Question

What are the stop codons in DNA replication?

Answer 1

During the process of translation, mRNA attach with tRNA. The codons on mRNA attach with complementary anticodons and codes to specific amino acids. Stop codons terminate the process of translation. There are mainly three types of stop codons.

Complete answer:
Three nucleotide bases pair together, to form codons. Codon functions have specific functions. One amino acid can be coded by different codons. Among all the bases 64 possible combinations are formed, 61 of them codes for amino acids. Remaining three codons are called stop codons. A stop codon is the codon which signals to stop the synthesis of the proteins.
The three stop codons are:
UAA (ochre)
UAG (amber)
UGA (umber)
The stop codons are also called nonsense codons or termination codons. They does not code for any amino acid. Charles Steinberg and Richard Epstein discovered UAG. They have a very specific function as they can cause the release of new polypeptide chain from the ribosome during protein synthesis. The termination occurs because there are no tRNAs with anticodons complementary to the stop codons.

Note: AUG is the start codon. It is the first codon in the transcribed Mrna during the process of translation. It is the most common codon. Methionine (met) in eukaryotes and formyl methionine (fmet) in prokaryotes are code by this codon. Some alternative codons are present in eukaryotes and prokaryotes. They code for amino acids other than methionine. These include AUA and AUU in humans and GUG and UUG in the prokaryotes.