons in the cis position
Which is an appropriate statement of involvement of the hydrophobic effect in protein folding? -
CORRECT ANSWER Nonpolar portions of the molecule associate with one another in the
interior of the protein.
All of the following would disrupt quaternary structure except: - CORRECT ANSWER Treat
with ascorbic acid (vitamin C).
The process of digestion in the stomach is carried out in two main ways. One way involves the
_____environment that exists in the stomach. - CORRECT ANSWER low pH
The pancreas releases _________ to buffer the pH of the stomach juices. - CORRECT ANSWER
NaHCO3
Pepsin requires _________ to achieve activity. - CORRECT ANSWER -zymogen activation
-low pH
-Partial denaturation of protein
