BSCI 207 Study Guide - Midterm Guide: Metabotropic Receptor, Round Window, Dopaminergic
10 Dec 2015
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Digestion & nutrient assimilation - gae #8 membrane transport. Eat food (ingest/uptake food from their environments, surround the food via epithelium) Digest the food (break down food into smaller usable molecules + waste) Absorb/import/use the small molecules in maintaining homeostasis. Excrete wastes either through solids, liquids (urine), or mixture of both. Digestion is a complex process, with different parts of the digestive tract specializing in different tasks (amylase in your spit begins the digestion, stomach breaks down macromolecules via stomach acid, gallbladder emulsifies liquids, etc etc) Absorption of nutrients requires lots of surface area to maximize absorption rate (think: microvilli & villi that increase surface area in small intestine) When molecules can cross the plasma membrane easily, transport is via passive diffusion. This can continue until the concentrations are equal on both sides. Molecules that don"t easily cross membranes (charged/polar molecules) have membrane channel proteins that allow facilitated diffusion.
