BIO 112 Lecture Notes - Lecture 27: Membrane Transport, Body Fluid, Metabolic Water
1 Dec 2016
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Hypertonic solution: more water in the middle leaves cell, membrane shrinks. Hypotonic solution: more water in cell that in the outside, membrane swells. Isotonic solution: equal on both sides of cell wall, no change. Balancing water gain and loss: one solution is to be an osmoconformer, body fluids are isosmotic to the environment, available only to marine animals, tend to live in notable conditions. Terrestrial: water + salt in, h20 and salt out. Adaptations to reduce water loss on land: the threat of desiccation is the largest problem. Body covering help prevent dehydration: waxy layers in exoskeletons, shells of land snails, multiple layers of dead, keratinized skin cells. Land animals balance their water budgets by drinking and eating moist foods, and using metabolic water produced through aerobic respiration, amount of water in feces and urine balances how much gets out. Osmoregulation has an energy cost diffusion tends to equalize concentrations in a system.
