B.Pharm. Bachelor of Pharmacy Bachelor of Pharmacy (B.Pharm.) Biochemistry 3

Question 1

Which bond links nucleotides together in a DNA strand?

Accepted Answer

Phosphodiester bond

Answer

Phosphodiester bonds connect the 3'-OH of one deoxyribose to the 5'-phosphate of the next nucleotide, forming the DNA backbone.

Question 2

During fatty acid synthesis, malonyl-CoA is formed by carboxylation of acetyl-CoA. Which cofactor is essential for this reaction?

Accepted Answer

Biotin

Answer

Acetyl-CoA carboxylase requires biotin as a CO2 carrier to carboxylate acetyl-CoA to malonyl-CoA in the committed step of fatty acid synthesis.

Question 3

The Km value of an enzyme for its substrate reflects:

Accepted Answer

The substrate concentration at which reaction rate is half of Vmax

Answer

By definition, Km is the substrate concentration ([S]) at which the reaction velocity equals Vmax/2, indicating enzyme-substrate affinity.

Question 4

Which purine base pairs with thymine in DNA?

Accepted Answer

Adenine

Answer

Adenine pairs with thymine via two hydrogen bonds in the Watson-Crick model of DNA base pairing.

Question 5

What is the net ATP yield from complete oxidation of one molecule of palmitate (16-carbon saturated fatty acid)?

Accepted Answer

129 ATP

Answer

Oxidation of palmitoyl-CoA yields 7 FADH2, 7 NADH, 8 acetyl-CoA; total accounting gives approximately 129 ATP equivalents.

B.Pharm. Bachelor of Pharmacy Practice Test