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why are 4 adp's phosphorylated from 2 * triose phosphate to form 4 atp when there are only 2 phosphate groups in total (one on each molecule)?
Original post by esmeralda123
why are 4 adp's phosphorylated from 2 * triose phosphate to form 4 atp when there are only 2 phosphate groups in total (one on each molecule)?


The triose phosphates are oxidised (lose hydrogen) forming 2 molecules of pyruvate. Coenzyme NAD+ (a co-enzyme is a helper molecule that carries chemical groups or ions around) collects the hydrogen ions forming 2reduced NAD (NADH + H+)4ATP are produced, but 2 were used up at the beginning so there is a net gain of2ATP. Overall,2 molecules of pyruvate and a small yield of ATP and reduced NAD are produced.
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Avatar for debbie394
debbie394
OP
11
Original post by Outspokencries
The triose phosphates are oxidised (lose hydrogen) forming 2 molecules of pyruvate. Coenzyme NAD+ (a co-enzyme is a helper molecule that carries chemical groups or ions around) collects the hydrogen ions forming 2reduced NAD (NADH + H+)4ATP are produced, but 2 were used up at the beginning so there is a net gain of2ATP. Overall,2 molecules of pyruvate and a small yield of ATP and reduced NAD are produced.


what is the difference between nad+ and nad because in the book it states nad to reduced nad but i see nad+ on the internet
Reply 3
Avatar for Jpw1097
Jpw1097
19
Original post by esmeralda123
why are 4 adp's phosphorylated from 2 * triose phosphate to form 4 atp when there are only 2 phosphate groups in total (one on each molecule)?


The first phosphate come hexokinase, an enzyme that phosphorylates glucose to form glucose-6-phosphate. Glucose-6-phosphate is then converted into fructose-6-phosphate via an isomerase reaction. Fructose-6-phosphate is then phosphorylated again to form fructose-1,6-bisphosphate. Fructose-1,6-bisphosphate then splits to form two triose phosphates (glyceraldehyde-3-phosphate) - now there are two phosphates. Each triose phosphate is phosphorylated again by a phosphate group forming 1,3-bisphosphoglycerate. As you can see, each 1,3-bisphosphoglycerates has two phosphates, meaning there are four phosphates in total. These phosphates are used to phosphorylate ADP to form 4 ATP via substrate-level phosphorylation.
Reply 4
Avatar for Jpw1097
Jpw1097
19
Original post by esmeralda123
what is the difference between nad+ and nad because in the book it states nad to reduced nad but i see nad+ on the internet


NAD on its own refers to NAD+. Reduced NAD is NADH. It is reduced by the addition of a H+ ion and two electrons (remember reduction is gain of electrons from chemistry).

NAD+ + H+ + 2e- +> NADH (i.e. reduced NAD)

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