Biochemistry - MCQ Practice Questions

Which of the following amino acids is NOT classified as a standard protein amino acid?

The primary structure of a protein is stabilized by which type of bond?

Which enzyme catalyzes the hydrolysis of peptide bonds from the C-terminal end?

Isoelectric point (pI) of a protein is defined as the pH at which:

Which of the following is an example of a globular protein?

Enzyme cofactors are non-protein substances that are essential for enzyme activity. Which of the following is NOT a cofactor?

The Michaelis-Menten equation describes enzyme kinetics. What does Km represent?

Which type of enzyme inhibition is characterized by a competitive interaction with the active site?

Denaturation of proteins can be caused by all EXCEPT:

Which amino acid sequence contains a hydrophobic amino acid that is commonly found in the hydrophobic core of proteins?

The quaternary structure of hemoglobin is maintained by interactions EXCEPT:

An enzyme shows maximum activity at pH 8.0. At pH 3.0, the enzyme loses its activity. This is primarily due to:

Which of the following correctly matches an enzyme with its substrate?

A protein with multiple subunits shows cooperative binding of substrate. This phenomenon is best explained by:

During protein synthesis, a missense mutation changes codon GAA to GUA. Which amino acid substitution occurs?

In a double displacement enzyme reaction mechanism, the enzyme forms a covalent intermediate. Which protease follows this mechanism?

A competitive inhibitor with Ki = 0.5 mM and Km = 2 mM is added to an enzyme reaction. What is the apparent Km in presence of this inhibitor at [I] = 1 mM?

Which statement about the relationship between protein structure and function is INCORRECT?

A protease enzyme shows reduced activity when Ca²⁺ is removed from the reaction mixture. This indicates that Ca²⁺ acts as a:

Which of the following is a characteristic feature of allosteric enzymes?