Question

How many bases are needed to specify three amino acids?

Answer 1

There is this unidirectional flow of genetic information in all living organisms. This is known as the central dogma or central dogma of molecular biology. This involves transcription of the DNA into an RNA molecule and translation of RNA to proteins. These proteins then go on to perform various cellular functions.

Complete answer:
-The DNA can replicate itself, this enables the cells to grow, repair, and reproduce. DNA can also be transcribed. A part of the DNA is made up of nucleotides that code for proteins. The other nucleotides of the DNA molecule are called the non-coding nucleotides.
-In the nucleus, RNA polymerases (enzymes) use the DNA molecule as a template to transcribe the genetic information onto a messenger RNA. Three different types of RNA aid in protein synthesis, mRNA, rRNA, and tRNA. The messenger RNA (mRNA) contains the genetic information copied from the DNA. The ribosomal RNA (rRNA) and proteins make up the ribosomes. Transfer RNA (tRNA) carries single amino acids.
-The mRNA enters the cytoplasm and binds to the ribosome. This is where protein synthesis occurs. The mRNA is read in the ribosome to produce a chain of amino acids (protein). The tRNA enters the ribosome and reads the mRNA. At a time, the tRNA reads three nucleotide bases on the mRNA. These three nucleotides on the mRNA are called codons.
-Each codon represents a single amino acid. The anticodon in the tRNA complements the codon in the mRNA. The tRNA will eventually leave the ribosome leaving behind the amino acid it carried. This goes on and a chain of amino acids is formed i.e. protein.
-Three nucleotide bases make up a single codon. Each codon represents a single amino acid. Therefore, nine nucleotide bases are required to code for three amino acids.

Note: A genetic code chart represents different combinations of the four nucleotide bases. From the chart, we get sixty-four different combinations i.e. sixty-four codons. Since we only have twenty amino acids, it was concluded that a single amino acid can be represented by more than one codon.
Out of the sixty-four codons, three codes for termination of translation.