What this page covers
Practice Step 1-style biochemistry questions on Vitamin B12 deficiency neurological mechanism (methylmalonyl-CoA mutase), including Terminal ileal resection, non-compliant supplementation, macrocytic anemia, dorsal column, UMN signs, with emphasis on enzyme / mechanism and answer-choice reasoning.
How to use this page
Review the topic and reasoning focus, then practice Step 1-style questions inside BiochemStep. The question set emphasizes mechanism-first answer-choice reasoning rather than passive content review.