mRNA contains three-base units that code for amino acids. These units are called _____.

mRNA contains three-base units that code for amino acids. These units are called _____.

• A. Codons
• B. Anticodons
• C. Exons
• D. Introns

Answer: (A)

In translation, the information in mRNA is read in three-nucleotide units called codons. Each codon specifies a particular amino acid to be added to the growing polypeptide, and the ribosome reads these codons in a 5' to 3' direction in a fixed reading frame. Some codons signal the start of translation (like AUG, which also codes for methionine) and others signal termination (stop codons). Anticodons are the complementary three-base sequences on tRNA that pair with codons to deliver the correct amino acid. Exons are the coding portions of a gene that stay in the final mRNA after splicing, while introns are noncoding segments removed before translation. So the three-base units in mRNA that code for amino acids are codons.

In translation, the information in mRNA is read in three-nucleotide units called codons. Each codon specifies a particular amino acid to be added to the growing polypeptide, and the ribosome reads these codons in a 5' to 3' direction in a fixed reading frame. Some codons signal the start of translation (like AUG, which also codes for methionine) and others signal termination (stop codons). Anticodons are the complementary three-base sequences on tRNA that pair with codons to deliver the correct amino acid. Exons are the coding portions of a gene that stay in the final mRNA after splicing, while introns are noncoding segments removed before translation. So the three-base units in mRNA that code for amino acids are codons.