Biochemistry Vitamins and Cofactors

Question 1

Thiamine (Vitamin B1) deficiency causes which neurological and cardiovascular condition?

Accepted Answer

Beriberi

Answer

Pellagra

Answer

Scurvy

Answer

Rickets

Question 2

Niacin (Vitamin B3) is a precursor for which essential electron carrier coenzymes?

Accepted Answer

NAD⁺ and NADP⁺

Answer

FAD and FMN

Answer

Coenzyme A and acetyl-CoA

Answer

Pyridoxal phosphate and pyridoxamine

Question 3

Biotin serves as a cofactor for carboxylase enzymes by acting as a carrier of:

Accepted Answer

CO₂ (carboxyl groups)

Answer

Acyl groups

Answer

Amino groups

Answer

Methyl groups

Question 4

Vitamin B12 (cobalamin) is required for which two reactions in humans?

Accepted Answer

Methionine synthesis and methylmalonyl-CoA mutase reaction

Answer

Fatty acid synthesis and glycolysis

Answer

DNA replication and RNA transcription

Answer

Heme synthesis and bilirubin metabolism

Question 5

Pyridoxal phosphate (PLP), the active form of Vitamin B6, is a cofactor for which class of enzymes?

Accepted Answer

Aminotransferases (transaminases) and other amino acid-metabolizing enzymes

Answer

Oxidoreductases only

Answer

Carboxylases

Answer

Kinases

Question 6

Riboflavin (Vitamin B2) is the precursor for which two coenzymes?

Accepted Answer

FAD and FMN

Answer

NAD⁺ and NADP⁺

Answer

CoA and acyl-CoA

Answer

Biotin and lipoic acid