If the DNA double helix in salmon contains 28% adenine, what is the percentage of thymine, guanine, and cytosine?

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All right. Hello everyone. So this question says in a certain species of bacteria, it is found that 30% of the DNA based pairs are composed of guanine. What is the percentage of adenine thymine and cytosine in the DNA of this bacteria? All right. So first and foremost, we are talking about the percentages of bases or base pairs, which means that we are going to have to discuss tg's rule. So Char's rule is named as such because of the observations made by Irwin Chargaff in the 19 fifties with regards to the DNA of multiple different species. Now recall the DNA specifically double stranded DNA is maintained in a double helix configuration because of base pairing at the center, right, complementary bases engage in hydrogen bonding which stabilizes the double helix. And so because of that hydrogen bonding, because of that base pairing, this allows us to understand the proportions of our base in a given DNA sample. And so what that essentially means to say is that the percentages of complementary bases should be equal to each other in double stranded DNA. So the percentage of adenine should be equal to that of thymine. And the percentage of cytosine should be equal to that of Gui. And so with this information, we can get a sense as to the distribution of these bases in our sample right in our DNA. So based on our given, we know that 30% of this DNA is made up of guanine. Therefore, because cytosine pairs with vine, the percentage of cytosine should also be 30%. And so now we know that 60% of the DNA is composed of cytosine and guanine. This means that a total of 40% is devoted to both Adenine and thymine. So 40% divided by two means that both of these bases should compose 20% of the overall DNA and there you have it. So Adenine represents 20%. Thymine also represents 20% and cytosine represents 30% because it pairs with guanine and there you have it. So with that being said, thank you so very much for watching and I hope you found this helpful.

If the DNA double helix in salmon contains 28% adenine, what is the percentage of thymine, guanine, and cytosine?

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Key Concepts

Base Pairing Rules

Percentage Composition of DNA Bases

Complementary Base Pairing