Oh, wow, oh, oh, oh, wow, oh, oh, wow.

Oh, wow.

Oh, my. Hello, you're listening to The Science of Everything podcast, episode 18,

Biochemistry basics.

So in today's episode, I'm going to talk about the basic principles of biochemistry,

which is the chemistry of living things and organic molecules.

And I'm going to talk about in particular the basic properties,

structure, and functions of the four main classes of bioorganic molecules, which are proteins, nucleic acids, lipids and carbohydrates.

And before I do that though, I'm going to give a brief outline of what organic molecules are

and why they're so important in living organisms and just generally about what biochemistry is about.

So biochemistry is kind of the foundational field for the study of biology,

because to understand biology, you have to understand cells, because every living thing is made up of cells,

and to understand cells, you have to understand the molecules from which they are made,

and those molecules are

biomolecules, and the study of those biomolecules is biochemistry. All organic molecules are made

from carbon, and carbon is, therefore in a sense, the building block of life. Everything that we

know that is alive is made largely from carbon, covalently bonded to atoms of hydrogen, oxygen, sulfur, nitrogen, a few other elements nearby on the periodic table.

Carbon is a relatively rare element in the natural world. It only accounts for 0.03% of the Earth's total crust, but it accounts for almost 20% of the total mass of a human body. So carbon is substantially

concentrated and well ever represented in terms of mass in living creatures. So why is carbon so important?

The reason is because carbon has four valence electrons, that is it has four electrons in its outermost shell, and that outermost shell has a capacity of eight. So four valence electrons. That is, it has four electrons in its outermost shell, and that

outermost shell has a capacity of eight. So, four valence electrons provides the largest number of

bonding opportunities, because, as mentioned in the previous episode, atoms tend to fill up

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