Question

Glycine, alanine, and valine are classified as nonpolar amino acids. Compare their codons. What similarities do you find? What differences do you find?

Short answer

Answer: The codon sequences for glycine, alanine, and valine share similarities in their first position, with a 'G' nucleotide. They differ in the second and third positions, where glycine has a 'G' in the second position, alanine has a 'C', and valine has a 'U'. The third position can vary among all four nucleotides (U, C, A, or G) for all three amino acids.

Step-by-step solution

Identify the codon sequences for glycine, alanine, and valine.

Look up the codon sequences using a genetic code table or other resources. The codons for glycine are GGU, GGC, GGA, and GGG. The codons for alanine are GCU, GCC, GCA, and GCG. The codons for valine are GUU, GUC, GUA, and GUG.

Compare the codon sequences to find similarities.

Upon examining the codons for glycine (GGU, GGC, GGA, GGG), alanine (GCU, GCC, GCA, GCG), and valine (GUU, GUC, GUA, GUG), we can observe that they all start with the letter 'G'. This indicates that these amino acids have a nonpolar side chain, and are more likely to be found in the interior of proteins due to their hydrophobic nature.

Examine the codon sequences for differences.

The differences in the codon sequences can be found in the second and third positions. For glycine, the second position is always 'G', while the third position can vary (U, C, A, or G). For alanine, the second position is always 'C', while the third position can vary (U, C, A, or G). For valine, the second position is always 'U', and the third position can vary (U, C, A, or G).

Summarize the results.

In conclusion, the codons for the nonpolar amino acids glycine, alanine, and valine share similarities in their first position, with a 'G' nucleotide. They differ in the second and third positions, where glycine has a 'G' in the second position, alanine has a 'C', and valine has a 'U'. The third position can vary among all four nucleotides (U, C, A, or G) for all three amino acids. These variations in the codon sequences allow for different nonpolar amino acids to be synthesized during protein synthesis, while maintaining some common features in their nonpolar side chains.