The initiation codon is ...... .

Determination of one amino acid by more than one codon is due to

$A$ polypeptide is produced as dictated by $mRNA$. The number of bases on the $mRNA$ that code for the polypeptide portion containing the $N$-terminal amino acid and the next $13$ amino acids is:

After a mutation at the gene level,the traits of an organism change due to a change in which of the following?

Nirenberg synthesized an $m-RNA$ containing $34$ poly-adenine and found a $11$ poly-lysine polypeptide structure. This proves that the genetic code for lysine is ......

How many nonsense codons are there?