BIO SCI D103 Lecture Notes - Lecture 3: Membrane Transport Protein, Green Fluorescent Protein, Electrochemical Gradient
24 Jul 2019
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Chapter 11: membrane transport of small molecules and the electrical properties of membranes. Gfp: green fluorescent protein: isolated from jellyfish, encoded by single gene which can be cloned and introduced into other cells, used to tag proteins, organelles, genes, etc. Reporter molecule: fluorescent probe to monitor gene expression. Can prove the fusion protein is functionally equivalent to untagged protein by using it to rescue a mutant lacking that protein. Diffusion rate depends on size and hydrophobicity. Smaller and more nonpolar = easier and faster diffusion. Ions are not evenly distributed across membranes: more in cytoplasm: k, more in ecm: na+, mg2+, ca2+, h+, cl- Vmax = transporter rate maximal due to transporter saturated: characteristic of a specific carrier, rate at which carrier can flip b/w its conformational states. Km = characteristic affinity for solute: conc. of solute when transport is half the max. Cells carry out active transport through: coupled transporters, atp driven pumps, light or redox driven pumps.
