Genetic Code

Definition

The genetic code is the set of rules by which information encoded in genetic material (DNA or RNA sequences) is translated into proteins. It is a universal language that allows cells to convert the digital information stored in genes into the functional molecules that carry out life's processes.

5 Must Know Facts For Your Next Test

1. The genetic code is nearly universal across all living organisms, with a few minor exceptions.
2. The genetic code is triplet-based, meaning that each amino acid is specified by a sequence of three consecutive nucleotides called a codon.
3. There are 64 possible codons, but only 20 standard amino acids, resulting in a redundant or degenerate code where multiple codons can code for the same amino acid.
4. The genetic code is read in the 5\' to 3\' direction, and translation always starts at a specific codon (AUG) that codes for the amino acid methionine.
5. Mutations in the genetic code can lead to changes in the amino acid sequence of a protein, potentially resulting in altered or non-functional proteins.

Review Questions

• Explain the relationship between the genetic code and protein synthesis.
  • The genetic code is the set of rules that allows cells to translate the information stored in DNA or RNA into the amino acid sequences that make up proteins. During the process of protein synthesis, the genetic code is read by the cellular machinery to determine which specific amino acids should be assembled into a polypeptide chain. This direct link between the genetic code and the production of functional proteins is essential for life, as proteins are the primary workhorses that carry out the vast majority of cellular processes.
• Describe the key features of the genetic code that contribute to its universality and redundancy.
  • The genetic code is nearly universal across all living organisms due to its triplet-based structure and the fact that it specifies the same 20 standard amino acids. This redundancy, where multiple codons can code for the same amino acid, allows for flexibility in the genetic code and helps to minimize the impact of mutations. The redundancy of the genetic code also contributes to its universality, as it enables the same basic set of rules to be used across a wide range of organisms, facilitating the transfer of genetic information between species.
• Analyze how mutations in the genetic code can affect the structure and function of proteins.
  • Mutations in the genetic code can lead to changes in the amino acid sequence of a protein, which can have significant impacts on the protein's structure and function. Depending on the type and location of the mutation, the resulting protein may be altered in its shape, stability, or ability to interact with other molecules. This can result in the protein becoming non-functional, less efficient, or even potentially harmful to the cell. Understanding the relationship between genetic code mutations and protein structure/function is crucial for identifying the underlying causes of genetic disorders and developing targeted therapies to address them.

Related terms

Codon: A sequence of three consecutive nucleotides in a DNA or RNA molecule that specifies a particular amino acid or signals the start or stop of protein synthesis.

Transcription:

The process of creating a complementary RNA copy of a sequence of DNA, which is the first step in gene expression.

Translation:

The process of synthesizing a protein from the information encoded in a messenger RNA (mRNA) molecule.