Question

Degeneracy of the genetic code denotes the existence of A. multiple codons for a single amino acid. B. codons consisting of only two bases. C. base triplets that do not code for any amino acid. D. different systems in which a given triplet codes for different amino acids. E. codons that include one or more of the unusual bases.

Short answer

Answer: The degeneracy of the genetic code refers to the property that some amino acids are coded by more than one codon, which means multiple codons can correspond to a single amino acid.

Step-by-step solution

Understanding degeneracy

The degeneracy of the genetic code refers to the property that some amino acids are coded by more than one codon. In other words, multiple codons can correspond to a single amino acid. This property provides the genetic code with some redundancy, which can be beneficial in protecting against mutations.

Analyzing the options

A. multiple codons for a single amino acid. B. codons consisting of only two bases. C. base triplets that do not code for any amino acid. D. different systems in which a given triplet codes for different amino acids. E. codons that include one or more of the unusual bases. Option A is consistent with the definition of degeneracy since it describes a scenario where there are multiple codons that code for a single amino acid. Option B is incorrect because a codon consists of three bases, not two. Option C is incorrect because degeneracy is not about base triplets that do not code for any amino acid. In fact, all 64 possible codons code for either an amino acid or act as a stop codon. Option D is incorrect because the genetic code is universal, and each triplet code generally does code for the same amino acid in different systems. Option E is incorrect because degeneracy does not have to do with unusual bases. Degeneracy is a property that comes from the standard genetic code, which uses the standard nucleotide bases (adenine, cytosine, guanine, and uracil).

Identifying the correct answer

Based on the analysis in Step 2, we can conclude that option A (multiple codons for a single amino acid) accurately represents the concept of degeneracy in the genetic code.

Key concepts

Codons

In the realm of genetics, codons are fundamental units of the genetic code, essential for translating genetic information into proteins. A codon is a sequence of three nucleotide bases in DNA or RNA that corresponds to a specific amino acid or signal during protein synthesis.

Codons act as the 'words' in the genetic language, and just like in any language, altering these 'words' can change the resulting 'sentence,' or in this case, the protein synthesized. The standard genetic code includes 64 different codons, each of which can signal for one of the 20 amino acids or serve as stop signals to end protein synthesis. This triplet code allows for a coherent transfer of information from nucleic acids to proteins, ensuring the accurate formation of proteins that are essential for cell functioning and organism development.

Amino Acids

Amino acids are the building blocks of proteins and play a myriad of roles in biological processes. These organic compounds contain both an amino group and a carboxyl group, and they link together via peptide bonds to form proteins. Proteins, which are composed of one or more chains of amino acids, are crucial to virtually all aspects of cell structure and function.

The genetic code directs amino acids to align in a specific order, creating a multitude of different proteins, each with a unique function determined by its sequence of amino acids. The precise order of these amino acids is dictated by the sequence of codons within a gene, highlighting the significance of the genetic code in translating the instructions within DNA into the functional molecules that sustain life.

Genetic Code Redundancy

Genetic code redundancy, also known as degeneracy, refers to the phenomenon where multiple codons encode the same amino acid. This characteristic is a form of built-in protection within the genetic code that can mitigate the effects of mutations.

For instance, if a mutation occurs, altering a single nucleotide within a codon, there's a chance that the new codon will still code for the same amino acid, thanks to redundancy. This fascinating aspect of genetic code ensures robustness and fidelity in protein synthesis. Redundancy might seem like a waste at first glance, but it is a sophisticated evolutionary strategy to shield the organism from genetic errors that could potentially be harmful.

Mutations Protection

The degeneracy of the genetic code confers a level of mutations protection to organisms. Mutations are changes in genetic sequence and can happen due to various factors, including errors in DNA replication, exposure to certain chemicals, or through radiation. However, not all mutations result in changes to proteins, thanks to the genetic code redundancy.

Some mutations are 'silent,' meaning that even though the DNA sequence changes, the encoded amino acid remains the same, thus the protein's function is not affected. This buffering effect maintains the integrity of proteins despite the genetic alterations and exemplifies the genetic code's resilience. This protective characteristic enhances an organism's survival by allowing a certain degree of genetic flexibility without detrimental consequences to protein function.