explain what you understand of the process of concurrent transcription, translation and mRNA degradation
Concurrent transcription, translation and mRNA degradation is the simultaneous occurrence of three processes in a cell, namely transcription, translation and mRNA degradation.
Transcription involves the synthesis of mRNA from a DNA template by RNA polymerase, which includes initiation, elongation and termination. During transcription, the DNA molecule unwinds and a complementary RNA molecule is synthesized from one of the strands.
Translation involves the synthesis of proteins from the mRNA template in ribosomes. During translation, the mRNA molecule undergoes a process called translation initiation, where it binds to a ribosome and begins translation. Elongation and termination steps then follow, leading to the synthesis of a protein from the mRNA template.
mRNA degradation involves the breakdown and disposal of mRNA molecules that are no longer required by the cell. This process is regulated to prevent the accumulation of unnecessary mRNAs in the cell. mRNA degradation can occur at different stages of transcription or translation, depending on the specific mRNA and cellular conditions.
Concurrent transcription, translation, and mRNA degradation can occur in a bacterial cell, where transcription and translation occur in the same compartment, the cytoplasm. In eukaryotes, transcription occurs in the nucleus and then mRNA is transported to the cytoplasm where it undergoes translation and eventual degradation. The coordination of these processes is essential for the efficient functioning of the cell.
Concurrent transcription, translation, and mRNA degradation are important processes that occur simultaneously in cells. Here is a step-by-step explanation of these processes:
1. Transcription: The first step is transcription, which takes place in the nucleus of eukaryotic cells or the cytoplasm of prokaryotic cells. During transcription, the DNA sequence of a gene is copied into a complementary RNA molecule called messenger RNA (mRNA). This process involves the enzyme RNA polymerase binding to the DNA at the gene's promoter region and synthesizing the mRNA by adding nucleotides according to the DNA template strand.
2. Translation: After transcription, translation occurs in the cytoplasm of cells. It is the process where the information in the mRNA molecule is used to produce proteins. The mRNA molecule leaves the nucleus and attaches to the ribosomes, which are protein synthesis complexes. The process of translation involves three key steps: initiation, elongation, and termination. In initiation, the small ribosomal subunit binds to the mRNA molecule, followed by the attachment of the large ribosomal subunit. Then, the ribosome scans the mRNA for the start codon (AUG) that signals the beginning of the protein sequence. Next, in elongation, transfer RNA (tRNA) molecules bind to specific amino acids and enter the ribosome, which uses the mRNA sequence to identify the appropriate tRNA molecules. The ribosome then catalyzes the formation of peptide bonds between the amino acids, resulting in a growing polypeptide chain. This process continues until the ribosome reaches a stop codon, signaling termination. At this point, the ribosome releases the completed polypeptide chain, and the mRNA and ribosome separate.
3. mRNA Degradation: Concurrently with transcription and translation, mRNA degradation occurs to regulate gene expression and prevent the accumulation of unwanted or damaged mRNA molecules. Several mechanisms contribute to mRNA degradation, such as exonucleolytic decay and endonucleolytic cleavage. Exonucleolytic decay involves enzymes known as exonucleases that degrade the mRNA from the 5' or 3' end, progressively shortening the mRNA molecule. Endonucleolytic cleavage occurs when specific endonucleases cleave the mRNA molecule internally, resulting in fragment degradation. These processes ensure that the mRNA molecules are efficiently cleared from the cell, allowing for dynamic control of gene expression.
In summary, concurrent transcription, translation, and mRNA degradation are essential processes in cells. Transcription generates mRNA from DNA, translation uses mRNA to synthesize proteins, and mRNA degradation maintains gene expression control by removing unnecessary or damaged mRNA molecules from the cell.