potential energy

[samie]

Which one has higher chemical potential energy- ATP, glucose, or glycogen?

[Poison]

If you are asking the highest energy they contain amon those 3: It is ATP. But on the other hand, If you even think only about glycolysis , you use 2 ATP and get 4 ATP back. (have 2 ATP in the end) If we involve other reactions too you get 36-38 ATP as total. You can use this logic for glycogen too.
But at first sight, if I understood correctly, Iwould say ATP.

[MrMistery]

On an exam question, i would answer glycogen. Since teachers aren’t usually as smart as needed to make such a logical argument as Poison did above 😆 😆

[samie]

Thanks for replying
I’m really confused with this questions since glycogen and glucose can produce more ATP. But then I think that ATP has more energy ❓ … 😡

[2810712]

Probably , u all are thinking of internal energy of those molecules [rotational, vibrational energy etc.]
ATP has directly ‘usable'[biologically] potential energy doesn’t mean it has highest energy,
Also, if glycogen or glucose don’t have thatmuch P.E. then from where does it come ??? We can say that they don’t have directly ‘uasable ‘
energy. It is their expected property as they help storage and transport of energy, without its ”loss”.
I’m curious about ur vievs…

hrushikesh

[MrMistery]

Absolutely right. In my opinion, glycogen has the most energy since it will produce something like 2000 molecules ATP from one glycogen molecule. But it is stored energy, you need 5 enzymes, phosphates+Krebs cycle enzymes+ FoF1 ATP-synthetase to get to it(hope i counted right 😀 )

[Poison]

In an exam answer: ATP. Because especially high school teachers usually don’t like logical thinking, and deciding on your own. It sounds stupid. But that is the case. I always argued with my teachers at the high school, because they gave wrong info. Anyway, I just wasted time. 🙂

[victor]

Let me give this:
In vitro way:
ATP —-> ADP + Pi Enthalpy change = 7.33 kkal/mole
Glucose + 6O2 —-> 6CO2 + 6H2O Enthalpy change = 686 kkal/mole

In vivo way: [just only for ATP]
ATP —-> ADP + Pi Enthalpy exchange = 13.33 kkal/mole

From this side, we can see the enthalpy energy resembles the potential energy of those 2 molecules.. 😀
Hope this helps..and for Biology, even though it’s less in math, be logic is also important.

[mith]

I’d say glycogen simply because it says potential energy. If it says ready to go activated compound, i’d go with atp.

[MrMistery]

Same with Dave.
@Ozge
I argue with my teacher all the time, and she is really cute when trying to prove her wrong opinions 😀 Anyway i like it that she always admits it when i am right. And i am always right 😀

[Poison]

My high school teachers never- yes never- said I’m right. Because they thought they know more than I do. I brought them many books (really advanced books) to prove I’m right but they still had doubt. Anyway, they were wrong. And I just wasted time. 🙂

*back to topic*
Ok maybe the term “potential energy” can make it able to argue. Then: glycogen. 🙂

[Fried Zygote Sandwich]

Yeah, it’s all to do with potential energy. Definately glycogen, as far as I’m concerned.

Potential energy is the energy stored in the chemical bonds that CAN be used in a chemical reaction. Doesn’t matter if it needs enzymes to activate it, it’s got potential energy.

Second reasoning, as I’m sure has already been pointed out, is glycogen is a glucose polymer (8 or 12 glucose I believe). So therefore it must obviously have more stored energy than glucose. So I’m 98.6% sure it’s glycogen. This question is a reasoning question, not an exact values question. If glucose produces more than one ATP and glycogen is more than one glucose then the obvious choice is glycogen.

[MrMistery]

Out of curiosity, how did you come up with the percentage of 98.6%? 😆 😆

[Fried Zygote Sandwich]

Through exhaustive statistical analysis! Nah, I made it up 🙂

[victor]

I think that Glycogen consists more than 8-12 glucose molecules..I’m sure that you mean is Oligosaccharides.. 😀
Let me explain it in Physics..potential energy is stored in the form of bond energy. So, the more bond energy a molecule have, the more potential energy it has….so, no doubt GLYCOGEN

[Fried Zygote Sandwich]

Agreed Victor.

As for glycogen, I found this on the web:

Glycogen is a glucose polymer resembling the starch in plants (so it is sometimes called “animal starch”). Glycogen is a highly branched glucose polymer. It is formed of small chains of 8 to 12 glucose molecules linked together with α (1→4) bonds. These small chains are in turn linked together with α (1→6) bonds. A single molecule of glycogen can be made of up to 120,000 molecules of glucose. It is stored in the form of granules in the cytosol, or cell fluid.

[Fried Zygote Sandwich]

So you’re right. It’s formed of chains OF 8 to 12 glucose molecules bonded together.

Is it oglio or polysaccharide? I’ve never understood the difference.

