What are the four major heterocyclic bases in DNA?

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All right. Hello everyone. So this question is asking us which of the following is not one of the primary heterocyclic bases found in DNA. And here we have four different answer choices labeled A through D with four different structures. So recall first and foremost that DNA and RN A for that matter are both nucleic acids. Now, nucleic acids are polymers which means that their monomers are composed of nucleotides. Nucleotides have three main components. They have a nitrogenous base or a heterocyclic base. They have a sugar backbone and they also have a phosphate group. Now, depending on the bases that are found in a particular sample, we can distinguish between DNA and RN A. For example, there are five bases that we should know. Right. We have Aine thymine, cytosine guanine and uracil. Now, thymine is remarkable in that it's unique to DNA. Thymine can only be found in DNA. On the other hand, uracil is unique to Arne, it can only be found in a sample of RNA, adenine, cytosine and guanine. On the other hand, can be found in both DNA and RNA. So going back to the question here, what the question is essentially asking is which one of the four bases is uracil because it's the one base that's not found in DNA. So from here, let's examine our choices. Once again, we have four, right? We have Adenine, excuse me, we have ABC and D. Now A and B are going to be examples of the purine base because they have two fused rings. Option A has an amino group branching off of the ring. So that makes it a anine and Option B has both a car bono group and an amino group branching off of the purine ring. This makes it Guan options C and D. On the other hand, are perimeter bases because they only have one aromatic ring structure. Option D has one car bal and one amino group branching off of the perimeter ring. This identifies it as timing whereas option C has two car bal groups attaching to the aromatic ring, this makes it Euros. So that's how you identify as yourself. So therefore, Uracil option C in the multiple choice is going to be our answer. It is the one base thats not found in DNA and there you have it. So with that being said, thank you so very much for watching and I hope you found this helpful.

What are the four major heterocyclic bases in DNA?

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Key Concepts

Heterocyclic Bases

Base Pairing

DNA Structure