What is meant by the term base pairing?

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Accepted Answer

All right. Hello everyone. So this question is asking us which of the following statements about base pairing is incorrect. So for a question like this, let's go ahead and just talk about each of the four answer choices individually and recall a few facts of base pairing as we go. So starting off with option A, it says that base pairing is the hydrogen bonded pairing of two complementary heterocyclic bases in the double helix of DNA. This is true, right? Because recall that DNA or RN A big nucleic acids are composed of nucleotides. These are the monomers of nucleic acids and nucleotides are created in part or composed in part of what are called nitrogenous spaces. And so it is these nitrogenous spaces that are in the interior of the double helix by maintaining hydrogen bonds with the nitrogenous bases of the other strand of DNA that double helix structure is stabilized and maintained. So here the base adenine would hydrogen bond with thymine of the other strand. When talking about DNA. If it's RN A, it would be adenine binding with uracil. But in both nucleic acids, we have cytosine bonding with guanine. So here, because option A is actually a true statement. It's not going to be the answer in this case. So moving on now to option B, it says that base pairing in DNA occurs during replication transcription and translation. Now this statement is also accurate, right, because it is the base pairing of DNA that maintains the double helix structure throughout the course of that DNA strand. So it's going to be present during replication transcription. And also translation. Option C says in base pairing, adenosine pairs with thymine in DNA or uracil in RN A. While guanine pairs with cytosine, this is correct because as talked about before, when discussing option A A pairs with T and DNA, A pairs with U and RN A and C and G pair together in both DNA and RN A. So C is true as well. This leads us with option D which says that in base pairing, a purine base can be paired with another purine base. This is incorrect. And let's briefly talk about why recall that we can differentiate between the two different, excuse me, between the four different, actually five different nitrogenous bases based on whether or not they are purines or pyrimidines. This is because the nitrogenous bases themselves are derivatives of either purine or perimeter. Now, the purines are adenine and guanine, whereas the pyrimidines are thymine, cytosine and uracil when talking about RN A. So based on these categories, right, based on which ones are purines and which ones are pines. We can see that there can only be a base pairing between one purine and one pine. We don't see two purines pairing together and we also don't see two pyrimidines pairing together. So because option D is incorrect, that's going to be our answer for this question 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 is meant by the term base pairing?

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Key Concepts

Base Pairing

Nucleotide Structure

Complementarity