PNB 2250 Chapter Notes - Chapter 7: Globin, Protozoa, Porphyrin
17 Sep 2016
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Hemoglobin adaptation & facillitated diffusion: hemoglobin and other proteins increase oxygen diffusion over small distances within ells, and through water. Facilitated diffusion: hb delivers gas close as possible to cells and then releasing it so active cells get the energy they need, accelerates rate by which oxygen diffuses through water. Only seen with hemoglobin: not seen with hemocyanin, only seen at low oxygen levels, thermodynamic effect bigger effect with myoglobin. The protein + the oxygen moves together to diffuse faster. Physiological benefits of facilitated diffusion via hemoglobin use: vertebrates. Not much, hemoglobin is too high inside red blood cells. Oxygen is also too high in rbcs: myoglobin. May help in working muscles when ischemic or hypoxic. Myoglobin acts to flatten oscillations by supplying oxygen when tissues are ischemic. Ischemia = caused by shortage of blood-supply to tissues: invertebrates. Evolutionary implications of hemoglobin/respiratory protein use: hemoglobin is found in all animals, many plants, bacteria, protozoa, and some invertebrates.
