2026 brand new bIOCHeMISTrY I- rUTGerS eXaM 1
PraCTICe QUeSTIOnS and anSwerS wITH raTIOnaLeS
<SUCCeSS GUaranTeed!!>
1. What is the pH of a 0.01 M solution of HCl?
A. 1
B. 2
C. 10
D. 12
Answer: B. Rationale: $\text{pH} = -\log[\text{H}^+] = -\log(0.01) = 2$.
2. A buffer solution at pH 7.0 contains a weak acid with a $\text{p}K_a$ of 7.0.
What is the ratio of [A-] to [HA]?
A. 0:1
B. 1:1
C. 10:1
D. 1:10
Answer: B. Rationale: Using the Henderson-Hasselbalch equation ($\text{pH} =
\text{p}K_a + \log([\text{A}^-]/[\text{HA}])$), if $\text{pH} = \text{p}K_a$,
then $\log([\text{A}^-]/[\text{HA}]) = 0$, meaning the ratio is $1$.
3. Which of the following is true for a spontaneous reaction?
A. $\Delta G > 0$
B. $\Delta G = 0$
C. $\Delta G < 0$
D. $\Delta H < 0$
Answer: C. Rationale: A spontaneous process in biochemistry is defined by a
decrease in free energy ($\Delta G < 0$).
4. The hydrophobic effect is primarily driven by:
,A. Van der Waals forces
B. Increase in entropy of water
C. Ionic bonding
D. Covalent bonding
Answer: B. Rationale: When hydrophobic molecules aggregate, water molecules
are released from "cages," increasing the entropy of the system.
5. Which amino acid has a side chain with a $\text{p}K_a$ near physiological pH?
A. Aspartate
B. Lysine
C. Histidine
D. Arginine
Answer: C. Rationale: The imidazole group of Histidine has a $\text{p}K_a$ near
6.0, allowing it to act as a proton donor/acceptor at physiological pH.
Section 2: Amino Acids and Protein Structure
6. Which amino acid is the only achiral one?
A. Alanine
B. Glycine
C. Proline
D. Valine
Answer: B. Rationale: Glycine has a hydrogen atom as its R-group; thus, the
$\alpha$-carbon is not bonded to four different groups.
7. Which amino acid is often found in "turns" due to its rigid structure?
A. Proline
B. Leucine
C. Phenylalanine
D. Glutamate
, Answer: A. Rationale: Proline’s cyclic structure restricts rotation of the peptide
bond, making it a "helix breaker."
8. The primary structure of a protein refers to:
A. The 3D arrangement of subunits
B. The sequence of amino acids
C. The presence of alpha-helices
D. Disulfide bonds
Answer: B. Rationale: The primary structure is defined exclusively by the linear
sequence of amino acids linked by peptide bonds.
9. Alpha-helices and beta-sheets are examples of:
A. Primary structure
B. Secondary structure
C. Tertiary structure
D. Quaternary structure
Answer: B. Rationale: These are local folding patterns stabilized by hydrogen
bonding between backbone amide and carbonyl groups.
10. Which interaction stabilizes the tertiary structure of a protein?
A. Peptide bonds
B. Hydrogen bonds, hydrophobic interactions, and disulfide bridges
C. Only ionic bonds
D. Phosphodiester bonds
Answer: B. Rationale: Tertiary structure is the overall 3D fold, stabilized by
various interactions between R-groups.
11. Which reagent is used to break disulfide bonds in proteins?
A. Urea
B. $\beta$-mercaptoethanol
C. SDS
PraCTICe QUeSTIOnS and anSwerS wITH raTIOnaLeS
<SUCCeSS GUaranTeed!!>
1. What is the pH of a 0.01 M solution of HCl?
A. 1
B. 2
C. 10
D. 12
Answer: B. Rationale: $\text{pH} = -\log[\text{H}^+] = -\log(0.01) = 2$.
2. A buffer solution at pH 7.0 contains a weak acid with a $\text{p}K_a$ of 7.0.
What is the ratio of [A-] to [HA]?
A. 0:1
B. 1:1
C. 10:1
D. 1:10
Answer: B. Rationale: Using the Henderson-Hasselbalch equation ($\text{pH} =
\text{p}K_a + \log([\text{A}^-]/[\text{HA}])$), if $\text{pH} = \text{p}K_a$,
then $\log([\text{A}^-]/[\text{HA}]) = 0$, meaning the ratio is $1$.
3. Which of the following is true for a spontaneous reaction?
A. $\Delta G > 0$
B. $\Delta G = 0$
C. $\Delta G < 0$
D. $\Delta H < 0$
Answer: C. Rationale: A spontaneous process in biochemistry is defined by a
decrease in free energy ($\Delta G < 0$).
4. The hydrophobic effect is primarily driven by:
,A. Van der Waals forces
B. Increase in entropy of water
C. Ionic bonding
D. Covalent bonding
Answer: B. Rationale: When hydrophobic molecules aggregate, water molecules
are released from "cages," increasing the entropy of the system.
5. Which amino acid has a side chain with a $\text{p}K_a$ near physiological pH?
A. Aspartate
B. Lysine
C. Histidine
D. Arginine
Answer: C. Rationale: The imidazole group of Histidine has a $\text{p}K_a$ near
6.0, allowing it to act as a proton donor/acceptor at physiological pH.
Section 2: Amino Acids and Protein Structure
6. Which amino acid is the only achiral one?
A. Alanine
B. Glycine
C. Proline
D. Valine
Answer: B. Rationale: Glycine has a hydrogen atom as its R-group; thus, the
$\alpha$-carbon is not bonded to four different groups.
7. Which amino acid is often found in "turns" due to its rigid structure?
A. Proline
B. Leucine
C. Phenylalanine
D. Glutamate
, Answer: A. Rationale: Proline’s cyclic structure restricts rotation of the peptide
bond, making it a "helix breaker."
8. The primary structure of a protein refers to:
A. The 3D arrangement of subunits
B. The sequence of amino acids
C. The presence of alpha-helices
D. Disulfide bonds
Answer: B. Rationale: The primary structure is defined exclusively by the linear
sequence of amino acids linked by peptide bonds.
9. Alpha-helices and beta-sheets are examples of:
A. Primary structure
B. Secondary structure
C. Tertiary structure
D. Quaternary structure
Answer: B. Rationale: These are local folding patterns stabilized by hydrogen
bonding between backbone amide and carbonyl groups.
10. Which interaction stabilizes the tertiary structure of a protein?
A. Peptide bonds
B. Hydrogen bonds, hydrophobic interactions, and disulfide bridges
C. Only ionic bonds
D. Phosphodiester bonds
Answer: B. Rationale: Tertiary structure is the overall 3D fold, stabilized by
various interactions between R-groups.
11. Which reagent is used to break disulfide bonds in proteins?
A. Urea
B. $\beta$-mercaptoethanol
C. SDS
