What determines the primary structure of a DNA molecule? a. stem-and-loop configuration b. complementary base pairing c. deoxyribonucleotide sequence d. hydrophobic interactions and hydrogen bonding

Video transcript

Hi everyone. Now let's look at our next problem, identify the incorrect statement about the primary structure of DNA molecules. So let's look to our answer choices. We're calling that we're looking for the incorrect statement and noticing that choice D. Is all statements are correct. So we do have a possibility that all three of the first choices are correct. So with that in mind, let's look through. We have a choice A. It is actually a sugar phosphate backbone and that is correct. Um We have it's a polymer of five carbon, five carbon sugars and those are linked by phosphate groups. So we have this alternating sugar ring, phosphate group, sugar ring, phosphate group. So that is correct. So we put a little dot there since we know that we do have an we're looking for the incorrect statement. Um but there's a possibility that all are correct. So we're not gonna eliminate anything yet. We'll just note there that this is correct. We could put a little T for true there. Choice B says it is stabilized by phosphor di ester linkages and this is correct also. So because the phosphate groups that link together the sugar rings, those bonds between the carbon in the sugar ring and then the phosphate and then the carbon and the next sugar ring. Those are phosphate ester bonds. And those are very strong covalin bonds which makes that structure um very stable. So that is also true. Well, let's keep on looking down to choice. See again, we're gonna note this is true. Since there's a possibility they all are. Let's look at choice C. Choi C says it is the most stable structure of D. N. A. And this is also true again, due to those very strong Covalin bonds in the phosphor diaspora linkages. Um We also think of the stabilizing effect of the double helix with the hydrogen bonds between the two strands, but covalin bonds are stronger than hydrogen bonds. So the primary structure that sugar phosphate backbone is the most stable structure of D. N. A. So we have three true statements here. So our answer is choice. D all statements are correct. See you in the next video.