[AdiDex]

what do you meant by modern theory of atom ??

[AdiDex]

You are just changing the arrangement of atoms .

You are breaking some of the old bonds and forming some new kind of bonds during the chemical reaction of burning .

[AdiDex]

I can't answer you that  why is this so.
Actually we know the life in such a manner that carbon is the basis of life that's why astronomers used to look out in space for some complex carbon molecules in search of living creature .

They can look for gold or platinum for searching the aliens , but they don't .
Because as far as we know carbon is the basic building block of life.

may be the answer of this question -:
"why only carbon , not gold or silver is responsible for life ? "
In my view -:
may be due to its special property - Catenation , no other elements can make such large and variable chains of atoms like carbon .
And life is all about to putting these large molecule together in some particular order  .
You should watch this video
https://youtu.be/5c6C3rHOdf8

[smghz]

I mean, they are ATOMIC components, not surface components, not something I can touch. And yet my tongue can still taste the glucose. Is it tasting the carbon, oxygen, and hydrogen? I'm quite interested in knowing this.

[mikasaur]

Taken from http://www.chemistryexplained.com/St-Te/Taste-Receptors.html


...other tastes including sweetness (as in sucrose, fructose, and artificial sweetener) are sensed by actually binding to specific membrane receptor proteins in taste receptor cells. The chemicals sensed as sweet bind to selective sites on a membrane receptor in a "lock-and-key" fashion (implying that only chemicals of a particular shape can fit in the binding site and initiate the response). Once the sweet chemical is bound, the membrane receptor initiates a series of chemical reactions inside the cell, leading eventually to a change in the flow of ions across the membrane and the release of neurotransmitter. Likewise, the bitterness of some chemicals is sensed by binding to other membrane receptors and then initiating a response. The taste of some amino acids is initiated by binding to a specific site on chemical-gated ion channels (channels that open when a chemical is bound) where the amino acid (the chemical) acts as the key. The umami taste of monosodium glutamate is sensed by binding to another type of membrane receptor (similar to the synaptic glutamate receptors of the brain) that allows ions to cross cell membranes.

[Furanone]

You can read about it here. It is the sweetness model developed by Shallenberger & Acree in the 1960s where sweet molecules have an A--H/B triangular shape that fits into the glucophore in a lock-and-key mechanism as Mikasaur mentions above.

http://www.aaccnet.org/publications/cc/backissues/1982/Documents/chem59_92.pdf

Sucrose (table sugar) which is the dissacharide of glucose and fructose bound together, has a relative sweetness of 1 yet glucose has relative sweetness of 0.7 and Fructose about 1.7. However, sucralose (Splenda) which is sucrose with three hydroxyls replaced with chlorine roups has a relative sweetness of 600!! It is not known what makes this so much sweeter whether it sends a more intense signal to brain or binds longer to receptor, but walking into a manufacturing plant that produces sucralose, the air you breath tastes sweet.

Also, interesting enough there is an enzyme called miraculin from the miracle berry grown in Western Africa, that when consumed (lathered over tongue and taste buds) will convert the sour (acidic) tastes to intense sweetness for about 1-2 hours after consumption. You can actually eat a lemon or lime whole without squinting and it will taste like the sweetest lemonade you've ever tasted. Again, it is not well understood the mechanism of action for this. Is it tricking your receptors into sending a sweet signal instead of a sour signal? Is it physically changing conformation of taste buds to bind in molecules in a different way? Definitely a way to keep things sweet and lower your carbs/calorie intake!

https://en.wikipedia.org/wiki/Miraculin

[smghz]

I learned that in the electron transport chain stage of the cellular respiration, proteins like NADH and FADH2 can actually swap electrons. But how can they swap ELECTRONS? I thought that electrons are so tiny the laws of physics don't even apply to them, so how can cells hold and yet swap things smaller than atoms? (BTW, do they even have a brain to do so?).

[Irlanur]

proteins like NADH and FADH2

these are not proteins.

I thought that electrons are so tiny the laws of physics don't even apply to them,

The laws of physics apply to everything. But they behave quite differently than things we know from everyday life.

do they even have a brain to do so?

this question suggests that you have very little science background. Can I ask what background you have? otherwise the communication will be very inefficient;)

[smghz]

But at least answer my question. There is no need to know about my background since my past posts reveal it pretty well. No need to fact-check a learner.

[Irlanur]

That's not the point. I can formulate an answer with a lot of name dropping and technical language. Or I can try to meet you at the point of what you know.

Anyway, the area of electron transfer reactions, especially in biology, is far from fully understood, but a whole lot of chemical reactions contain a electron transfer. Did you ever hear about redox reactions?

Often, the electron transfer is also only "formal", e.g. if a hydride is transferred.

how can cells hold and yet swap things smaller than atoms? (BTW, do they even have a brain to do so?)

how should cells have a brain and why would they need one for this purpose?

[Babcock_Hall]

smghz,

Irianur answered two of your questions.  My impression was the same as his, namely that you do not know much science.  There is no shame in that, but one tailors one's explanations based upon what one's listeners know.  The behavior of electrons is a good case in point.  Electrons have a very small mass.  Our Newtonian understanding of macroscopic objects is not going to be successful at explaining their behavior.  Yet, if you know nothing of quantum mechanics, then there is no point in giving you an explanation which assumes otherwise.

[smghz]

So guys can you give me advice on how I can improve my science? I am going to university next year (namely, Umich, which is known for being really great [and difficult] at teaching bio and chem)? Unfortunately I haven't gotten the preparation necessary in MS and HS. How did you guys get to be what you are now? I'd be completely indebted.

[kriggy]

I think the best place is to start reading on wikipedia about the topics that you are interested in. If you are still on high school then maybe go ask your science teacher if he/she can recomment you biology and chemistry textbook But remember, its long way run, It takes a time and will to get to the place where the guys are right now.