Final answer:
The central dogma of molecular biology explains that genetic information flows from DNA to RNA (mRNA) and then to protein in eukaryotic cells.
Step-by-step explanation:
The central dogma of molecular biology, proposed by Francis Crick, outlines the fundamental flow of genetic information within living organisms. This conceptual framework describes the unidirectional transfer of genetic information from DNA to RNA to protein, reflecting the key processes involved in the synthesis of cellular components. The central dogma serves as a foundational principle in understanding how genetic instructions encoded in DNA are ultimately translated into the functional proteins that orchestrate various biological processes.
In eukaryotic cells, the central dogma begins with the transcription of genetic information from DNA to messenger RNA (mRNA). During transcription, a specific segment of DNA, typically a gene, serves as a template for the synthesis of complementary mRNA molecules by RNA polymerase enzymes. This process occurs within the nucleus of the eukaryotic cell, where the DNA is housed. The resulting mRNA molecule carries the genetic code in the form of nucleotide sequences, representing the instructions for building a specific protein.
Once the mRNA has been transcribed, it undergoes a series of modifications, including the addition of a protective cap at the 5' end and a poly-A tail at the 3' end. These modifications enhance the stability and functionality of the mRNA molecule. Subsequently, the mature mRNA exits the nucleus and enters the cytoplasm, where the cellular machinery responsible for protein synthesis is located.
In the cytoplasm, the mRNA serves as a template for translation, the second key step in the central dogma. During translation, ribosomes read the nucleotide sequence of the mRNA in sets of three, known as codons. Each codon corresponds to a specific amino acid, the building blocks of proteins. Transfer RNA (tRNA) molecules, carrying the corresponding amino acids, match their anticodons to the mRNA codons, facilitating the assembly of a polypeptide chain. This chain of amino acids eventually folds into a functional protein.