Question

"Breaking the genetic code" has been referred to as one of the most significant scientific achievements in modern times. Describe (in outline or brief statement form) the procedures used to break the code.

Short answer

Question: Briefly describe the steps involved in breaking the genetic code. Answer: Breaking the genetic code consists of understanding the genetic code's components, such as nucleotides, codons, and proteins. Then, the roles of messenger RNA (mRNA) and transfer RNA (tRNA) in protein synthesis are identified. Scientists deciphered the code using synthetic mRNAs and in vitro translation to determine the codons for each amino acid. Finally, a "Universal" Genetic Code Table was developed to show the relationship between nucleotide sequence and amino acid sequence.

Step-by-step solution

Understand the Genetic Code

The genetic code is the set of rules by which information encoded in DNA and RNA sequences is translated into proteins in living cells. It defines how the nucleotide sequence of the genetic material (DNA or RNA) is translated into the amino acid sequence that forms proteins.

Identify the Genetic Code's Components

The genetic code consists of three key components: (1) nucleotides, which are the building blocks of DNA and RNA and come in four types (adenine, guanine, cytosine, and thymine or uracil); (2) codons, which are groups of three nucleotides that specify an amino acid or serve as a stop signal; and (3) proteins, which consist of chains of amino acids called polypeptides that are responsible for various functions in living organisms.

Determine the Role of Messenger RNA (mRNA)

Messenger RNA (mRNA) plays an essential role in the translation of genetic information into proteins. The DNA sequence is transcribed into mRNA, which is then transferred from the nucleus to the cytoplasm of the cell. Here, the mRNA acts as a template for assembling the corresponding protein.

Understand the Role of Transfer RNA (tRNA)

Transfer RNA (tRNA) molecules serve as the link between mRNA and amino acids during the process of protein synthesis. Each tRNA molecule carries a specific amino acid and recognizes a complementary codon in the mRNA. This ensures that the appropriate amino acid is added to the growing polypeptide chain as dictated by the mRNA sequence.

Decrypting the Genetic Code Using Synthetic mRNAs and In Vitro Translation

Scientists deciphered the genetic code by using chemically synthesized mRNAs of known sequences and studying the amino acid sequences of the proteins synthesized in vitro. Through various experiments, researchers were able to determine the specific codons that correspond to individual amino acids, as well as the stop codons that signal the end of a protein.

Develop the "Universal" Genetic Code Table

Once the correspondence between the codons and amino acids was determined, scientists were able to compile a table that shows the relationship between the nucleotide sequence and the amino acid sequence. This table, known as the "Universal" Genetic Code Table, is a vital tool for understanding how genetic information is translated into proteins in living organisms.