IGCSE/GCSE/O & A Level/IB/University Student Forum

Qualification => Subject Doubts => GCE AS & A2 Level => Sciences => Topic started by: Blizzard on June 21, 2011, 09:43:16 am

Title: Biology Respiration Question
Post by: Blizzard on June 21, 2011, 09:43:16 am

Hi everyone I have a question concerning the A2 Unit 5 Biology on the topic of aerobic respiration.

I'd like to know that during the oxidative phosphorylation process how many ATP molecules are produced by each FAD and NAD molecules? My textbook said that it produce 2 and 3 ATP molecules respectively while my revision notes published by CGP said that in recent discoveries each FAD produces 1.5 ATP molecules while each NAD produces 2.5 molecules... Can anyone help me??

Thanks!!

Title: Re: Biology Respiration Question
Post by: guMnam on June 21, 2011, 12:07:43 pm

the 1.5 and 2.5 thing is not for us .. its a development and we dont need to remember that.. all we need to know that each FAD gives 2 ATP and each NAD gives 3 ATP :)

Title: Re: Biology Respiration Question
Post by: Blizzard on June 21, 2011, 12:54:17 pm

oh really?? thanks a lot! but the revision guides really say each FAD produces 1.5 ATP molecules while each NAD produces 2.5 molecules... well i think i'll just go for the general...

Title: Re: Biology Respiration Question
Post by: guMnam on June 21, 2011, 09:02:04 pm

yea :)

Title: Re: Biology Respiration Question
Post by: dlehddud on August 17, 2011, 08:15:27 am

The reason for the different values is the following:

During oxidative phosphorylation, each reduced NAD molecule has the potential to produce 3 ATP molecules, and reduced FAD has the potential to produce 2 ATP. However, 25% of the energy produced from the electron transport chain goes into actively transporting ADP into the mitochondria (how else would they make ATP? ADP+Pi-->ATP). Thus, the total number of ATP molecules they *actually* produce is 75% of the two values: namely, 2.5 ATP for reduced NAD, and 1.5 ATP for reduced FAD.

I hope that clarifies it :)

Title: Re: Biology Respiration Question
Post by: Romeesa-Chan on August 17, 2011, 08:37:32 am

Quote from: dlehddud on August 17, 2011, 08:15:27 am

The reason for the different values is the following:

During oxidative phosphorylation, each reduced NAD molecule has the potential to produce 3 ATP molecules, and reduced FAD has the potential to produce 2 ATP. However, 25% of the energy produced from the electron transport chain goes into actively transporting ADP into the mitochondria (how else would they make ATP? ADP+Pi-->ATP). Thus, the total number of ATP molecules they *actually* produce is 75% of the two values: namely, 2.5 ATP for reduced NAD, and 1.5 ATP for reduced FAD.

I hope that clarifies it :)

Thanks for the clarification. ;D

+rep ;)