Yet another science question!

[underu2000]

The question is, "Do biological processes like cellular respiration convert matter into pure energy?"

 

 

 

No its not homework. Myself, I always thought the answer is a resounding "NO", since until now I used to think that the only way to do this is through nuclear fission/fusion or some kind of antimatter explosion (theoretical). And take e=mc2 for example, if food were to be converted into energy, we would have astronomical amounts of energy in our bellies. Instead, energy itself would never be evident, but just stored in energy-molecules of ATP.

 

 

 

Why ask in the first place? Well, recently me and my buddies were chatting about eating food and stuff and somewhere he said "food is turned into energy", which is when I corrected him and told him my explanation. Then he bet me in cash, and thinking I'm getting easy money, I agreed.

 

 

 

This is where it goes downhill. When we asked, three teachers, yes three science teachers agreed with him, saying "Yes, matter can be converted into energy in our bodies". To supplement his case, he added "Why do you think we don't poop as much as we eat?" and "Energy is the fourth state of matter anyway (plasma)". Although I disagree even with these few comments, I'm fighting a losing battle here. And I DO NOT want to part with good money!

 

 

 

So tell me If I'm wrong after all; can matter (food) be turned into pure energy through a normal chemical reaction?

[warri0r45]

The food (carbs, for example) carries energy in it's chemical bonds. The chemical bonds are manipulated (as in broken, reformed to produce new compounds) in the Krebs cycle of cellular respiration to produce more efficiently usable high energy compounds, such as ATP. So the food is not converted to energy, it's converted to other compounds which carry more efficiently usable energy. All the energy does is get converted from chemical bond to chemical bond. In a high energy molecule such as ATP, the energy stored in the phosphate-phosphate bond is so great that is can manipulate other compounds, such as opening a channel in a membrane protien to let selected ions through, for example.

 

 

 

Biological energy needs to be acessable and targetable. This can't be done unless you store this energy in a molecule.

 

 

 

Just saying 'food is turned into energy' is a bit off in my opinion. What about protiens? They are used structurally, not energetically (unless they really need to be, which for a healthy person they don't) You also find fats around every cell in your body performing a structural role. Carbs and nucleic acids have structural roles too; addition to protiens for cell to cell recognition and information carrying, respectively, for some examples. All of these compounds do carry energy in thier chemical bonds, though.

[underu2000]

The food (carbs, for example) carry energy in thier chemical bonds. The chemical bonds are manipulated (as in broken, reformed to produce new compounds) in the Krebs cycle of cellular respiration to produce more efficiently usable high energy compounds, such as ATP. So the food is not converted to energy, it's converted to other compounds which carry more efficiently usable energy. All the energy does is get converted from chemical bond to chemical bond. In a high energy molecule such as ATP, the energy stored in the phosphate-phosphate bond is so great that is can manipulate other compounds, such as opening a channel in a membrane protien to let selected ions through, for example.

 

 

 

Biological energy needs to be acessable and targetable. This can't be done unless you store this energy in a molecule.

 

Permission to memorize above passage and recite it at nearest opportunity?

 

I can? Cool, thanks!

 

But that is what I thought too, that by the law of conservation of mass the matter will not be converted into energy but more matter in different molecules. I'll have to pretend those teachers just heard me wrong.

[Hitman247m]

My science is a bit spotty, but, uh, I don't think it's possible to have pure energy, there is always a seperate by-product of a chemical reaction...

 

 

 

Just don't quote me on that, lmao :lol:

[Randox]

All the food is not converted into energy. If that were true we would never take a dump and we would proboly die from electro magnetic radiation. The chemical reactions do result in a net gain of energy.

 

 

 

A much simpler example is oxygen. The process plants use to convert carbon dioxide into O2 (an oxygen molocule) reqires an input of energy, provided by the sun. This makes the O2 sort of like a battery, the plant has now stored a small bit of the suns energy in this molocule, and when our bodies preform the exact same chemical reaction in reverse, we get the energy that was stored there.

