129 articles
Biochemistry & the Chemistry of Life
Proteins, carbohydrates, lipids, DNA, enzymes and the chemistry happening inside living things.
The Electron Transport Chain
How mitochondria turn NADH into ATP: the four complexes, ubiquinone and cytochrome c, redox potentials and the energy released, proton pumping and Mitchell's chemiosmotic theory, ATP synthase as a rotary motor, ATP yields, poisons and uncouplers.
Competitive vs Non-competitive Inhibition
How enzyme inhibitors work: competitive, non-competitive and uncompetitive inhibition compared, their effects on Km and Vmax, Lineweaver–Burk patterns, irreversible inhibitors, feedback inhibition, and real drugs and poisons.
Enzyme Kinetics: Michaelis–Menten Explained
Michaelis–Menten kinetics made clear: the reaction scheme, the saturation curve, deriving v = Vmax[S]/(Km + [S]), what Km, Vmax and kcat mean, catalytic efficiency, Lineweaver–Burk plots and a fully worked example.
Glycolysis Step by Step
All ten steps of glycolysis with the enzyme, reaction type and energy change for each: the investment and payoff phases, substrate-level phosphorylation, the net yield of 2 ATP and 2 NADH, regulation at PFK-1, and the fates of pyruvate.
The Krebs Cycle
The citric acid cycle step by step: the link reaction, the eight reactions of the cycle with carbon counts and products, where CO₂, NADH, FADH₂ and GTP come from, why it's a cycle, regulation, and its role as the hub of metabolism.
The Light-Dependent Reactions
The light-dependent reactions of photosynthesis in detail: photosystems II and I, water splitting at the manganese cluster, the Z-scheme and redox potentials, electron carriers, NADPH formation, proton gradients and ATP synthase, and cyclic electron flow.
Protein Folding: How Chains Find Their Shape
How an unfolded chain of amino acids finds one precise 3D shape: Anfinsen's experiment, the hydrophobic effect, Levinthal's paradox and folding funnels, chaperones, misfolding diseases such as Alzheimer's and prions, and AI structure prediction.
Transcription and Translation from a Chemist's View
How cells turn a DNA sequence into a protein, focusing on the chemistry: RNA polymerase and template strands, mRNA processing, the genetic code, charging tRNA with ATP, the ribosome as a ribozyme, peptide bond formation and the energy cost of a protein.
Steroids: The Four-Ring Molecules
The chemistry of steroids: the four fused rings, numbering, how cholesterol becomes cortisol, testosterone and oestradiol, how steroid hormones act on genes, vitamin D, steroid drugs, and the yam chemistry that made the contraceptive pill possible.