Final answer:
G/C rich codons code for various amino acids, including alanine, arginine, glycine, and proline, depending on the nucleotide sequence. Organisms may exhibit a codon bias reflecting their genome's nucleotide composition.
Step-by-step explanation:
G/C rich codons code for various amino acids, depending on the specific sequence of the three nucleotide bases that make up the codon. The genetic code is universal but can show variations in terms of codon usage bias among different organisms. Organisms with a G/C codon bias are often found to have genomes that are also G/C-rich, as indicated by Chargaff's base ratios. For example, the DNA codon GCA corresponds to the amino acid alanine, not arginine as previously suggested, and other codons that are rich in G and C may code for amino acids like arginine (CGT, CGC, CGA, CGG, AGA, AGG), glycine (GGT, GGC, GGA, GGG), and proline (CCT, CCC, CCA, CCG). Knowing what specific amino acids a G/C rich codon codes for requires consulting the genetic code chart.