DNA uses a triplet codon code to specify amino acid sequences in proteins.

OpenStax Biology for AP® Courses: 15.1 The Genetic Code. https://openstax.org/books/biology-ap-courses/pages/d05f0477-d3a8-4703-a413-3499cb2eab72@

But how do genes located on a chromosome ultimately produce a polypeptide that can result in a physical phenotype such as hair or eye color—or a disease like cystic fibrosis or hemophilia? The Central Dogma describes the normal flow of genetic information from DNA to mRNA to protein: DNA in genes specify sequences of mRNA which, in turn, specify amino acid sequences in proteins. The process requires two steps, transcription and translation. During transcription, genes are used to make messenger RNA (mRNA). In turn, the mRNA is used to direct the synthesis of proteins during the process of translation. Translation also requires two other types of RNA: transfer RNA (tRNA) and ribosomal RNA (rRNA). The genetic code is a triplet code, with each RNA codon consisting of three consecutive nucleotides that specify one amino acid or the release of the newly formed polypeptide chain; for example, the mRNA codon CAU specifies the amino acid histidine. The code is degenerate; that is, some amino acids are specified by more than one codon, like synonyms you study in your English class (different word, same meaning). For example, CCU, CCC, CCA, and CCG are all codons for proline.

Degeneracy of the Genetic Code has Played an Important Role in Evolution of Organisms. 2016. https://doi.org/10.15226/2377-4274/3/1/00111

Genetic information transferred from DNA to mRNA by transcription is transmitted to protein through translation on ribosome. During the translation, the universal or standard genetic code written with triplet base sequence is used, which specifies a kind of amino acid, like as that GUC, CAC, AAG and UUC correspond to Val, His, Lys and Phe, respectively. As well known, the genetic code is degenerate mainly at the third codon position, for example GGN, GCN and GUN, 4 codons each, code for Gly, Ala and Val, respectively (Figure 1). However, it is totally unknown about the reason why the genetic code is degenerate.

Biology : a guide to the natural world. 2011. https://archive.org/details/biologyguidetona0000krog_g7a1

translation Figure 14.5 Triplet Code Each triplet of DNA bases codes for a triplet of MRNA bases (a codon) … every mRNA triplet in it codes for an amino acid. Note, in Figure 1, that three mRNA codons specify “stop” … codes for a single amino acid. Each triplet of mRNA bases that codes for an amino acid is called a codon

Biology : a guide to the natural world. 2013. https://archive.org/details/biologyguidetona0000krog

Translation Figure 14.6 Triplet Code Each triplet of DNA bases codes for a triplet of mRNA bases (a codon) … every mRNA triplet in it codes for an amino acid. Note, in Figure 1, that three mRNA codons specify “stop” … codes for a single amino acid. Each triplet of mRNA bases that codes for an amino acid is called a codon

Codon Size Reduction as the Origin of the Triplet Genetic Code. 2009. https://doi.org/10.1371/journal.pone.0005708

The genetic code appears to be optimized in its robustness to missense errors and frameshift errors. In addition, the genetic code is near-optimal in terms of its ability to carry information in addition to the sequences of encoded proteins. As evolution has no foresight, optimality of the modern genetic code suggests that it evolved from less optimal code variants. The length of codons in the genetic code is also optimal, as three is the minimal nucleotide combination that can encode the twenty standard amino acids. The apparent impossibility of transitions between codon sizes in a discontinu

Genetic code. https://en.wikipedia.org/wiki/Genetic_code

triplets or codons) into proteins. Translation is accomplished by the ribosome, which links proteinogenic amino acids in an order specified by messenger Genetic code is a set of rules used by living cells to translate information encoded within genetic material (DNA or RNA sequences of nucleotide triplets or codons) into proteins. Translation is accomplished by the ribosome, which links proteinogenic amino acids in an order specified by messenger RNA (mRNA), using transfer RNA (tRNA) molecules to carry amino acids and to read the mRNA three nucleo Genetic code is a set of rules used by living cells to translate information encoded within genetic material (DNA or RNA sequences of nucleotide triplets or codons) into proteins. Translation is accomplished by the ribosome, which links proteinogenic amino acids in an order specified by messenger RNA (mRNA), using transfer RNA (tRNA) molecules to carry amino acids and to read the mRNA three nucleotides at a time. The genetic code is highly similar among all organisms and can be expressed in a simple table with 64 entries. The codons specify which amino acid will be added next during protein biosynthesis. With some exceptions, a three-nucleotide codon in a nucleic acid sequence specifies a single amino acid. The vast majority of genes are encoded with a single scheme (see the RNA codon table). That scheme is often called the canonical or standard genetic code, or simply the genetic code, though variant codes (such as in mitochondria) exist. Th… A reading frame is defined by the initial triplet of nucleotides from which translation starts. It sets the frame for a run of successive, non-overlapping codons, which is known as an "open reading frame" (ORF). For example, the string 5'-AAATGAACG-3' (see figure), if read from the first position, contains the codons AAA, TGA, and ACG ; if read from the second position, it contains the codons AAT and GAA ; and if read from the third position, it contains the codons ATG and AAC. Every sequence can, thus, be read in its 5' → 3' direction in three reading frames, each producing a possibly distinct amino acid sequence: in the given example, Lys (K)-Trp (W)-Thr (T), Asn (N)-Glu (E), or Met (M)-Asn (N), respectively (when translating with the vertebrate mitochondrial code). When DNA is double-stranded, six possible reading frames are defined, three in the forward orientation on one strand and three reverse on the opposite strand. Protein-coding frames are defined by a start codon, usually the first AUG codon in the RNA, (ATG in DNA) sequence. In eukaryotes, open reading frames in exons are often interrupted by introns.

DNA and RNA codon tables. https://en.wikipedia.org/wiki/DNA_and_RNA_codon_tables

A codon table can be used to translate a genetic code into a sequence of amino acids. The standard genetic code is traditionally represented as an RNA A codon table can be used to translate a genetic code into a sequence of amino acids. The standard genetic code is traditionally represented as an RNA codon table, because when proteins are made in a cell by ribosomes, it is messenger RNA (mRNA) that directs protein synthesis. The mRNA sequence is determined by the sequence of genomic DNA. In this context, the standard genetic code is referred to A codon table can be used to translate a genetic code into a sequence of amino acids. The standard genetic code is…