[MrMistery]

Actually the glycogen molecule is a bit more complex than that. There are 4 enzymes that participate in it’s synthesis and all of them remain atached to the molecule whn it is “finished”. Of these, the most important is called glycogenin(spelling?) which is the core of the glycogen molecule. Also, it does not resemble strach it actually resembles a component of starch called amilopectine, but it is more ramificated(is that a word?)

[Terry K.]

Definitely Glycogen. ATP, it’s great and all, but not as great of an energy provider as glucose, which is not as good of a provider as glycogen. I actually had a question like this one on an exam. The question was:
Which of the following has the potential energy?
A. ATP
B. Lipids (obviously not right)
C. Glucose
D. Starch

The answer is Starch of course. If you think in the same context, and replace Starch with Glycogen, then Glycogen is the correct answer. But just knowing what I do, the answer is GLYCOGEN. I’m 200% sure(and that’s pretty darn sure)!!!

[victor]

quote Fried Zygote Sandwich:

So you’re right. It’s formed of chains OF 8 to 12 glucose molecules bonded together.

Is it oglio or polysaccharide? I’ve never understood the difference.

“oligo-” means “few”
“poly-” means “many” 😆

[Terry K.]

yeah, just think of a monosaccharide as an (O), so if you use (O) as a monosaccharide, then an oligo- would be (O-O) while a poly would be (O-O-O…..) so on and so forth. Got it?

[Fried Zygote Sandwich]

Okay that much I knew. But what defines oligosaccharides? 2,3,4? Is there a specific number….or?

[Poison]

2-10 (aproximately)——-> Oligosaccharide
more than 10 (approximately)—> Polysaccharide

[Fried Zygote Sandwich]

Mmm, that’s what I don’t like about oligosaccharides…. Too subjective. It should bi mono, di, and poly. Oligosaccharides are too…..elusive.

[victor]

Agreed… 😀 …seems that it just like they create those name… 😕

[Poison]

thats right, they created that.

[2810712]

One question here… How does the life make the energy in glycogen and the glycos ‘not directly usable’???
See glucose from glycogen and ATP from glucose and the reverse both are feasible reactions… How come that happens… What are the G0 and S and E and H changes… i think any process can’t be feasible from both sides… I’m confused… its many days i’ve read any thermobook… sorry … but please help…
Also, Bond energy isn’t the stored energy in the bond its the energy required to breake the bond or the energy ‘released’ when the bond is FORMED. THe energy i’m thinking to be the stored part is the vibrational, rotational etc. type of internal Es … Oh bye i’ve to brush up all my ex-biologies that are useful in biology.

Ur’s questful,
hrushikesh

[victor]

Just refer to the law of thermodynamics I: energy can’t be created nor destroyed, it just can be re-arranged in the forms.

In the case of Biology..just imagine where there’s a place where many glucose molecules stuck in together. Because glucose molecule is polar, their polarity tends to get closer each other and form a glycogen (adding energy levels in the form of chemical bonds).

Bond energy means the amount of energy that needed whether to form the bond or to break the bond. (that’s why in chemistry, they divide bond energy into 2 groups: breaking bond-energy and forming bond-energy). When this bond is broken, some energy particles get spreaded out through [E=mc^2] and taking the most miserable form of energy, heat. Tha’s what we called Enthropy….

Hope you get my point,
Victor

[jayson]

quote Terry K.:

Definitely Glycogen. ATP, it’s great and all, but not as great of an energy provider as glucose, which is not as good of a provider as glycogen. I actually had a question like this one on an exam. The question was:
Which of the following has the potential energy?
A. ATP
B. Lipids (obviously not right)
C. Glucose
D. Starch

The answer is Starch of course. If you think in the same context, and replace Starch with Glycogen, then Glycogen is the correct answer. But just knowing what I do, the answer is GLYCOGEN. I’m 200% sure(and that’s pretty darn sure)!!!

Can you please explain how Lipid have less potential energy than the rest ? Lipids have glycerol and fatty acids, so naturally they should have the greatest potential energy (ignoring that lot more energy is required to break down the lipid into usable form!)

Thanks.

[victor]

I can say that cyclic bond structure in the glucose molecule [precursor of glycogen] contains more potential energy than alifatic bond sructure does in the bonding of glycerol and 3 chain of carbocylic acids……

[MrMistery]

don’t lipids have more potential energy than sugars? I mean from one gram of lipids you get 9.1 kcal while from 1 gram of glucose you get only 4.3 kcal
Of course, a starch or glycogen molecule have a lot more energy than that of one fat molecule, but if the options were: glucose, ATP, ADP, lipids(just an example) i would go with lipids….

