Vitamins and Coenzymes — MCQs

At which site in the kidneys does the 1,25-hydroxylation of Vitamin D take place?

A 30-year-old male patient on Isoniazid therapy for Tuberculosis developed rashes on exposed parts of the body and disorientation of memory. His family also reports a history of diarrhea. What is the most likely diagnosis?

An epidemiologic study observes increased numbers of respiratory tract infections among children living in a community in which most families are at the poverty level. The infectious agents include Streptococcus pneumoniae, Haemophilus influenzae, and Klebsiella pneumoniae. Most of the children have had pneumonitis and rubeola infection. The study documents increased rates of keratomalacia, urinary tract calculi, and generalized papular dermatosis in these children as they reach adulthood. These children are most likely to have a deficiency of which of the following vitamins?

Which clotting factors are dependent on Vitamin K?

About scurvy, all are true EXCEPT:

Which of the following fat-soluble vitamins functions as a coenzyme?

Wernicke's encephalopathy, during refeeding syndrome, can be precipitated in deficiency of which of the following vitamin?

Posterior column sensations in lower limbs are lost in which deficiency?

A 52-year-old man presents with painless, gradual vision loss in his right eye over two hours. He has a history of myocardial infarction and takes aspirin daily. The physical examination reveals no vision in the right eye. At the molecular level, which of the following components is essential for the first step of the visual cascade?

In humans and other primates, as well as in guinea pigs, which vitamin cannot be synthesized due to the absence of the enzyme L-gulonolactone oxidase?