ATP PRODUCTION - (Jun/14/2006 )

Hiii

Could someone please tell me why maximal rates of ATP production are different for different fuel sources?...eeek I cannot find any info. in my notes only the order it goes down in...eg: muscle atp...creatine phosphate...muscle glycogen to lactate etc etc...but how to explain this...anyhelp would by much appreciated...I have a exam on sat. and im freaking out!!!

not sure exactly what you're asking, but perhaps this will help?

you have to burn energy to make energy...it's the amount you are in the black at the end that chages...different sources take more energy to make the ATP, depending on what it takes to get the precursors into the proper form to get shunted into the right pathways... resulting in a different net gain

did I help at all?

when you eat a snickers bar....(my old biochemistry prof used this analogy for everything )

you get sugars, fats, proteins, all kinds of stuff that can be turned into fuel, right? so your body has to convert it (using various enzyme-driven processes) into glucose-6-phosphate so that it can enter glycolysis, right? you don't just absorb glucose directly from a candy bar. you have to burn some ATPs in order to break down the components into simple sugars that can be sent through glycolysis

This is why complex carbs are 'better for you' too...your body has to burn energy to use them as fuel, the net gain of energy per moles of sugar is lower, thus there is less fuel that is made and you should be less likely to gain excess weight than if you ate an equivalent amount of straight simple sugar

this is an example; does it help?

k sorry if I keep on asking dumb questions....so say when complex carbs are eaten such as (potatoes?) it is easier to burn that as they are just polymers of simple sugars so hence easier to break down and use as energy generating ATP? ....so say why do use fatty tissue or proteins in the body last to generate ATP? is this because these are complex structures that require alot f enerygy to break them down?...with the candy bar example we eat all these things in it such as proteins etc so itll take some time to break it down whereas straight ATP from the muscle is used first cos BOOM its just there and creatine phosphatecan just phosphorylate ADP and muscle glygogen can be converted to glucose and overall is it the more ATP produced by a certain source the shorter period of time it can be used for....I have no idea where I'm going with this...Seriously if everything I've said is WRONG i give up on the question!!!!! and pray a question like this doesn't come up in my exam!!!

when you eat a snickers bar....(my old biochemistry prof used this analogy for everything )

you get sugars, fats, proteins, all kinds of stuff that can be turned into fuel, right? so your body has to convert it (using various enzyme-driven processes) into glucose-6-phosphate so that it can enter glycolysis, right? you don't just absorb glucose directly from a candy bar. you have to burn some ATPs in order to break down the components into simple sugars that can be sent through glycolysis

This is why complex carbs are 'better for you' too...your body has to burn energy to use them as fuel, the net gain of energy per moles of sugar is lower, thus there is less fuel that is made and you should be less likely to gain excess weight than if you ate an equivalent amount of straight simple sugar

this is an example; does it help?

OK so after I posted that last post I think I have a reasonable answer....or I HOPE!-after much searching online

ok so if i was to write something like during exercise fuel is burnt to release energy in the form of ATP. however different fuels produce different amounts of ATP due to the fact some exercise is more strenuous that others. Say for example we do a 100m sprint this will take a few seconds and hence the ATP can be supplied from Muscle as this storage of feul only lasts a few seconds anyway. However when something like cross-country skiing is carried out much more energy is needed for a longer period of time so hence muscle ATP is not suffecient and other fuel sources need to be burnt such as converting muscle glycogen to lactate producing ATP..

overall..........it can be said depending on the exercise you do and how long you do t for different feul sources are used as some release more ATP thatn others and expecially those reactions that use oxgen such as glucose being broken down to C02 and water...I don't actually think ive said WHY!...neway if this is right...can you please tell me also just say if you were to write an answer what would YOU right...I'm know it sounds like I'm just trying to get an answer but this question is really fustrating me (even though I said i'd give up in the post above)...

so if more enery is needed to get precursor into right pathway less ATP is produced and if less energy is needed more ATP is produced or is it vice versa????????????????????????

i would assume such question needs an answer of the amount of atp produced.

Ex : sugar : enter the embden meyerhoff pathway then krebs cycle.
So you can calculate ATP consumed and produced. Final result is 31ATP if i'm not wrong..


Then you take the example of sugar in an effort. Anaerobic conditions. So lactate produced, and global production of ATP is minimized.

Then you consider lipids.... etc.