PSL300H1 Study Guide - Midterm Guide: Internal Resistance, Schwann Cell, Receptive Field
Document Summary
Permeable = small molecules + gases + ions [small] a. Small lipid-soluble molecules + gases [small + non-polar] Small water-soluble molecules + ions [small + polar] High concentration low concentration [down conc. gradient] No energy from atp hydrolysis needed [passive] Saturated = number of solute substances > number of transporters. Low concentration high concentration [against conc. gradient] Small molecules + gases + ions [small] One substance down conc. gradient another substance up conc. gradient. Low concentration high concentration [against concentration gradient] No energy from atp hydrolysis needed b. c. d. b. c: channels, membrane channels protein. A central pore on the membrane formed by 4-5 subunits of membrane spanning. Selectivity filter = only specific substances can diffuse. Not always open, controlled by a branch of protein structure [gate] Sensitive to potential difference across membrane (like depolarization) Inside of a cell = usually negative. S4 segment = the 4th transmembrane domain of the protein (positive) Polarized s4 attracted inside closed.
