Molecular genetics and gene expression

Molecular genetics and gene expression is part of Biology in the MCAT Biological and Biochemical Foundations section. The questions below are written in the style of the real test, each with the answer and a worked explanation.

Question types you will see here include operon logic and mutant strains, mutation to protein outcome, rNA processing and transcript reading and transcription factor and reporter assay.

Common traps: treating operator mutations as trans-acting (they are cis-only); missing catabolite repression by glucose when lactose is present; reversing which operon type is repressed by its product.