Biology 1202B Lecture Notes - Lecture 13: Chemiosmosis, Electrochemical Gradient, Intermembrane Space
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3 things that regulate respiratory control: levels of oxygen, adp/atp ratio, nadp+/nadh ratio. Look at pathway as traffic - things get backed up. Fork in the road - bifurcation: pyruvate has to make a decision if it"s going to take the hypoxia pathway or. Pyruvate dehydrogenase: enzyme evolved in converting pyruvate to acetyl coa. Under hypoxic conditions, ratio will be low, nad+ will be low and nadh will be high, Etc is not working, its backed up. Fermentation takes backed up nadh --> nad+ (etc can"t do it, i"ll do it) Athletes can have anaerobic respiration for 3 min. Cancer cells rely on anaerobic respiration: up regulates hif-1, and uses it to sustain it"s life. Sensor = transcription factor called hif-1 is activated in the cell under hypoxic conditions. Cells react faster when o2 is low. When o2 is ok, hif gets degraded --> goes to proteasomes: hif-1 alpha. Found in the cytoplasm, always there, always expressed.
