PNB 2250 Lecture Notes - Lecture 8: Hydrogen Sulfide, Hemoglobin, Protein Structure
16 Sep 2016
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Respiratory proteins: help transport carbon dioxide. Need less oxygen to saturate red blood cells. Oxygen gets easily on and off: smaller animals. Harder to get on and off red blood cells. Higher metabolic rate (10-20 fold higher) than larger animals. Fish: unique adaptations, aquatic environment has much less oxygen than terrestrial, proportional to metabolic activity, slow moving fish extract oxygen more efficiently, fast moving need more, extract less efficiently. Usually hemoglobin-like but with different protein structure or number of subunits: almost always contain iron, usually left shifted compared to mammals. Oxygen is more sporadic: giant tube worms- live in thermal vents. 144 subunit hemoglobin, very red, binds oxygen in the presence of hydrogen sulfide which would kill people. Insects: recently discovered to have hemoglobin within organs and tracheal system. Increases ability to store internal oxygen: adaptation. Hemoglobin and other proteins increase oxygen diffusion over small distances within cells.
