StemPy Lab: Free STEM Lessons, Python Labs and Mock Tests
Standard content
“Biomolecules: Enzyme Kinetics and Pathways in Depth” is available to Standard subscribers.
Beyond the textbook: how proteins fold and why shape means function, and Michaelis-Menten kinetics with the Lineweaver-Burk plot. Then competitive and non-competitive inhibition by numbers, and how pathways are controlled by feedback, with a full timed paper.
3Lessons11Problems2Python Labs1Question Set1Mock Test
Protein folding and function: A protein works only in its folded shape. Hydrophobic collapse, hydrogen bonds, salt bridges and disulphide bridges hold that shape, and chaperones help it form. Heat, pH and urea unfold it. The net charge of a protein depends on pH and is zero at its isoelectric point.
Enzyme kinetics by numbers: The rate of a simple enzyme is v = Vmax[S]/(Km + [S]). Km is the substrate concentration that gives half of Vmax. Vmax grows with the amount of enzyme, and Km does not. A Lineweaver-Burk plot straightens the curve, so Vmax and Km can be read from its two intercepts.
Inhibition and the control of pathways: A competitive inhibitor raises the apparent Km and leaves Vmax unchanged. A non-competitive inhibitor lowers Vmax and leaves Km unchanged. Allosteric enzymes have an S-shaped curve. A pathway is usually controlled at its first committed step by feedback from its end product.