Biochemistry MCQ

Glycogen Metabolism

• Glycogen branching enzyme hydrolyzes alpha(1-6) glycosidic branching bond of glycogen molecules.
• Glycogen phosphorylase is an enzyme responsible for glycogenolysis.

Iron Absorption

• Non-heme bound iron Fe2+ is easily absorbed.

Purine Biosynthesis

• Carbon atoms at 4 and 5 positions and N at 7 position are contributed by glycine.
• Glutamine contributes to purine biosynthesis.

Demyelination

• Multiple sclerosis is characterized by demyelination of nerves.

Nucleotide Metabolism

• d-UMP is converted to TMP by methylation.
• Pyrimidine biosynthesis begins with the formation of dihydroorotate from glutamine, ATP, and CO2.

Ketone Bodies

• All tissues, except RBC, can use ketone bodies.
• Cardiac muscle, brain, and renal cortex can use ketone bodies.

Enzyme Activity

• Amylase activity increases under the action of sodium chloride.

Gout

• Gout is characterized by increased plasma levels of uric acid.

Metabolic Pathways

• Reactions involved in the synthesis of ketone bodies are presented.

Galactose Metabolism

• UDP-Galactose 4-epimerase, galactose-1-phosphate uridyl transferase, and galactokinase are enzymes involved in galactose metabolism.

Enzyme Specificity

• Enzymes can be specific with respect to optical activity of the product formed, structure of the substrate, and type of reaction.

Glycogen Synthesis

• Hepatic glycogenolysis is a primary source of blood glucose during fasting state.
• Glycogenin is required for de novo synthesis of glycogen.

Pyrimidine Ring

• The two nitrogen atoms of the pyrimidine ring are contributed by aspartate and ammonia.

Bilirubin Metabolism

• Bilirubin is produced by the breakdown of heme, is transported to and conjugated in the liver, and is then secreted with other bile components into the small intestine.

ATP Synthesis

• The FADH2 and NADH2 produced by the oxidation of one acetyl-CoA result in the synthesis of about 11 ATPs.

Glucose Metabolism

• Pyruvate kinase catalyses an irreversible reaction.
• An elevated level of insulin leads to a decreased level of fructose 2,6-biphosphate in hepatocytes.

Lipoprotein Lipase

• Lipoprotein lipase is immobilized on the surface of membranes by heparin foot.

Porphyrin Biosynthesis

• Aminolevulinic acid, the first product in porphyrin biosynthesis in eucaryotes, is synthesized from succinyl CoA and glycine.