Why does the combustion of sugar in laboratory does not need to be controlled by an enzyme whereas the same chemical reaction within the human body does?
2007-10-14 23:38:48 · 13 answers · asked by ArabianFalcon 2 in Science & Mathematics ➔ Biology
The basic principle here is that reactions happen faster at higher temperatures. (If you need this principle explained, you'd better post another question).
In a lab, you can make the temperature as high as you want (by providing a flame, presumably) to get the sugar to release its energy in a fast reaction.
In the human body, we cannot have those sorts of temperatures because our cells would die in the heat. Enzymes accelerate the rate of reaction without the need for the high temperatures, which is why we need enzymes in order to get the energy from sugars in our bodies.
2007-10-15 00:03:18 · answer #1 · answered by whellad 2 · 1⤊ 0⤋
The reaction needs to be controlled. In the lab, you can burn sugar, and the reaction will produce enough heat to keep the combustion going. In a cell, you can't use such high temperatures, since it would be lethal to the cell.
The rate of reaction needs to be controlled as well. The amount of energy a cell needs changes over time (i.e. when you're resting, you need less energy than when you are running) You can turn enzymes on and off (either by regulating the production and degradation of the enzymes themselves, or by using a coenzyme to alter the activity itself) and confine a reaction to a certain portion of the cell. With combustion, you have a certain amount of sugar, and once it starts burning, the flames spread throughout the sample and continue until it is all burned up.
Finally, combustion doesn't yield any energy that is useable by the cell. If you burn sugar, all you end up with is heat and waste products. With enzymes, the energy release from sugar breakdown can be used to convert ADP to ATP. Other parts of the cell can then use the energy trapped in the ATP by converting ATP to ADP. Simple anaerobic bacteria use a few enzymes to break down glucose and produce a little ATP, but more complicated aerobic organisms can break down glucose to form ATP as well as channel some of the waste products (like hydrogen bound into NADPH) over to the mitochondria where more enzymes can produce even more ATP. Basically, the more enzymes that are involved in glucose breakdown, the more efficient the process and the more useable energy is obtained.
2007-10-15 08:11:34 · answer #2 · answered by andymanec 7 · 0⤊ 0⤋
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2016-03-12 23:19:36 · answer #3 · answered by Mary 4 · 0⤊ 0⤋
In a lab the "combustion" of sugar is UNCONTROLLED. They are allowed to go as fast as the reaction will go. It actually burns.
But inside the body all reactions have to be controlled. It is called "rate of reaction". Inside the body there are no fires and no matches to start the reaction (and you don't want it either).
Also enzymes lowers the "activation energy" so reactions can happen at lower temperatures (ex: below burning temperatures).
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Just think it wouldn't be any good to drink soda and then the sugar literally ignite in your belly.
Good Luck.
P.S. I agree with you. They often leave out critical details in classrooms. But the fact you are asking is a good sign that you are one of the thinking students.
2007-10-14 23:42:30 · answer #4 · answered by Lover not a Fighter 7 · 0⤊ 1⤋
What temperature are you using in the lab? All reactions require favourable conditons before they will start. Heating the sugar provides energy to break the sugar bonds. The enzyme changes the conditions necessary for reaction to proceed by reducing the activation energy of the intermediate compounds, therefore it can take place at body temperature.
2007-10-15 02:48:37 · answer #5 · answered by Anonymous · 0⤊ 0⤋
because inside the body, the high temperature required to combust the sugar cannot be attained (well to put it simply, your cells will die if it's too hot :P) so enzymes are needed to speed up and make the reaction possible by acting as catalysts. :D in the lab, the heat required could easily be attained by putting the sugar over a flame..! :D
2007-10-14 23:57:18 · answer #6 · answered by wheeeeeeee..! 2 · 0⤊ 0⤋
Have a look at this experiment setting fire to a mixture of potassium nitrate(Saltpeter) and table sugar. The enzymes ensure that only the exactly correct amount of energy is released - "burnt" is a slightly misleading term perhaps.
2007-10-14 23:45:29 · answer #7 · answered by morwood_leyland 5 · 0⤊ 1⤋
Because the sugar in the body is mixed with other bodily fluids such as blood and saliva. Enzyme rich materials.
2007-10-14 23:41:34 · answer #8 · answered by smokey virginia 3 · 0⤊ 0⤋
Enzymes in the human body are what control everything. In a lab, people are the ones who control it... makes sense?
2007-10-14 23:41:43 · answer #9 · answered by Melissa 4 · 0⤊ 0⤋
Because in the lab the combustion is via an external source?
I mean a flame is used to start the process.
The Catalyst is the whacking fire!
2007-10-14 23:44:14 · answer #10 · answered by InTheGreatSatan 2 · 0⤊ 1⤋