what “carbon based” life means



what “carbon based” life means

In: Biology

It means that the atom that is used for the base of nearly all of the ‘life sustaining’ molecules is carbon. Carbon forms the basis for nearly every important molecule in the body – our proteins, DNA, cell walls, etc all use carbon as the base scaffolding.

All life we know if is carbon-based, but it is theorized that other atoms (like silicon) with similar properties to carbon could potentially fill that role in other lifeforms. It is just theory, as we have never found any living thing that uses anything but carbon for the base.

All life as we know it is carbon based–that is, it’s primarily made up of all sorts of long-chain carbon compounds. Carbon can form very long stable molecules, which means it produces a whole variety of building materials to work with.

The only other element we know of that can do anything similar is silicon, and even then it only works if the silicon is combined with oxygen, so while SF authors will quite happily insert silicon-based lifeforms into their works, there’s a great deal of doubt whether such a thing could actually exist.

Basically, all our cells, the way we get energy, etc., all use molecules which are made out of carbon with some other things added on. For example, we make energy from glucose, which is made out of carbon with some oxygen and hydrogen attached.
There are other life forms, although relatively rare, that are based on other things like sulphur: They would use molecules which are mostly sulphur to create energy

It refers to organisms who’s “building blocks” (in our case cells -> organs) are primarilly made out of chemicals that heavily rely on carbon molulecules bound with some other elements to work.

This also implies that the way in which we produce energy (to move and stay alive) also relies on processing chemicals with high carbon contents.

So far we have only found carbon-based life, however it is theorized that life could also arise from other elements in the right conditions. Silicon is apparently the main candidate for an alternative type of lifeform.

Almost all the chemicals used in constructing a living creature are based around a chain of carbon atoms, mostly surrounded by hydrogen in a lot of cases. There are near-infinite ways in which these chains can branch off one another, or be bonded, or have different groups of chemicals attached to them to create the chemicals to build life.

This answer comes from more of a chemistry perspective than a biology one, but there you go.

When I make a really nice bolognese, I call it a tomato-based sauce. Why? Because the sauce is mainly defined by how the tomato tastes, acts and reacts. When you look at life on earth, the biology is mainly defined by the behaviours and characteristics of carbon. Sure, the human body might be mainly “other stuff”, just like how my bolognese is full of non-tomato ingredients – but the carbon is one of the big defining elements. Just like how there’s other bases to use for a sauce, we have theories that it’s possible to use other elements as the base for life. We haven’t found any, for obvious reasons, but it may be possible.

The main macromolecules that make up our bodies include the following:

– proteins

– nucleic acids

– carbohydrates

– lipids

I am unable to show a photo here – but if you go to google images and search for images of the chemical structure of each of the above macromolecules, you will notice something similar between all of these molecules.

All of these molecules have Carbon atoms that make up the main structure / framework for each of those molecule types.

Given this fact about Carbon as the basis for the structure of the main macromolecules in our bodies, there is something that may surprise you…

OXYGEN is actually the most abundant element in the human body.

Here is a breakdown:

96 percent of the human body is made of 4 elements: oxygen (65 percent), carbon (18.5 percent), hydrogen (9.5 percent) and nitrogen (3.3 percent).

If life is supposedly “carbon based”, why does oxygen make up over 65% of the human body?

The answer is WATER.

Water makes up 60% of our bodies, but life is still said to be carbon-based, because the structural components of our bodies (tissues, organs, etc.) are made of molecules that have carbon as the main element in the chemical structure.

edit: clarity