Biochem 13: Introduction to Metabolism

Up to this point, Medlock Holmes has examined the pieces of life — their structure, their interactions, their messages. In this episode, he steps back and watches the system in motion.Metabolism is not a list of pathways. It is an economy. Molecules are built, broken, exchanged, and recycled with remarkable coordination. In this opening episode of Bioenergetics & Metabolism, we explore how cells organise countless chemical reactions into coherent, regulated networks that respond to need, availability, and demand.Drawing on Lehninger’s systems-level view and Harper’s clinically grounded overview of metabolic fuels, this episode introduces the core logic of metabolism: catabolism and anabolism, energy coupling, pathway integration, and metabolic flexibility. Glucose, fatty acids, and amino acids are not rivals — they are interchangeable currencies, exchanged according to circumstance.Medlock learns that metabolism is less about chemistry and more about judgement. Which fuel to burn. Which pathway to prioritise. When to store, and when to release. Disease emerges when this judgement falters — when flow is blocked, misdirected, or rigid.This episode sets the map. From here on, every pathway has a context.Key Topics Explored* What metabolism is — and what it is not* Catabolic versus anabolic pathways* Energy coupling and ATP as currency* Metabolic fuels and tissue preference* Integration and regulation of pathways* Clinical framing of metabolic dysfunction This is a public episode. If you'd like to discuss this with other subscribers or get access to bonus episodes, visit drmanaankarray.substack.com/subscribe