 

 

 

However it is not the food itself that is converted into energy, it is the energy relesed by exothermic reactions that consume the food. And in all honesty, teh output of our rear ends is actualy about the same as our intake of solids. [cabbage] is just fairly dense, but very little of the food exits the body by means other than urine, fecies and methane gas. Thats what your teacher forgot about anus output, we also fart :thumbsup:

 

 

 

Oh and the 4th state of mater (plasma) is not pure energy. Thats the biggest pile of Bull [cabbage] i've seen in a long time. It's much closer to a highly ionized gas at extreme tempereatures, with a density simaler to a liquid (not entirly certain about the density part). Tell you science teacher to stop spouting lies. Rember if the food molecuels were actualy converted into energy, the results would be like a 1/4 power atomic bomb going off in your chest 24 hours a day. :ohnoes:

 

 

 

I also like wariors answer, I think he took both biology and chemistry. I do chemistry and physics.

[Rebdragon]

God, I had a discussion with my mom last week about this.

 

 

 

Took me half an hour to explain to her that energy is just kept in molecules as bond energy, and that E=mc2 (an equation I see used far too much...) had nothing to do with it.

 

 

 

Photosynethesis put energy from sun in chemical bonds, cellular respiration break bonds to use energy. Simple as that.

[warri0r45]

The semantics here are kind of annoying me.

 

 

 

I think "Matter (food) is sometimes coverted into compounds whose purpose is to release energy, depending on what type of compound from the food is in consideration and the needs of the organism" is more fitting than "Matter (food) is converted into energy" when talking biology.

 

 

 

Anyway let me take this opportunity to analyse some of the positions of persons in your opening post.

 

 

 

"Do biological processes like cellular respiration convert matter into pure energy?"

Processes such as cellular respiration convert matter into more usable forms such as ATP. The breakdown of ATP releases energy used to do work and this inevitably produces heat energy as a byproduct. In evidence of the evolution of these energy forms is the fact that you have a body temperature and can move. The key here is that the products of the breakdown of ATP are still there; ADP (adenosine diphosphate) and a phosphate molecule. They didn't do anything cosmological and dissapear into pure energy (forgive my sucky physics).

 

"food is turned into energy"

The half truths and lack of detail in this statement make me consider it misleading. First, as explained, energy is released from certain compounds derived from food, those compounds aren't converted into energy. Secondly, this statement seems all inclusive. A lot of food turns into compounds used structurally, not energetically, thus not all food "turns into" energy.

 

"Yes, matter can be converted into energy in our bodies"

 

This is a step up from the quote of your friend. This one is not all inclusive because it correctly adds 'can'. Yet, the semantics here are still annoying me. Certain matter in us releases energy; it does not get converted into it.

 

"Why do you think we don't poop as much as we eat?"

Perhaps your friend failed to realise this is likely largely because stuff he eats becomes stuff which makes up him. It's not less because it's converted into energy; it's less because we need it to form the structural components of our cells.

 

 

 

There we go, got it off my chest. : If someone knows something about bioenergetics or the physics of biology which I don't, which is highly likely because I haven't studied it much, feel free to correct me.

[silver_wits]

holy hell.. those are some amazingly long posts.

 

But look up the definition of a "calorie"

 

A calorie is the amount of food it takes to heat 1 cell 1 degree.

 

now.. isn't heat a form of energy?

[warri0r45]

holy hell.. those are some amazingly long posts.

 

But look up the definition of a "calorie"

 

A calorie is the amount of food it takes to heat 1 cell 1 degree.

 

now.. isn't heat a form of energy?

 

 

 

Yep, heat energy is most definately released from biochemical reactions. The deal here is that it's released as a result of matter changing it's chemical bonds via chemical reactions. The matter itself isn't turning into heat energy, it's the change in chemical bonds which is key here.

[Barihawk]

Yes, heat is energy.

