In DNA, a group of three bases that specifies an amino acid is known as a

• A. Codon
• B. Allele
• C. Chromosome
• D. Diploid

Answer: (A)

Three-base units in the genetic code act as words that specify which amino acid will be added to a growing protein chain. In DNA (and the corresponding mRNA read during translation), this unit is called a codon. Each codon encodes a particular amino acid (with some amino acids having multiple codons) or signals to start or stop translation. This makes codons the precise units that translate the genetic message into a protein sequence. The other terms refer to different genetic features: an allele is a variant form of a gene; a chromosome is a large DNA molecule carrying many genes; diploid means having two complete sets of chromosomes.