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Cytosine bases may spontaneously change into uracil bases. DNA has an enzyme asssociated with it that corrects this fault. If DNA contained uracil as a base, the repair enzyme would have no way of distinguishing between uracils normally present in the DNA code and uracils that had formed from cytosine. Therefore thymine is present instead of uracil.
Wiki User
∙ 15y ago
Wiki User
∙ 9y agoThere are four reasons for this:
First, thymine is a methylated analogue of uracil, DNA can be protected from nuclei by methylation.
Second, uracil has more base pair affinity to adenine, but it can also pair up with other bases including itself. This can lead to mutations in our genetic material.
Third, repair enzymes find it easier to recognize the DNA if it is methylated.
Fourth, uracil can also get converted or replaced by cytosine leading to mutations.
Due to all these reasons our DNA is protected from mutations by methylation.
Wiki User
∙ 14y agofirst of all we should know that thymine only differs than uracil by having a methyl group ! the whole answer is about mutation , suppose we have (( G=C )) base pairing where cytosine most often is deaminated to uracil in DNA
the uracil formed tends to bind to Adenine base rather than guanine causing in mutation
the thymine plays an important rule here by ensuring DNA replication is happening faithfully ! the DNA polymerase enzymes can detect present of unusual base URACIL and can replace it then
Wiki User
∙ 9y agoUracil is one of the constituent bases of RNA. It replaces thymine in RNA because it requires less energy to produce.
Wiki User
∙ 13y agoIn DNA, the base pairings are:
Cytosine-Guanine
Adenine-Thymine,
In RNA, the base pairings are:
Cytosine-Guanine
Adenine-Uracil.
Wiki User
∙ 13y agoDNA has thymine and RNA has Uracil nitrogen base.
Wiki User
∙ 11y agoUracil is only a base pair for RNA.
Wiki User
∙ 11y agobecause uracil is easy to synthesize
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What nucleotide complements adenine?
Thymine in DNA, and Uracil in RNA
What are three types of pyrimidines?
Cytosine and thymine are the nitrogenous bases used in DNA. Uracil substitutes for thymine in RNA.
What are the 5 nitrogen?
The five nitrogenous bases in DNA and RNA are adenine, guanine, thymine, cytosine, and in RNA uracil.
The nitrogenous base found in RNA but not in DNA is?
RNA and DNA are very similar (that is, mRNA is similar, tRNA is quite different). mRNA is basically a single strand of DNA (DNA is a double helix, mRNA is singular), with two differeneces. Firstly, the sugar making up the backbone of the mRNA strand is a ribose sugar, not a deoxyribose sugar (like on DNA). Secondly, the nitrogenous base thymine (which is found on DNA) is replaced witha another base called uracil. It's also worth noting that mRNA, while manufactured in the nucleus, can leave the nucleus and enter the cell cytoplasm - DNA cannot do this.
Is adenine present in trna?
Yes.There are four bases in RNA. Adenine and guanine are purines (having two rings sharing one side); cytosine and uracil are pyrimidines (having a single ring).
Does RNA contain the nitrogen base uracil?
NO. RNA contains URACIL while in DNA it is THYMINE, the uracil replaces the thymine.
Does DNA contain uracil?
No. Uracil is a pyrimidine that is exclusive to RNA. In DNA, thymine is in place of uracil.
What is a pyrimidine base found in RNA but not in DNA?
Thymine
Which molecules is typically found in DNA but not RNA?
Thymine is found in DNA but not in RNA. Uracil replaces thymine in RNA. In other words: DNA has thymine. RNA has uracil.
What nitrogen base can pair with adenine?
What does adenine match with?
In DNA, adenine pairs with thymine. In RNA, adenine pairs with uracil.
