BIOL 1000 Lecture Notes - Lecture 5: Signal Transduction, Steroid Hormone Receptor, Cell Membrane
Document Summary
Explain how the plasma membrane structure provides selective permeability: barrier to water-- soluble (polar) molecules, charge molecules and large molecules, small hydrophobic (non-- polar) molecules (e. g. o2, co2, n2) readily diffuse through bilayer (with. Compare and contrast passive and active transport across eukaryotic membranes concentration gradient) Passive transport: the movement of a substance across a membrane without the need to expend chemical energy such as atp: simple diffusion diffusion across the membrane based on concentration gradient. Rate of simple diffusion depends on molecular size and solubility: facilitated diffusion diffusion of molecules across a membrane through the aid of a transporter. Active transport: transport that requires energy, against the concentration gradient. Important for creating and maintaining concentration gradients so that passive diffusion can occur when necessary. Describe exocytosis and endocytosis, and the cellular processes in which these processes would occur. Describe osmosis, discussing how tonicity influences this process.
