Uracil In DNA Replication: Why And Detailed facts

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Uracil is one among the five nitrogenous bases in the nucleic acids- DNA, RNA. (Adenine, Guanine, cytosine, thymine and uracil).

Uracil in DNA replication- Uracil does not have a predominant role in DNA Replication but yes, recent studies have shown that the presence of uracil is noted in DNA replication. Uracil arises sometimes due to incorporation of Deoxyuridine Monophosphate during the process of DNA replication.

Is uracil present in a DNA Strand or Uracil in DNA Replication?

DNA has four nitrogenous bases namely Adenine, Guanine, Cytosine, Thymine.

No, Uracil is not present in a DNA strand, instead Thymine is present in DNA on behalf of uracil.

uracil in dna replication
DNA Synthesis
Image Credits- Wikimedia

Uracil is present only in RNA (Adenine, cytosine, guanine, uracil) strands.

Uracil acid
Uracil Acid
Image Credits- Wikimedia

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Does DNA use uracil?

DNA being the genetic material for most of the organisms, do not have uracil as one of nitrogenous bases in them.

Though they are not present as one of the nitrogenous bases (Adenine, Guanine, Cytosine, thymine) in rare cases uracil is formed due to the deamination  of cytosine by hydrolytic deamination process.

This leads to U:G mispairing which leads to mild impact in mutations.

This formation is very rare and will have an impact in evolutionary change.

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Why is uracil not present in a DNA strand ?

Uracil is present in RNA and not in DNA.

The reason behind the Uracil being present in RNA and not in DNA is that uracil is not that well resistant towards any photochemical mutations which is the base of stability in the nucleic acids.

Thymine is more resistant to photochemical mutation and thus is very stable and is present in DNA.

The stability is the base for the protection of the genetic message.

Retaining the genetic messages and protecting them without any changes or mutations is the ideal job role of a DNA, this is why DNA has thymine.

Whereas the RNA like mRNA is short lived and also any mistakes or errors due to the instability will not result in any long lasting damages, this is also the reason why uracil is present in RNA and not in DNA.

And the other reason is thymine can undergo oxidation process easily when compared to uracil. Thymine which is usually present only inside the nucleus is protected by the oxygen molecule inside the nucleus.

While, RNA is present outside the nucleus and they are resistant to oxidation process.

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Uracil in DNA polymerase:

DNA Polymerase is a family of enzymes that synthesis the nucleotides of DNA during DNA Replication.

Uracil arises sometimes due to incorporation of Deoxyuridine Monophosphate during the process of DNA replication and due to the deamination of cytosine forming U:G mismatches, which is rare.

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Properties/ Characteristics of Uracil:

  • Uracil is a colorless organic compound that is present in RNA– Ribonucleic Acid.
  • Uracil falls under the pyrimidine class of compounds.
  • Uracil is also involved in the transport of hereditary property.
  • RNA molecule have a five carbon sugar which is called as the ribose sugar, a highly negatively charged phosphate molecule which is the backbone of the entire molecule and the nitrogenous base which can be Adenine, uracil cytosine and guanine.
  • The complementary strand for uracil is Adenine, which is a purine.
  • Example: One strand of RNA is

A U U G C A U A G G G G C C U U U A A C C U G G C A U A G G

The complementary strand will be

U A A C G U A U C C C C G G A A A U U G G A C C G U A U C C

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