Draw the chemical structure of a dinucleotide composed of A and G. Opposite this structure, draw the dinucleotide composed of T and C in an antiparallel (or upside-down) fashion. Form the possible hydrogen bonds.

Video transcript

Hi everyone. Let's take a look at this practice problem together. How many hydrogen bonds will be formed by a strand of the DNA mentioned below. And were given our strand. But I'm going to write it a bit bigger. So it's easier to see A T C c g c T A. Okay, recall that adenine. And timing when they bond they form two hydrogen bonds Whereas guanine and cytosine when bonded together, formed three hydrogen bonds. So if we go up and add the total number of each of our nucleotides and then multiply them by the corresponding hydrogen bonds and add that all up together. That's going to give us our total. So let's put that into action. So we have 1234 added means for added means they will form two hydrogen bonds when they bond with a timeline. So that's going to give us eight hydrogen bonds for adding binding to finding. Now let's do timing. We've got 123 timing. So two times two hydrogen bonds. That's going to equal four hydrogen bonds. When timing pairs with adenine. Then we've got 1, 2, 3 side busines. So three times three because remember cytosine and guanine formed three hydrogen bonds. That's going to equal nine hydrogen bonds when citizen pairs with guanine. And then finally we have one guanine. So one times three equals three hydrogen bonds when guanine pairs with cytosine. Now if we add all of this up, this is going to give us the total number of hydrogen bonds. So we have eight plus four equals plus three equals 15 plus nine equals 24. So that's 24 hydrogen bonds total. So our answer will be C. 24. Alright, Everyone. I hope you found this helpful, and I'll see you soon for the next practice problem.