What this page covers
Practice Step 1-style biochemistry questions on Retinoblastoma / Rb / two-hit hypothesis, including Leukocoria in a toddler with a chalky white calcified retinal mass suggests retinoblastoma, active Rb blocks G1/S progression by binding E2F, with emphasis on mechanism / pathway 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.