PPCHEM Q4 M10 FINALS

The vitamin originally termed a “vital amine” but later found not to contain nitrogen includes which of the following?

• Thiamine

• Riboflavin

• Cholecalciferol

• Pyridoxine

Fat-soluble vitamins are stored predominantly in which body compartments, contributing to their potential toxicity upon excessive intake?

• Blood plasma and cerebrospinal fluid

• Lysosomes within cells

• Adipose tissue and liver fat stores

• Extracellular matrices

Which vitamin is synthesized endogenously in human skin under UV radiation and exists as ergocalciferol in plants and cholecalciferol in animals?

• Vitamin A

• Vitamin C

• Vitamin D

• Vitamin E

Pellagra, characterized by dermatitis, diarrhea, and dementia, results primarily from the deficiency of which vitamin?

• Niacin

• Riboflavin

• Thiamine

• Pyridoxine

The absorption of vitamin B12 requires intrinsic factor secreted by which organ?

• Liver

• Pancreas

• Stomach

• Small intestine

Chronic high-dose intake of which vitamin has been clinically linked to irreversible sensory neuropathy?

• Pyridoxine

• Biotin

• Thiamine

• Folic acid

Thiamine pyrophosphate , the active coenzyme form of vitamin B1, primarily functions in which key metabolic process?

• Fatty acid β-oxidation

• Glycolysis and the citric acid cycle as a coenzyme for oxidative decarboxylation

• DNA replication

• Electron transport chain

During pregnancy, which vitamin supplementation is vital to reduce the risk of neural tube defects in the developing fetus?

• Niacin

• Cyanocobalamin

• Folate

• Ascorbic acid

Which vitamin’s deficiency causes impaired hydroxylation of proline and lysine residues in collagen, leading to weakened connective tissues and bleeding gums?

• Vitamin A

• Vitamin C

• Vitamin D

• Vitamin K

Cracks at the corners of the mouth, photophobia, and sore throat are classical signs of which vitamin deficiency?

• Thiamine

• Niacin

• Riboflavin

• Pyridoxine