Biochemistry Practice Test 1

1. Which of the following is false about NMR spectroscopy?

The intramolecular magnetic field around an atom in a molecule changes the resonance frequency giving structural information about the atom

NMR is an abbreviated form of Nuclear Magnetic Resonance

It is a technique that exploits magnetic properties of atomic nuclei

The intermolecular magnetic field around an atom in a molecule changes the resonance frequency giving structural information about the atom

2. Hydrolysis reactions are catalyzed by enzymes called ___________

Oxidoreductase

Ligase

Isomerase

Hydrolase

3. ΔG is negative for which of the following processes?

Oxidation of nitrogen

Melting of ice and evaporation of water

Burning of chlorine

Oxidation of gold

4. The factor which does not affect pK_a value of an amino acid is _________

The loss of charge in the α-carboxyl and α-amino groups

Molecular weight

Other environmental factors

The interactions with other peptide R groups

5. Which of the following bases has the highest pK_a value?

KCl

KNO₃

NaNO₃

NaOH

6. Calculate the pH of a mixture of 0.10M acetic acid and 0.20M sodium acetate. The pK_a of acetic acid is 4.76.

6.1

4.1

7.1

5.1

7. Cleaving of peptide chain is done by _________

Tryptophan

Arginine

Trypsin

Tyrosine

8. Which of the following statements is false?

Reduced cysteine is further acetylated by iodoacetate

Reduction of cysteine residue with performic acid is done to break disulfide bond in proteins

Oxidation of cysteine residue with performic acid is done to break disulfide bond in proteins

Reduction of cysteine residue with dithiothreitol is done to break disulfide bond in proteins

9. Which of the following statements is true about two-dimensional electrophoresis?

Separates proteins of identical molecular weight that differ in pI

Separates proteins of different molecular weight and different pI

Separates proteins of identical molecular weight, same pI but different charge

Isoelectric focusing is also termed as two-dimensional electrophoresis

10. Which of the following is not a condensation reaction?

R-OH + inorganic phosphate phosphate ester + H₂O

6CO₂ + 6 H₂O C₆H₁₂O₆ + 6CO₂

ADP + inorganic phosphate ATP + H₂O

R-COOH + inorganic phosphate Acyl phosphate + H₂O