🧬 Proteins | Structure, Classification & Functions | Medical Biochemistry for USMLE Step 1
13 videos • 2 views • by Dr.G Bhanu Prakash Animated Medical Videos his high-yield biochemistry session gives you a clear, exam-smart tour of proteins—how they are built, how they fold, how we classify them, and why their functions are central to human physiology and Step 1 questions. We start with amino acid chemistry and the peptide bond, then walk through the four levels of protein structure: primary (sequence and genetic variants), secondary (α-helices, β-sheets, turns; H-bonding and proline effects), tertiary (hydrophobic collapse, salt bridges, disulfide bonds), and quaternary (multi-subunit assemblies like hemoglobin). You’ll learn how pH, temperature, and solvents drive denaturation or misfolding, and how chaperones assist proper folding. Classification is made intuitive: globular vs fibrous, membrane vs soluble, simple vs conjugated (heme, glyco-, lipo-, metallo-proteins), plus functional classes—enzymes, receptors, transporters, structural proteins, contractile proteins, hormones, immunoglobulins, and clotting factors. We connect structure to function with clinical pearls: collagen’s triple helix and vitamin C in hydroxylation (scurvy), elastin and α1-antitrypsin in emphysema, prion and amyloid misfolding in neurodegeneration, hemoglobin allostery and the Bohr effect (2,3-BPG, fetal Hb), and how protein assays (Biuret/Lowry/Bradford), electrophoresis, and chromatography show up in labs. Enzyme basics are integrated where Step 1 loves to test them—active sites, cofactors/coenzymes, Michaelis–Menten kinetics (Vmax, Km), inhibition patterns (competitive vs noncompetitive), and how post-translational mods (phosphorylation, glycosylation, ubiquitination) switch protein activity on and off. By the end, you’ll have a compact mental map linking chemistry → structure → classification → function → pathology, so you can decode biochemical vignettes quickly and accurately in a U.S./Western clinical context.