So now remember that secondary structures give rise to two repeating patterns. Here, we're going to talk about the second pattern, which is called our beta pleated sheet. Now, here, this is a secondary structure consisting of two or more beta strands oriented side by side. If we take a look at the right, we see that again, our primary structure comes from the connecting of amino acids in a sequence through peptide bonds. We know that it can give our alpha helix as a secondary structure.

But now we're going to talk about a beta pleated sheet as another secondary structure. Now the name pleated, it's because of their zigzag pattern. If we take a look here, sheet. If we really visualize this, we have our two peptide chains that are hydrogen bonding to one another. Remember, here we have hydrogen bonding happening here, here, here, and here.

So I've basically hydrogen and also here, and that looks, and here. So these are all our spots of hydrogen bonding. Got all of them. Yes. So this is all our sites of hydrogen bonding that connects these two peptide chains to one another, and we can see that these chains that are hydrogen bonding to each other, they kind of reside if you look at it like on a full piece of paper.

That's what we talk about pleated, the zigzagging pattern. Think of paper being folded. The way the two chains orient themselves because of this hydrogen bonding, because of this way the beta strands orient themselves side by side gives us this depiction of a sheet. Now, here, we're talking about the chains, but remember there are R groups. R groups, because of spacing, can't be in the interior.

That's where hydrogen bonding is occurring. So what they do is they orient themselves above and below this sheet. So we're going to say the R groups, they're going to extend above or below the beta sheet. So here we have the R groups on top, so they're above the sheet, and then we have these R groups on the bottom below the sheet. And this all has to do with spacing and taking the optimal shape when it comes to these peptide chains.

Right. So remember, we have our primary structure. The primary structure leads to our secondary structure. This is happening to create two different types of possible shapes where we have alpha helices and beta sheets.