 

 

 

The others have already answered for me :(.

[Randox]

holy hell.. those are some amazingly long posts.

 

But look up the definition of a "calorie"

 

A calorie is the amount of food it takes to heat 1 cell 1 degree.

 

now.. isn't heat a form of energy?

 

 

 

And your point would be what exactly?

 

 

 

Yes by relesing energy we will proboly have heat as a by product, or some other form of EM radiation.

 

 

 

And I belive a calorie is the heat energy needed to heat an ounce or ml (not sure) by 1 degree centigrade. But that dosen't mean that any matter was converted to energy, but that the 'potential energy' in teh chemical bonds was converted to 'kinetic energy' for use by the body. (please note the usage of both potential and kinetic energy in that context is incorrect, but it may help people understand the concept better).

[Rebdragon]

holy hell.. those are some amazingly long posts.

 

But look up the definition of a "calorie"

 

A calorie is the amount of food it takes to heat 1 cell 1 degree.

 

now.. isn't heat a form of energy?

 

 

 

Yep, heat energy is most definately released from biochemical reactions. The deal here is that it's released as a result of matter changing it's chemical bonds via chemical reactions. The matter itself isn't turning into heat energy, it's the change in chemical bonds which is key here.

 

Ya, if I recall don't our most efficient chemical reactions still only work at 39% efficiency, with the rest of the energy escaping as heat energy? :-k

[Barihawk]

holy hell.. those are some amazingly long posts.

 

But look up the definition of a "calorie"

 

A calorie is the amount of food it takes to heat 1 cell 1 degree.

 

now.. isn't heat a form of energy?

 

 

 

Yep, heat energy is most definately released from biochemical reactions. The deal here is that it's released as a result of matter changing it's chemical bonds via chemical reactions. The matter itself isn't turning into heat energy, it's the change in chemical bonds which is key here.

 

Ya, if I recall don't our most efficient chemical reactions still only work at 39% efficiency, with the rest of the energy escaping as heat energy? :-k

 

 

 

Just think of how much BTU the human body puts out. Most of that heat is dissipated through the skin, else we would cook from the amount of heat generated by our natural processes.

[warri0r45]

holy hell.. those are some amazingly long posts.

 

But look up the definition of a "calorie"

 

A calorie is the amount of food it takes to heat 1 cell 1 degree.

 

now.. isn't heat a form of energy?

 

 

 

Yep, heat energy is most definately released from biochemical reactions. The deal here is that it's released as a result of matter changing it's chemical bonds via chemical reactions. The matter itself isn't turning into heat energy, it's the change in chemical bonds which is key here.

 

Ya, if I recall don't our most efficient chemical reactions still only work at 39% efficiency, with the rest of the energy escaping as heat energy? :-k

 

 

 

Yep, I've heard similar numbers before.

[Adventurer]

I don't think I can answer most of your question, but for the poop thing:

 

 

 

Isn't biomass lost at every level because of energy needs and isn't some of it also used in growth/repair?

[r2d2]

if you want a simplified answer:

 

 

 

Plants convert sunlight, CO2 and H2O into glucose and O2. humans then (either directly or indirectly) eat the plants, and absorb the glucose. It is then broken down into energy, CO2 an H2O, consuming energy in the process.

 

This is assuming aerobic respiration, but anaerobic has mainly the same principles.

[underu2000]

Thanks for the confirmations of my ideas people. It's just that I have no way to prove that his second grade thinking of "food becomes energy" is wrong, especially since he has more people agreeing with him. It's appalling, I wanted to smack every teacher and peer we asked, except my ex-chem teacher who said "No, you can only do this through radioactivity".

 

 

 

And as for the heat being released, it isn't completely relevant. It so happens that respiration is for the most part exothermic, giving out a lot of heat which keeps our body temperature stable. But regardless, the matter isn't transforming into energy, just that the new molecules formed have less energy within their bonds and release the extra energy as heat.