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Title: One batch of isolated, purified mitochondria was placed into a pH 7.2 solution Post by: bunton33 on Sep 26, 2010 One batch of isolated, purified mitochondria was placed into a pH 7.2 solution. Another batch of identical mitochondria was placed into a pH 3.2 solution. The rates of electron transport in the two batches were measured. At pH 7.2 the rate was normal, but at pH 3.2 electron transport had stopped completely. In fact, it was seen that small amounts of NADH were synthesized from NAD+ in the pH 3.2 solution. Explain how synthesis of NADH could happen under these conditions.
Title: One batch of isolated, purified mitochondria was placed into a pH 7.2 solution Post by: bio_man on Sep 26, 2010 I don't think this question was well thought of because the electron transport chain uses NADH, but does not produce it. It can't be glycolysis because we only have mitochondria - glycolysis occurs in the cytoplasm. The only thing that is left is the citric acid cycle which occurs inside the mitochondria because the citric acid cycle produces NADH from free-floating NAD+ molecules via specific enzymes. Since NADH is the reduced version of NAD+, it likely obtained its hydrogen (H+) ions from the high acidic medium in which the mitochodria were placed into: high acid = lots of H+.
What are your thoughts? Title: One batch of isolated, purified mitochondria was placed into a pH 7.2 solution Post by: bunton33 on Sep 26, 2010 i was wondering the same thing. yes i thought that the acidic 3.2ph having H protons would make sense for the NADH whereas the 7.2ph basic would have hydroxide ions. Thanks again!
Title: One batch of isolated, purified mitochondria was placed into a pH 7.2 solution Post by: bunton33 on Sep 27, 2010 why does it occur in the basic solution?
Title: One batch of isolated, purified mitochondria was placed into a pH 7.2 solution Post by: bio_man on Sep 27, 2010 A better question would be, why wouldn't it occur in a basic solution?
Title: One batch of isolated, purified mitochondria was placed into a pH 7.2 solution Post by: bunton33 on Sep 27, 2010 thats what i meant sorry. it is because of the hydroxide ions?
Title: One batch of isolated, purified mitochondria was placed into a pH 7.2 solution Post by: bio_man on Sep 27, 2010 The reaction still occurs because there is still hydrogen ions in a basic solution, but very little (unless you are at a pH of 14).
Title: One batch of isolated, purified mitochondria was placed into a pH 7.2 solution Post by: Biology Forums on Sep 28, 2010 Recall that electron transport produces an electrochemical gradient of H+ regardless.
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