Why does DNA have thymine when RNA has uracil?

Answer 1

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.

Answer 2

There 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.

Answer 3

first 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

Answer 4

Uracil is one of the constituent bases of RNA. It replaces thymine in RNA because it requires less energy to produce.

Answer 5

In DNA, the base pairings are:

Cytosine-Guanine

Adenine-Thymine,

In RNA, the base pairings are:

Cytosine-Guanine

Adenine-Uracil.

Answer 6

DNA has thymine and RNA has Uracil nitrogen base.

Answer 7

Uracil is only a base pair for RNA.

Answer 8

because uracil is easy to synthesize