[mikki]

Virtually every living cell starts with glycolysis. (The one metabolic pathway common in all living organisms). Lots of energy is held inside the chemical bonds holding glucose together. 11 enzymes and 11 chemical reactions are designed to rearrange and breakdown one glucose (6-carbon molecule) into 2 pyruvate molecules. (3-carbons). In the process, 2 ADP molecules are turned into 2 ATP using some of that liberated energy. The path divides as pyruvate moves on. Higher Forms of cells and animals have evolved a way to suck more of the energy out of glucose than just 2 measly ATP- THE KREBS CYCLE and the etc. With oxygen and inside the mitochondria, pyruvate is converted into CO2 and water. liberating enough energy in the process to build at least 34 more ATP. 36 ATPs (2 from glycolysis added to the 34 from the Krebs Cycle) sounds like a lot of energy, but it is still only about 40-45% of what was originally contained in the glucose.

[victor]

So, lipid’s calories are beaten by the accumulation of glucose forming glycogen…..

[mikki]

Ok I asked Dr. Neill, my professor and he said, this about it. “All have potential energy. All of these ultimately can be used in cell respiration”

So then I sent the question to our graduate teaching assistant aka my lab instructor and this is a copy and paste of her reply. She always types in caps so that we can find her answers within the email easily. Nobody get upset because this is not yelling.

“THIS IS A WEIRD QUESTION, PERHAPS TAKEN OUT OF CONTEXT FOR ME? ALL CAN HAVE THE POTENTIAL FOR ENERGY, AND ATP IS ENERGY, RIGHT, THEREFORE IF IT’S FLOATING AROUND, IT HAS POTENTIAL, RIGHT? AND THE OTHER THREE CAN BE CONVERTED IN VARIOUS WAYS TO ENERGY. PERHAPS THE PERSON ASKING THE QUESTION HAS SOMETHING IN MIND I AM UNAWARE OF.”

[MrMistery]

@mikki
No ofense, but your lab instructor doesn’t seem to know much biochemistry

quote :

AND ATP IS ENERGY

ATP is not energy. It simply releases energy(7.3kcal) when it is broken down.

quote :

THEREFORE IF IT’S FLOATING AROUND, IT HAS POTENTIAL, RIGHT?

I don’t really understand what she meant by this: maybe potential energy in a gravitational field where something is considered to have potential energy if they can convert it into kynetic energy by falling. We are discussing a whole different thing here…

quote :

36 ATPs (2 from glycolysis added to the 34 from the Krebs Cycle) sounds like a lot of energy

And a little correction here: the krebs cycle produces a measly one GTP and one ATP, it is oxidative phosphorilation that produces the most ATP

@victor
Yeap, that’s basically what i’m saying

[mikki]

I’m sorry MrMistery but my information came straight from the 7th edition of Reece and Campbell Biology book. Take it up with them if you think my information is incorrect.

[mikki]

One more thing, my lab instructor……..here is a small fraction of her curriculum vitae:
Research Assistant, Tropical Herpetofauna Catalogue, University of Texas at Arlington
2005 Graduate Student Senator for M.S. Biology program, University of Texas at Arlington
2005 Co-Chair, Guest Speaker Committee, Phi Sigma Biology Honors Society, University of Texas at Arlington
2004 Lead Graduate Teaching Assistant, Cell and Molecular Biology, University of Texas at Arlington
2003 Graduate Teaching Assistant, Cell and Molecular Biology, University of Texas at Arlington.
M.S. The University of Texas at Arlington, 2003
A.B. Boston College, Psychology (cum laude, high honors)

Yes, you’re right she doesn’t know much about biochemsitry does she?_____________________________________________________________________________
____________________________________________________________________________________

[MrMistery]

I didn’t mean to offend you or your teacher. Of course i can’t say judge someone from advice givven over the internet so i said “doesn’t seem”. According to that, i was wrong…
About campbell book? What page? I have it..

[victor]

Mine is the fifth edition…um, can yo tell me what chapter it is???

[2810712]

One thing we all must discuss and get clear is what is it actually that makes something energy-giving… I think every process reduces the capacity of the system to do useful work , but still the same process might absorb/give out heat and may increase or decrease the entropy of the system. The ways in which the system can give out energy seems to be – giving out heat and/or increasing entropy of the surrounding. This is what our P.E. does when it gets K.E.fied.
To deside whether some molec. is ‘energetic’ or not we must know why is something ‘energetic’ or ‘having P.E’. eg. due to closely posed O- in ATP,repulsive forces r developed that givethe bonds their potential energy.
Note that ATP is also not somuch reactive in cellular environment, so the energy-utilization can be done properly.
One may ask that why are such energy-rich compounds stable[glucose,starch,lipids etc.], i think the requaired conditions are not present always, in order to take out this energy from them… [some reactions in the initial steps of glyclysis need APT , enzymes etc.] this is imp. as otherwise how would cells have ‘stored ‘ the ‘energy’.
correct me whenever and wherever possible.
Enough P.E. seems to be developed here in the discussion… but we must
keep it isothermal.

yours always endoknowledgic,
hrushikesh

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