What components join together to form the backbone of a nucleic acid?

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Accepted Answer

All right. Hello everyone. So this question is asking us which of the following best describes the components that alternate to form the backbone of a DNA molecule. Option A says alternating sequence of amino acids and peptide bonds. B says alternating sequence of phosphate groups and deoxy rival sugars C says nitrogenous bases and hydrogen bonds. And option D says fatty acids and sermons. So let's recall a few things about DNA, right, DNA, if you recall is a polymer, which means it's made up of multiple monomers that are attached together to create the larger DNA molecule. Right? Those mole molecules, excuse me are known as nucleotides. So to understand the answer to this question, we have to recall what makes a nucleotide, which is what ultimately makes the backbone of a DNA molecule. So let's start by drawing it, right. The first component is the sugar backbone and the sugar backbone determines whether or not this is going to be DNA or RN A. So because we're talking about DNA specifically, then the sugar backbone is known as deoxyribose in which there's a hydroxy group on carbon number three of the sugar itself, but not on carbon number two, that's why it's called deoxy rivals ribose. On the other hand, is the sugar backbone of RNA nucleotides and it has hydroxy groups on both positions. So the second component that I want to mention here is the phosphate group, which is attached to carbon number five, which is actually outside of the sugar ring itself. So here's my phosphate group and I'm running out of space. So I'm going to move this structure off to the side. Now there's one more component and that component is the nitrogenous base that's attached to carbon number one of the sugar itself. So now the question is which of these components are alternating to form the backbone. And to that end, it's important to understand how these nucleotides are being held together to create the larger structure. So earlier, we talked about the hydroxy group on the three prime carbon of the rivals sugar, sorry deoxy rivals here. And we also talked about the phosphate group attached to the five prime carbon that's outside of the rink. Well, when it comes to making a polymer of DNA nucleotides, then what happens is that the five prime phosphate group is attaching itself to the three prime hydroxy group of the prior nucleotide that creates a change. And so what this does is ensure that the backbone is actually on the outsides of the DNA molecule. The nitrogenous bases are then in the center or in the interior base pairing with its complementary base on the other DNA strand. So our answer is going to be option B in the multiple choice because the backbone of a DNA molecule is composed of alternating sequences of phosphate groups and deoxy rival sugars. So there you have it. And with that being said, thank you so very much for watching and I hope you found this helpful.

What components join together to form the backbone of a nucleic acid?

Verified video answer for a similar problem:

Key Concepts

Nucleotides

Phosphodiester Bonds

Sugar-Phosphate Backbone