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				b. with water (gills) - the major advantage is lack of water loss - the major problems are: i. slow rate of diffusion of O2in water ii. lower O2 solubility in water
		- 10 ml/l vs 200 ml/l in air iii. more work to move across surface iv. effect of high water temperature As water temperature rises, so does body temperature and metabolic rate, increasing the demand for O2. At The same time, the solubility for dissolved gases (O2) decreases. D. Mechanism Diffusion is the only mechanism for gas exchange at the level of the cell; there are no special transport proteins. Thus, it's governed by Fick's law. Rate = Diffusion coefficient x area for exchange x (C1 - C2) L (C1-C2) = concentration difference between locations 1 & 2. L = the distance between 1 & 2. 1. Variables a. Diffusion coefficient There are only two available possibilities: air > water b. surface area c. length of path d. concentration difference Q. How can you maximize exchange? - increase surface area, decrease path length and maximize the concentration difference. Look for strategies that affect each parameter.
			B. Fish gills 1. Exchange in water a. major advantage is lack of water loss				42.19