Questions and Ansẉers
2026\2027 update
1. The hydrophobic effect, which drives the folding of proteins and
the formation of lipid bilayers, is primarily caused by:
A) Strong covalent bonds between nonpolar molecules
B) A decrease in the entropy of water molecules surrounding
nonpolar molecules
C) An increase in the entropy of the system when water is released
from ordered cages around hydrophobic molecules
D) Ionic attractions between water and oils
Answer: C
2. Which of the following equations is correctly used to calculate the
pH of a buffer solution?
A) Michaelis-Menten equation
B) Henderson-Hasselbalch equation
C) Nernst equation
D) Gibbs free energy equation
Answer: B
3. The O-H bond in a water molecule is best classified as a(n):
A) Nonpolar covalent bond
B) Polar covalent bond
,C) Ionic bond
D) Hydrogen bond
Answer: B
4. A biochemical reaction with a positive standard free energy
change (ΔG°') is:
A) Exergonic and spontaneous
B) Endergonic and requires an input of energy
C) At equilibrium
D) Releasing heat
Answer: B
5. Which functional group can donate a proton, making it capable of
acting as an acid?
A) Amino group (-NH2)
B) Hydroxyl group (-OH)
C) Carboxyl group (-COOH)
D) Methyl group (-CH3)
Answer: C
6. Water's high heat of vaporization is due to its:
A) Low molecular weight
B) Extensive network of hydrogen bonds
C) Nonpolar nature
D) Ability to dissociate into H+ and OH-
Answer: B
, 7. Which amino acid side chain is capable of forming disulfide
bridges to stabilize tertiary protein structure?
A) Methionine
B) Serine
C) Cysteine
D) Glycine
Answer: C
8. The secondary structures of proteins (alpha-helices and beta-
sheets) are primarily stabilized by:
A) Hydrogen bonds between the backbone amino and carbonyl
groups
B) Covalent disulfide bonds
C) Hydrophobic interactions between side chains
D) Ionic bonds between R groups
Answer: A
9. Which amino acid is known to disrupt or "break" an alpha-helix
due to its rigid cyclic structure?
A) Alanine
B) Proline
C) Leucine
D) Glutamate
Answer: B