A long, long time ago a fool said that “we are what we eat”, if it was true then why are we not just a huge mass of sugar chains and proteins soaked in water? Would it not be exciting to see other blobs walking down the street? If you have not thought about it, yes … it would be gross.
Most of the food that we eat is made up of one of the most important “bricks of life”; that is, carbohydrates (or sugars, or saccharoids). To close friends they reveal their real nature: they are just a bunch of molecules consisting of C(arbon), H(ydrogen) and O(xygen) in the ratio of 1:2:1 connected together thanks to the love they share for each other (i.e. chemical bonds). If you really want to be one of their coolest friends you will need to call them by their “nickname”, that is (CH2O)n (with “n” indicating the number of C’s present in the molecule). This “n”, as you may have already thought, is variable (e.g. from a minimum of n=3, to n=6 and more) and deeply affects how the molecule is going to be used by our organism as well as its structure.
What are the differences that you can spot between the molecules I have just shown you? First of all you can notice that every structure has a different amount of atoms of Carbon. Secondly, you can definitely see that the three-carbon molecule is “linear” (visualise it as a stick with a few others that branch off of it, it is known that you cannot use it to practice with a Braavosi, but it will be still useful to beat Joffrey up). Why is that? Usually, carbohydrates can exist in the form of straight chains (e.g. the glyceraldehyde), but when added to an aqueous solution they curl up in the form of a ring. This happens because carbohydrates can be really scared of water, causing a reaction called “nucleophilic addition” (which I will explain only if you would like to know more about it!).
Something to know about biological molecules is that the structure matters, a lot. In fact, even just the slight structural difference can cause a change in how we see the compound. With the formula (CH2O)6 or C6H12O6 we indicate the type of sugar that we normally use during baking (in the concentrated form), also known as glucose, but there are two other carbohydrates with the exact same formula. These two are called “isomers”, which are molecules with same empirical formula but differences in the structure (an example? Lannisters: they have the same surname, but some of them are smaller, one likes to play with cats instead of … well, people and so on). The first one of these two molecules is called “fructose” and differs from the glucose for the position of the carbonyl carbon (the C=O), and falls in the group of “structural isomers” (differences in the carbon skeleton, which is the “central stick”). On the other hand we have “galactose”, whose hydroxyl group (-OH, also known as the “surprise group”) and hydrogen have a different arrangement in the structure (falling in the group of “stereoisomers”, where the modifications happen in the orientation of the functional groups – and I will talk about these in another article). The question is: why should I care about this? BECAUSE YOUR ORGANISM HAS SUPER POWERS. Our taste buds and enzymes have the ability to spot the differences between these molecules: for example, fructose is sweeter than glucose. Moreover, our organism can use a molecule of glucose and one of fructose to create what we call a disaccharide, which is two monosaccharides linked together by a reaction.
But what is a monosaccharide? What about disaccharides and … wait, I heard of polysaccharides too! WHAT ARE THESE? Why carbohydrates are so important to us? WWHHHYYY?
I will answer to all these questions in the next article so … stay tuned!
May the science be ever in your favour!
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I will be more than happy to hear anything from you all 🙂